Patent Publication Number: US-2023143866-A1

Title: Time display method and electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Chinese Patent Application No. 202010219136.7, filed with the China National Intellectual Property Administration on Mar. 25, 2020 and entitled “TIME DISPLAY METHOD AND ELECTRONIC DEVICE”, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to the field of electronic device technologies, and in particular, to a time display method and an electronic device. 
     BACKGROUND 
     With development of electronic technologies, electronic devices such as a smartphone and a tablet computer are increasingly popular, and users are increasingly dependent on electronic devices. For example, the electronic device is a mobile phone. A user taps to wake a screen of the mobile phone many times every day. In most cases, a purpose of waking the screen of the mobile phone is to view time, various notifications, and the like. To meet people&#39;s function requirements for electronic devices, an always on display (always on display, AOD) function is set on many electronic devices, to improve display effects of the electronic devices and user experience. 
     When a digital clock is displayed in an always-on-display interface of the electronic device, a pattern may be displayed as a background or a foreground of the digital clock. A current always on display effect is as follows: A location relationship between the digital clock and the pattern is a front-to-back relationship. In one case, the digital clock is superimposed on the pattern, which forms a visual effect that a digit is in front of the pattern and the pattern is behind the digit. In another case, the pattern is superimposed on the digital clock, which forms a visual effect that the pattern is in front of a digit and the digit is behind the pattern. The two display effects are both monotonous, and therefore, user&#39;s pursuit of a richer display effect cannot be met. 
     SUMMARY 
     Embodiments of this application provide a time display method and an electronic device, to provide a richer display effect for a user when an electronic device displays a digital clock in an always-on-display state. 
     According to a first aspect, an embodiment of this application provides a time display method, and the method is applied to an electronic device with a display. The method includes: The electronic device obtains a first image, a second image, and a third image, where the first image includes a first part of a target control, the second image includes a second part of the target control, and the third image includes a digital clock. The electronic device sequentially superimposes the first image, the third image, and the second image to generate a to-be-displayed image. In the to-be-displayed image, the first part and the second part of the target control form the target control, and the target control overlaps at least one digit of the digital clock. The electronic device displays the to-be-displayed image when the display is in an always-on-display state. 
     Based on this solution, the electronic device sequentially superimposes the first image including the first part of the target control, the third image including the digital clock, and the second image including the second part of the target control, to generate the to-be-displayed image. In the generated to-be-displayed image, the first part and the second part of the target control form the target control, and an interspersed visual effect that the first part of the target control is displayed behind the digit and the second part of the target control is displayed in front of the digit can be formed. Compared with a display effect that a digit and an entire target control form a simple front-to-back relationship, a richer display effect can be provided for a user in this solution when the electronic device displays the digital clock in the always-on-display state. 
     In a possible design, the digital clock includes digits used to represent hours and digits used to represent minutes. The digits used to represent hours are in a different row from the digits used to represent minutes. The digits used to represent hours include a first digit in the tens place and a second digit in the ones place. The target control included in the to-be-displayed image overlaps the first digit. 
     In this design, the first digit is a digit that is in the tens place and that represents hours, and a possible value of the first digit is 0, 1, or 2. In a timing process of the digital clock, the first digit changes three times in a timing period of 24 hours, and a change frequency of the first digit is lower than that of the second digit, a third digit, and a fourth digit, so that power consumption can be reduced. 
     In a possible design, that the electronic device obtains a first image and a third image may be implemented by separately invoking the first image and the third image according to a file name of the first image and a file name of the third image. The file name of the first image includes a layout type of the digital clock, a value of the digit that overlaps the target control on the digital clock, and a location relationship between the first image and the digital clock. The file name of the third image includes the clock layout type of the digital clock, the value of the digit that overlaps the target control on the digital clock, and a location relationship between the third image and the digital clock. 
     For example, the layout type of the digital clock is a single-clock layout, the value of the digit that overlaps the target control on the digital clock is 0, the location relationship between the first image and the digital clock is that the first image is a background of the digital clock, and the location relationship between the first image and the digital clock is that the first image is a foreground of the digital clock. In this example, the file name of the first image is single_digit0_bg.png, and the file name of the second image is single digit0_fg.png. 
     In a possible design, a size of the first part of the target control is less than a size of the first image, and a size of the second part of the target control is less than a size of the second image. In this design, the target control does not cover the entire superimposed image, that is, there is a transparent and hollow area on the to-be-displayed image. In this way, when the to-be-displayed image is displayed in the always-on-display state, only pixels in an area in which the target control is located need to emit light, so that screen burning can be prevented. 
     In a possible design, a layout of the digital clock may be a single-clock layout, or may be a dual-clock layout. 
     In a possible design, each digit included in the digital clock corresponds to three groups of image resources, the three groups of image resources include one group of image resources corresponding to the single-clock layout and two groups of image resources respectively corresponding to two clocks in the dual-clock layout, and each group of image resources includes the first image used as a background layer and the second image used as a foreground layer. 
     In a possible design, image formats of the first image, the second image, and the third image are all a portable network graphics png format. In the to-be-displayed image generated by superimposing the first image, the second image, and the third image, all areas other than the digit on the digital clock and the target control are transparent and hollow. 
     In a possible design, the target control may be one pattern, including but not limited to a bird pattern, a fish pattern, a fan pattern, or the like. Alternatively, the target control may include at least two patterns. For example, the target control contains two fishes. One fish is used as the first part of the target control and is superimposed with the first digit on the digital clock, to become the background of the first digit. The other fish is used as the second part of the target control and is superimposed with the first digit, to become the foreground of the first digit. In this way, the generated to-be-displayed image includes the target control containing two fishes. 
     In a possible design, first information may further be displayed when the display is in the always-on-display state, and a color of the first information may be set to be consistent with a color of the digit of the digital clock. For example, the first information may include but is not limited to information such as a location, an icon, a date, and a push message. The color of the first information is set to be consistent with the color of the digit of the digital clock, which helps improve user experience. 
     In a possible design, the method may further include: The electronic device detects a tap operation on the target control, and plays a time of the digital clock in response to the tap operation. 
     According to a second aspect, an embodiment of this application provides an electronic device, and the electronic device includes a processor, a memory, and a display. The display is configured to display a user interface. The memory is configured to store one or more computer programs. When the computer program is executed by the processor, the electronic device is enabled to perform the following operations: obtaining a first image, a second image, and a third image, where the first image includes a first part of a target control, the second image includes a second part of the target control, and the third image includes a digital clock; sequentially superimposing the first image, the third image, and the second image to generate a to-be-displayed image, where in the to-be-displayed image, the first part and the second part of the target control form the target control, and the target control overlaps at least one digit of the digital clock; and displaying the to-be-displayed image when the display is in an always-on-display state. 
     In a possible design, the digital clock includes digits used to represent hours and digits used to represent minutes. The digits used to represent hours are in a different row from the digits used to represent minutes. The digits used to represent hours include a first digit in the tens place and a second digit in the ones place. The target control included in the to-be-displayed image overlaps the first digit. 
     In a possible design, when the computer program is executed by the processor, the electronic device is further enabled to perform the following operation: separately invoking the first image and the third image according to a file name of the first image and a file name of the third image. The file name of the first image includes a layout type of the digital clock, a value of the digit that overlaps the target control, and a location relationship between the first image and the digital clock. The file name of the third image includes the clock layout type of the digital clock, the value of the digit that overlaps the target control, and a location relationship between the third image and the digital clock. 
     In a possible design, a size of the first part of the target control is less than a size of the first image, and a size of the second part of the target control is less than a size of the second image. 
     In a possible design, a layout of the digital clock is a single-clock layout or a dual-clock layout. 
     In a possible design, each digit included in the digital clock corresponds to three groups of image resources, the three groups of image resources include one group of image resources corresponding to the single-clock layout and two groups of image resources respectively corresponding to two clocks in the dual-clock layout, and each group of image resources includes the first image used as a background layer and the second image used as a foreground layer. 
     In a possible design, image formats of the first image, the second image, and the third image are all a portable network graphics png format. 
     In a possible design, the target control is a bird pattern. 
     In a possible design, the target control includes at least two patterns. 
     In a possible design, when the computer program is executed by the processor, the electronic device is further enabled to perform the following operation: displaying first information when the display is in the always-on-display state, where a color of the first information may be set to be consistent with a color of the digit of the digital clock. 
     In a possible design, when the computer program is executed by the processor, the electronic device is further enabled to perform the following operations: detecting a tap operation on the target control, and playing a time of the digital clock in response to the tap operation. 
     According to a third aspect, an embodiment of this application further provides an electronic device, where the electronic device includes modules/units for performing the method in any possible design according to any one of the foregoing aspects. These modules/units may be implemented by hardware, or may be implemented by hardware by executing corresponding software. 
     According to a fourth aspect, an embodiment of this application further provides a computer-readable storage medium. The computer-readable storage medium includes a computer program. When the computer program is run on an electronic device, the electronic device is enabled to perform the method in any possible design in any one of the foregoing aspects. 
     According to a fifth aspect, an embodiment of this application further provides a computer program product. When the computer program product runs on a terminal, the electronic device is enabled to perform the method in any possible design in any one of the foregoing aspects. 
     These or other aspects of this application are more concise and easier to understand in the description of the following embodiments. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram of a hardware structure of an electronic device according to an embodiment of this application; 
         FIG.  2    is a block diagram of a software structure of an electronic device according to an embodiment of this application: 
         FIG.  3    is a schematic diagram of a user interface according to an embodiment of this application; 
         FIG.  4   a    is a schematic diagram of an always-on-display interface according to an embodiment of this application; 
         FIG.  4   b    is a schematic diagram of another always-on-display interface according to an embodiment of this application; 
         FIG.  4   c    is a schematic diagram of still another always-on-display interface according to an embodiment of this application; 
         FIG.  5    is a schematic diagram of a process of always on display according to an embodiment of this application; 
         FIG.  6    is a schematic diagram of a single-clock layout according to an embodiment of this application; 
         FIG.  7    is a schematic diagram of a dual-clock layout according to an embodiment of this application; 
         FIG.  8   a    is a schematic diagram of a single-clock image resource specification according to an embodiment of this application: 
         FIG.  8   b    is a schematic diagram of a dual-clock image resource specification according to an embodiment of this application: 
         FIG.  9    is a schematic diagram of another process of always on display according to an embodiment of this application; 
         FIG.  10    is a schematic flowchart of an always-on-display method according to an embodiment of this application; and 
         FIG.  11    is a schematic diagram of a structure of an electronic device according to an embodiment of this application. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     For ease of understanding, the following uses examples to describe some concepts related to embodiments of this application for reference. Details are as follows: 
     Always on display (always on display): In an always-on-display state, an electronic device may separately light some pixels to display content such as a clock, a date, and a weather condition. 
     The always-on-display state is a state in which a screen is turned off. 
     An always-on-display area is an area that is on a display panel and that is used to display information when the electronic device is in the always-on-display mode. When the electronic device is in a screen-locked state, some subpixels on the display panel (that is, some subpixels lighting the display panel) may be in an on state, and the other subpixels are in an off state. In this way, some areas of the display panel remain in a steady-on state, and the other areas are in a blank-screen state. The steady-on area may be referred to as an always-on-display area. 
     The following describes the technical solutions in embodiments of this application with reference to the accompanying drawings in embodiments of this application. The terms “first” and “second” below in the descriptions of embodiments of this application are merely used for a description purpose, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. Therefore, a feature limited by “first” or “second” may explicitly or implicitly include one or more features. 
     Embodiments disclosed in this application may be applied to an electronic device with a display, and the electronic device has an always-on-display function. In some embodiments of this application, the electronic device may be a portable electronic device, such as a mobile phone, a tablet computer, a wearable device (for example, a smartwatch) with a wireless communication function, or a vehicle-mounted device, that includes a function such as a personal digital assistant and/or a music player. An example embodiment of the portable electronic device includes but is not limited to a portable electronic device using iOS®, Android®, Microsoft®, or another operating system. The portable electronic device may alternatively be, for example, a laptop computer (Laptop) with a touch-sensitive surface (for example, a touch panel). It should be further understood that in some other embodiments of this application, the electronic device may alternatively be a desktop computer with a touch-sensitive surface (for example, a touch panel). 
       FIG.  1    is an example of a schematic diagram of a structure of an electronic device  100 . 
     It should be understood that the electronic device  100  shown in the figure is merely an example, and the electronic device  100  may have more or fewer components than those shown in the figure, may combine two or more components, or may have different component configurations. Components shown in the figure may be implemented by hardware that includes one or more signal processing and/or application-specific integrated circuits, software, or a combination of hardware and software. 
     As shown in  FIG.  1   , the electronic device  100  may include a processor  110 , an external memory interface  120 , an internal memory  121 , a universal serial bus (universal serial bus, USB) interface  130 , a charging management module  140 , a power management module  141 , a battery  142 , an antenna  1 , an antenna  2 , a mobile communications module  150 , a wireless communications module  160 , an audio module  170 , a speaker  170 A, a receiver  170 B, a microphone  170 C, a headset jack  170 D, a sensor module  180 , a button  190 , a motor  191 , an indicator  192 , a camera  193 , a display  194 , a subscriber identification module (subscriber identification module, SIM) card interface  195 , and the like. The sensor module  180  may include a pressure sensor  180 A, a gyroscope sensor  180 B, a barometric pressure sensor  180 C, a magnetic sensor  180 D, an acceleration sensor  180 E, a distance sensor  180 F, an optical proximity sensor  180 G, a fingerprint sensor  180 H a temperature sensor  180 J, a touch sensor  180 K, an ambient light sensor  180 L, a bone conduction sensor  180 M, and the like. 
     The following specifically describes each part of the electronic device  100  with reference to  FIG.  1   . 
     The processor  110  may include one or more processing units. For example, the processor  110  may include an application processor (application processor, AP), a modem processor, a graphics processing unit (graphics processing unit, GPU), an image signal processor (image signal processor, ISP), a controller, a memory, a video codec, a digital signal processor (digital signal processor, DSP), a baseband processor, a neural-network processing unit (neural-network processing unit, NPU), and/or the like. Different processing units may be independent components, or may be integrated into one or more processors. The controller may be a nerve center and a command center of the electronic device  100 . The controller may generate an operation control signal based on an instruction operation code and a time sequence signal, to complete control of instruction fetching and instruction execution. 
     A memory may be further disposed in the processor  110 , and is configured to store instructions and data. In some embodiments, the memory in the processor  110  is a cache memory. The memory may store instructions or data just used or cyclically used by the processor  110 . If the processor  110  needs to use the instructions or the data again, the processor  110  may directly invoke the instructions or the data from the memory, to avoid repeated access and reduce a waiting time of the processor  110 . Therefore, system efficiency can be improved. 
     The processor  110  may run an always-on-display method according to embodiments of this application. When different components are integrated into the processor  110 , for example, a CPU and a GPU are integrated, the CPU and the GPU may cooperate to perform the operation prompt method provided in embodiments of this application. For example, in the operation prompt method, some algorithms are performed by the CPU, and other algorithms are performed by the GPU, to achieve relatively high processing efficiency. 
     In some embodiments, the processor  110  may include one or more interfaces. For example, the interface may include an inter-integrated circuit (inter-integrated circuit, I2C) interface, an inter-integrated circuit sound (inter-integrated circuit sound, I2S) interface, a pulse code modulation (pulse code modulation, PCM) interface, a universal asynchronous receiver/transmitter (universal asynchronous receiver/transmitter, UART) interface, a mobile industry processor interface (mobile industry processor interface, MIPI), a general-purpose input/output (general-purpose input/output, GPIO) interface, a subscriber identity module (subscriber identity module, SIM) interface, a universal serial bus (universal serial bus, USB) interface, and/or the like. 
     The I2C interface is a two-way synchronization serial bus, and includes one serial data line (serial data line, SDA) and one serial clock line (derail clock line, SCL). In some embodiments, the processor  110  may include a plurality of groups of I2C buses. The processor  110  may be separately coupled to the touch sensor  180 K, a charger, a flash, the camera  193 , and the like through different I2C bus interfaces. For example, the processor  110  may be coupled to the touch sensor  180 K through the I2C interface, so that the processor  110  communicates with the touch sensor  180 K through the I2C bus interface, to implement a touch function of the electronic device  100 . 
     The I2S interface may be configured to perform audio communication. In some embodiments, the processor  110  may include a plurality of groups of I2S buses. The processor  110  may be coupled to the audio module  170  through the I2S bus, to implement communication between the processor  110  and the audio module  170 . In some embodiments, the audio module  170  may transmit an audio signal to the wireless communications module  160  through the I2S interface, to implement a function of answering a call through a Bluetooth headset. 
     The PCM interface may also be used to perform audio communication, and sample, quantize, and code an analog signal. In some embodiments, the audio module  170  may be coupled to the wireless communications module  160  through a PCM bus interface. In some embodiments, the audio module  170  may also transmit an audio signal to the wireless communications module  160  through the PCM interface, to implement a function of answering a call through a Bluetooth headset. Both the I2S interface and the PCM interface may be used for audio communication. 
     The UART interface is a universal serial data bus, and is configured to perform asynchronous communication. The bus may be a two-way communications bus. The bus converts to-be-transmitted data between serial communication and parallel communication. In some embodiments, the UART interface is usually configured to connect the processor  110  to the wireless communications module  160 . For example, the processor  110  communicates with a Bluetooth module in the wireless communications module  160  through the UART interface, to implement a Bluetooth function. In some embodiments, the audio module  170  may transmit an audio signal to the wireless communications module  160  through the UART interface, to implement a function of playing music through a Bluetooth headset. 
     The MIPI interface may be configured to connect the processor  110  to a peripheral component such as the display  194  or the camera  193 . The MIPI interface includes a camera serial interface (camera serial interface, CSI), a display serial interface (display serial interface, DSI), and the like. In some embodiments, the processor  110  communicates with the camera  193  via the CSI, to implement a photographing function of the electronic device  100 . The processor  110  communicates with the display  194  via the DSI, to implement a display function of the electronic device  100 . 
     The GPIO interface may be configured by software. The GPIO interface may be configured as a control signal or a data signal. In some embodiments, the GPIO interface may be configured to connect the processor  110  to the camera  193 , the display  194 , the wireless communications module  160 , the audio module  170 , the sensor module  180 , or the like. The GPIO interface may alternatively be configured as an I2C interface, an I2S interface, a UART interface, an MIPI interface, or the like. 
     The USB interface  130  is an interface that conforms to a USB standard specification, and may be specifically a mini USB interface, a micro USB interface, a USB Type-C interface, or the like. The USB interface  130  may be configured to connect to a charger to charge the electronic device  100 , or may be configured to transmit data between the electronic device  100  and a peripheral device, or may be configured to connect to a headset for playing audio through the headset. The interface may be further configured to connect to another electronic device such as an AR device. 
     It may be understood that an interface connection relationship between the modules illustrated in embodiments of this application is merely an example for description, and does not constitute a limitation on a structure of the electronic device  100 . In some other embodiments of this application, the electronic device  100  may alternatively use an interface connection manner different from that in the foregoing embodiment, or use a combination of a plurality of interface connection manners. 
     The charging management module  140  is configured to receive a charging input from the charger. The charger may be a wireless charger or a wired charger. In some embodiments of wired charging, the charging management module  140  may receive a charging input of a wired charger through the USB interface  130 . In some embodiments of wireless charging, the charging management module  140  may receive a wireless charging input through a wireless charging coil of the electronic device  100 . The charging management module  140  supplies power to the electronic device through the power management module  141  while charging the battery  142 . 
     The power management module  141  is configured to connect to the battery  142 , the charging management module  140 , and the processor  110 . The power management module  141  receives an input from the battery  142  and/or the charging management module  140 , and supplies power to the processor  110 , the internal memory  121 , the display  194 , the camera  193 , the wireless communications module  160 , and the like. The power management module  141  may be further configured to monitor parameters such as a battery capacity, a battery cycle count, and a battery health status (electric leakage or impedance). In some other embodiments, the power management module  141  may alternatively be disposed in the processor  110 . In some other embodiments, the power management module  141  and the charging management module  140  may alternatively be disposed in a same device. 
     A wireless communication function of the electronic device  100  may be implemented by using the antenna  1 , the antenna  2 , the mobile communications module  150 , the wireless communications module  160 , the modem processor, the baseband processor, and the like. 
     The antenna  1  and the antenna  2  are configured to transmit and receive electromagnetic wave signals. Each antenna in the electronic device  100  may be configured to cover one or more communications frequency bands. Different antennas may be further multiplexed, to improve antenna utilization. For example, the antenna  1  may be multiplexed as a diversity antenna of a wireless local area network. In some other embodiments, the antenna may be used in combination with a tuning switch. 
     The mobile communications module  150  may provide a wireless communication solution that includes 2G/3G/4G/5G or the like and that is applied to the electronic device  100 . The mobile communications module  150  may include at least one filter, a switch, a power amplifier, a low noise amplifier (low noise amplifier, LNA), and the like. The mobile communications module  150  may receive an electromagnetic wave through the antenna  1 , perform processing such as filtering or amplification on the received electromagnetic wave, and transmit the electromagnetic wave to the modem processor for demodulation. The mobile communications module  150  may further amplify a signal modulated by the modem processor, and convert the signal into an electromagnetic wave for radiation through the antenna  1 . In some embodiments, at least some functional modules in the mobile communications module  150  may be disposed in the processor  110 . In some embodiments, at least some functional modules of the mobile communications module  150  may be disposed in a same device as at least some modules of the processor  110 . 
     The modem processor may include a modulator and a demodulator. The modulator is configured to modulate a to-be-sent low-frequency baseband signal into a medium-high frequency signal. The demodulator is configured to demodulate a received electromagnetic wave signal into a low-frequency baseband signal. Then, the demodulator transmits the low-frequency baseband signal obtained through demodulation to the baseband processor for processing. The low-frequency baseband signal is processed by the baseband processor and then transmitted to the application processor. The application processor outputs a sound signal by an audio device (which is not limited to the speaker  170 A, the receiver  170 B, or the like), or displays an image or a video by the display  194 . In some embodiments, the modem processor may be an independent component. In some other embodiments, the modem processor may be independent of the processor  110 , and is disposed in a same device as the mobile communications module  150  or another functional module. 
     The wireless communications module  160  may provide a wireless communication solution that is applied to the electronic device  100  and that includes a wireless local area network (wireless local area networks, WLAN) (for example, a wireless fidelity (wireless fidelity, Wi-Fi) network), Bluetooth (Bluetooth, BT), a global navigation satellite system (global navigation satellite system. GNSS), frequency modulation (frequency modulation. FM), a near field communication (near field communication, NFC) technology, an infrared (infrared, IR) technology, or the like. The wireless communications module  160  may be one or more components integrating at least one communications processing module. The wireless communications module  160  receives an electromagnetic wave by the antenna  2 , performs frequency modulation and filtering processing on an electromagnetic wave signal, and sends a processed signal to the processor  110 . The wireless communications module  160  may further receive a to-be-sent signal from the processor  110 , perform frequency modulation and amplification on the signal, and convert the signal into an electromagnetic wave for radiation through the antenna  2 . 
     In some embodiments, the antenna  1  and the mobile communications module  150  in the electronic device  100  are coupled, and the antenna  2  and the wireless communications module  160  in the electronic device  100  are coupled, so that the electronic device  100  can communicate with a network and another device by using a wireless communications technology. The wireless communications technology may include a global system for mobile communications (global system for mobile communications, GSM), a general packet radio service (general packet radio service, GPRS), code division multiple access (code division multiple access, CDMA), wideband code division multiple access (wideband code division multiple access, WCDMA), time-division code division multiple access (time-division code division multiple access, TD-SCDMA), long term evolution (long term evolution, LTE), BT, a GNSS, a WLAN, NFC, FM, an IR technology, and/or the like. The GNSS may include a global positioning system (global positioning system, GPS), a global navigation satellite system (global navigation satellite system. GLONASS), a BeiDou navigation satellite system (BeiDou navigation satellite system, BDS), a quasi-zenith satellite system (quasi-zenith satellite system, QZSS), and/or a satellite based augmentation system (satellite based augmentation systems, SBAS). 
     The electronic device  100  may implement a display function through the GPU, the display  194 , the application processor, and the like. The GPU is a microprocessor for image processing, and is connected to the display  194  and the application processor. The GPU is configured to: perform mathematical and geometric computation, and render an image. The processor  110  may include one or more GPUs, which execute program instructions to generate or change display information. 
     The display  194  is configured to display an image, a video, and the like. The display  194  includes a display panel. The display panel may be a liquid crystal display (liquid crystal display, LCD), an organic light-emitting diode (organic light-emitting diode, OLED), an active-matrix organic light emitting diode (active-matrix organic light emitting diode. AMOLED), a flexible light-emitting diode (flex light-emitting diode, FLED), a mini-LED, a micro-LED, a micro-OLED, a quantum dot light emitting diode (quantum dot light emitting diodes, QLED), or the like. In some embodiments, the electronic device  100  may include one or N displays  194 , where N is a positive integer greater than 1. 
     In embodiments of this application, the display  194  may be one integrated flexible display, or may be a spliced display including two rigid screens and one flexible screen located between the two rigid screens. 
     The electronic device  100  may implement a photographing function through the camera  193 , the ISP, the video codec, the GPU, the display  194 , the application processor, and the like. 
     The ISP may be configured to process data fed back by the camera  193 . For example, during photographing, a shutter is pressed, and light is transmitted to a photosensitive element of the camera through a lens. An optical signal is converted into an electrical signal, and the photosensitive element of the camera transmits the electrical signal to the ISP for processing, to convert the electrical signal into a visible image. The ISP may further perform algorithm optimization on noise, brightness, and complexion of the image. The ISP may further optimize parameters such as exposure and a color temperature of a photographing scenario. In some embodiments, the ISP may be disposed in the camera  193 . 
     The camera  193  may be configured to capture a static image or a video. An optical image of an object is generated through the lens, and is projected onto the photosensitive element. The photosensitive element may be a charge coupled device (charge coupled device, CCD) or a complementary metal-oxide-semiconductor (complementary metal-oxide-semiconductor, CMOS) phototransistor. The photosensitive element converts an optical signal into an electrical signal, and then transmits the electrical signal to the ISP to convert the electrical signal into a digital image signal. The ISP outputs the digital image signal to the DSP for processing. The DSP converts the digital image signal into an image signal in a standard format such as RGB or YUV. In some embodiments, the electronic device  100  may include one or N cameras  193 , where N is a positive integer greater than 1. 
     The digital signal processor is configured to process a digital signal, and may process another digital signal in addition to the digital image signal. For example, when the electronic device  100  selects a frequency, the digital signal processor is configured to perform Fourier transformation on frequency energy. 
     The video codec is configured to compress or decompress a digital video. The electronic device  100  may support one or more video codecs. In this way, the electronic device  100  may play back or record videos in a plurality of coding formats, for example, moving picture experts group (moving picture experts group, MPEG)-1, MPEG-2, MPEG-3, and MPEG-4. 
     The NPU is a neural-network (neural-network, NN) computing processor. The NPU quickly processes input information by referring to a structure of a biological neural network, for example, a transfer mode between human brain neurons, and may further continuously perform self-learning. Applications such as intelligent cognition of the electronic device  100  may be implemented through the NPU, for example, image recognition, facial recognition, speech recognition, and text understanding. 
     The external memory interface  120  may be used to connect to an external memory card, for example, a micro SD card, to extend a storage capability of the electronic device  100 . The external memory card communicates with the processor  110  through the external memory interface  120 , to implement a data storage function. For example, files such as music and videos are stored in the external memory card. 
     The internal memory  121  may be configured to store computer-executable program code. The executable program code includes instructions. The internal memory  121  may include a program storage area and a data storage area. The program storage area may store an operating system, an application required by at least one function (for example, a voice playing function or an image playing function), and the like. The data storage area may store data (such as audio data and an address book) created during use of the electronic device  100 , and the like. In addition, the internal memory  121  may include a high-speed random access memory, or may include a nonvolatile memory, for example, at least one magnetic disk storage device, a flash memory, or a universal flash storage (universal flash storage, UFS). The processor  110  runs instructions stored in the internal memory  121  and/or instructions stored in the memory disposed in the processor, to perform various function applications and data processing of the electronic device  100 . 
     The electronic device  100  may implement an audio function, for example, music playing and recording, through the audio module  170 , the speaker  170 A, the receiver  170 B, the microphone  170 C, the headset jack  170 D, the application processor, and the like. 
     The audio module  170  is configured to convert digital audio information into an analog audio signal for output, and is also configured to convert analog audio input into a digital audio signal. The audio module  170  may be further configured to code and decode audio signals. In some embodiments, the audio module  170  may be disposed in the processor  110 , or some functional modules in the audio module  170  are disposed in the processor  110 . 
     The speaker  170 A, also referred to as a “loudspeaker”, is configured to convert an audio electrical signal into a sound signal. The electronic device  100  may be used to listen to music or answer a call in a hands-free mode over the speaker  170 A. 
     The receiver  170 B, also referred to as an “earpiece”, is configured to convert an electrical audio signal into a sound signal. When a call is answered or speech information is received through the electronic device  100 , the receiver  170 B may be put close to a human ear to listen to a voice. 
     The microphone  170 C, also referred to as a “mike” or a “mic”, is configured to convert a sound signal into an electrical signal. When making a call or sending a voice message, a user may make a sound near the microphone  170 C through the mouth of the user, to input a sound signal to the microphone  170 C. At least one microphone  170 C may be disposed in the electronic device  100 . In some other embodiments, two microphones  170 C may be disposed in the electronic device  100 , to collect a sound signal and implement a noise reduction function. In some other embodiments, three, four, or more microphones  170 C may alternatively be disposed in the electronic device  100 , to collect a sound signal, implement noise reduction, and identify a sound source, to implement a directional recording function and the like. 
     The headset jack  170 D is configured to connect to a wired headset. The headset jack  170 D may be a USB interface  130 , or may be a 3.5 mm open mobile terminal platform (open mobile terminal platform, OMTP) standard interface or cellular telecommunications industry association of the USA (cellular telecommunications industry association of the USA, CTIA) standard interface. 
     The pressure sensor  180 A is configured to sense a pressure signal, and can convert the pressure signal into an electrical signal. In some embodiments, the pressure sensor  180 A may be disposed on the display  194 . There are a plurality of types of pressure sensors  180 A, such as a resistive pressure sensor, an inductive pressure sensor, and a capacitive pressure sensor. The capacitive pressure sensor may include at least two parallel plates made of conductive materials. When a force is applied to the pressure sensor  180 A, capacitance between electrodes changes. The electronic device  100  determines pressure intensity based on the change in the capacitance. When a touch operation is performed on the display  194 , the electronic device  100  detects intensity of the touch operation through the pressure sensor  180 A. The electronic device  100  may also calculate a touch location based on a detection signal of the pressure sensor  180 A. In some embodiments, touch operations that are performed in a same touch position but have different touch operation intensity may correspond to different operation instructions. 
     The gyroscope sensor  180 B may be configured to determine a moving posture of the electronic device  100 . In some embodiments, angular velocities of the electronic device  100  around three axes (namely, axes x, y, and z) may be determined through the gyroscope sensor  180 B. The gyroscope sensor  180 B may be configured to implement image stabilization during photographing. The gyroscope sensor  180 B may also be used in a navigation scenario and a somatic game scenario. 
     The barometric pressure sensor  180 C is configured to measure barometric pressure. In some embodiments, the electronic device  100  calculates an altitude through the barometric pressure measured by the barometric pressure sensor  180 C, to assist in positioning and navigation. 
     The magnetic sensor  180 D includes a Hall sensor. The electronic device  100  may detect opening and closing of a flip cover by using the magnetic sensor  180 D. In some embodiments, when the electronic device  100  is a clamshell phone, the electronic device  100  may detect opening and closing of a flip cover based on the magnetic sensor  180 D. Further, a feature such as automatic unlocking upon opening of the flip cover is set based on a detected opening or closing state of the flip cover. 
     The acceleration sensor  180 E may detect accelerations in various directions (usually on three axes) of the electronic device  100 . When the electronic device  100  is still, a magnitude and a direction of gravity may be detected. The acceleration sensor  180 E may be further configured to identify a posture of the electronic device, and is used in an application such as switching between a landscape mode and a portrait mode or a pedometer. 
     The distance sensor  180 F is configured to measure a distance. The electronic device  100  may measure the distance in an infrared manner or a laser manner. In some embodiments, in a photographing scenario, the electronic device  100  may measure a distance through the distance sensor  180 F to implement quick focusing. 
     The optical proximity sensor  180 G may include, for example, a light-emitting diode (LED) and an optical detector, for example, a photodiode. The light-emitting diode may be an infrared light-emitting diode. The electronic device  100  emits infrared light by using the light-emitting diode. The electronic device  100  detects infrared reflected light from a nearby object through the photodiode. When sufficient reflected light is detected, it may be determined that there is an object near the electronic device  100 . When insufficient reflected light is detected, the electronic device  100  may determine that there is no object near the electronic device  100 . The electronic device  100  may detect, by using the optical proximity sensor  180 G, that the user holds the electronic device  100  close to an ear for a call, to automatically turn off a screen for power saving. The optical proximity sensor  180 G may also be used in a smart cover mode or a pocket mode to automatically perform screen unlocking or locking. 
     The ambient light sensor  180 L is configured to sense ambient light brightness. The electronic device  100  may adaptively adjust brightness of the display  194  based on the sensed ambient light brightness. The ambient light sensor  180 L may also be configured to automatically adjust white balance during photographing. The ambient light sensor  180 L may also cooperate with the optical proximity sensor  180 G to detect whether the electronic device  100  is in a pocket, to avoid an accidental touch. 
     The fingerprint sensor  180 H is configured to collect a fingerprint. The electronic device  100  may use a feature of the collected fingerprint to implement fingerprint-based unlocking, application lock access, fingerprint-based photographing, fingerprint-based call answering, and the like. For example, a fingerprint sensor may be configured on a front side (below the display  194 ) of the electronic device  100 , or a fingerprint sensor may be configured on a rear side (below the rear-facing camera) of the electronic device  100 . In addition, the fingerprint sensor may be alternatively configured in the touchscreen to implement a fingerprint recognition function. In other words, the fingerprint sensor may be integrated with the touchscreen to implement the fingerprint recognition function of the electronic device  100 . In this case, the fingerprint sensor may be disposed in the touchscreen, or may be a part of the touchscreen, or may be disposed in the touchscreen in another manner. In addition, the fingerprint sensor may further be implemented as a full-panel fingerprint sensor. Therefore, the touchscreen may be considered as a panel on which a fingerprint may be collected at any position. In some embodiments, the fingerprint sensor may process a collected fingerprint (for example, the fingerprint sensor may check whether the fingerprint is verified) and send a fingerprint processing result to the processor  110 , and the processor  110  performs corresponding processing based on the fingerprint processing result. In some other embodiments, the fingerprint sensor may further send the collected fingerprint to the processor  110 , so that the processor  110  processes the fingerprint (for example, verifies the fingerprint). In this embodiment of this application, the fingerprint sensor may use any type of sensing technology, which includes but is not limited to an optical sensing technology, a capacitive sensing technology, a piezoelectric sensing technology, an ultrasonic sensing technology, and the like. 
     The temperature sensor  180 J is configured to detect a temperature. In some embodiments, the electronic device  100  executes a temperature processing policy through the temperature detected by the temperature sensor  180 J. For example, when the temperature reported by the temperature sensor  180 J exceeds a threshold, the electronic device  100  lowers performance of a processor nearby the temperature sensor  180 J, to reduce power consumption for thermal protection. In some other embodiments, when the temperature is less than another threshold, the electronic device  100  heats the battery  142  to prevent the electronic device  100  from being shut down abnormally due to a low temperature. In some other embodiments, when the temperature is lower than still another threshold, the electronic device  100  boosts an output voltage of the battery  142  to avoid abnormal shutdown caused by a low temperature. 
     The touch sensor  180 K is also referred to as a “touch panel”. The touch sensor  180 K may be disposed on the display  194 , and the touch sensor  180 K and the display  194  constitute a touchscreen, which is also referred to as a “touch screen”. The touch sensor  180 K is configured to detect a touch operation performed on or near the touch sensor. The touch sensor may transfer the detected touch operation to the application processor to determine a type of the touch event. A visual output related to the touch operation may be provided through the display  194 . In some other embodiments, the touch sensor  180 K may also be disposed on a surface of the electronic device  100  at a location different from that of the display  194 . 
     The bone conduction sensor  180 M may obtain a vibration signal. In some embodiments, the bone conduction sensor  180 M may obtain a vibration signal of a vibration bone of a human vocal-cord part. The bone conduction sensor  180 M may also be in contact with a body pulse to receive a blood pressure beating signal. In some embodiments, the bone conduction sensor  180 M may also be disposed in the headset, to obtain a bone conduction headset. The audio module  170  may obtain a speech signal through parsing based on the vibration signal that is of the vibration bone of the vocal-cord part and that is obtained by the bone conduction sensor  180 M, to implement a speech function. The application processor may parse heart rate information based on the blood pressure beating signal obtained by the bone conduction sensor  180 M, to implement a heart rate detection function. 
     The button  190  includes a power button, a volume button, and the like. The button  190  may be a mechanical button, or may be a touch button. The electronic device  100  may receive a key input, and generate a key signal input related to a user setting and function control of the electronic device  100 . 
     The motor  191  may generate a vibration prompt. The motor  191  may be configured to provide an incoming call vibration prompt and a touch vibration feedback. For example, touch operations performed on different applications (for example, photographing and audio playback) may correspond to different vibration feedback effects. The motor  191  may also correspond to different vibration feedback effects for touch operations performed on different areas of the display  194 . Different application scenarios (for example, a time reminder, information receiving, an alarm clock, and a game) may also correspond to different vibration feedback effects. A touch vibration feedback effect may be further customized. 
     The indicator  192  may be an indicator light, and may be configured to indicate a charging status and a power change, or may be configured to indicate a message, a missed call, a notification, and the like. 
     The SIM card interface  195  is configured to connect to a SIM card. The SIM card may be inserted into the SIM card interface  195  or removed from the SIM card interface  195 , to implement contact with or separation from the electronic device  100 . The electronic device  100  may support one or N SIM card interfaces, where N is a positive integer greater than 1. The SIM card interface  195  may support a nano-SIM card, a micro-SIM card, a SIM card, and the like. A plurality of cards may be inserted into a same SIM card interface  195  at the same time. The plurality of cards may be of a same type or different types. The SIM card interface  195  may be compatible with different types of SIM cards. The SIM card interface  195  is also compatible with an external memory card. The electronic device  100  interacts with a network through the SIM card, to implement functions such as conversation and data communication. In some embodiments, the electronic device  100  uses an eSIM, that is, an embedded SIM card. The eSIM card may be embedded into the electronic device  100 , and cannot be separated from the electronic device  100 . 
     Although not shown in  FIG.  1   , the electronic device  100  may further include a Bluetooth apparatus, a positioning apparatus, a flash, a micro projection apparatus, a near field communication (near field communication, NFC) apparatus, and the like. Details are not described herein. 
     All the following embodiments may be implemented in an electronic device  100  with the foregoing hardware structure (for example, a mobile phone or a tablet computer). The hardware structure of the electronic device  100  is described in  FIG.  1   . In the following embodiments, an Android (Android) system with a layered architecture is used as an example to describe a software structure of the electronic device  100 . 
       FIG.  2    is a block diagram of a software structure of the electronic device  100  according to an embodiment of the present invention. 
     As shown in  FIG.  2   , a layered architecture is used for the software structure of the electronic device. In the layered architecture, software is divided into several layers, and each layer has a clear role and task. The layers communicate with each other through a software interface. In some embodiments, an Android system is divided into four layers from top to bottom: an application layer, an application framework layer, an Android runtime (Android runtime) and system library, and a kernel layer. 
     The application layer may include a series of application packages. As shown in  FIG.  2   , the application packages may include applications such as Call, Camera, Gallery, Calendar, Phone, Map, Navigation. WLAN, Bluetooth, Music, Video, and Messages. 
     The application framework layer provides an application programming interface (application programming interface, API) and a programming framework for an application at the application layer. The application framework layer includes some predefined functions. As shown in  FIG.  2   , the application framework layer may include a window manager, a content provider, a view system, a phone manager, a resource manager, a notification manager, and the like. 
     The window manager is configured to manage a window program. The window manager may obtain a size of the display, determine whether there is a status bar, perform screen locking, take a screenshot, and the like. 
     The content provider is configured to store and obtain data, and enable the data to be accessed by an application. The data may include a video, an image, an audio, calls that are made and answered, a browsing history and bookmarks, an address book, and the like. 
     The view system includes visual controls such as a control for displaying a text and a control for displaying an image. The view system may be configured to construct an application. A display interface may include one or more views. For example, a display interface including an SMS message notification icon may include a text display view and an image display view. 
     The phone manager is configured to provide a communication function of the electronic device  100 , for example, management of a call status (including answering, declining, or the like). 
     The resource manager provides various resources such as a localized string, an icon, an image, a layout file, and a video file for an application. 
     The notification manager enables an application to display notification information in a status bar, and may be configured to convey a notification message. The notification manager may automatically disappear after a short pause without requiring a user interaction. For example, the notification manager is configured to notify download completion, give a message notification, and the like. The notification manager may alternatively be a notification that appears in a top status bar of the system in a form of a graph or a scroll bar text, for example, a notification of an application that is run on a background, or may be a notification that appears on the screen in a form of a dialog window. For example, text information is displayed in the status bar, an announcement is given, the electronic device vibrates, or the indicator light blinks. 
     The Android runtime includes a kernel library and a virtual machine. The Android runtime is responsible for scheduling and management of the Android system. 
     The kernel library includes two parts: a performance function that needs to be invoked in java language, and a kernel library of Android. 
     The application layer and the application framework layer run on the virtual machine. The virtual machine executes java files of the application layer and the application framework layer as binary files. The virtual machine is configured to implement functions such as object lifecycle management, stack management, thread management, security and exception management, and garbage collection. 
     The system library may include a plurality of function modules, for example, a surface manager (surface manager), a media library (Media Libraries), a three-dimensional graphics processing library (for example, OpenGL ES), and a 2D graphics engine (for example, SGL). 
     The surface manager is configured to manage a display subsystem and provide fusion of 2D and 3D layers for a plurality of applications. 
     The media library supports playback and recording in a plurality of commonly used audio and video formats, and static image files. The media library may support a plurality of audio and video coding formats such as MPEG-4, G.264, MP3, AAC, AMR, JPG, and PNG. 
     The three-dimensional graphics processing library is configured to implement three-dimensional graphics drawing, image rendering, composition, layer processing, and the like. 
     The 2D graphics engine is a drawing engine for 2D drawing. 
     The kernel layer is a layer between hardware and software. The kernel layer includes at least a display driver, a camera driver, an audio driver, and a sensor driver. 
     The following describes some examples of user interfaces (user interface, UI) provided by the electronic device  100 . The term “user interface” in the specification, claims, and accompanying drawings of this application is a medium interface for interaction and information exchange between an application or an operating system and a user, and implements conversion between an internal form of information and a form that can be accepted by the user. The user interface is usually represented in a form of a graphical user interface (graphical user interface, GUI), and is a user interface that is related to a computer operation and that is displayed in a graphic manner. An interface element may be an icon, a window, a control, or the like displayed on a display of the electronic device. The control may include visible interface elements such as an icon, a button, a menu, a tab, a text box, a dialog box, a status bar, a navigation bar, or a widget (widget). 
       FIG.  3    shows an example of a user interface  300  displayed on the display  194  of the electronic device  100 . 
     As shown in  FIG.  3   , the user interface  300  is an always-on-display interface of the electronic device. The user interface  300  may include a digital clock  301 . The digital clock  301  may include a time digit. A layout style of the digital clock may be horizontal display, that is, digits used to represent hours are displayed in a same line (or row) as digits used to represent minutes. It should be understood that  FIG.  3    does not limit the layout style of the digital clock in this embodiment of this application. The layout style of the digital clock in this application may alternatively be another style, for example, double-row display, as shown in  FIG.  4   a   ,  FIG.  4   b   , or  FIG.  4   c   . To be specific, the digits used to represent hours are displayed in a different line (or row) from the digits used to represent minutes. The digits used to represent hours may be displayed in the first line (or row), and the digits used to represent minutes may be displayed in the second line (or row): or the digits used to represent minutes may be displayed in the first line (or row), and the digits used to represent hours may be displayed in the second line (or row). 
     In some other embodiments, the user interface  300  may further include a date  302 , a weather widget (widget)  303 , and the like, and may further include icons  304  of various applications, for example, a WeChat icon, a Phone icon, a Messages icon, and a current battery level. In some other embodiments, the user interface  300  may further include a push message  305 , for example, a WeChat message reminder. 
     It may be understood that  FIG.  3    merely shows an example of the always-on-display interface on the electronic device  100 , and constitutes no limitation on this embodiment of this application. 
     In an always-on-display scenario, when the electronic device displays a digital clock, a bird pattern is used as a background or a foreground of the digital clock, and two visual effects are mainly formed. One visual effect is shown in  FIG.  4   a    in which time is superimposed on the bird pattern to form a visual effect that the time is in front of the bird pattern. The other visual effect is shown in  FIG.  4   b    in which the bird pattern is superimposed on the time to form a visual effect that the bird pattern is in front of the time. The two visual effects are relatively monotonous, and therefore, user&#39;s pursuit of a richer display effect cannot be met. 
     Therefore, this application provides a time display method. The method is applicable to an electronic device with a display, and the electronic device has an always-on-display function. In the method, the electronic device obtains a first image, a second image, and a third image, where the first image includes a first part of a target control, the second image includes a second part of the target control, and the third image includes a digital clock. The first image, the third image, and the second image are sequentially superimposed to generate a to-be-displayed image. In the to-be-displayed image, the first part of the target control becomes a background (background, bg) of the digital clock, and the second part of the target control becomes a foreground (foreground, fg) of the digital clock. The first part used as the background and the second part used as the foreground form the complete target control. The target control overlaps at least one digit of the digital clock. For example, the target control is a complete bird pattern. As shown in  FIG.  4   c   , the first image includes the first part of the target control, that is, a tail of the bird, the second image includes the digital clock, and the third image includes the second part of the target control, that is, a body part of the bird. In a to-be-displayed image obtained by superimposing the three images, the tail of the bird is used as the background of the digit “0” included in the digital clock, and the body part of the bird is used as the foreground of the digit “0”, so that an interspersed visual effect that the first part of the target control is in front of the digit “0” and the second part of the target control is behind the digit “0” is formed. Compared with a display effect that the digit “0” and the entire target control form a single front-to-back relationship, a richer display effect can be provided for a user according to the time display method in this application when the electronic device displays the digital clock in an always-on-display state. 
     It should be understood that the time display method provided in this embodiment of this application is not only applicable to a digital clock, but also applicable to an analog clock. In the following embodiments, only a digital clock is used as an example for description. 
     The following describes in detail the time display method provided in this embodiment of this application with reference to the accompanying drawings. 
     In this embodiment of this application, the digital clock may be a 24-hour clock, or may be a 12-hour clock. For ease of description, the following embodiments are described by using an example in which the digital clock is a 24-hour clock. 
     For example, as shown in  FIG.  5   , the time on the digital clock is 08:08. The time on the digital clock includes digits used to represent hours and digits used to represent minutes, and the digits used to represent hours are in a different row from the digits used to represent minutes. The digits used to represent hours include a first digit in the tens place and a second digit in the ones place, where the first digit may be a value such as 0, 1, or 2, and the second digit may be a value such as 0, 1, 2, . . . , or 9. The digits used to represent minutes include a third digit in the tens place and a fourth digit in the ones place, where the third digit may be a value such as 0, 1, 2, . . . , or 6, and the fourth digit may be a value such as 0, 1, 2, . . . , or 9. 
     The target control may be superimposed on any one or more of the first digit, the second digit, the third digit, and the fourth digit on the digital clock, to obtain the to-be-displayed image. The target control in the to-be-displayed image is superimposed on any one or more digits, to form an interspersed visual effect. The following embodiment is described by using an example in which the target control is superimposed on one digit on the digital clock to obtain the to-be-displayed image. 
     For example, the target control is a bird pattern. The bird pattern may be superimposed on the first digit on the digital clock, to obtain a to-be-displayed image. In the to-be-displayed image, the bird pattern overlaps the first digit, to form an interspersed visual effect. The first digit is a digit that is in the tens place and that represents hours, and a possible value of the first digit is 0, 1, or 2. In a clocking process of the digital clock, the first digit changes three times in 24 hours, and a change frequency of the first digit is lower than that of the second digit, the third digit, and the fourth digit. In this way, compared with a case in which the bird pattern is superimposed on another digit (for example, the second digit, the third digit, or the fourth digit) for display, the case in which the bird pattern is superimposed on the first digit for display can reduce power consumption. 
     The following describes the time display method in this embodiment of this application by using an example in which the target control (the bird pattern) is superimposed on the first digit of the digital clock. 
     In an example, the value of the first digit is “0”, a part of the target control is at the foreground layer, and the other part is at the background layer. As shown in  FIG.  5   , an image  501  at the foreground layer includes a first part of a bird, an image  502  at a digit layer includes the digit “0”, and an image  503  at the background layer includes a second part of the bird. An image  504  is obtained after the image  501 , the image  502 , and the image  503  are superimposed. In the image  504 , the first part of the bird and the second part of the bird form a complete bird pattern. In the image  504 , the target control (the bird pattern) and the digit “0” form an interspersed visual effect, that is, a visual effect that the first part of the bird is in front of the digit “0” and the second part of the bird is behind the digit “0”. 
     In another example, the value of the first digit is “1”, a part of the target control is at the foreground layer, and the other part is at the background layer. As shown in  FIG.  5   , an image  511  at the foreground layer includes a first part of a bird, an image  512  at a digit layer includes the digit “1”, and an image  513  at the background layer includes a second part of the bird. An image  514  is obtained after the image  511 , the image  512 , and the image  513  are superimposed. In the image  514 , the first part of the bird and the second part of the bird form a complete bird pattern. In the image  514 , the target control (the bird pattern) and the digit “I” form an interspersed visual effect, that is, a visual effect that the first part of the bird is in front of the digit “1” and the second part of the bird is behind the digit “1”. 
     In still another example, the value of the first digit is “2”, and the entire target control is at the foreground layer. As shown in  FIG.  5   , an image  521  at the foreground layer includes an entire bird pattern, an image  522  at a digit layer includes the digit “2”, and an image  523  at the background layer has no pattern. An image  524  is obtained after the image  521 , the image  522 , and the image  523  are superimposed. In the image  524 , a visual effect that the entire target control (the bird pattern) is in front of the digit “2” is formed. 
     In the foregoing several examples, values of the first digit of the digital clock are different. The target control may be divided differently as shapes of the digits “0”, “1”, and “2” are different. Different values respectively correspond to different first parts of the target control in the images at the foreground layer, and different values respectively correspond to different second parts of the target control in the images at the background layer. Therefore, in the image  504 , the image  514 , and the image  524  that are obtained after the images at the foreground layer, the digit layer, and the background layer corresponding to the values are superimposed, visual effects of superimposing the target control (the bird pattern) and the first digit are also different. In this way, the bird pattern may be flexibly combined with the shape of the digit, and different superimposition effects are displayed as time of the digital clock changes, which provides a richer visual effect for the user. 
     In this embodiment of this application, a format of any one of the image at the background layer, the image at the digit layer, and the image at the foreground layer is a portable network graphics (portable network graphic, png) format. In this way, areas other than the bird pattern in the image at the background layer and the image at the foreground layer are transparent and hollow, and an area other than the digit in the image at the digit layer is transparent and hollow. Superimposition of the images at the three layers does not affect display of the digit on the digital clock, and does not affect display of the bird pattern. In addition, pixels in only an area in which the digital clock and the target control (the bird pattern) are located need to emit light on the to-be-displayed image, so that power consumption can be reduced. 
     In the foregoing example, the visual effect of the always on display is described by using only an example in which the first digit is superimposed on the bird pattern. For a time display method in which the second digit, the third digit, or the fourth digit is superimposed on the target control, refer to related descriptions of the foregoing example. Details are not described herein again. 
     In this embodiment of this application, the layout of the digital clock may be a single-clock layout shown in  FIG.  6   . As shown in  FIG.  6   , a digital clock  601  is displayed in an always-on-display interface. For example, the electronic device may obtain a current geographical location, and set a time of the digital clock  601  based on a time zone of the current geographical location. In some other embodiments, the layout of the digital clock may alternatively be a dual-clock layout shown in  FIG.  7   . Two clocks may display times at two different locations. For example, a time of one digital clock may be set based on a time zone corresponding to a home location (for example, a location of household registration or a location of a common residence), and a time of the other digital clock may be set based on a time zone corresponding to a current location (for example, a destination of a business trip) of the electronic device. As shown in  FIG.  7   , a digital clock  701  and a digital clock  703  are displayed in an always-on-display interface. For example, a time on the digital clock  701  is a local time and date in Hohhot, China. A house icon (as shown in a dashed-line box  702 ) is displayed below the digital clock  701 , and the time of the digital clock  701  is a time based on a time zone of a home location. A time on the digital clock  703  is a local time and date in Amsterdam. A positioning icon (as shown in a dashed-line box  704 ) is displayed below the digital clock  703 , and the time of the digital clock  703  is a time based on a time zone of a current location of the electronic device. 
     For example, the target control and the first digit are superimposed. A value of the first digit may be 0, 1, or 2, and each value of the first digit may correspond to three groups of image resources, including one group of single-clock image resources and two groups of dual-clock image resources. File names of a group of image resources may be in the following format: clock type_digit n_background.png and clock type_digit n_foreground.png. A single-clock prefix is single, and a dual-clock prefix is dual. For example, if the value of the first digit is “0”, the digit n may be represented as digit (digit)  0 ; if the value of the first digit is “1”, the digit n may be represented as digit1: or if the value of the first digit is “2”, the digit n may be represented as digit2. 
     For example, if the value of the first digit is “2”, file names of a group of single-clock image resources corresponding to the value of the first digit are single_digit2_bg.png and single_digit2_fg.png, and file names of two groups of dual-clock image resources corresponding to the value of the first digit are dual1_digit2_bg.png, dual1_digit2_fg.png, dual2_digit2_bg.png, and dual2_digit2_fg.png. 
     In this embodiment of this application, an image specification of an image resource may be set to a fixed size, and does not change with a time digit. Using the single-clock layout as an example, a width corresponding to the image specification of the single-clock image resource may be set to be consistent with the width of the display. As shown in  FIG.  8   a   , a width is 360 dp, and a height is 248 dp. Using the dual-clock layout as an example, an image specification of each dual-clock image resource (an image  820  and an image  830 ) may be 180 dp in width and 248 dp in height, as shown in  FIG.  8     b.    
     In this example, in an image corresponding to each image resource, the size of the target control is less than the size of the image. For example, for an image  810  shown in  FIG.  8   a   , the size of the image is 360 dp in width and 248 dp in height. A bird pattern  811  in the image does not cover the entire image, that is, the image  810  has a transparent and hollow area. In this way, when the image  810  is displayed in the always-on-display interface, only pixels in an area in which the bird pattern  811  is located need to emit light, so that screen burning can be prevented. 
     In addition, the image specification is set to be relatively large, so that display of target controls of a plurality of shapes and sizes can be supported. When a superimposed target control is designed for the digital clock, the size of the target control is not limited to only one size. Otherwise, the target control cannot be displayed when the target control is replaced with another target control of a relatively large size. 
     The following describes an always on display (AOD) layout. 
     For example, the AOD layout is shown as the theme.xml file: 
     
       
         
           
               
             
               
                   
               
             
            
               
                  &lt;?xml version=“1.0” encoding=“utf-8”&gt; 
               
               
                  &lt;HWTheme&gt; 
               
               
                   &lt;item style=“ digitclock” /&gt;, // The clock style is digital clock 
               
               
                   &lt;item clock=“ 3” /&gt;, // A layout style of the digital clock is marked 
               
               
                   &lt;item foreground=“ 1” /&gt;, // A location of a foreground image is 
               
               
                 marked (an optional value is 0, 1, or 2) 
               
               
                   &lt;item background=“ 1” /&gt;, // A location of a background image is 
               
               
                 marked (an optional value is 0, 1, or 2) 
               
               
                   &lt;item fondcolor=“#FFF222” /&gt;, // A value is a hexadecimal value 
               
               
                 corresponding to an RGB value. This attribute takes effect for a date, 
               
               
                 lunar calendar, geographical location, and pure-color icon skin change. 
               
               
                 If this attribute is not set, a default color #FFFFFF is used 
               
               
                  &lt;/HWTheme&gt; 
               
               
                   
               
            
           
         
       
     
     In the AOD layout, the layout style of the digital clock may be a horizontal display style shown in  FIG.  3   , or may be a dual-row display style shown in  FIG.  4   a   ,  FIG.  4   b   ,  FIG.  4   c   , or the like. 
     In some embodiments, a value of the location of the foreground image may indicate a display location, on the digital clock, of a part of the target control in the image at the foreground layer. A value of the location of the background image may indicate a display location, on the digital clock, of the other part of the target control in the image at the background layer. Optional values of the locations of the foreground image and the background image are 0, 1, or 2. When the values of the locations of the foreground image and the background image are “0”, it indicates that the corresponding image at the foreground layer and the corresponding image at the background layer do not change over time. When a display effect of the target control is designed, a display area of the digital clock needs to be avoided to ensure that a digit is not blocked. 
     When the values of the locations of the foreground image and the background image are “1”, the target control is displayed at the location of the first digit. A value of the first digit on a 24-hour digital clock may be 0, 1, or 2, and each value may correspond to three groups of image resources. 
     When the value of the first digit is “0”, the corresponding three groups of image resources are named as follows. 
     single_digit0_fg.png, single_digit0_bg.png; 
     dual1_digit0_fg.png, dual1_digit0_bg.png; and 
     dual2_digit0_fg.png, dual2_digit0_bg.png; 
     when the value of the first digit is “1”, the corresponding three groups of image resources are named as follows: 
     single_digit1_fg.png, single_digit1_bg.png; 
     dual1_digit1_fg.png, dual1_digit1_bg.png; and 
     dual2_digit1_fg.png, dual2_digit1_bg.png; or 
     when the value of the first digit is “2”, the corresponding three groups of image resources are named as follows: 
     single_digit2_fg.png, single_digit2_bg.png; 
     dual1_digit2_fg.png, dual1_digit2_bg.png: and 
     dual2_digit2_fg.png, dual2_digit2_bg.png. 
     Names of the foregoing image resources need to match and cannot be changed. When 0, 1, and 2 are separately displayed at the location of the first digit, an image at the foreground layer and an image at the background layer that correspond to the value of the first digit are simultaneously displayed at the location of the first digit, so that different visual effects obtained by superimposing the target control and the first digit can be displayed based on a change of the value of the first digit. 
     When the values of the locations of the foreground image and the background image are “2”, the target control is displayed at the location of the second digit. The value of the second digit on the 24-hour digital clock may be 0, 1, 2, . . . , or 9, and each value may correspond to three groups of image resources. 
     When the value of the second digit is “0”, the corresponding three groups of image resources are named as follows: 
     single_digit0_fg.png, single_digit0_bg.png; 
     dual1_digit0_fg.png, dual1_digit0_bg.png: and 
     dual2_digit0_fg.png, dual2_digit0_bg.png; 
     when the value of the second digit is “1”, the corresponding three groups of image resources are named as follows: 
     single_digit1_fg.png, single_digit1_bg.png; 
     dual1_digit1_fg.png, dual1 digit1_bg.png; and 
     dual2_digit1 fg.png, dual2_digit1_bg.png; 
     . . . 
     when the value of the second digit is “9”, the corresponding three groups of image resources are named as follows: 
     single_digit9_fg.png, single_digit9_bg.png; 
     dual1_digit9_fg.png, dual1_digit9_bg.png; and 
     dual2_digit9_fg.png, dual2_digit9_bg.png. 
     Names of the foregoing image resources need to match and cannot be changed. When 0, 1, 2, . . . , and 9 are separately displayed at the location of the second digit, the foreground image and the background image corresponding to the value of the second digit are simultaneously displayed at the location of the second digit. 
     In some other embodiments, the target control may alternatively be displayed on a digit that represents minutes on the digital clock. In this case, values of the locations of the foreground image and the background image may be alternatively 3 or 4. 
     When the values of the locations of the foreground image and the background image are “3”, the target control is displayed at the location of the third digit. The value of the third digit on the 24-hour digital clock may be 0, 1, 2, . . . . or 6, and each value may correspond to three groups of image resources. 
     When the value of the third digit is “0”, the corresponding three groups of image resources are named as follows: 
     single_digit0_fg.png, single_digit0_bg.png; 
     dual1_digit0_fg.png, dual1_digit0_bg.png; and 
     dual2_digit0_fg.png, dual2_digit0_bg.png: 
     . . . 
     when the value of the third digit is “6”, the corresponding three groups of image resources are named as follows: 
     single_digit6_fg.png, single_digit6_bg.png; 
     dual1_digit6_fg.png, dual1_digit6_bg.png; and 
     dual2_digit6_fg.png, dual2_digit6_bg.png. 
     Names of the foregoing image resources need to match and cannot be changed. When 0, 1, 2, . . . , and 9 are separately displayed at the location of the third digit, the foreground image and the background image corresponding to the value of the third digit are simultaneously displayed at the location of the third digit. 
     When the values of the locations of the foreground image and the background image are “4”, the target control is displayed at the location of the fourth digit. The value of the third digit on the 24-hour digital clock may be 0, 1, 2, . . . , or 9, and each value may correspond to three groups of image resources. For specific image resources, refer to names of image resources corresponding to each value of the second digit when the values of the locations of the foreground image and the background image are “2”. Details are not described herein again. 
     In the AOD layout, digits on the digital clock are in an image format and the colors of the digits cannot be changed. When other information in addition to the digital clock is displayed in the always-on-display interface, a color of the other information may be different from the color of the digit. In this embodiment of this application, the color of the other information may be set and changed. Generally, a default color may be set to white. When the color of the other information needs to be changed, a value of item fondcolor in the theme.xml file is changed. 
     In an example, a single-clock layout is used as an example. As shown in  FIG.  6   , a color of information such as a date (for example, a Gregorian calendar date or a lunar calendar date), various application icons, and a battery level (for example, information marked by a dashed-line box  602 ) displayed below the digital clock  601  may be set. In this way, the color of the information marked by the dashed-line box  602  may be changed, so that the color of the digital clock displayed in the always-on-display interface is consistent with the color of other information. This helps improve user experience. 
     In another example, a dual-clock layout is used as an example. As shown in  FIG.  7   , a color of information (for example, information marked by a dashed-line box  702 ) such as a location, an icon, and a date (for example, a Gregorian calendar date and a day in a week) displayed below the digital clock  701  may be set, and a color of information (for example, information marked by a dashed-line box  704 ) such as a location, an icon, and a date (for example, a Gregorian calendar date and a day in a week) displayed below the digital clock  703  may be set. In this way, the colors of the information marked by the dashed-line box  702  and the dashed-line box  704  may be changed, so that the color of the digital clock displayed in the always-on-display interface is consistent with the color of other information. This helps improve user experience. 
     In this embodiment of this application, the target control may be a pattern of a bird in the foregoing example, or may be a pattern of another object, including but not limited to a pattern of a flower, a pattern of the moon, a pattern of a fan, and the like, which are not listed one by one herein. 
     In the foregoing embodiments, an example in which the target control includes a pattern of one object (such as a bird) and the target control and one digit of the digital clock are superimposed for display is used for description. 
     In some other embodiments, the target control and a plurality of digits of the digital clock may be superimposed for display to form an interspersed visual effect. It should be understood that the target control may be a pattern of one object, or may include patterns of a plurality of objects. 
     The following describes another possible implementation of the time display method in this application by using an example in which the target control includes patterns of two objects and the target control and two digits are superimposed for display. The two objects are patterns of different goldfish. 
     As shown in  FIG.  9   , a target control includes a goldfish  01  in an image  901  and a goldfish  02  in an image  903 . An image  902  includes a digital clock. The image  901 , the image  902 , and the image  903  are superimposed, the goldfish  01  in the image  901  is used as a background layer of two digits (a first digit and a third digit) of the digital clock, and the goldfish  02  in the image  903  is used as a foreground layer of the two digits (the first digit and the third digit) of the digital clock. Then, a to-be-displayed image  904  is obtained. In the to-be-displayed image  904 , the goldfish  01  and the goldfish  02  form a target control, and an interspersed visual effect that the goldfish  01  is behind the first digit (whose value is 0) and the third digit (whose value is 0) (that is, used as a background) and the goldfish  02  is in front of the first digit (whose value is 0) and the third digit (whose value is 0) (that is, used as a background) can be formed. 
     In some other embodiments, the goldfish  01  in the image  901  and the goldfish  02  in the image  903  may alternatively be superimposed on only one digit on the digital clock to form an interspersed visual effect, or may be superimposed on three digits on the digital clock to form an interspersed visual effect, or may be superimposed on four digits on the digital clock to form an interspersed visual effect. For a specific implementation, refer to the example in  FIG.  9   . Details are not described herein again. 
     In the example shown in  FIG.  9   , for related content of the AOD layout, refer to the related content of the AOD layout in the foregoing embodiment. Details are not described herein again. 
     In this embodiment of this application, the to-be-displayed image displayed in the always-on-display interface may be always displayed at a same location on the display, or may be displayed at a changed location at a time interval. For example, the to-be-displayed image is displayed by moving a first quantity of pixels every preset duration. For example, the to-be-displayed image may be displayed by moving several pixels every 1 minute. Longer preset duration indicates a larger value of the first quantity. In this way, a display location at which the electronic device displays the to-be-displayed image in the always-on-display state changes at a time interval, so that pixels that emit light to display the to-be-displayed image on the display at a time interval vary. Compared with a case in which same pixels emit light when the electronic device displays the to-be-displayed image in the always-on-display state, a risk of pixel damage can be reduced, and a risk of screen burning of the electronic device can further be reduced. 
     In this embodiment, when the to-be-displayed image is displayed in the always-on-display state, the to-be-displayed image may be separately displayed in two non-overlapping areas at time intervals. In this way, when the to-be-displayed image is displayed in the two non-overlapping areas, pixels that emit light are completely different, so that a risk of screen burning of the display can be reduced. 
     With reference to the foregoing embodiments and the accompanying drawings, an embodiment of this application provides an always on display method. The method may be implemented on an electronic device having the hardware structure shown in  FIG.  1   . As shown in  FIG.  10   , the always on display method in this embodiment of this application may include the following steps. 
     Step  1001 : Obtain a first image, a second image, and a third image, where the first image includes a first part of a target control, the second image includes a second part of the target control, and the third image includes a digital clock. A layout of the digital clock may be a single-clock layout, or may be a dual-clock layout. 
     Using  FIG.  9    as an example, the first image may be an image  901 , the second image may be an image  903 , the third image may be an image  902 , and the target control is a bird pattern. 
     Step  1002 : Sequentially superimpose the first image, the third image, and the second image to generate a to-be-displayed image, where in the to-be-displayed image, the first part and the second part of the target control form the target control, and the target control overlaps at least one digit of the digital clock. 
     Using  FIG.  5    as an example, a to-be-displayed image shown as an image  904  is obtained after the image  901 , the image  903 , and the image  902  are superimposed. 
     Step  1003 : Display the to-be-displayed image when a display is in an always-on-display state. 
     Based on this method, the electronic device sequentially superimposes the first image including the first part of the target control, the third image including the digital clock, and the second image including the second part of the target control, to generate the to-be-displayed image. In the generated to-be-displayed image, the first part and the second part of the target control form the target control, and an interspersed visual effect that the first part of the target control is displayed behind the digit and the second part of the target control is displayed in front of the digit can be formed. Compared with a display effect that a digit and an entire target control form a simple front-to-back relationship, a richer display effect can be provided for a user in this solution when the electronic device displays the digital clock in the always-on-display state. 
     In a possible implementation, the digital clock includes digits used to represent hours and digits used to represent minutes, and the digits used to represent hours are in a different row from the digits used to represent minutes. In another implementation, the digits used to represent hours and the digits used to represent minutes that are included in the digital clock may alternatively be located in a same row. 
     The digits used to represent hours include a first digit in the tens place and a second digit in the ones place, and the target control included in the to-be-displayed image partially overlaps the first digit. The first digit is a digit that is in the tens place and that represents hours, and a possible value of the first digit is 0, 1, or 2. In a timing process of the digital clock, the first digit changes three times in a timing period of 24 hours, and a change frequency of the first digit is lower than that of the second digit, a third digit, and a fourth digit, so that power consumption can be reduced. 
     In a possible design, that the electronic device obtains a first image and a third image may be implemented by separately invoking the first image and the third image according to a file name of the first image and a file name of the third image. The file name of the first image includes a layout type of the digital clock, a value of the digit that overlaps the target control on the digital clock, and a location relationship between the first image and the digital clock. The file name of the third image includes the clock layout type of the digital clock, the value of the digit that overlaps the target control on the digital clock, and a location relationship between the third image and the digital clock. 
     For example, the layout type of the digital clock is a single-clock layout, the value of the digit that overlaps the target control on the digital clock is 0, the location relationship between the first image and the digital clock is that the first image is a background of the digital clock, and the location relationship between the first image and the digital clock is that the first image is a foreground of the digital clock. In this example, the file name of the first image is single_digit0_bg.png, and the file name of the second image is single_digit0_fg.png. [01%] In a possible design, a size of the first part of the target control is less than a size of the first image, and a size of the second part of the target control is less than a size of the second image. In this design, the target control does not cover the entire superimposed image, that is, there is a transparent and hollow area on the to-be-displayed image. In this way, when the to-be-displayed image is displayed in the always-on-display state, only pixels in an area in which the target control is located need to emit light, so that screen burning can be prevented. 
     In a possible design, each digit included in the digital clock corresponds to three groups of image resources, the three groups of image resources include one group of image resources corresponding to the single-clock layout and two groups of image resources respectively corresponding to two clocks in the dual-clock layout, and each group of image resources includes the first image used as a background layer and the second image used as a foreground layer. 
     In a possible design, image formats of the first image, the second image, and the third image are all a portable network graphics png format. In the to-be-displayed image generated by superimposing the first image, the second image, and the third image, all areas other than the digit and the target control on the digital clock are transparent and hollow. 
     In a possible design, the target control may be one pattern, including but not limited to a bird pattern, a fish pattern, a fan pattern, or the like. Alternatively, the target control may include at least two patterns. For example, the target control contains two fishes. One fish is used as the first part of the target control and is superimposed with the first digit on the digital clock, to become the background of the first digit. The other fish is used as the second part of the target control and is superimposed with the first digit, to become the foreground of the first digit. In this way, the generated to-be-displayed image includes the target control containing two fishes. 
     In a possible design, first information may further be displayed when the display is in the always-on-display state, and a color of the first information may be set to be consistent with a color of the digit of the digital clock. For example, the first information may include but is not limited to information such as a location, an icon, a date, and a push message, for example, information marked by a dashed-line box  602  in  FIG.  6   , or information marked by a dashed-line box  702  and a dashed-line box  704  in  FIG.  7   . The color of the first information is set to be consistent with the color of the digit of the digital clock. This helps improve user experience. 
     In a possible design, the method may further include: The electronic device detects a tap operation on the target control, and plays a time of the digital clock in response to the tap operation. 
     In the foregoing embodiments provided in this application, the method provided in embodiments of this application is described from a perspective of an electronic device serving as an execution body. To implement functions in the method provided in embodiments of this application, the electronic device may include a hardware structure and/or a software module, and implement the functions in a form of the hardware structure, the software module, or a combination of the hardware structure and the software module. Whether a function in the foregoing functions is performed by using the hardware structure, the software module, or the combination of the hardware structure and the software module depends on particular applications and design constraints of the technical solutions. 
     When hardware is used for implementation, for hardware implementation of the electronic device, refer to  FIG.  11    and related descriptions thereof. 
     As shown in  FIG.  11   , an electronic device  100  includes a touchscreen  1101 , where the touchscreen  1101  includes a touch panel  1107  and a display  1108 ; one or more processors  1102 ; a memory  1103 ; one or more application programs (not shown); one or more computer programs  1104 ; and a sensor  1105 . The foregoing components may be connected by using one or more communications buses  1106 . The one or more computer programs  1104  are stored in the memory  1103  and are configured to be executed by the one or more processors  1102 . The one or more computer programs  1104  include instructions, and the instructions may be used to perform the method in any one of the foregoing embodiments. 
     An embodiment of this application further provides a computer storage medium. The computer storage medium stores computer instructions. When the computer instructions are run on an electronic device, the electronic device is enabled to perform the related method steps, to implement the time display method in the foregoing embodiments. 
     An embodiment of this application further provides a computer program product. When the computer program product is run on a computer, the computer is enabled to perform the foregoing related steps, to implement the time display method in the foregoing embodiments. 
     In addition, an embodiment of this application further provides an apparatus. The apparatus may be specifically a chip, a component, or a module. The apparatus may include a processor and a memory that are connected to each other. The memory is configured to store computer executable instructions. When the apparatus runs, the processor may execute the computer executable instructions stored in the memory, to enable the chip to perform the translation method in the foregoing method embodiments. 
     The electronic device, the computer storage medium, the computer program product, or the chip provided in embodiments of this application may be all configured to perform the corresponding method provided above. Therefore, for beneficial effects that can be achieved, refer to the beneficial effects of the corresponding method provided above. Details are not described herein again. 
     The foregoing descriptions about implementations allow a person skilled in the art to understand that, for the purpose of convenient and brief description, division into the foregoing function modules is taken as an example for illustration. During actual application, the foregoing functions can be allocated to different modules and implemented according to a requirement, that is, an inner structure of an apparatus is divided into different function modules to implement all or some of the functions described above. 
     In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the described apparatus embodiment is merely an example. For example, division into the modules or the units is merely logical function division and may be other division in actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electrical, mechanical, or other forms. 
     The units described as separate parts may or may not be physically separate, and parts displayed as units may be one or more physical units, may be located in one place, or may be distributed on different places. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of embodiments. 
     In addition, function units in embodiments of this application may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units may be integrated into one unit. The integrated unit may be implemented in a form of hardware, or may be implemented in a form of a software functional unit. 
     When the integrated unit is implemented in a form of a software functional unit and sold or used as an independent product, the integrated unit may be stored in a readable storage medium. Based on such an understanding, the technical solutions of embodiments of this application essentially, or the part contributing to the conventional technology, or all or some of the technical solutions may be implemented in the form of a software product. The software product is stored in a storage medium and includes several instructions for instructing a device (which may be a single-chip microcomputer, a chip, or the like) or a processor (processor) to perform all or some of the steps of the methods described in embodiments of this application. The foregoing storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (read-only memory, ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disc. 
     The foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art in the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.