Patent Publication Number: US-RE48596-E

Title: Interface engine providing a continuous user interface

Description:
CLAIM OF PRIORITY 
     More than one reissue application has been filed for the reissue of U.S. Pat. No. 7,954,066. This application is an application for reissue of U.S. Patent No. 7,954,066, entitled “Interface Engine Providing a Continuous User Interface,” issued May 31, 2011, and is a continuation of U.S. patent application Ser. No. 13/907,321, entitled “Interface Engine Providing a Continuous User Interface,” filed May 31, 2013, which is an application for reissue of U.S. Pat. No. 7,954,066, entitled “Interface Engine Providing a Continuous User Interface,” issued May 31, 2011, which was a continuation application of U.S. patent application Ser. No. 10/092,360, entitled “Interface Engine Providing a Continuous User Interface,” filed Mar. 5, 2002 now U.S. Pat. No. 6,957,392, incorporated herein by reference, which claims the benefit of U.S. Provisional Application No. 60/349,671, entitled “Interactive System,” filed Jan. 16, 2002, incorporated herein by reference. 
    
    
     CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application is related to U.S. patent application titled “Presentation Server,” by Eric D. Bloch, Max David Carlson, Christopher Kimm, J. Bret Simister, Oliver W. teele, David T. Temkin and Adam G. Wolff, filed on the same day as the present application and incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to interfaces for computer systems. 
     2. Description of the Related Art 
     Graphical user interfaces have become heavily integrated in many aspects of people&#39;s lives. People constantly interact with these interfaces in their every day business and pleasure activities. Example interfaces include computer operating systems and applications, Internet sites, personal digital assistants, and cellular telephones. 
     Graphical interfaces should provide users with a continuous interactive experience, much like people experience in their everyday interactions with other people and physical objects. People experience a physical object&#39;s characteristics smoothly transitioning from one state to the next through a continuum of intermediate states. When a spring is compressed, a person sees the fluid transitions the spring makes from the decompressed state to the compressed state. People&#39;s physical world experiences also lead them to expect that changes in one object can interrupt and alter the state of another object. This is seen when a baseball bat breaks while striking a ball—causing the ball to change its position and the bat to alter it&#39;s form and position through a fluid continuum of adjustments. 
     Traditional user interfaces, however, provide users with discrete displays that transition from one predefined state to another—failing to show any display states between the beginning state and end state. If a user calls for the size of a displayed icon to be expanded, traditional interfaces only display the fully expanded icon without showing a gradual progression of the icon&#39;s dimension changes. Additionally, the icon&#39;s instantaneous transition cannot respond to a user&#39;s efforts to interrupt or reverse the operation. This is not how people interact with their surroundings. Imagine if the above-mention spring transitioned from decompressed to fully compressed without having any intermediate states. 
     A user&#39;s interface to an Internet site through a network browser is one of the least continuous interfaces. Traditional browsers receive network content in descriptive HTML pages. Browsers alter HTML page displays by making network requests for updated HTML pages. This results in significant periods of time elapsing between display updates—prohibiting Internet sites from delivering display updates in a continuous fashion. 
     The ability to deliver a continuous user interface is seriously hampered by the lack of suitable interface development tools. Traditional development tools only allow developers to employ predefined displays that sharply transition between discrete states. The predefined displays are based on prewritten scripts for each display that developers cannot control. Individual pre-coded components of a system may exhibit some continuous behavior, but this is limited to these components and not supported as a framework for the entire system. In some instances, a developer writes a custom script to provide a more continuous interface for a display, but the developer&#39;s efforts are limited solely to that one display—making the developer&#39;s scripting of a complete continuous interface with many displays too difficult and expensive to achieve. 
     SUMMARY OF THE INVENTION 
     The present invention, roughly described, provides for effectively implementing a continuous user interface. In one implementation, the interface provides a user with displays that transition fluidly, interact seamlessly with other on-screen displays, and respond in real time to user input interruptions. 
     In one example, the interface provides a window that alters its properties in response to another window&#39;s properties changing. The windows can each alter different properties, such as one window changing position in response to the other window expanding. The windows&#39;respective transitions occur in fluid motion that brings the transitions to life for the user. The interface allows a user to interact via mouse or keyboard to reverse either window transition in mid-stream. The interface projects the fluid transitions of the interrupted window in response to the user&#39;s input, so the user feels like he or she is interacting with a real world object. 
     Underlying the user interface is an interface engine with a modular architecture crafted to support continuous user interfaces. The interface engine is constructed from a framework of modular control elements that drive interface operation. Developers create an interface by selecting control elements and specifying the desired display operations, instead of scripting custom code to control each display operation. The selected control elements are responsible for generating display transitions that are fluid, interruptible, and adaptable based on the operation parameters a developer provides. 
     In one implementation, the framework of modular control elements includes views and attribute modifiers. Views are responsible for displaying visual interface graphics. Each view is capable of supporting child views and resources, such as graphical window displays and media content and more basic components such as buttons and graphical objects. In response to system events, such as user inputs, a view modifies itself using a set of attribute modifiers that are available to all of the views. 
     One set of attribute modifiers includes layouts, animators, and constraints. A layout manages the attributes of a view&#39;s child views, including child view position and size. An animator modifies a view&#39;s appearance over a specified period of time. A constraint imposes limits on a view attribute in response to a detected event, such as the modification of another view attribute. For example, one view may constrain itself to being centered within another view—making the display transitions of the views interrelated. 
     An example view provides a planning program interface with a main view that contains child views for a calendar and contacts list. A user clicks an on-screen button with a mouse to prompt changes in the planning program&#39;s interface. In response to the user input, the main view calls a layout to rearrange the positions of the calendar and contacts list. The main view, calendar, and contacts list each call respective animators and constraints to make specified appearance adjustments. The called layouts, animators, and constraints drive the interface platform to display the appearance and arrangement transitions as fluid continuums. 
     Developers can employ the above-described views and attribute modifiers to create an endless number of engines for driving continuous interfaces. In one instance, developers are provided with existing views, layouts, animators, and constraints to fit together when building an interface. In other instances, developers are also allowed to create custom views that call the provided layouts, animators, and constraints—enabling developers to build a highly customized interface without scripting individual display transitions. Additionally, a developer&#39;s custom views can work in concert with other views provided by a system or created by other developers. 
     A developer&#39;s interface engine description is compiled into an operating interface engine and delivered to a rendering platform, such as a computer system. In one implementation, an Internet site delivers an interface engine to a browser plug-in instead of providing only descriptive HTML pages—enabling the browser&#39;s users to access network resources in a continuous interface environment. 
     Internet site designers and desktop application designers are only two examples of developers that benefit from the ability to construct modular interface engines. The benefits of easily providing continuous user interfaces is not limited to the Internet and desktop applications identified above. The modular interface engine architecture has applicability to any user interface environment. For example, video game systems and simulation systems could be greatly enhanced in further embodiments of the present invention. 
     The present invention can be accomplished using hardware, software, or a combination of both hardware and software. The software used for the present invention is stored on one or more processor readable storage media including hard disk drives, CD-ROMs, DVDs, optical disks, floppy disks, tape drives, RAM, ROM or other suitable storage devices. In alternative embodiments, some or all of the software can be replaced by dedicated hardware including custom integrated circuits, gate arrays, FPGAs, PLDs, and special purpose computers. 
     These and other objects and advantages of the present invention will appear more clearly from the following description in which the preferred embodiment of the invention has been set forth in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a block diagram of a system providing a continuous user interface in accordance with the present invention. 
         FIGS. 2A and 2B  show a rendering area with an interface driven by an interface engine in accordance with the present invention. 
         FIG. 3  shows a set of interface engine building blocks employed by a developer to implement an interface engine for providing a continuous user interface. 
         FIG. 4A  shows an interface engine view structure for the interface displayed in the rendering area in  FIGS. 2A and 2B . 
         FIG. 4B  depicts a block diagram for one embodiment of an interface engine view. 
         FIG. 5  illustrates one version of a sequence of operations carried out by an interface engine to change view attributes. 
         FIGS. 6A-6C  show an exemplar animation of resources in a rendering area. 
         FIG. 7  shows one version of a sequence of operations carried out by an interface engine to call an animator. 
         FIG. 8  depicts one version of a sequence of operations carried out by an interface engine to call a layout. 
         FIG. 9  illustrates one version of a sequence of operations carried out by an interface engine layout. 
         FIGS. 10A and 10B  show one version a sequence of operations carried out by an interface engine animator. 
         FIG. 11  depicts a block diagram for one implementation of a system for generating and executing an interface engine. 
         FIG. 12  shows a block diagram for one embodiment of a network-based system for generating and executing an interface engine. 
         FIG. 13  shows one implementation of components for a presentation server. 
         FIG. 14  illustrates one version of a sequence of operations performed to provide a resource environment with an interface engine. 
         FIG. 15  shows a block diagram for one embodiment of components in a computing system that can be used to implement the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a system  10  for providing a continuous user interface in accordance with the present invention. Rendering environment  12  renders resources in system  10  and delivers the rendered resources to rendering area  14  for display—providing an interface for users of system  10 . Interface engine  16  directs the rendering of resources by rendering environment  12 . Resources are graphical elements, including vector graphics, bitmaps, and streaming media. One example of rendering environment  12  is the Flash Player from Macromedia. Those skilled in the art recognize that alternate embodiments of system  10  employ other rendering environments. 
     As will be explained below, interface engine  10  has a novel modular architecture that enables system  10  to deliver a continuous interface that responds to user inputs in real time. In one embodiment, system  10  shows users the continuous animation of resources in rendering area  14 , instead of showing only discrete snap shots of different resource displays. For example, a user sees the opening of a window unfold over time, instead of immediately seeing a fully opened window. 
     The power of a continuous user interface is also illustrated by a user&#39;s ability to interrupt and change the course of resource animations, with the result being a smooth transition in the resource display. For example, while a resource display is being animated to expand in rendering area  14 , a user command can interrupt the expansion to begin an alternate animation, such as a constriction. System  10  shows the user the continuous cumulative affect of the expansion animation and constriction animation—differing significantly from traditional interfaces that would only show a discrete snapshot of the expanded resource and a discrete snapshot of the constricted resource. 
     In one implementation, a unique set of building blocks provides a framework for developers to utilize in creating interface engine  16 . As will be explained in greater detail below, this framework allows developers to employ objects that drive the smooth transition of resource states—eliminating the need for developers to write separate customized scripts for displaying each resource. The framework&#39;s building blocks can be utilized for displaying many different resources—allowing developers to create continuous display transitions by merely specifying beginning display conditions, desired ending display conditions, and the transition duration. The building blocks offload the user from constructing low level scripts to carry out resource animation and layouts. 
       FIG. 2A  depicts an example interface displayed on rendering area  14 . Resource  30  is a canvas providing a graphical backdrop for Media resource  32  and Planner resource  48 , which provide graphical backdrops for their respective child resources. Rendering area  14  displays Calendar resource  50 , Lists resource  52 , Contacts resource  54 , and Notes resource  56  within Planner resource  48 . Calendar resource  50  displays a calendar for a selected month. Lists resource  52  shows a list of action items. Contacts resource  54  displays a listing of contact information for different individuals and entities. Notes resource  56  displays a user&#39;s personal notes. 
     Rendering area  14  displays Music resource  34  and Video resource  36  inside Media resource  32 . Music resource  34  displays a set of graphics (not shown) related to selecting and playing music. Within Video resource  36 , rendering area  14  displays resources for Viewing Screen  38 , Slider  42 , and Button  40 . Viewing Screen resource  38  displays a selected video clip. Button resource  40  displays a button used to start and stop the video clip in Viewing Screen resource  38 . Slider resource  42  displays a volume level indicator for the video clip in Viewing Screen resource  38 . Inside Slider  42 , rendering area  14  displays Slide Button resource  44 , which allows a user to set the video clip&#39;s volume. 
       FIG. 3  shows one implementation of a building block framework developers can use to create a continuous interface engine that drives the interface shown in  FIG. 2A . Building block set  70  includes view set  71  and attribute modifier set  72 .  FIG. 3  provides an overview of the relationship between views and attribute modifiers. More details regarding views and attribute modifiers are provided below with reference to later numbered figures. 
     Each view in view set  71  identifies one or more resources for displaying in a rendering area, such as the resources shown in  FIG. 2A . Each view has a set of attributes, including a resource identifier, that define the view&#39;s operation. For example, attributes dictate the view&#39;s appearance, the conditions for altering the view&#39;s appearance, and the mechanism for altering the view&#39;s appearance. As a view&#39;s appearance changes, so does the display of its identified resource in rendering area  14 . Another set of view attributes identifies child views that are associated with the view. For example, Media resource  32  and Planner resource  48  in  FIG. 2A  are driven by child views of the view driving Canvas resource  30 . 
     A view calls attribute modifiers in set  72  to alter view attributes in response to events, such as a user input or an attribute change in the view or another view. For example, if a user issues a command to expand the display of a view&#39;s resource, the view calls an attribute modifier in set  72  to change appearance related attributes in the view. In another example, a view in rendering area  14  is expanded and this expansion signals a second view to shrink. The second view calls an attribute modifier to carry out the shrinking transition. In further embodiments, developers can design their own views for inclusion in view set  71 . 
     In one embodiment, attribute modifier set  72  includes three types of attribute modifiers—layouts  73 , animators  74 , and constraints  75 . Layout set  73  includes multiple layouts that can each be called by any of the views in set  71  to alter the view&#39;s child views. Animator set  74  includes multiple animators that can be called by any view in set  71  to animate the view&#39;s appearance. Constraint set  75  includes multiple constraints that can each be called by any of the views in set  71  to modify a view attribute in response to the state of another attribute changing. In a further embodiment, a view can call an attribute modifier to modify an attribute in another view. In one implementation, developers can design their own attribute modifiers for inclusion in set  72 . 
     Framework  70  significantly benefits interface engine developers by eliminating the need for them to write scripts to perform attribute modification. Developers can employ the building blocks in framework  70  to define the operation of views at a high level—identifying the desired attribute modifiers, the magnitude of modification desired, and the modification time period. The views, in conjunction with the attribute modifiers, are fully responsible for implementing the specified modifications. 
       FIG. 4A  shows a view structure in one embodiment of interface engine  16  for generating the interface shown on rendering area  14  in  FIG. 2A . Interface engine  16  is formed by a set of interrelated views that direct the operation of rendering environment  12 . Each view identifies one or more resources for display in rendering area  14 . Some views also identify one or more child views for display within rendering area  14 . 
     Canvas view  80  identifies bitmap resource  30 , which provides a background display for the interface shown in rendering area  14 . Canvas view  80  also identifies two child views—Media view  82  and Planner view  84 . Media view  82  and Planner view  84  identify Media resource  32  and Planner resource  48 , respectively. Media view  82  identifies two child views, Music view  86  and Video view  88 , that identify Music resource  34  and Video resource  36 , respectively. 
     Video view  88  identifies 3 child views, Screen view  98 , Button view  100 , and Slider view  102 . These child views identify Viewing Screen resource  38 , Button resource  40 , and Slider resource  42 , respectively. Slider view  102  identifies child Slide Button view  103 , which identifies Slide Button resource  44 . Planner view  84  identifies four child views, Notes view  90 , Lists view  92 , Contacts view  94 , and Calendar view  96 —identifying Notes resource  56 , Lists resource  52 , Contacts resource  54 , and Calendar resource  50 , respectively. 
       FIG. 4A  only shows one example of an interface engine view structure. Those skilled in the art recognize that interface engine  16  can employ many different views to create different interfaces. 
       FIG. 4B  shows one embodiment of view  120  within interface engine  16 , such as the views shown in  FIG. 3 . View  120  has a set of attributes, including child view set  122 , property set  124 , function set  126 , and resource set  128 . Property set  124  specifies properties that define the appearance of view  120 . In one implementation, property set  124  includes properties for the view&#39;s rendering area position, height, width, rotation, and transparency. 
     In one embodiment, resource set  128  contains a single resource. In one implementation, view  120  provides a pointer to resource  128 . In an alternate implementation, view  120  contains resource  128 . In further embodiments, view  120  identifies multiple resources. 
     Child view set  122  identifies child views that are associated with view  120 . In one implementation, view  120  names a set of child views that are to be displayed within view  120  in rendering area  14 . In an alternate embodiment, the child views in set  122  do not need to be displayed entirely within view  120 . The child views are allowed to extend outside view  120  without being clipped by view  120 . Although view  120  is shown as identifying child views  122 , a view is not required to identify child views. 
     Function set  126  contains functions that respond to events occurring within system  10 , such as user inputs. Function set  126  includes a variety of functions for modifying view  120  and child views  122 . Functions directly alter view attributes or call attribute modifiers within interface engine  16  to make attribute modifications. As explained above, the attribute modifiers reside outside of view  120 , so other views in the interface engine can utilize the same attribute modifiers. This modular architecture facilitates interface engine  16  providing a continuous user interface. Greater details regarding this feature are explained below. 
     The attribute modifiers in interface engine  16  include layouts, animators, and constraints, as explained above with reference to  FIG. 3 . A layout modifies one or more attributes of a view&#39;s child views. In one embodiment, the child views are associated with the view calling the layout. In alternate embodiments, the child views are associated with a different view. In one example, a layout vertically aligns a view&#39;s child views. An animator animates a view property. In one implementation, interface engine  16  has animators for modifying view position, height, width, rotation, and transparency over a specified period of time. A constraint is called to modify an attribute of one view in response to the value of another attribute. In some instances, the attribute triggering the constraint is associated with a different view than the attribute being modified. An example constraint sets the position property of one child view with respect to the position of another child view. In one embodiment, the attribute modifiers of interface engine  16  employ floating point calculation to enhance graphical display quality.  FIG. 4B  and the above description only illustrate examples of the layouts, animators and constraints that can be included in embodiments of interface system  16 . Those skilled in the art will recognize that many more are possible. 
     View  120  calls animators  146 ,  148 , and  150  to modify properties in property set  124 . View  120  calls layout  130  to modify the attributes of child views  122 . View  120  calls constraints  140 ,  142 , and  144  to set values for properties in property set  124  in response to changes in attributes in interface engine  16 . 
     In one implementation of interface engine  16 , layouts call animators.  FIG. 4B  shows layout  130  calling animators  132  and  134 . In one example, a layout calls a set of animators to animate a layout change over a period of time. In another example, a layout calls a set of animators to determine property changes for a set of child views between an initial orientation and a final orientation. For instance, animators are useful for determining child view positions in non-linear layouts. 
     In a further implementation of interface engine  16 , an animator calls other animators to modify view properties. This is illustrated in  FIG. 4B , by animator  150  calling animators  152  and  154  and animator  134  calling animators  136  and  138 . An example of an animator calling other animators arises when a view calls an animator to change the view&#39;s position in multiple dimensions. In this example, the primary animator calls one animator to make vertical position changes and another animator to make horizontal position changes. The primary animator provides the combined vertical and horizontal position changes to the view. 
     Interface engine  16  employs the view architecture shown in  FIG. 4B  to modify the interface shown in  FIG. 2A  to have the appearance shown in  FIG. 2B . Interface engine  16  directs rendering environment  12  to move Slide Button resource  44 , shrink and move Calendar resource  50 , and expand and move Contacts resource  54 . 
     Slide Button view  103  calls an animator (not shown) to move the position of Slide Button view  103  to the right. Calendar view  96  calls a set of animators (not shown) to shrink its height. Contacts view  94  calls a set of animators (not shown) to increase its height. Planner view  84  calls a layout (not shown) to rearrange the position of Calendar view  96  and Contacts view  94 . 
     The actions taken by the above-referenced views to change the interface display on rendering area  14  are initiated by functions in the referenced views. For example, Slide Button view  103  has a function that responds to a user clicking on Slide Button resource  44  and moving it. Similarly, Planner view  84 , Contacts view  94 , and Calendar view  96  have functions that respond to a user calling for: (1) Calendar resource  50  to be shrunk, (2) Contacts resource  54  to be expanded, and (3) the positions of Contracts resource  54  and Calendar resource  50  to be exchanged. Greater details about the internal operations of views, layouts, and animators are provided below. 
       FIG. 5  shows a sequence of operations carried out by one embodiment of interface engine  16  for changing the attributes of view  120 . View  120  initially executes functions to set view attributes (step  200 ). Example attribute settings include determining and setting view properties  124 , adding child views  122 , deleting child views  122 , duplicating child views  122 , attaching resource  128 , unloading resource  128 , setting constraints on view properties, and releasing constraints on view properties. 
     In one embodiment, the following property setting functions are available in view  120 : (1) setProp—setting a desired value for a property; (2) getProp—identifying a current value for a property; (3) setPropRelative—setting a value for a property relative to a reference view; (4) getPropRelative—identifying a value for a property relative to a reference view; (5) setVisible—setting a view to be visible or hidden; (6) getMouse—identifying a position of a mouse cursor; (7) bringToFront—setting a child view to be the front most view within a set of child views; (8) setScale—setting a scale for a view&#39;s height or width; and (9) addToProp—adding a value to a property. 
     In setting a property constraint, view  120  identifies the constraint, a property to constrain, and an offset for the constraint to apply. In one embodiment, the offset limits a view&#39;s property relative to another view. For example, view  120  limits a child button view&#39;s position to be within a specified distance from the right edge of its parent view. In alternate embodiments, view  120  provides different parameters to the constraint. For example, view  120  may provide a parameter specifying the view to be constrained, if view  120  is not the constrained view. 
     After setting the attributes, view  120  responds to events (step  212 ). An event is an occurrence that causes view  120  to change an attribute value. One example of an event is a user input, such as clicking and moving a mouse. Another example is the changing value of an object&#39;s attribute in interface engine  16 , such as an attribute change in a view. View  120  determines which layout, animator, or constraint to call in response to the event. In some instances, the view calls a combination of layouts, animators, and constraints. In one embodiment, view  120  calls an animator in response to a user input and calls a layout and/or constraint in response to an attribute value change. 
     The operation of view  120  is event driven. If no event occurs, view  120  maintains its current state (step  212 ). If an event is detected, view  120  calls the appropriate layout (step  202 ), constraint (step  212 ), animator (step  206 ), or a combination thereof. A called layout lays out child views  122  (step  204 ). Called animators animate view  120  (step  208 ). A called constraint sets a value for an attribute, such as a property. As part of the layout, animation, and constraint steps (steps  204 ,  208 , and  211 ), view  120  receives new values for the view&#39;s attributes from the called layout, animators, and/or constraints. In one example, view  120  uses these attribute values to update the corresponding properties of the view&#39;s resource. 
     When view  120  calls a constraint (step  210 ), a function calls the constraint and identifies the property being constrained and an acceptable constraint offset, as described above for setting a constraint. When new attributes are not within a tolerable range, the constraint resets the attributes to acceptable values. Greater details regarding layouts and animators are provided below. 
     Although  FIG. 5  shows step  212  being repeated after layout call step  202 , animate call step  206 , and constraint call step  210 , the event determination (step  212 ) is not delayed until all animation, constraint, and layout is complete. Layouts, animations, and constraints can occur over a specified period of time. During this time, view  120  still recognizes and responds to view changing events, which are detected in step  212 . 
       FIGS. 6A-6C  show a view change that can be performed by interface engine  16  in accordance with the present invention. This change exemplifies the fluid transitions provided by interface engine  16 .  FIG. 6A  shows view  230  with child views  232 ,  234 ,  236 , and  238 . An event calls for view  230  to be constricted with a horizontal child view arrangement, as shown in  FIG. 6C . View  230  calls an animator to adjust its height and a layout to change the arrangement of child views  232 ,  234 ,  236 , and  238 . Interface engine  16  is able to continuously enhance view  230  by displaying many intermediate versions of view  230 , such as the intermediate version shown in  FIG. 6B . This enables interface engine  16  to make smooth transitions between view states. 
     As will be explained below, view  230  can set the period of time for an animator or layout to carry out changes in attribute values. This allows interface  16  to display many small changes to the height of view  230 . This also allows small changes in child view layouts to be displayed. The layout responsible for arranging child views  232 ,  234 ,  236 , and  238  calls animators to determine position changes for these child views over the same period of time that view height is animated. The called animators provide new position values for each child view along a path from the child view&#39;s position in  FIG. 6A  to the child view&#39;s position in  FIG. 6C . The continuous position changes are displayed in a rendering area to provide the user with a fluid view of the layout change from  FIG. 6A  to  FIG. 6C .  FIG. 6B  provides a snapshot of one such display. 
     Interface engine  16  obtains further enhancement from the independent operation of animators, as shown in  FIG. 5 .  FIG. 5  shows a view employing multiple animators simultaneously (steps  206  and  208 ). The view is able to call a new animator whenever an event calls for animation, regardless of whether previously called animators have completed their animation. The view accumulates the animation from the newly called animators and previously called animators—making the view&#39;s intermediate displays reflect real-time effects of user inputs. In alternate embodiments, a view can dictate that a later called layout or animator override a previous layout or animator or be queued behind the previously called layout or animator. 
       FIG. 7  shows one implementation of a sequence of operations performed by a view when calling an animator (step  206 ,  FIG. 5 ). The view identifies the animator (step  260 ) and provides the animator with parameters (step  262 ). In one embodiment, steps  260  and  262  are performed by a single function. In an alternate embodiment, steps  260  and  262  are performed separately. 
     In one implementation, the view provides parameters identifying the following: (1) prop—identifying a property to animate; (2) from—identifying the starting value for the property; (3) to—identifying the ending value for the property; (4) duration—identifying the duration of the property&#39;s animation; and (5) isRelative—indicating whether the called animator is applied to the property relatively. In alternate embodiments, an animator does not require all of these parameters or may include additional parameters. For example, one animator does not require the “from” parameter. As another example, a parameter specifies whether to accumulate the values from the called animator with other animators. 
     When an animator calls other animators in one embodiment, the view is required to provide parameters for the primary animator and the animators it calls. In alternate embodiments, this is not required. 
       FIG. 8  shows one version of a sequence of operations performed by a view when calling a layout (step  202 ,  FIG. 5 ). The view identifies the layout (step  270 ) and provides the layout with parameters (step  272 ). In one embodiment, steps  270  and  272  are performed by a single function. In an alternate embodiment, steps  270  and  272  are performed separately. 
     One example of a layout parameter includes an indicator of the child views to be effected by the layout. This can be achieved by listing the views to be laid out or the views to be ignored by the layout. Another example parameter is a layout duration time period—identifying the time a layout is to use in performing its adjustment of child view attributes. In alternate implementations, no parameters need to be supplied—eliminating the need for step  272 . 
     The process for calling a constraint (step  210 ,  FIG. 5 ) is essentially the same as shown in  FIGS. 7 and 8  for calling animators and layouts. The difference is that the view employs the previously described constraint parameters. 
       FIG. 9  shows a sequence of operation performed by a layout in one implementation of interface engine  16  to layout one or more child views (step  204 ,  FIG. 5 ). The layout selects a child view (step  300 ) and changes the child view&#39;s attributes in accordance with the layout (step  302 ). For example, the layout may change the properties of the child view to modify its size and position. In some embodiments, the layout also calls one or more animators (step  306 ), as described above. The called animators animate the child view (step  308 ). In one embodiment, the animators provide new property values that the layout substitutes into the child view&#39;s property set. 
     After processing the child view, the layout determines whether any child views remain to be processed (step  312 ). If not, the layout is complete. Otherwise, the layout selects a new child view and repeats the above-described process shown in  FIG. 9 . As described above, multiple layouts can be in progress at the same time and layouts can make sets of continuous changes to child view attributes over a specified duration. The flow charts in  FIGS. 5 and 9  show linear processes for the convenience of illustration. In operation, however, multiple layout operations can be in progress, with the process steps described in  FIGS. 5 and 9  being performed. 
       FIG. 10A  illustrates a sequence of operations performed by an animator in one embodiment of interface engine  16  to animate a view (step  208 ,  FIG. 5  and step  308 ,  FIG. 9 ). The called animator receives a set of animation parameters, as described above (step  320 ). The selected animator then performs an animation operation (step  322 )—calculating a new property value and returning the new value. The view, layout, or animator that called the animator receives the new value. In the case of a view, in one embodiment, the new property value is added to or written over a present property value. 
     In one example, a view calls an animator to increase the view&#39;s height. The animator calculates an increment of the height increase and passes it back to the view, which incorporates the new value into the view&#39;s property set. The size of the increment is based on the animation duration appearing in the animation parameters and an animation interval of interface engine  16 .  FIG. 10B  illustrates the effect of the animation interval, by showing the steps for performing animation (step  322 ) in one embodiment. The animator waits for a signal in interface engine  16  that an animation interval has expired (step  325 )—indicating that the animator should provide the next property value. When the animator interval signal is detected, the animator generates the next property value (step  327 ) and forwards the value to the property&#39;s view (step  329 ). 
     The called animator determines whether more animation operations are required for the view (step  323 ,  FIG. 10A ). In one embodiment, the animator makes this determination by determining whether the end property value specified in the animation parameters has been reached. If the end value has not been reached, the above-described animation process from  FIG. 10A  is repeated. Otherwise, the animation is complete. 
     In one embodiment, a view receives values from many animators during the same time period. In one instance, the view receives values from multiple animators for the same property during overlapping time periods. As discussed above for the layout process, multiple sets of continuous property value changes can be received by a view and reflected in a display, during overlapping animation durations. This capability enables a continuous interface to fluidly adapt to interruptions in a current display transition. A user can introduce an event that causes a new animation to begin, even though a prior animation is not complete. Both animators co-exist—giving the rendering area display a fluid transition, instead of showing the user discrete screen snapshots. The ability of interface engine  16  to handle multiple layouts and constraints in parallel further enhances this benefit. 
       FIG. 11  shows one implementation of a system  330  for generating and executing interface engine  16 . In system  330 , presentation server  334  creates interface engine  16  by compiling an interface engine description (not shown) and specified data and media  332 . Presentation server  334  then delivers the interface engine to client rendering platform  336 , which includes a rendering environment and rendering area. 
       FIG. 12  presents one embodiment of a network-based system  350  for generating and executing interface engine  16 . Application server  351  supports presentation server  354  and database management system  352 . In one embodiment, application server  351  hosts an Internet site that delivers content in the form of an interface engine in accordance with the present invention. Presentation server  354  is similar to presentation server  334 , except presentation server  354  retrieves data and media from database  356  through database management system  352 . 
     Presentation server  354  generates and delivers an interface engine in accordance with the present invention in response to a request from HTTP client  362 . In one embodiment, HTTP client  362  and application server  351  communicate over network  360  through web server  358 . Once the interface engine reaches HTTP client  362  it operates within plug-in  364 . In one implementation, plug-in  354  provides a rendering environment, such as a Macromedia Flash Player environment. 
       FIG. 13  shows components in one implementation of a presentation server. Presentation server  390  includes interface engine description  392 , which describes an interface engine in accordance with the present invention. Those skilled in the art will recognize that description  392  can be written in many different programming languages, including XML and other proprietary languages. Description  392  also specifies data and media  394  to be employed by the interface engine as resources. 
     Media transcoder  398  converts the specified data and media  394  into a format that can be incorporated into the interface engine. Interface compiler  396  combines the output of media transcoder  398  and description  392  and compiles them to generate interface engine  402 . Presentation server  390  delivers interface engine  402  to rendering platform  404 . 
     In one embodiment, interface compiler  396  generates interface engine  402  in the form of a .swf file for operation in a Marcomedia Flash Player rendering environment in platform  404 . Those skilled in the art will recognize that many other rendering environments and file formats are suitable for embodiments of the present invention. Those skilled in the art also recognize that methods of compiling files into .swf formats for operation in a Flash Player are well known. 
       FIG. 14  shows a sequence of operations performed by a presentation server  390  to provide an interface engine. Presentation server  390  receives a request for content from a rendering platform, such as HTTP client  362 . In response to the request, presentation server  390  access interface engine description  392  (step  432 ). Presentation server  390  also accesses data and media  394  specified by description  392  and/or the rendering platform request (step  436 ). 
     Presentation server  390  compiles the description  392  and data and media  394  to create executable code for interface engine  402  (step  438 ). Presentation server  390  then transmits the executable code for interface engine  402  to a client rendering environment in rendering platform  404  (step  440 ). In one embodiment, this rendering environment is plug-in  364  in HTTP client  362  in  FIG. 12 . The rendering environment then executes the code for interface engine  402  (step  442 ). 
     Greater details regarding application servers, presentation servers, and their operation appear in U.S. patent application Ser. No. 10/092,010, entitled, “Presentation Server,” and filed on the same day as the present application. This application is incorporated herein by reference. 
       FIG. 15  illustrates a high level block diagram of general purpose computer system  500 . System  500  may be employed in embodiments of the present invention to provide the functionality of a rendering environment and area, an interface engine, a presentation server, and an application server. Accordingly, computer system  500  may be employed for performing a number of processes, including those described above with reference to  FIGS. 1-14 . 
     Computer system  500  contains processing unit  505 , main memory  510 , and interconnect bus  525 . Processing unit  505  may contain a single microprocessor or a plurality of microprocessors for configuring computer system  500  as a multiprocessor system. Processing unit  505  is employed in conjunction with a memory or other data storage medium containing application specific program code instructions to implement the functionality of a rendering environment and area, an interface engine, a presentation server, an application server, a view, or an attribute modifier. 
     Main memory  510  stores, in part, instructions and data for execution by processing unit  505 . If a process, such as the processes described with reference to  FIGS. 1-14 , is wholly or partially implemented in software, main memory  510  can store the executable instructions for implementing the process when the computer is in operation. For example, main memory  510  can store program code instructions employed by a rendering environment and area, an interface engine, a presentation server, an application server, a view, and an attribute modifier. In one implementation, main memory  510  includes banks of dynamic random access memory (DRAM) as well as high speed cache memory. 
     In one implementation, computer system  500  further includes mass storage device  520 , peripheral device(s)  530 , portable storage medium drive(s)  540 , input control device(s)  570 , graphics subsystem  550 , and output display  560 . In alternate implementations, computer system  500  does not include all of the devices shown in  FIG. 15 . 
     For purposes of simplicity, all components in computer system  500  are shown in  FIG. 15  as being connected via bus  525 . However, computer system  500  may be connected through one or more data transport means in alternate implementations. For example, processing unit  505  and main memory  510  may be connected via a local microprocessor bus, and mass storage device  520 , peripheral device(s)  530 , portable storage medium drive(s)  540 , and graphics sub-system  550  may be connected via one or more input/output busses. 
     Mass storage device  520  is a non-volatile storage device for storing data and instructions for use by processing unit  505 . Mass storage device  520  can be implemented in a variety of ways, including a magnetic disk drive or an optical disk drive. In software embodiments of the present invention, mass storage device  520  stores the instructions executed by computer system  500  to perform processes such as those described with reference to  FIGS. 1-14 . 
     Portable storage medium drive  540  operates in conjunction with a portable non-volatile storage medium to input and output data and code to and from computer system  500 . Examples of such storage mediums include floppy disks, compact disc read only memories (CD-ROM), memory sticks, and integrated circuit non-volatile memory adapters (i.e. PC-MCIA adapter). In one embodiment, the instructions for enabling computer system  500  to execute processes, such as those described with reference to  FIGS. 1-14 , are stored on such a portable medium, and are input to computer system  500  via portable storage medium drive  540 . 
     Peripheral device(s)  530  may include any type of computer support device, such as an input/output interface, to add additional functionality to computer system  500 . For example, peripheral device(s)  530  may include a communications controller, such as a network interface card or integrated circuit, for interfacing computer system  500  to a communications network or point-to-point links with other devices. Instructions for enabling computer system  500  to perform processes, such as those described with reference to  FIGS. 1-14 , may be downloaded into the computer system&#39;s main memory  510  over a communications network. Computer system  500  may also interface to a database management system over a communications network or other medium that is supported by peripheral device(s)  530 . 
     Input control device(s)  570  provide a portion of the user interface for a user of computer system  500 . Input control device(s)  570  may include an alphanumeric keypad for inputting alphanumeric and other key information, a cursor control device, such as a mouse, a trackball, stylus, or cursor direction keys. In order to display textual and graphical information, computer system  500  contains graphics subsystem  550  and output display  560 . Output display  560  can include a cathode ray tube display or liquid crystal display. Graphics subsystem  550  receives textual and graphical information, and processes the information for output to output display  560 . 
     The components contained in computer system  500  are those typically found in general purpose computer systems. In fact, these components are intended to represent a broad category of such computer components that are well known in the art. 
     The process steps and other functions described above with respect to embodiments of the present invention may be implemented as software instructions. More particularly, the process steps described with reference to  FIGS. 1-14  may be implemented as software instructions. For one software implementation, the software includes a plurality of computer executable instructions for implementation on a general purpose computer system. Prior to loading into a general purpose computer system, the software instructions may reside as encoded information on a computer readable medium, such as a magnetic floppy disk, magnetic tape, and compact disc read only memory (CD—ROM). In one hardware implementation, circuits may be developed to perform the process steps and other functions described herein. 
     The foregoing detailed description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. The described embodiments were chosen in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.