Areas within the pixel images are represented with rectangles . A pixel image data type is included to remember the actual pixel values. These are displayed in the data window as shown in Figure 4.5 . Operators include vector arithmetic for navigating around the display and pixel pattern matching for finding the locations of one pixel image within another. The properties also can map directly to understandable meanings.
Points can map to a particular object displayed in a graphical user interface.
Icon-sized pixel images can map to a particular icon that appears in a graphical user interface. The next chapter shows that the properties map to other useful meanings, and do so reliably enough to be used in programs. Since pixel data access only provides one-way interprocess communication, that is, from applications to user programs, the prototype includes other operators to support additional interprocess communication. Any interprocess communication technique that provides communication from user programs to the applications could have been chosen. However for Triggers-IV, keyboard macros and mouse macros were the logical choice for a number of reasons.