Setting Properties for Animated or Moving Objects
For animation controls, such as the animation control displayed when copying files, use the ROLE_SYSTEM_ANIMATION object role. For graphics that are occasionally animated, use the ROLE_SYSTEM_GRAPHIC object role with the State set to STATE_SYSTEM_ANIMATED.
Use the STATE_SYSTEM_ANIMATED flag to mark an object whose appearance changes rapidly. Clients use this flag to avoid notifying users repeatedly for what is really a single series of visual changes.
An example of this is marquee text, which is disclosed progressively as it scrolls across the screen. Such objects are given the attribute of STATE_SYSTEM_ANIMATED. In most cases the object's Value string reflects the entire text, even the portion not currently visible. Changing the Value string frequently to correspond to the text currently visible is not recommended because it results in far too many EVENT_OBJECT_VALUECHANGE events that do not convey useful information.
For example, in a window that contains a rectangular region that shows the word "Yes!" moving in a figure-eight pattern, the Role is ROLE_SYSTEM_GRAPHIC, the Value property is the string displayed, the Location property is the bounding rectangle around the text, and the STATE_SYSTEM_ANIMATED attribute flag is set. The Description is "The word 'Yes!' is moving around the screen in a figure-eight pattern." The server generates only EVENT_OBJECT_STATECHANGE events when the object starts or ceases animation.