Method for preemptive screen rendering
View Patent ↗A method of rendering screen of a computer display device under conditions requiring frequent repainting of the screen is disclosed. The display is a part of a computer system running an application under control of an operating system. The application detects the onset of conditions requiring frequent repainting of the screen by checking messages sent by the operating system to the application's message queue. The application then starts the repainting of the screen based on the information retrieved from the queue while checking periodically the message queue to see if the originally detected conditions still apply. If this is the case, the application terminates the original repainting operation and starts a new repainting operation based on the updated information retrieved from the message queue. This cycle is repeated until it is determined that the originally detected conditions no longer apply, in which case a final complete repaint of the screen takes place. The method is particularly useful for the display of a graphically complex scene during a navigation operation, such as panning or zooming, when complete repainting of the scene as the navigation progresses fails to provide to the user an acceptable visual feedback of the navigation progress.
1. A method of rendering a screen of a computer display device under conditions requiring frequent repainting of the screen, the display device being a part of a computer system running a graphic visualization application under control of an operating system, the method comprising the steps of:
a. detecting the onset of conditions requiring frequent repainting of the screen;
b. obtaining from the operating system information necessary for repainting;
c. partly repainting the screen by rendering a predetermined number of objects of a scene graph;
d. checking whether the conditions of step a. still apply; and
e. repeating steps b. through d. until the conditions of step a. no longer apply,
the steps a., b., and d. being carried out based on messages sent by the operating system to the application's message queue, the screen displaying a graphically complex visualization scene represented in the computer system as the scene graph.
2. A method according to claim 1 , wherein step c. is repeated and more objects are added to the scene if in step d. no navigation-related message is found in the message queue.
3. A method according to claim 2 , wherein the screen is repainted in the order of traversing the scene graph.
4. A method according to claim 1 , wherein the operating system is MS Windows operating system.
5. A method according to claim 1 , wherein the conditions requiring frequent repainting of the screen are a result of a navigation operation initiated by an application user.
6. A method to claim 5 , wherein the scene is navigated with an input device.
7. A method according to claim 6 wherein the input device is a mouse or a keyboard.
8. A method according to claim 5 , wherein the navigation operation is selected from the group consisting of panning, rotating and zooming.
9. A computer based system for rendering on a screen of a computer display device under conditions requiring frequent repainting of the screen, the computer based system running a graphic visualization application under control of an operating system, the computer based system comprising:
a. module for detecting the onset of conditions requiring frequent repainting of the screen;
b. module for obtaining from the operating system information necessary for repainting;
c. module for partly repainting the screen by rendering a predetermined number of objects of scene graph;
d. module for determining whether the conditions still apply, the obtaining module, the repainting module and the determining module repeatedly operating while the conditions are apply,
the detecting module, the obtaining module and the determining module being operated based on messages sent by the operating system to the application's message queue, the screen displaying a graphically complex visualization scene represented in the computer based system as a scene graph.
10. A computer based system according to claim 9 , wherein the repainting module includes module for allowing more objects to be added to the scene when no navigation-related message is found in the message queue.
11. A computer based system according to claim 10 , wherein the repainting module ensures that the screen is repainted in the order of traversing the scene graph.
12. A computer based system according to claim 9 , wherein the operating system is MS Windows operating system.
13. A computer based system 9 , wherein the conditions requiring frequent repainting of the screen are operatively coupled to a navigation operation initiated by an application user.
14. A computer based system according to claim 13 , wherein the navigation operation is provided by an input device that accepts inputs from the application user.
15. A computer based system according to claim 13 , wherein the navigation operation is selected from the group of consisting of panning, rotating and zooming.
16. A computer storage medium storing computer readable code embodied therein for rendering a screen of a computer display device under conditions requiring frequent repainting of the screen, the display device being a part of a computer system running a graphic visualization application under control of an operating system, comprising:
a. code for detecting the onset of conditions requiring frequent repainting of the screen;
b. code for obtaining from the operating system information necessary for repainting;
c. module for partly repainting the screen by rendering a predetermined number of objects of scene graph;
d. code for checking whether conditions of step a. still apply; and
e. code for repeating the codes b. through d. until the conditions of the code a. no longer apply,
the codes a., b., and d. being carried out based on messages sent by the operating system to the application's message queue, the screen displaying a graphically complex visualization scene represented in the computer system as the scene graph.
17. A computer storage medium according to claim 16 , wherein the code c includes code for allowing more objects to be added to the scene when no navigation-related message is found in the message queue.
18. A computer storage medium according to claim 16 , wherein the code c includes code for partly repainting the screen in the order of traversing the scene graph.
19. A computer based system according to claim 16 , wherein the code c detects the onset of a result of a navigation operation initiated by an application user.