Research On Transplant And Optimization Of The Embedded Brower Graphics Library

With the rapid development of mobile Internet and cloud computing, many commercial giants have launched their WebOSs and netbooks loading with the WebOSs, WebOS has become a trend in embedded technology filed. At the same time, the development of the standards of the browser has made great contribution to helping web browser to replace the local operating system as a new application platform. The combination of the two produced a lightweight, fast, safe and convenient operating system which based on browser. As the user browsing interface and platform of applications, the response speed and rendering efficiency of broser directly affect the user experience. The support of 2D, 3D graphics and multimedia in HTML5 also raised higher requirement to the browser’s rendering performance. Duing to the shortage of embedded devices and low rendering efficiency, the browser rendering kernel needs to be optimized.This thesis analyzed the system architecture of Chromium OS and its development environment, and then it was ported to panda board. We also analyzed the browser kernel system architecture and rendering proceture, especially, we made detailed study on two-dimensional Skia graphics engine. Finally, we designed a parallel rendering architecture which combined the hardware acceleration and software rendering for 2D rendering. This architecture executes some operations using hardware acceleration such as layer blending, rectangle filling and some with software rendering such as simple web pages. It is a considering of the performance and memory usage. At the end, the design was proven effective.Clipping is a very important part of the graphics rendering pipeline, and it includes many types. The line clipping is one most important and basic. The Cohen-Sutherland Algorithm may produce invalid intersection points, which will reduce the efficiency of the whole algorithm. In this thesis, the algorithm is improved. The improved algorithm can determine all the line segments that are totally inside or outside the clipping window. For the lines that have part of the intersection the improved algorithm can rapidly judge which clipping window edge has real intersection points with the line segments. In addition, this thesis studied the the realization of the two-dimensional clipping in Skia. And the improved algorithm is verified by comparing Cohen-Sutherland algorithm with the improved Cohen-Sutherland algorithm. And in order to be more convincing, it compared them with the realization in Skia.In this thesis, the transplantion of Chromium OS is an attempt to the development of WebOS, and it is meaningful for developers of WebOS. The design of parallel rendering system and improved Cohen-Sutherland algrorithm have made great increases in the rendering performance. Also, they have reference value and model significance for the optimization of browser rendering engine and grahics library.