A Study On Key Technique Of Mobile Flash Rendering

With the arise of leisure economy and mobile phone era of three-dimensional entertainment, mobile Flash animation is gradually forming a global industry, and is considered as the most promising wireless value-added services. At present, some high-end phones are already equipped with Adobe provided Flash Lite player, which can fluently play Flash animations. However, in the low-end mobile phones, due to cost, resource-constrained hardware and other reasons, playing Flash animations still has performance bottleneck. This article aim at the low-end smart phones, make research on Flash vector animation rendering mainly from 3 aspects, so to enhance the performance of Flash animation player. The research work is as follows:(1) Before Flash rendering pipeline rasterlization, there's a difficult balance problem between accuracy and speed in curve decomposition process, for this, we propose a heuristic decomposition algorithm for the curve. The algorithm combines two factors of curve length and curvature, by calculating the Bezier curves of between the distance and angle between the two endpoints and two control points' connection, find the number of decomposition steps. Experimental have shown that the algorithm's complexity are low, accurately generates sub-line segment which fit the curve.(2) Traditional anti-aliasing algorithm need large amount of computing time with low sampling accuracy, which can not meet the modern display devices which have higher and higher brightness level, so we presents a sub-pixel precision area sampling anti-aliasing algorithm. Algorithm use bit operation to vastly calculate pixel cover area, and the brightness levels is up to 2~n (n for the sub-pixel digits, usually n get 8). Compared with the existing anti-aliasing algorithm, the new algorithm has the same algorithm complexity, can vastly generate delicate image, and applied to mobile devices with no hardware calculation module.(3) Refer to Flash file's path structure, each edge has the two filling types, so one edge can not be filled with one time scan, refer to the video continuity principle, we propose a one time scan filling strategy and a variety of caching strategies. Based on the fact that edges are not intersect with each other in one shape, we connect them into an enclosed area of one whole shape structure before rasterlization, so to finish the filling in one time scan; By the principle of continuity in Flash video nodes' and rendering pipeline at all levels, we cache already generated results, avoid repeated calculations and thus effectively improve the rendering speed.The Flash player we develop in this paper run on Amoi E600 low-end mobile platform( whose key performance indicators are: CPU frequency is 312M, the system RAM 64M, resolution 240×320 pixel) can smoothly playback most Flash files, frame rate per second is 12,which shows the validity of our achievement.