| The fast rise of smart phone, multimedia player and other portable equipmentmarket makes increasing requirement for best brilliant user interface and smoothermultimedia content. With the features of smaller storage space requirements, imagequality lossless after rotation, scaling or other operations, the vector graphics used inembedded system of portable equipment more and more common.According to OpenVG1.1defined rendering pipeline, this paper achieves a highperformance and low-cost2D vector graphic processer which is implemented byhardware and software co-operation and completely compatible with OpenVG1.1. Ituses a hardware unit to handle the arithmetic operations such as “Path” relatedalgorithms, stroke/fill path generation, trapezoid anti-aliasing rasterization, etc. It can beused under variety of embedded systems to accelerate the vector graphic UI andmultimedia content with OpenVG API supporting.The design of the hardware accelerator unit is primarily targeted at “Path” inOpenVG processing pipeline, coordinate conversion, and rendering anti-aliasing. Alltypes of curve path are unified by cubic Bezier curve, which is de-composited tostraight line segments by deCastlejau algorithm. Anti-aliasing is rendered byover-sampling, which uses greater precision to over-sample the color components ofeach pixel, and spread the color information to the pixels nearby to achieve a smoothtransition and reduce the jagged edges of aliasing graphics.After researching and summarizing the OpenVG API and pipeline definition, eachfunctional module is implemented by optimized algorithm, to reduce the consumptionof internal SRAM and improve the graphics rendering performance. The graphicprocesser finally implemented as a C-language behavior model, which can be easilytransfer to hardware description language (HDL)2D vector graphic processer. Throughthe test of user test program and benchmark, the correctness of the design features andthe compatibility of OpenVG specification have been proved. |
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