Research On Key Technologies Of Smart Vector Font Engine In Embedded Systemand Engineering-oriented Validation

Font is an important part of GUI in embedded system. There are two kinds of font file data format, Bitmap font and Vector font in embedded system. Bitmap font is not resizable, for high resolution screen, the display data is large and display speed is lower than TrueType vector font. Using vector font in embedded system can get better display effect and can dynamically render the font style, font size and font color. Compared with bitmap font, using TrueType vector font can achieve high quality scale, revolve and oblique of character, realize WYSIWYG (what you see is what you get).Using vector font in embedded system needs the corresponding font engine. So research on smart font engine has import practical significance.This thesis studies several key technologies concerning embedded smart font engine. It analyzes the algorithm of source font engine FreeType, uses binary search to optimize glyph search algorithm to increase the search speed, Also, this thesis analyzes the algorithm principle of raster and smooth, realizes coverage based anti-alias algorithm and applies it in a new font raster.To solve the problem of deficiency with the bitmap font driver model, the author puts forward vector font driver, constructs vector font driver model and uses it in embedded system. Through all the above optimization methods applied to font engine, finally a font engine developed,which is suitable for embedded system.As for the deficiency of font color display and transmission in embedded system, this thesis also propose a color processing technology to realize short messages color transmission. Meanwhile, in order to realize 24 bit color rendering, the color gradient algorithm is used to get edge gradient effect. By using fusion of font color, gray level and background, color blending algorithm make font display look more harmonious. All the results are tested with simulation.The smart font engine engineering-oriented validation is used in MTK platform. First, we tested it for function of resize, rotation and obliqueness on cell phone. The cell phone is F531, CPU colock is 104MHz, ROM and RAM is 16M and 4M.Tests show the function is realized.Meanwhile, the speed is tested using MTK simulator.Theoretical analysis and experimental simulation shows, the smart font engine introduced in this thesis is independent engine, suitable for low storage and low capacity embedded system, and can support TrueType vector font with ease to transplant.