四 GM813X OSD叠加原理（智源GM813X多国语言OSD开发）

GM813X osd叠加原理，通过font组合，排版，贴入。

根据GM813x文档说明：

OSD contains the following features:
  Supports 455 user-programmable fonts
  Supports font size of 12x18
  Supports 16 programmable palette colors
  Supports eight OSD windows in a frame for each channel
  Maximum 64 fonts in horizontal or vertical direction, and maximum 256 fonts in a font window
  Supports zoom-in with locked aspect ratio: x2, x3, and x4
  Supports zoom-in without locked aspect ratio (Horizontal/Vertical):
x2/x1, x4/x1, x4/x2, x1/x2, x1/x4, and x2/x4
  Supports eight font/background transparencies:
0%, 25%, 37.5%, 50%, 62.5%, 75%, 87.5%, and 100%
  Supports programmable 16-type background color
  Supports border function with 16-type border color
  Supports three marquee modes:
  One horizontal-line marquee effect
  One vertical-line marquee effect
  One horizontal-line flip effect
  Supports programmable border size (Maximum of 32 pixels)

 

OSD Font
The unit of fonts stored in the OSD Font RAM is 12x18. The OSD window adjusts the row and column
spaces to control the space between fonts. Figure 5-1 shows an example of the font bitmap for the
character of “A”. Users can customize the font bitmap and add/replace the new font bitmap to capture the
internal OSD Font RAM through the middleware API. Figure 5-2 shows an example of font and window
color relationship.

 

 字库提取源码demo，以及转码demo：http://download.csdn.net/detail/duola_rain/8067977