Tivaware & alpha blending

Armando,

  The graphics library does not support alpha blending today and the closest you can get is transparent blit (where a single color in the source image is made transparent allowing part of the background to shine through). The main reason for this is that GrLib has traditionally been used with displays which have integrated controllers and frame buffers. In these cases, there is sometimes no way to read from that frame buffer and, if there is a read path, it's typically 10s or 100s of times slower than the write path. To perform alpha blending, you need to read the current frame buffer, mix a new pixel color with it, and write the result back so, obviously, this would be either enormously slow or completely impossible on these displays.

  Moving forward, however, you are likely to see improvements in the capabilities of the displays supported by GrLib and I would like to add alpha blending function when this becomes sensible. Doing it in a way that maintains backwards compatibility will be the trick and we'll have to spend some time working through how we implement this. Don't look for it within a couple of months, though!