Pixie and NiGui

[treeform]

Small correction pixie uses RGBX format. Where X is pre-multiplied alpha. It 
probably will not matter for most things but important to keep in mind. 
Pre-multiplied is great if you are going to use this with blending and more 
complex graphics stack. It’s much faster to do operations on. But might get in 
the way when interfacing with other libs that accept straight alpha.