Speedy Painter is an OpenGL based painting software for Windows.

It supports Wacom digitizers to vary size and opacity of brush strokes according to pen pressure.

Speedy Painter Features:

Reference view that follows zoom! Available using the F3 key
Export drawing process into a video: ready to upload it on YouTube!
Multiple layers
Ability to vary stroke size and/or opacity according to pen pressure (supports Wacom digitizers)
Replay of drawing process
Import/export drawing process
Loading of most common image formats
Canvas rotation
Canvas flip
Selection mask