Writing axle OS's desktop compositor

$ Writing axle OS's desktop compositor


$ axle OS demo


$ awm source layout


$ z-indexes


$ Blitting windows


$ Simple render strategy


$ Getting started


$ Add in some windows


$ Clearing the canvas


$ And some windows again...


$ Tradeoffs


$ Correct but unusably slow


$ Obscured draws


$ Quantifying obscured draws


$ Splitting visible regions


$ Coalescing visible regions


$ Splits gallery


$ Rect splitting tests


$ Spatial indexes


$ Computing visible regions


$ Slower window animations


$ Alongside more desktop elements...


$ Checking our overdraw


$ Redraw requests


$ Frames over time


$ Code evolution


$ Coordinating dirty regions


$ Back to the drawing board


$ Redraw uncovered content upon mouse moves


$ Redraw uncovered content upon mouse moves


$ Union mouse difference in redraw rect


$ Window animations recompute the window's drawable regions


$ Composite computed visible regions via detected dirty rects


$ Newly uncovered regions receive a background draw


$ Window drags cause a full redraw in the affected area


$ Modifying the z-index updates occlusions


$ Redraw title bars


$ Add in some shortcuts...


$ Shortcuts redraw on mouse interaction


$ Shortcuts are queued for draw upon creation


$ All done!


$ Simulating inputs, testing outputs


$ Compositing is tricky


$ Thanks!