HeadlessRasterScratch

Reuses exact source-color weights during one synchronous rasterization or native frame preparation. Calls belong to the constructing thread. The key is the complete ARGB tint; destination, cutoff and geometry are not retained. At most four least-recently-used tints each retain sixteen alpha rows, with less than 256 KiB of primitive storage in total. No image, command or destination is retained. Close releases every table and permanently rejects further use.