RenderQuality
How much of the canvas the feedback buffers cover, and whether that may drop while frames run slow.
Only drawings with a trail render into a buffer; the rest draw straight onto the canvas and are not affected. With dynamic on, five moderately slow frames take the buffers down by a tenth. A severe stall reduces the pixel count immediately using its measured cost, including below quarter scale on a large display. Buffers climb back two percent a second while frames are quick again. The foreground remains at full size. Set dynamic to false to insist on the requested resolution.