Does anything bad happen if the "expandBy: 1" is removed? I tried removing it
in my Squeak trunk image, and "CompassDialMorph new openInWorld" (which is one
user of TransformationMorph) seems to work nicely.
I bet it's there to avoid gribblies left behind when dragging. The damage rectangle needs to be large enough to cover every pixel touched even in rotated versions.
Maybe the
"
truncated expandBy: 1
" should be something like "rounded outwards"?
But generally speaking, as long as we have the warpblt hack + integer coords instead of a proper hierarchical transform framework we will run into these rounding issues again and again.