WorldIndexAt() translates the pixel below the mouse cursor in screen
space (0,0 at top-left corner of the application window) into a world
coordinate in the level shown inside the canvas, taking into account the
canvas's position on the window and the scroll position.
It now translates correctly when zoom In or Out, so the "Abs:" mouse
position level in the status bar shows correctly.
Zoom features that are still jank:
- Scrolling while zoomed in, the chunks to the top/left start unloading
too rapidly and outpacing the scroll, eventually level is invisible
- Drawing and committing pixels to the image while zoomed in/out is
unpredictable where the pixels actually land.
- Actors in the level don't move or zoom at all.
Noah Petherbridge
37f6177a17