* Implement Brush Sizes for drawtool.Stroke and add a UI to the tools panel
to control the brush size.
* Brush sizes: 1, 2, 4, 8, 16, 24, 32, 48, 64
* Add the Eraser Tool to editor mode. It uses a default brush size of 16
and a max size of 32 due to some performance issues.
* The Undo/Redo system now remembers the original color of pixels when
you change them, so that Undo will set them back how they were instead
of deleting the pixel entirely. Due to performance issues, this only
happens when your Brush Size is 0 (drawing single-pixel shapes).
* UI: Add an IntVariable option to ui.Label to bind showing the value of
an int reference.
Aforementioned performance issues:
* When we try to remember whole rects of pixels for drawing thick
shapes, it requires a ton of scanning for each step of the shape. Even
de-duplicating pixel checks, tons of extra reads are constantly
checked.
* The Eraser is the only tool that absolutely needs to be able to
remember wiped pixels AND have large brush sizes. The performance
sucks and lags a bit if you erase a lot all at once, but it's a
trade-off for now.
* So pixels aren't remembered when drawing lines in your level with
thick brushes, so the Undo action will simply delete your pixels and not
reset them. Only the Eraser can bring back pixels.
* Touching "fire" pixels in a level will pop up the End Level alert box
saying you've died by fire and can restart the level.
* Update level.WriteFile() to prune broken links between actors before
save. So when a linked actor is deleted, the leftover link data is
cleaned up.
* Slight optimization in Canvas.drawStrokes: if either end of the stroke
is not within view of the screen, don't show the stroke.
* The game's tick counter was moved from Doodle.ticks to shmem.Tick
where it is more easily available from every corner of the code.
* Fix a bug in the Level Editor where dragging an already-existing actor
from one part of your map to another, would cause it to lose all its
data (especially its UUID), breaking links to other doodads. Now the
existing Actor catches a ride on the drag object to be reinserted
later.
* Animate the Link Line visualizers between actors. They now animate a
blinking color between magenta and grey-ish.
* Add support for the LineTool and RectTool while in the EditorMode to
easily draw straight lines and rectangle outlines.
* Key bindings were added to toggle tools in lieu of a proper UI to
select the tool from a toolbar.
* "F" for Pencil (Freehand) Tool (since "P" is for "Playtest")
* "L" for Line Tool
* "R" for Rectangle Tool
* If the current edit tool is Actor or Link, use the new drawtool.Stroke
object to draw visual lines connecting every pair of linked actors in
the level. The lines are hidden during normal editing and gameplay and
only appear when you're possibly manipulating your actors and links.
* Add new pkg/drawtool with utilities to abstract away drawing actions
into Strokes and track undo/redo History for them.
* The freehand Pencil tool in EditorMode has been refactored to create a
Stroke of Shape=Freehand and queue up its world pixels there instead
of directly modifying the level chunker in real time. When the mouse
button is released, the freehand Stroke is committed to the level
chunker and added to the UndoHistory.
* UndoHistory is (temporarily) stored with the level.Level so it can
survive trips to PlayScene and back, but is not stored as JSON on
disk.
* Ctrl-Z and Ctrl-Y in EditorMode for undo and redo, respectively.
