This patch removes size policies and preferred sizes, and replaces them
with min-size and max-size for each widget.
Box layout now works in 3 passes:
1) Set all items (widgets/spacers) to their min-size
2) Distribute remaining space evenly, respecting max-size
3) Place widgets one after the other, adding spacing in between
I've also added convenience helpers for setting a fixed size (which is
the same as setting min-size and max-size to the same value.)
This significantly reduces the verbosity of widget layout and makes GML
a bit more pleasant to write, too. :^)
The most used feature of any image editor, undo. Each tool now
notifies the ImageEditor that they completed an action, where
it'll take a snapshot if its current state.
For now, a snapshot is just a copy of the whole image and its
layers. There's a hard limit on the amount of actions it stores.
Each tool can have its own set of properties that can be modified
through a panel on the right side.
The tools I've added properties for are:
Pen:
Thickness
Brush:
Size
Hardness
Spray:
Thickness
Density
Bucket:
Threshold
Indexed bitmaps used to allocate four times the required amount of memory.
Also, we should acknowledge that the underlying data is not always RGBA32,
and instead cast it only when the true type is known.
We use this to automatically update the thumbnail in LayerListWidget
when you draw into a layer. We also use it to repaint the ImageEditor
when the image changes somehow. :^)
