Bitmaps are now identified by an enum class instead of by pointers.
Bitmap loading and caching is now handled by a class in common, and
we no longer compile most bitmaps into the binary, so there is no
longer a bitmaps static library.
Instead, bitmaps are archived to a .tar.gz file which is installed
in ${KICAD_DATA}/resources/images.tar.gz
The source PNGs are checked in to Git as the original CPP files were,
so that people can build without the required dependencies to convert
SVGs to PNGs.
Initial support is also added for dark theme icons, although this
is not yet exposed in the GUI.
Stubs are present for multi-resolution image resources, but this is
not fully-baked yet and could use some refinement.
You can now choose the behavior of dragging with the
middle and right mouse buttons.
You can also choose which modifier keys to use for
panning and zooming with the scroll wheel or trackpad.
You can also customize the zoom speed, which makes
it possible to have a good zoom experience on a wider
range of input devices.
You can also now zoom by dragging with the right or
middle button if desired.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/3885
Fixes https://gitlab.com/kicad/code/kicad/-/issues/4348