Break the non-PCB-specfic parts of PCB_REFERENCE_IMAGE out
to a common REFERENCE_IMAGE class, which is then composed into
the PCB_REFERENCE_IMAGE. This will make it easier to bring the
transform origin logic to eeschema without repetition.
There was a gentle mish-mash of booleans, some with
true being left/right and some up/down, and some functions that
can flip in both axes (which is never actually done, and doesn't
really make geometric sense).
Replace all this with the FLIP_DIRECTION enum class, which makes
the intention completely unambiguous.
This also then allows a small scattering of simplifications,
because everything takes the same type and you don't have to
fiddle booleans to fit.
- Keep original image data. When loading JPEG, this avoid recompression
that changes file data and decreases image quality
- Allow schematic and page layout editors to store non-PNG data as well
- Move page layout editor to store base64 instead of hex-coded data
When users add an image to the board, this change keeps the original
file format when saving instead of converting the files into PNG-format,
which had the effect of making some board files much larger and slower
Fixes https://gitlab.com/kicad/code/kicad/-/issues/14892
This allows a const BITMAP_BASE to expose const image
data. This is currently done with const_casts, which is
"OK", only as long as the source image is not declared
const, in which case it's undefined behaviour.
Also immediately dereference the pointer to a reference
if it's not checked to make the non-null requirements
explicit at the point of access.
