First, add automatic detection of toolkit DPI scaling options. For now, this
is, in order,
* Check the GDK_SCALE option under GTK+ (users can set this to force the scaling)
* Check the value from WX's GetContentScalingFactor(). This will start to work
correctly from WX 3.1 and GTK+ 3.10.
Then, add a user-settable override in the main prefs panel, next to the icon
scaling. This is independent of the icon scaling options.
DPI handling is performed in a standalone class, so they can be shared between
the prefs UI and the OpenGL backend easily. Also means Cairo could use the same
interface in future.
Also adjust the OpenGL grid drawing code to use the computed scale factor,
which avoids over-thick grids in scaled environments (the user can manually
thicken the grid if wanted).
Fixes: lp:1797308
* https://bugs.launchpad.net/kicad/+bug/1797308
Cherry-pick of: 567bdd9b9 (master)
gal: pixel alignment for Cairo.
gal: pixel alignment for OpenGL
Cleanup of pixel alignment patches
gal/opengl: more pixel alignment patches:
- works on Retina displays now
- pixel alignment for circles
- correct 1-pixel strokes
- fixed unfinished 1-pixel line ends
GAL: Restore antialiasing options in Cairo
GAL: Fix arc drawing
Removes DrawArcSegment, which drew arcs whose edge was optionally
stroked (a feature that we did not use). Fixes Cairo arc drawing issue
where arcs were not visible in pcbnew.
gal: further cleanup
gal: removed unused shader parameter
John Beard
Tomasz Włostowski
Bernhard Stegmaier