189 of QET's 266 fixed-size icons are black line art with no dark
variant, so on a dark palette they were black on a dark toolbar, and
Fusion's disabled rendering lightened them into something more readable
than the enabled state (GitHub #466, #870; bugtracker 335 for the
element panels, which keep their own fix).
The theme "qet-dark" holds light-ink copies of the line-art icons in
ico/themes/qet-dark, generated by misc/make_icon_themes.py. Colored
icons are not copied; the theme inherits them from "qet". An icon counts
as line art when fewer than 20% of its visible pixels are saturated. The
copies keep hue and alpha and invert lightness, scaled so each icon's
darkest ink becomes (220,220,220), the dark palette's text color. The
eight SVG icons get their color replaced the same way.
QETApp::applyIconTheme() picks "qet-dark" for a dark palette and "qet"
otherwise. It runs from initIconTheme(), again from initStyle() once the
palette is final, and on the OS color scheme switch. Icons created with
QIcon::fromTheme() re-resolve on their next paint, so nothing else
changes.
With light-ink files, Fusion's own disabled rendering comes out dimmer
than enabled with no extra code.
tests/qttest/tst_qeticons: every name resolves in both themes, every
dark file has light ink, and a Fusion tool button shows its icon at 3:1
in both themes with disabled weaker than enabled.
Jeff Patterson
800ddfbcbe
