Note: This issue is about general problems with existing dark theme support on macOS and Linux. For macOS-specific issues, see #1229. For dark mode support on Windows, see QTBUG-72028.

When using Pencil with a dark theme (in this case Adapta-Nokto via the gtk style of Qt), there currently are some components that don't adapt properly. Most of this was originally mentioned in #540 (comment) and then simply extracted into this separate issue upon suggestion of @scribblemaniac.

These are the issues that I see there right now, in no particular order:

• The main menu bar looks like it has some custom styling overwriting the theme that should be removed, e.g. the text colour is set according to the theme but the background color clearly isn't. Submenus are not affected and look just fine. See Remove custom styling #634.

• The "Display" pane apparently uses some kind of custom-made (and therefore unthemed) buttons, which probably should be exchanged with Qt's standard buttons. See Remove custom styling #634.

• The contrast in the system information section of the about dialog ranges from bad to completely nonexistent with dark themes, depending on the exact theme. See macOS dark mode not detected automatically #1229 for a screenshot.

• The timeline needs support for theming; currently it doesn't adapt at all. Will probably be solved together with Timeline Rewrite #533

• Some icons contain fragments of white where they transition from colour to transparency, indicating that they were originally designed for light backgrounds. These icons should be edited or remade accordingly. Obvious examples:

  • The move tool
  • The brush tool
  • The playback controls
  • The "Duplicate Frame" button
  • The zoom entries in the View menu

  In some other icons those fragments are also present, but barely even noticeable.

  See Toolbar icon design #603 and I'm interested in redesigning all icons in the software #1356.

• Some icons don't contrast well with the dark background and should be redesigned accordingly. Obvious examples:

  • The select tool
  • The restore and close buttons on each pane

  See Toolbar icon design #603 and I'm interested in redesigning all icons in the software #1356.

Some additional remarks:

• The icon-related might be solved by switching to a monochrome icon theme, which is what most other programs explicitly supporting both light and dark themes do (e.g. MyPaint, Krita, MuseScore). These programs show light icons when using a dark theme and dark icons when using a light theme
• If a user option for switching between a light and a dark theme is desired (as it has been mentioned before), it might be worth to have a look at Krita and/or MuseScore, which are also Qt programs offering this kind of functionality
• For macOS-specific issues, see macOS dark mode not detected automatically #1229
• For Windows dark mode support, see QTBUG-72028