Environment variables in VCL

General

These are the general environment variables used in the VCL:

  • SAL_USE_VCLPLUGIN - use a VCL plugin

  • SAL_RTL_ENABLED - Enable RTL UI

  • SAL_NO_NWF - disable native widgets

  • SAL_FORCEDPI - force a specific DPI (gen, gtk3/gtk4, qt5/qt6/kf5/kf6 plugins only)

  • SAL_FORCE_HC - force high-contrast mode

  • SAL_USE_SYSTEM_LOOP - calls std::abort on nested event loop calls. Currently just for Qt with many crashes. WIP.

  • SAL_NO_FONT_LOOKUP - disable font search and fallback and always use a hard-coded font name (for some unit tests)

  • SAL_NON_APPLICATION_FONT_USE - control use of non-bundled fonts, values are deny or abort; for now only works on platforms using fontconfig (i.e., on Linux, but neither on macOS nor on Windows); also see gb_CppunitTest_set_non_application_font_use for using it in unit tests

  • SAL_ALLOW_DEFAULT_HINTING - use default font hinting for the platform. Enables medium/full hinting style which is otherwise reverted to (s)light.

  • LO_COLLECT_UIINFO - enable the uitesting logging, value is expected to be a relative file name that will be used to write the log under instdir/uitest/.

  • VCL_DOUBLEBUFFERING_AVOID_PAINT - don't paint the buffer, useful to see where we do direct painting

  • VCL_DOUBLEBUFFERING_FORCE_ENABLE - enable double buffered painting

  • VCL_DOUBLEBUFFERING_ENABLE - enable a safe subset of double buffered painting (currently in Writer, not in any other applications)

  • VCL_DEBUG_DISABLE_PDFCOMPRESSION - disable compression in the PDF writer

  • SAL_DISABLE_WATCHDOG - don't start the thread that watches for broken GL/Vulkan/OpenCL drivers

  • SAL_NO_MOUSEGRABS - for debugging - stop blocking UI if a breakpoint is hit

Gtk+

  • VCL_GTK3_PAINTDEBUG - in debug builds, if set to 1 then holding down shift+0 forces a redraw event, shift+1 repaints everything, and shift+2 dumps cairo frames to pngs as /tmp/frame<n>.png
  • GDK_SCALE=2 - for HiDPI scaling (just supports integers)

Bitmap

  • VCL_NO_THREAD_SCALE - disable threaded bitmap scale
  • VCL_NO_THREAD_IMPORT - disable threaded bitmap import
  • EMF_PLUS_DISABLE - use EMF rendering and ignore EMF+ specifics

OpenGL

  • SAL_DISABLEGL - disable OpenGL use
  • SAL_GL_NO_SWAP - disable buffer swapping if set (should show nothing)
  • SAL_GL_SLEEP_ON_SWAP - sleep for half a second on each swap-buffers.

Skia

  • SAL_DISABLESKIA=1 - force disabled Skia
  • SAL_ENABLESKIA=1 - enable Skia, unless denylisted (and if the VCL backend supports Skia)
  • SAL_FORCESKIA=1 - force using Skia, even if denylisted
  • SAL_SKIA=raster|vulkan|metal - select Skia's drawing method, by default Vulkan or Metal are used if available
  • SAL_DISABLE_SKIA_CACHE=1 - disable caching of complex images
  • SAL_SKIA_KEEP_BITMAP_BUFFER=1 - SkiaSalBitmap will keep its bitmap buffer even after storing in SkImage

OpenGL,Skia

  • SAL_WITHOUT_WIDGET_CACHE - disable LRU caching of native widget textures

Qt

  • QT_SCALE_FACTOR=2 - for HiDPI testing (also supports float)
  • SAL_VCL_QT_NO_FONTCONFIG - ignore fontconfig provided font substitutions
  • SAL_VCL_QT_NO_NATIVE - disable QStyle'd controls
  • SAL_VCL_QT_USE_QFONT - use QFont for text layout and rendering (default is to use cairo)
  • SAL_VCL_QT_USE_WELDED_WIDGETS - enable use of welded Qt widgets also for dialogs created from .ui files
  • SAL_VCL_QT_NO_WELDED_WIDGETS - disable the use of welded Qt widgets completely (also for simple message dialogs), reverts to previous VCL widget behavior

Mac

  • SAL_FORCE_HIDPI_SCALING - set to 2 to fake HiDPI drawing (useful for unittests, windows may draw only top-left 1/4 of the content scaled)