Gtk3 migration

GTK 2 -> 3

GNOME Migration guide

• All preparation steps seem to work already (so we hopefully only have to look at the time of migration sections)
• Building with Gtk3 gives no errors during cmake preparations (simply remove libgtk2 and install libgtk3)

Known current issues

• GtkRuler is not supported. Best idea is probably to look at some other opensource project which used GtkRuler and ported it to gtk3 (Inkscape)
  • GIMP commit where GTKruler was ported to gimpRuler
  • ink-ruler.h (Current)
  • ink-ruler.cpp (Current)
  • ruler.cpp (2014)
  • ruler.h (2013)
• Build files with specific errors for Scroom and GtkRuler
• (4-5-21) GTKRuler3 now has no build errors, but has not been tested yet repo

Changes during migration (Only done for Scroom and not Canon plugin)

• Replace size_request by get_preferred_width/height
  • Found nothing
• Replace GdkRegion by cairo_region_t
  • GdkRectangle
  • gdk_region_get_clipbox()
  • gdk_region_destroy()
• Replace GdkPixmap by cairo surfaces
  • Found nothing
• Replace GdkColormap by GdkVisual
  • Found nothing
• GdkDrawable is gone
  • There are two files still using GDK_Drawable_get_visible: gui/source 448 & libs/tiled-bitmaps/tools 26. Change needed to use GDK_window instead
• Event filtering
  • Found nothing
• Backend-specific code
  • Found nothing
• GtkPlug and GtkSocket
  • Found nothing
• The GtkWidget::draw signal
  • Already uses Cairo but not sure if its compatible with GTK 3
• GtkProgressBar orientation
  • Found nothing
• Check your expand and fill flags
  • ???
• Scrolling changes
  • Found nothing
• GtkObject is gone
  • Found nothing
• GtkEntryCompletion signal parameters
  • Found nothing
• Resize grips
  • Found nothing