GTK+ 3 migration

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This page is out-of-date. Inkscape trunk must be built with GTK+ 3. See: Gtk issues
Inkscape trunk will soon stop supporting GTK+ 2 builds.
The forthcoming Inkscape 0.92 release will still use GTK+ 2.
See the migration page for details.

Inkscape currently makes use of the GTK+ 2.20 library API. Ultimately, we will need to switch to the new GTK+ 3 API. This version of the library introduces a number of major changes that are incompatible with GTK, so we need to make some changes to Inkscape.


Building Inkscape against GTK+ 3

First, configure Inkscape to build against GTK+ 3 using configure --enable-gtk3-experimental. I prefer to use a separate subfolder for these experimental builds.

# Create a subfolder in the source directory for the experimental builds
mkdir build-gtk3
cd build-gtk3

# Configure to use GTK+ 3
../configure --enable-gtk3-experimental

After this, you can build as usual.

Current status

Inkscape builds successfully against GTK+ 3, but the resulting program is unstable and isn't recommended for users yet. A few key issues are as follows:

  • Several significant bugs affect the GTK+ 3 builds. Please see the list of known bugs, and please report any more that you find!
  • The Gtk+ 3 builds introduce a number of dependencies, including version 3.3.4 of the GDL dockable-dialog library (Gtk+ 2 builds use an internal copy of the library). Most linux distributions now provide this. We're tracking the dependencies... keep an eye on the list.
  • There is currently no easy way of building against Gtk+ 3 on Windows. However, there is work in progress.
  • Gtk+ 3 is still evolving. To avoid being affected by the level of pain we experienced with the Gtk+ 2 -> Gtk+ 3 migration, we should aim to stay as up-to-date with our API usage as possible... i.e., eliminate #deprecated symbols as soon as possible!

Guidance from upstream

The GTK+ 3 reference manual offers some guidance for the upgrade process.

Deprecated symbols

There are a few macros that can be defined during compilation to protect us against usage of deprecated GTK+ 3 symbols, by doing something like:

make -k CPPFLAGS+="-DMACRO"

where "MACRO" should be replaced by a macro from the following list:

  • GTK_DISABLE_DEPRECATED - prevent usage of deprecated GTK+ symbols
  • GDK_DISABLE_DEPRECATED - prevent usage of deprecated GDK symbols
  • GTKMM_DISABLE_DEPRECATED - prevent usage of deprecated Gtkmm symbols
  • GDKMM_DISABLE_DEPRECATED - prevent usage of deprecated Gtkmm symbols

In addition to this, several deprecated symbols (in a number of libraries) have been tagged with the "deprecated" attribute in their C/C++ declarations. Most compilers will therefore warn you at compile time if the symbol is in use. To turn these warnings into errors, you can do something like:

make -k CPPFLAGS+="-Werror=deprecated-declarations"

In all the above cases, the "-k" flag is used to tell make to keep processing after errors have been found. This lets us generate a complete "todo" list of errors in the code rather than just seeing the first.