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gdk_pixbuf_get_from_window()
and gdk_cairo_set_source_window()
GTK+ 4 is a major new version of GTK+ that breaks both API and ABI compared to GTK+ 3.x. Thankfully, most of the changes are not hard to adapt to and there are a number of steps that you can take to prepare your GTK+ 3.x application for the switch to GTK+ 4. After that, there's a small number of adjustments that you may have to do when you actually switch your application to build against GTK+ 4.
The steps outlined in the following sections assume that your application is working with GTK+ 3.22, which is the final stable release of GTK+ 3.x. It includes all the necessary APIs and tools to help you port your application to GTK+ 4. If you are still using an older version of GTK+ 3.x, you should first get your application to build and work with the latest minor release in the 3.22 series.
Over the years, a number of functions, and in some cases, entire widgets have been deprecated. These deprecations are clearly spelled out in the API reference, with hints about the recommended replacements. The API reference for GTK+ 3 also includes an index of all deprecated symbols.
To verify that your program does not use any deprecated symbols, you can use defines to remove deprecated symbols from the header files, as follows:
make CFLAGS+="-DGDK_DISABLE_DEPRECATED -DGTK_DISABLE_DEPRECATED"
Note that some parts of our API, such as enumeration values, are not well covered by the deprecation warnings. In most cases, using them will require you to also use deprecated functions, which will trigger warnings.
Style properties do not exist in GTK+ 4. You should stop using them in your custom CSS and in your code.
GTK+ 4 removes the GDK_WA_CURSOR flag. Instead, just use
gdk_window_set_cursor()
to set a cursor on the window after
creating it.
GTK+ 4 also removes the GDK_WA_VISUAL flag, and always uses
an RGBA visual for windows. To prepare your code for this,
use gdk_window_set_visual (gdk_screen_get_rgba_visual()
) after
creating your window.
GTK+ 4 also removes the GDK_WA_WMCLASS flag. If you need this
X11-specific functionality, use XSetClassHint()
directly.
GTK+ 4 always uses RGBA visuals for its windows; you should make sure that your code works with that.
At the same time, you should stop using GdkVisual APIs, this object not longer exist in GTK+ 4. Most of its APIs are deprecated already and not useful when dealing with RGBA visuals.
GTK+4 removes these GtkBox child properties, so you should not use them. You can replace GtkBox:padding using the “margin” properties on your GtkBox child widgets.
The fill child property can be replaced by setting appropriate values
for the “halign” and “valign” properties of the child
widgets. If you previously set the fill child property to TRUE
, you can
achieve the same effect by setting the halign or valign properties to
GTK_ALIGN_FILL
, depending on the parent box -- halign for a horizontal
box, valign for a vertical one.
GtkBox also uses the expand child property. It can be replaced by setting “hexpand” or “vexpand” on the child widgets. To match the old behavior of the GtkBox's expand child property, you need to set “hexpand” on the child widgets of a horizontal GtkBox and “vexpand” on the child widgets of a vertical GtkBox.
Note that there's a subtle but important difference between GtkBox's
expand and fill child properties and the ones in GtkWidget: setting
“hexpand” or “vexpand” to TRUE
will propagate up
the widget hierarchy, so a pixel-perfect port might require you to reset
the expansion flags to FALSE
in a parent widget higher up the hierarchy.
The getters in the GtkStyleContext API, such as
gtk_style_context_get_property()
, gtk_style_context_get()
,
or gtk_style_context_get_color()
only accept the context's current
state for their state argument. You should update all callers to pass
the current state.