This patch adds the GtkScrollablePolicy type property to GtkScrollable
and implements it in all subclasses. GtkScrolledWindow observes this
property to make a good guess about when to show/hide scrollbars for
height-for-width content.
Most scrollable children do not do height-for-width *yet* but
most certainly will (toolpalette, treeview, iconview, textview
widgets all TODO), for scrollable widgets that do have a minimum
and natural size, it's important for them to observe the state
of this property in order to properly drive the scroll adjustments
according to the desired GtkScrollablePolicy. This patch makes
GtkViewport do this.
Patch also adds tests/testscrolledwindow.c to display the effects
of this property.
The scrollable patch removed set_scroll_adjustments (NULL, NULL) from
gtk_tree_view_init() which ensured the treeview would have adjustments
at all times, this patch adds set_v/hadjustment (NULL) to _init to ensure
the same thing (without it, there are crashes when trying to access the
adjustments notably from set_headers_visible() in gedit).
I.e. Since we are now calling get_preferred_width() to ensure a good 'for_size'
for get_height_for_width() we need to avoid warning about this internal expected
recursion.
These properties use GdkRGBA to render the cell renderer's content.
Note that Pango attributes are used to render the foreground color,
so the alpha value is currently ignored.
This new function takes a GdkRGBA in order to set the background to
an alpha color. Keep in mind that RGBA visuals and a composited environment
are still necessary to have an alpha background displayed.
GdkRGBA is a boxed struct similar to GdkColor, with the difference
that it stores alpha information as well, and colors are stored in
[0..1] doubles, in the cairo spirit.
gdk_cairo_set_source_rgba() has been also added to allow easier handling
of this new type.
