This replaces all internal gadgets with widgets.
Remaining problem: "block" nodes have a min-width of 32px in Adwaita,
but when allocated in continuous mode, the levelbar doesn't care and
underallocates them.
GtkLevelBar supports adding custom offsets as style classes, and they
are applied whenever the :value property matches. The current code,
however, only updates any CSS nodes when an offset is found, causing
it to not update when a discrete value changes but no custom offset
is added.
Fix that by always updating the CSS nodes.
https://bugzilla.gnome.org/show_bug.cgi?id=773799
Add a new ::measure vfunc similar to GtkCssGadget's that widget
implementations have to override instead of the old get_preferred_width,
get_preferred_height, get_preferred_width_for_height,
get_preferred_height_for_width and
get_preferred_height_and_baseline_for_width.
We create and destroy gadgets inside the levelbar hierarchy here,
and if we don't explicitly remove their CSS nodes from the parent,
they stick around.
We had some odd special-casing for the lowest and highest offset
that did not quite work. The new rule is simple: If the value
is between offset n-1 and n, it gets the style for offset n.
https://bugzilla.gnome.org/show_bug.cgi?id=761416
During the gadget conversion, the drawing of discrete levelbars
was unintentionally changed to draw a wide trough but narrow
blocks, which does not look great. So go back to the previous
way of drawing things.
https://bugzilla.gnome.org/show_bug.cgi?id=761428
Instead of having old and new style, now have a GtkCssStyleChange opaque
object that will compute the changes you are interested in for you.
This simplifies change signal handlers quite a bit and avoids lots of
repeated computation in every signal handler.
Instead of issuing g_warning, fill the provided GError.
This lets us test this error handling, and is the right
thing to do. Use the new GtkBuilder helpers and
g_markup_collect_attributes to do so.
We want to be able to style the empty blocks independently of all the
offset styles, so remove the current style class when painting an empty
block.
https://bugzilla.gnome.org/show_bug.cgi?id=707695
Try to do a better job of keeping example content
from being too wide. It is often rendered as <pre>
text so the only time we can wrap it is in the source.
It is best to full break lines at all punctuation and
to try to keep the width under 70 chars or so.
