Invalidation region coalescing now happens recursively as draw() runs, and the
widget's x/y as now drawing coordinates are 0,0 based.

Now other CSS files can be referenced from the currently parsed file:

@import url (other-file.css);
@import url (/some/file.css);

This is done anyway on each iteration to parse_rule() in parse_stylesheet()

It will now return a full path, and check about the file being sane.

Given there are other rules such as @import (which will be supported),
keep a sane namespace here, so for (re)defining a color name, in the CSS
file it will look like:

@define-color color-name #fff;
@define-color other-color mix (@color-name, #f00, 0.4);

The value it parses is similar to the border-image CSS3 property,
so strings like this will be accepted:

  border-image: url (foo.png) 4 3 4 3 repeat repeat;

the image path is relative to the parsed CSS file dirname if no
absolute path is provided.

It will contain a 9-sliced image, so it can be rendered as rectangles with any
dimensions.

This is a private boxed object to contain information about a border image
in order to render it in a size independent way.

This function recalculates the style for all widgets on a screen.

This functions loads a CSS file from a installed theme.

The providers are added as soon as gtk GtkSettings object for the screen
is created.

This is so the style context has all necessary information before
triggering a style change on setting the path.

These functions allow per-screen style providers. also, the changed signal
will be emitted whenever a style context changes.

This function is analogous to gtk_widget_reset_rc_styles(),
updates style recursively on a widget.

This signal is emitted whenever the widget's style changes.

This function will regenerate all styling information.

Ironically, it currently just handles gradients, the name is to conform
to current CSS gradient implementation trends.

The former will handle GtkSymbolicColors, which will be resolved and
cached at query time.

This type defines a gradient between 2 symbolic colors, with any number
of color stop between these. At the moment it has been put besides
GtkSymbolicColor, although should be completely private, it will likely
need extending in the future for radial gradients.

At some point, it maybe should also be used for images, so painting
both a gradient and an image is consistent.