This removes the use of GtkTextDisplay (a PangoRenderer) to use
the GskPangoRender which generates render nodes. Part of this means
improving the GskPangoRenderer to support the necessary features for
displaying a GtkTextView.
Primarily, this is a merging of GtkTextDisplay features into
GskPangoRender. Additionally, GtkTextDisplay was removed to allow for
gtk_text_layout_snapshot() to be implemented elsewhere.
The code didn't change, it was just shuffled around to make the
with_bounds() versions of the text rendering unnecessary and instead
pass through the generic append_node() path.
We pulled out the bounds calculation for performance reasons, but the
caller can't know how to properly compute them. Inside gtk+, we can do
that but it's not good enough for public API.
If widgets want to clip things, they now need to do it themselves.
By not taking care of clip, we avoid the need to track clip. And by not
tracking clip, we can avoid all unnecessary cache invalidations that we
were doing for render nodes whenever the clip changed.
And when you are scrolling, the clip changes *a lot*.
This is the equivalent snapshot function to pango_cairo_show_layout().
Not to be confused with gtk_snapshot_render_layout(), which is the
equivalent to gtk_render_layout().
This fixes the build of GTK+ master on Visual Studio 2013 (and possibly
others) as snprintf() may not be supported even if the required C99
features are supported by the compiler.
https://bugzilla.gnome.org/show_bug.cgi?id=773299
This commit takes several steps towards rendering text
like we want to.
The creation of the cairo surface and texture is moved
to the backend (in GskVulkanRenderer). We add a mask
shader that is used in the next text pipeline to use
the texture as a mask, like cairo_mask_surface does.
There is a separate color text pipeline that uses the
already existing blend shaders to use the texture as
a source, like cairo_paint does.
The text node api is simplified to have just a single
offset, which determines the left end of the text baseline,
like all our other text drawing APIs.
I see 'out of memory' errors and crashes inside libvulkan when
creating nodes that have empty bounds and end up in the fallback
paths, like a shadow around an empty text node. Prevent this
by not creating text nodes in that case.
Copy the PangoCairoRenderer into GTK+, rename it to GskPangoRenderer,
and strip it down far enough to build without private pango apis.
This means we currently don't support hexboxes or shapes.
Currently, this lives in gtk, but it might be nicer to put it
in gsk eventually.
