From https://drafts.csswg.org/css-backgrounds-4/#background-clip
"The background is painted within (clipped to) the intersection of the
border box and the geometry of the text in the element and its in-flow
and floated descendants"
This change implements it in the following way:
1. Traverse the descendants of the element, collecting the Gfx::Path of
glyphs into a vector.
2. The vector of collected paths is saved in the background painting
command.
3. The painting commands executor uses the list of glyphs to paint a
mask for background clipping.
Co-authored-by: Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
We now keep the color value as a StyleValue up until we go to paint the
gradient, which makes `currentColor` work, along with any other color
values that can't be immediately converted into a `Gfx::Color` while
parsing.
Although DistinctNumeric, which is supposed to abstract the underlying
type, was used to represent CSSPixels, we have a whole bunch of places
in the layout code that assume CSSPixels::value() returns a
floating-point type. This assumption makes it difficult to replace the
underlying type in CSSPixels with a non-floating type.
To make it easier to transition CSSPixels to fixed-point math, one step
we can take is to prevent access to the underlying type using value()
and instead use explicit conversions with the to_float(), to_double(),
and to_int() methods.
