This removes the awkward hack to recompute the layout transform at paint
time, and makes it possible for path sizes to be computed during layout.
For example, it's possible to use relative units in SVG shapes (e.g.
<rect>), which can be resolved during layout, but would be hard to
resolve again during painting.
This allows applying SVG <mask>s to elements. It is only implemented for
the simplest (and default) case:
- mask-type = luminance
- maskContentUnits = maskContentUnits
- maskUnits = objectBoundingBox
- Default masking area
It should be possible to extend to cover more cases. Though the layout
for maskContentUnits = objectBoundingBox will be tricky to figure out.
This also combines the viewbox mapping into the same transform and
reuses some code by using Path::copy_transformed() rather than manually
mapping each segment of the path.
This simplifies the ownership model between DOM/layout/paint nodes
immensely by deferring to the garbage collector for figuring out what's
live and what's not.
This removes a set of complex reference cycles between DOM, layout tree
and browsing context.
It also makes lifetimes much easier to reason about, as the DOM and
layout trees are now free to keep each other alive.
This patch adds a bunch of Paintable subclasses, each corresponding to
the Layout::Node subclasses that had a paint() override. All painting
logic is moved from layout nodes into their corresponding paintables.
Paintables are now created by asking a Layout::Box to produce one:
static NonnullOwnPtr<Paintable> Layout::Box::create_paintable()
Note that inline nodes still have their painting logic. Since they
are not boxes, and all paintables have a corresponding box, we'll need
to come up with some other solution for them.
This patch begins the support for the 'view-box' attribute that can be
attached to <svg>'s.
The FormattingContext determines the size of the Element according to
the specified 'width' and 'height' or if they are not given by the
'viewbox' or by the bounding box of the path if nothing is specified.
When we try to paint a SVG Path that belongs to a <svg> that has the
'view-box' and a specified 'height'/'width', all the parts of the path
get scaled/moved accordingly.
There probably are many edge cases and bugs still to be found, but this
is a nice start. :^)
