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. :^)
Previously we used a native ui button to draw the buttons.
These buttons can however not be styled with css.
To allow these to be styled with css, we create a button with
the UA stylesheet that resembles the system ui button.
Instead of making a full copy of every NodeState when cloning a
FormattingState, we make NodeState ref-counted and implement a basic
copy-on-write mechanism.
FormattingState::get_mutable() now makes a deep copy of the NodeState
when first accessed *if* it is shared with other FormattingStates.
We'll have to do something more proper to support this scenario
eventually, but for now let's at least not crash just because somebody
put an SVG <path> inside an HTML element.
Let's have one function that determines the type of transformation
needed, and another to actually perform the transformation.
This makes it much easier to read, and we don't have to duplicate the
logic for doing the transformation.
We now consider a layout box as having definite size in these cases:
- The size is a <length>.
- The size is a <percentage> and the containing block has definite size.
This is not complete, but a bit more accurate than what we had before.
Previously we were computing the bottom edge of a line box by finding
the bottommost fragment on the line.
That method didn't give correct results for line boxes with no fragments
(which is exactly what you get when inserting a bunch of <br> elements.)
To cover all situations, we now keep track of the bottommost edge in the
LineBox object itself.
Using WeakPtr to remember which LineBoxFragment owns which Box was
imposing some annoying constraints on the layout code. Importantly, it
was forcing us to heap-allocate fragments, which makes it much harder to
clone a FormattingState.
This patch replaces the WeakPtr with a coordinate system instead.
Fragments are referred to by their line box index + fragment index
within the line box.
The primary benefit of this is that it's unsigned, as you can't have a
negative amount of children. Plus, all the users of child_count expect
it to be size_t.
We now validate that the provided tag names are valid XML tag names,
and otherwise throw an "invalid character" DOM exception.
2% progression on ACID3. :^)
Since we now honor the CSS font-size values when deciding line box
metrics, we sometimes find ourselves needing to paint text with a bitmap
font into a box that isn't large enough for the glyphs.
As it turns out, it looks a bit better if we just grow the paint rect to
fit the glyphs (instead of painting chopped-off glyphs.) So let's just
do that for now.
If vertical-align is a length value, we lift each line box fragment that
far from the baseline of the line box.
This is rather messy, and we'll have to improve factoring as we add
support for more alignment types.
The purpose of "entering" a box is to collect box model metrics that
apply to content fragments within the box. However, inline-blocks are
special, in that their inner content does not directly participate in
the inline formatting context outside it.
We were neglecting to pop nodes from the box model stack. The metrics
were already being zeroed out when used, but let's not grow the stack
needlessly.
Instead of just the outline, fill them with some semi-transparent color.
Also add tag name, ID, classes and coordinates to the little tooltip.
Finally, use the border box instead of the context box for metrics,
same as other browsers.
Instead of awkwardly visiting and mutating lengths inside StyleValues,
we now simply create a new StyleValue instead.
This fixes an issue where inherited relative lengths could get
absolutized using a parent as reference, and then not having the correct
values when used in a child context.
