Instead of using string everywhere, have the CSS parser produce enum
values, since they are a lot nicer to work with.
In the future we should generate most of this code based on a list of
supported CSS properties.
Since LayoutText always inherits style, it shouldn't store any style of
its own. This patch adds a LayoutNodeWithStyle class to sit between
LayoutNode and everyone who wants to inherit from LayoutNode except
LayoutText :^)
Since LayoutText can never have children, we also know that the parent
of any LayoutNode is always going to be a LayoutNodeWithStyle.
So this patch makes LayoutNode::parent() return LayoutNodeWithStyle*.
Since LayoutText inherits all of its style information from its parent
Element anyway, it makes more sense to load the font at a higher level.
And since the font depends only on the style and nothing else, this
patch moves font loading (and caching) into StyleProperties. This could
be made a lot smarter to avoid loading the same font many times, etc.
There's no need for LayoutText to inherit from LayoutInline.
I had the wrong idea here: I was thinking that everything that can be
laid out inline should inherit from LayoutInline, but that's clearly
not sufficient for something like LayoutReplaced which can be laid out
in either way.
The default style for "a" tags now has { color: -libhtml-link; }.
We implement this vendor-specific property by querying the containing
document for the appropriate link color.
Currently we only use the basic link color, but in the future this can
be extended to remember visited links, etc.
Okay, I got that a bit wrong. Here's what CSS 2.1 says:
"The properties of anonymous boxes are inherited from the enclosing
non-anonymous box. Non-inherited properties have their initial value."
This patch implements a better behavior by only copying the inherited
properties from the parent style.
LayoutReplaced objects can now participate in inline layout.
It's very hackish, but basically LayoutReplaced will just add itself to
the last line in the containing block.
This patch gets rid of the idea that only LayoutInline subclasses can
be split into lines, by moving the split_into_lines() virtual up to
LayoutNode and overriding it in LayoutReplaced.
This patch adds parsing of <img> into HTMLImageElement objects.
It also adds LayoutImage and its parent class LayoutReplaced, which is
going to represent CSS "replaced elements."
This patch implements basic support for presentational hints, which are
old-school HTML attributes that affect style.
You add support for a presentational hint attribute by overriding
Element::apply_presentational_hints(StyleProperties&) and setting all
of the corresponding CSS properties as appropriate.
To make the background color fill the entire document, not just the
bounds of the <body> element's LayoutNode, we special-case it in the
HtmlView::paint_event() code for now. I'm not entirely sure what the
nicest solution would be, but I'm sure we'll discover it eventually.
There was nothing left in ComputedStyle except the box model metrics,
so this patch gives it a more representative name.
Note that style information is fetched directly from StyleProperties,
which is basically the CSS property name/value pairs that apply to
an element.
Each HtmlView now has a main_frame(), which represents the main frame
of the web page. Frame inherits from TreeNode<Frame>, which will allow
us to someday implement a Frame tree (to support the <frame> element.)
This patch makes StyleProperties heap-allocated and ref-counted so that
a LayoutNode can be without one. The ref-counting also allows anonymous
blocks to share style with their parent block.
LayoutText never needs a StyleProperties, since text always inherits
style from its parent element. This is handled by style_properties().
This is not ideal, as refusing to break lines will easily overflow the
containing block, and we have no way of dealing with overflow yet.
But as long as you provide enough width, it does look nice. :^)
Font::width(string) will subtract one Font::glyph_spacing() from the
result, since we don't put any spacing after the last glyph.
This was messing up text layout here, since we assumed each glyph
width also included the glyph spacing.
Inline layout is now done by LayoutBlock. Blocks with inline children
will split them into line boxes during layout.
A LayoutBlock can have zero or more LineBox objects. Each LineBox
represents one visual line.
A LineBox can have any number of LineBoxFragment children. A fragment
is an offset+length into a specific LayoutNode.
To paint a LayoutBlock with inline children, we walk its line boxes,
and walk their fragments, painting each fragment at a time by calling
LineBoxFragment::render(), which in turn calls the LayoutNode via
LayoutText::render_fragment(). Hit testing works similarly.
This is very incomplete and has many bugs, but should make it easier
for us to move forward with this code.
Every LayoutNode indirectly belongs to some Document. For anonymous
LayoutNodes, we simply traverse the parent chain until we find someone
with a Node from which we can get a Document&.
LayoutText can't simply rely on its LayoutNode::rect() for hit testing.
Instead, we have to iterate over the individual runs and see if we're
hitting any of them.
Also, LayoutNode::hit_test() now always recurses into children, since
we can't trust the rect() to tell the truth (inline rects are wrong.)
Also remove the color values from the ComputedStyle object and get them
via StyleProperties instead.
At the moment, we only handle colors that Color::from_string() parses.
This currently uses a gross hack where it subtracts 11px from the
previous sibling bottom to calculate its top. This should be fixed
by switching to a proper two-phase line layouting model, were we
first distribute inline elements into lines and figure out their
horizontal positions and heights; then compute the needed line
heights and position inline elements there vertically.
