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.
You can now query Document::title() to get a String containing whatever
is inside the document's <title> tag.
In support of this, this patch adds the <html>, <head> and <title>
elements.
We now show a tooltip for the hovered node's enclosing HTML element's
title attribute, if one is present.
This patch also adds HTMLHeadingElement. The tags h1-h6 will now create
the right kind of objects.
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 is a simple command that can be used to display HTML from a given
file, or from the standard input, in an HtmlView. It replaces the `tho`
(test HTML output) command.
