HtmlView will now invoke the on_link_hover hook when the cursor enters
or leaves a DOM node that has an enclosing link element.
This patch also updates the meaning of Node::enclosing_link_element()
to find the nearest HTMLAnchorElementAncestor *with an href attribute*.
Use a zero-timer to schedule a style update after invalidating style
on any node. Nodes now have a needs_style_update flag which helps us
batch and coalesce the work.
We also start style updates at the root and work our way through the
document, updating any node that has the needs_style_update flag set.
This is slower than what we were doing before, but far more correct.
There is a ton of room for improvement here. :^)
It's now possible to set a page background image via <body background>.
Also, HtmlView now officially handles rendering the body element's
background (color, image or both.) LayoutBox is responsible for all
other background rendering.
Note that it's not yet possible to use CSS background-image properties
directly, since we can't parse them yet. :^)
Capture a weak pointer to the element and pass that to the load finish
callback in HTMLImageElement::load_image(). This allows us to ignore
completed loads if the <img> element is no longer around.
Some inline stylesheets use HTML comments like "<!--blah blah-->".
The HTML parser currently generates a comment child node of the <style>
element whenever this happens, and we don't want the comment itself to
be interpreted as part of the stylesheet.
This class introduces LayoutTable, LayoutTableRow and LayoutTableCell.
These are produced by "display" values table, table-row and table-cell
respectively.
Note that there's no layout happening yet, I'm just adding the classes.
We now wait until the pixels are actually needed before fully decoding
images in <img> elements.
This needs some more work and is currently a bit memory-wasteful since
we'll hang on to the raw image data forever.
To streamline the layout tree and remove irrelevant data from classes
that don't need it, this patch adds two new LayoutNode subclasses.
LayoutNodeWithStyleAndBoxModelMetrics should be inherited by any layout
node that cares about box model metrics (margin, border, and padding.)
LayoutBox should be inherited by any layout node that can have a rect.
This makes LayoutText significantly smaller (from 140 to 40 bytes) and
clarifies a lot of things about the layout tree.
I'm also adding next_sibling() and previous_sibling() overloads to
LayoutBlock that return a LayoutBlock*. This is okay since blocks only
ever have block siblings.
Do also note that the semantics of is<T> slightly change in this patch:
is<T>(nullptr) now returns true, to facilitate allowing to<T>(nullptr).
This patch makes it possible to call Node::invalidate_style() and have
that node and all of its ancestors recompute their style.
We then figure out if the new style is visually different from the old
style, and if so do a paint invalidation with set_needs_display().
Note that the "are they visually different" code is very incomplete!
Use this to make hover effects a lot more efficient. They no longer
cause a full relayout+repaint, but only a style invalidation.
Style invalidations are still quite heavy though, and there's a lot of
room for improvement there. :^)
This is currently very aggressive. Whenever the Document's hovered node
changes, we invalidate all style and do a full relayout.
It does look cool though. So cool that I'm adding it to the default
stylesheet. :^)
When style is invalidated (for example when an external stylesheet
finishes loading) we delete the whole layout tree and build a new one.
This is necessary since the new style information may result in a
different layout tree.
When layout is invalidated (window resized, image dimensions learned,
etc..) we keep the existing layout tree but run the layout algorithm
once again.
There's obviously lots of room for improvement here. :^)
The layout root is now kept alive via Document::m_layout_root.
This will allow us to do more layout-related things inside the inner
layer of LibHTML without reaching out to the HtmlView.
I'd like to keep HtmlView at a slightly higher level, to prevent it
from getting too complex.
This patch also fixes accidental disconnection of the layout tree from
the DOM after doing a layout tree rebuild. ~LayoutNode() now only
unsets the DOM node's layout_node() if it's itself.
This patch adds the CharacterData subclass of Node, which is now the
parent class of Text and a new Comment class.
A Comment node is one of these in HTML: <!--hello friends-->
Since these occur somewhat frequently on the web, we need to be able
to parse them.
This patch also adds a child rejection mechanism to the DOM tree.
Nodes can now override is_child_allowed(Node) and return false if they
don't want a particular Node to become a child of theirs. This is used
to prevent Document from taking on unwanted children.
The <br> element will produce a special LayoutBreak node in the layout
tree, which forces a break in the line layout whenever encountered.
This patch also makes LayoutBlock use the current line-height as the
minimum effective height for each line box. This ensures that having
multiple <br> elements in a row doesn't create 0-height line boxes.
This patch removes the hard-coded hack for "display: list-item" from
LayoutBlock and adds LayoutListItem and LayoutListItemMarker.
Elements with "display: list-item" now generate a LayoutListItem, which
may then also generate a LayoutListItemMarker if appropriate. :^)
Just in time for Serenity's 1st birthday, here is the <blink> element!
This patch adds a bunch of different mechanisms to enable partial
repaints of the layout tree (LayoutNode::set_needs_display()))
It also adds LayoutNode::is_visible(), which can be toggled to prevent
a LayoutNode from rendering anything (it still takes up space though.)
Node.normalize() is a standard DOM API that coalesces Text nodes.
To avoid clashing with that, rename it to fixup().
This patch also makes it happen automagically as part of parsing.
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.
This patch adds basic support for external stylesheets. It currently
only works with file:// URLs.
We do a synchronous full relayout after loading a stylesheet, which is
definitely on the aggressive side, but it gives us something to work
on improving. :^)
This is a lot nicer than first_child_with_tag_name(...).
The is<T>(Node) functions are obviously unoptimized at the moment,
and this is about establishing pleasant patterns right now. :^)
These helpers return the next/previous sibling Node that's actually an
element. This will be useful in the CSS engine since CSS doesn't care
about text nodes.
This allows any external actor to signal that the document layout may be
stale. This can be used when loading resources, changing the size or
placement of an element, adding/removing nodes, or really any time.
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.
Instead of branching on the Node type, let subclasses decide how their
layout nodes get constructed.
This will allow elements to create custom layout nodes if they want.
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."
You can now pass a file:/// URL to HtmlView and it will take care of
the loading logic for you. Each Document remembers the URL it was
loaded from, which allows us to also have reload().
This patch also adds a very simple function for resolving relative
URL's into absolute ones.
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.
