Add LayoutPosition and LayoutRange classes. The layout tree root node
now has a selection() LayoutRange. It's essentially a start and end
LayoutPosition.
A LayoutPosition is a LayoutNode, and an optional index into that node.
The index is only relevant for text nodes, where it's the character
index into the rendered text.
HtmlView now updates the selection start/end of the LayoutDocument when
clicking and dragging with the left mouse button.
We don't paint the selection yet, and there's no way to copy what's
selected. It only exists as a LayoutRange.
After the splitting-into-lines pass, remove any trailing whitespace
from all of a block's line boxes.
This improves the appearance of text-align: justify/right :^)
In order for this to work nicely, I made the line box classes use float
instead of int for its geometry information.
Justification works by distributing all of the whitespace on the line
(including the trailing whitespace before the line break) evenly across
the spaces in-between words.
We should probably use floating point (or maybe fixed point?) for all
the layout metrics stuff. But one thing at a time. :^)
This patch implements basic support for <a href="#foo"> fragment links.
To figure out where we actually want to scroll to, we have to do
something different based on the layout node's box type. So if it's a
regular LayoutBox we can just use the LayoutBox::position().
However, if it's an inline layout node, we use the position of the
first line box fragment in the containing block contributed by this
layout node or one of its descendants.
Basically the same exact fix as I did for replaced elements. There's no
point in inserting a line break at the start of a line if all you're
trying to achieve is make more horizontal space for something.
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. :^)
If the current line box already has zero width, there's no point in
inserting a line break to make space, since we'll just be at x=0 after
breaking as well.
This removes an ugly unnecessary line break before images wider than
their containing block. :^)
This is a total hack to get around the auto-detection mechanism for
whether a block has inline or block children. We'll say that tables
never have inline children for now, and then anything that actually
turns out to be an inline child will just be ignored by layout.
Instead of computing whether a block's children are inline based on the
first child, make it an imperatively-set flag.
This gives us some flexibility to ignore things like text nodes inside
a <table>, for example. I'm still unsure what the "correct" way to deal
with those will be. We'll find out sooner or later. :^)
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.
If a LayoutNode is split into line box fragments, we need to walk our
fragments and invalidate them. It was not enough to do this only for
LayoutBox nodes.
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. :^)
Replaced elements will now properly create line breaks when they use up
the available horizontal space.
This fixes an issue with <img>'s lining up instead of breaking.
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.
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.
We currently hard-code the line height to 140% of the font glyph height
and this patch doesn't fix the hard-coding, but at least moves it out
of LayoutText and into StyleProperties where it can be re-used until
the day we go and do a proper implementation of CSS line-height. :^)
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.)
Before breaking the Text node contents into words, collapse all of the
whitespace into single space (' ') characters. This fixes broken
rendering of paragraphs with newlines in them. :^)
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*.
