LibHTML will now use the palette colors for the default document background and
the text. As always, a page can override this default styling with CSS if it
really wants a specific color or style.
Fixes https://github.com/SerenityOS/serenity/issues/963
GApplication now has a palette. This palette contains all the system
theme colors by default, and is inherited by a new top-level GWidget.
New child widgets inherit their parents palette.
It is possible to override the GApplication palette, and the palette
of any GWidget.
The Palette object contains a bunch of colors, each corresponding to
a ColorRole. Each role has a convenience getter as well.
Each GWidget now has a background_role() and foreground_role(), which
are then looked up in their current palette when painting. This means
that you no longer alter the background color of a widget by setting
it directly, rather you alter either its background role, or the
widget's palette.
When the visible viewport rect changes, we walk the layout tree and
check where each LayoutImage is in relation to the viewport rect.
Images outside have their bitmaps marked as volatile.
Note that the bitmaps are managed by ImageDecoder objects. If a bitmap
is purged by the kernel while volatile, we construct a new ImageDecoder
next time we need pixels for the image.
Using int was a mistake. This patch changes String, StringImpl,
StringView and StringBuilder to use size_t instead of int for lengths.
Obviously a lot of code needs to change as a result of this.
This patch adds "submit" inputs and default (text box) inputs, as well
as form elements that can be submitted.
Layout of input elements is implemented via a new LayoutWidget class
that allows you to put an arbitrary GWidget in the layout tree.
At the moment, the DOM node sets the initial size of the LayoutWidget,
and then the positioning is done by the normal layout algorithm.
We also now support submitting a <form method="GET">, which does a full
replacing load with a URL based on the form's action + a query string
built from the name/value of input elements within the submitted form.
This is pretty neat! :^)
Before this patch, all of the excess spacing caused by line-height was
"padding" the line boxes below the text.
To fix this, we make line box fragments use the font height as their
height, and then let the inline layout algorithm adjust the Y positions
to distribute the vertical space.
Always paint border edges so they join nicely with their buddy edges.
This makes borders look nice even if all sides have different widths.
Also switch the border code to using floating point numbers since
otherwise things get very ugly very fast.
The borders still look very wrong with any border-width other than 1,
but at least we can see that they have the right color, and end up in
mostly the right place :^)
This code was using the text from the DOM as a reference for how much
whitespace to remove from the end of a line box.
Since the DOM may contain uncollapsed whitespace, it would sometimes
be out of sync with the collapsed text used by the rest of the layout
system.
These CSS properties constrain the computed width of a block-level box
to a maximum, followed by a minimum value.
This makes the "better mother fricken website" look more like it's
intended to (which helps makes the author's point, I suppose.)
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. :^)
