According to the CSS font matching algorithm specification, it is
supposed to be executed for each glyph instead of each text run, as is
currently done. This change partially implements this by having the
font matching algorithm produce a list of fonts against which each
glyph will be tested to find its suitable font.
Now, it becomes possible to have per-glyph fallback fonts: if the
needed glyph is not present in a font, we can check the subsequent
fonts in the list.
This change fixes a problem that we should not call `to_px()` to
resolve any length or percentage values during paintables traversal
because that is supposed to happen while performing layout.
Also it improves performance because before we were resolving border
radii during each painting phase but now it happens only once during
layout.
BorderRadiusCornerClipper usage to clip border radius is specific to
CPU painter so it should not be stored in painting commands.
Also with this change bitmaps for corner sampling are allocated during
painting commands replaying instead of commands recording.
Previously, we determined the positions of glyphs for each text run at
the time of painting, which constituted a significant portion of the
painting process according to profiles. However, since we already go
through each glyph to figure out the width of each fragment during
layout, we can simultaneously gather data about the position of each
glyph in the layout phase and utilize this information in the painting
phase.
I had to update expectations for a couple of reference tests. These
updates are due to the fact that we now measure glyph positions during
layout using a 1x font, and then linearly scale each glyph's position
to device pixels during painting. This approach should be acceptable,
considering we measure a fragment's width and height with an unscaled
font during layout.
Currently, in CPU painter, border painting is implemented by building
a Gfx::Path that is filled by Gfx::AntiAliasingPainter. In the GPU
painter, we will likely want to do something different, and with a
special command, it becomes possible.
Also, by making this change, the CPU executor also benefits because now
we can skip building paths for borders that are out of the viewport.
By consistently accepting only device pixel values instead of a mix of
CSSPixels and DevicePixels values, we can simplify the implementation
of paint_border() and paint_all_borders().
Reduction of bug:
```html
<!DOCTYPE html><style>
html {
overflow-x: hidden;
overflow-y: scroll;
}
div {
background: orange;
height: 1000px;
width: 500px;
}
</style><body><div>
```
Fixes https://github.com/SerenityOS/serenity/issues/21690 and painting
on many other websites (null.com, servo.org).
By storing painting command coordinates relative to the nearest
stacking context we can get rid of the Translate command.
Additionally, this allows us to easily check if the bounding
rectangles of the commands cover or intersect within a stacking
context. This should be useful if we decide to optimize by avoiding
the execution of commands that will be overpainted by the results of
subsequent commands.
With the recording painter the actual painting operations are delayed,
so now if multiple corner clippers are constructed, and they use a
shared bitmap they can interfere with each other. The use of this shared
bitmap was somewhat questionable anyway, so this is not much of a loss.
This fixes the border-radius.html test page.
This modification introduces a new layer to the painting process. The
stacking context traversal no longer immediately calls the
Gfx::Painter methods. Instead, it writes serialized painting commands
into newly introduced RecordingPainter. Created list of commands is
executed later to produce resulting bitmap.
Producing painting command list will make it easier to add new
optimizations:
- It's simpler to check if the painting result is not visible in the
viewport at the command level rather than during stacking context
traversal.
- Run painting in a separate thread. The painting thread can process
serialized painting commands, while the main thread can work on the
next paintable tree and safely invalidate the previous one.
- As we consider GPU-accelerated painting support, it would be easier
to back each painting command rather than constructing an alternative
for the entire Gfx::Painter API.
Instead of resolving lengths used in the backdrop-filter during
painting, we can do that earlier in apply_style().
This change moves us a bit closer to the point when the stacking
context tree will be completely separated from the layout tree :)
This fixes an issue where the value would be out of sync with reality
in anonymous wrapper block boxes, since we forgot to compute m_visible
after assigning the computed values to them.
Fixes#21106
d06d4eb made the `clip` property apply to children of an absolute-
positioned element, but caused it not to be applied to the element the
property was applied to directly.
To fix this, apply the clip in new `before_paint()` and `after_paint()`
functions. Doing so keeps painter state from leaking from `paint()`,
but still allows subclasses of `PaintableBox` clip their contents
correctly without repeating the application of the clip rectangle.
This is intended to annotate conversions from unknown floating-point
values to CSSPixels, and make it more obvious the fp value will be
rounded to the nearest fixed-point value.
In general it is not safe to convert any arbitrary floating-point value
to CSSPixels. CSSPixels has a resolution of 0.015625, which for small
values (e.g. scale factors between 0 and 1), can produce bad results
if converted to CSSPixels then scaled back up. In the worst case values
can underflow to zero and produce incorrect results.
Fixes bug when "clip" property does not affect abspos children.
This change makes "clip" property to be applied together with
"overflow: hidden" in `apply_clip_overflow_rect()` that already
handles abspos children correctly.
Instead of applying relative offsets (like position:relative insets)
during painting and hit testing, we now do a pass at the end of layout
and assign the final resolved offsets to paintables.
This makes painting and hit testing easier since they don't have to
think about relative offsets, and it also fixes a bug where offsets were
not applied to text fragments inside inline-flow elements that were
themselves position:relative.
Fixes painting of nested nodes in scrollable containers by moving
painter's scroll offset translation from paint_node() to
before_children_paint() and after_children_paint().
Build a grid snapped to device pixels and use it to construct the
rectangles for the cell edges, same as for collapsed borders. This is
especially important when border-spacing is set to 0 since it avoids
gaps between adjacent cells which have borders set.
It is only PaintableBox that can have scrollable overflow so it doesn't
make sense to have handle_mousewheel() implementation in Paintable.
Also new implementation of handle_mousewheel() takes in account overflow
limits from scrollable_overflow_rect().
...along with `outline-color`, `outline-style`, and `outline-width`.
This re-uses the existing border-painting code, which seems to work well
enough!
This replaces the previous code for drawing focus-outlines, with generic
outline painting for any elements that want it. Focus outlines are now
instead supported by this code in Default.css:
```css
:focus-visible {
outline: auto;
}
```
The `clip_shrink` optimization in `paint_background()` now also
correctly uses DevicePixels, instead of reducing a DevicePixel rect by
a CSSPixels amount.
Using fixed-point saturated arithmetics for CSSPixels allows to avoid
accumulating floating-point errors.
This implementation is not complete yet: currently saturated
arithmetics implemented only for addition. But it is enough to not
regress any of layout tests we have :)
See https://github.com/SerenityOS/serenity/issues/18566
This finally fixes the issue where stacking contexts that have either a
transform or opacity != 1 would clip their descendants to the root of
the stacking context.
Always use `would_be_fully_clipped_by_painter` to check if painting can
be skipped.
This allows to quickly find all the places where this check happens and
also removes incosistency that before we checked for intersection with
viewport rect in some places and for intersection with painter clip
rect in other places.
This makes it possible to set a pseudo-element as the inspected node
using Document::set_inspected_node(), Document then provides
inspected_layout_node() for the painting related functions.
