Before this change, you could only scroll the current hovered scroll
container, even if it was at the beginning or end and thus having no
effect.
Now, if it doesn't update, it will not be classed as handled and will
move onto the next scroll container.
of `PaintableBox` and `PaintableWithLines`.
If we ended up with non-identity transform in `hit_test()` of PB or PWL
and have to account for transforms, means we forgot to skip stacking
context while iterating through children.
- Add missing check to skip paintable that eastablishing a stacking
context in `PaintableBox::hit_test_children()`
- Otherwise it mostly reverts changes done by 4070f5a7e
The overlay shown for the node hovered in the inspector is painted as
part of the normal tree traversal of all paintables. This works well in
most cases, but falls short in specific scenarios:
* If the hovered node or one of its ancestors establishes a stacking
context and there is another element that establishes a stacking
context close by or overlapping it, the overlay and especially the
tooltip can become partially hidden behind the second element. Ditto
for elements that act as if they established a stacking context.
* If the hovered node or one of its ancestors involves clipping, the
clip is applied to the overlay and espicially the tooltip. This can
cause them to be partially invisible.
* Similarly, if the hovered node or one of its ancestors has a defined
mask, the mask is applied to the overlay, often making it mostly
invisible.
* No overlays are shown for SVG nodes because they are painted
differently from HTML documents.
Some of these problems may be fixable with the current system. But some
seem like they fundamentally cannot work fully when the overlays are
painted as part of the regular tree traversal.
Instead we pull out painting the overlay as a separate pass executed
after the tree traversal. This way we ensure that the overlays are
always painted last and therefore on top of everything else. This also
makes sure that the overlays are unaffected by clips and masks. And
since overlay painting is independent from painting the actual elements,
it just works as well.
However we need to be careful, because we still need to apply some of
the steps of the tree traversal to get the correct result. Namely we
need to apply scroll offsets and transforms. To do so, we collect all
ancestors of the hovered node and apply those as if we were in the
normal tree traversal.
The debug option 'Show Line Box Borders' and the inspector overlay for
text nodes are conceptually similar. However they use two different
code paths. This commits unifies both to use the same code.
Previously line box borders were drawn in every phase. This caused
redundent lines to be drawn on top of each other. But it also caused
boxes to appear for text that was not visible on screen because other
elements overlayed it. That was confusing to look at since all text on
the page is highlighted at the same time using this debug functionality.
This fixes an issue where text decorations (e.g. underlines) of text
split across multiple fragments would have unintended 1px gaps.
Gains us 2 WPT passes (imported)
Previously, the first `HTMLHtmlELement` in the given document would
always be used when determining whether to propagate background
properties to the body element. This meant the wrong root element was
used for SVG `foreignObject` elements, which could lead to a crash.
Now follows the same pattern as PaintableBox and StackingContext, where
it exits if hidden, then hit tests children, then hit tests itself if
it's `visible_for_hit_testing()`.
We now also store `outline-width` in ComputedValues as a `CSSPixels`
since we know it's an absolute length at `apply_style` time - this saves
us some work in converting to CSSPixels during layout.
Gains us 46 new passes since we now interpolate keywords (thick, thin,
etc) correctly.
Also loses us 4 WPT tests as we longer clamp negative values produced by
interpolation from the point of view of getComputedStyle (although the
'used' value is still clamped).
The transform of each paintable was being applied multiple times due to
the recursive nature of the hit testing methods. Previously it used
combined_css_transform to transform the position, and then it would pass
that position to children, which would then apply combined_css_transform
again, and so on.
PaintableBoxes are also not hit tested anymore when having a stacking
context. A similar check is done in PaintableWithLines, but it was
missing from PaintableBox. Without this check some elements can get
returned multiple times from a hit test.
StackingContexts with zero opacity will now also get hit tested, as it
should have been before.
PaintableBox::handle_mouseleave is turning off scrollbar updating, but
the user might still have the primary button down to scroll. Don't turn
it off if grabbing the thumb to scroll.
Resolves crashing on MacOSX AppKit and Qt where gutter_size is 0 when
mouse is moved outside window.
Previously we would paint the cursor the entire height of the text
fragment - this didn't look great with large line-heights. Now we only
paint it the height of the actual text, with the top of the cursor
aligning with the font "ascent" and the bottom the "descent".
There's no need to have separate display list item for drawing triangle
wave when we could simply use StrokePathUsingColor. By switching to
StrokePathUsingColor we could also reduce painting because it supports
filtering out by bounding box.
PaintContext dates back to a time when display lists didn't exist and it
truly represented "paint context". Renaming it to better align with its
current role.
The faux position we created here is adjusted by the device pixel ratio
later on, which would invoke integer overflow on screens with a DPR
greater than 1.
Instead of creating special data for a mouse move event, let's just add
an explicit leave event handler.
This migrates TextNode::text_for_rendering() to Utf16String and deals
with the fallout. As a consequence, this effectively reverts commit
3df83dade8.
The layout test expecation file updates are because we now express text
lengths and offsets in UTF-16 code units.
The selection-over-multiple-code-units expectation file update actually
represents a correctness fix. Our result now matches Firefox.
Until now, every paint phase of every PaintableBox injected its own
clipping sequence into the display list:
```
before_paint: Save
AddClipRect (1)
...clip rectangles for each containing block with clip...
AddClipRect (N)
paint: ...paint phase items...
after_paint: Restore
```
Because we ran that sequence for every phase of every box, Skia had to
rebuild clip stack `paint_phases * paintable_boxes` times. Worse,
usually most paint phases contribute no visible drawing at all, yet we
still had to emit clipping items because `before_paint()` has no way to
know that in advance.
This change takes a different approach:
- Clip information is now attached as metadata `ClipFrame` to each
DisplayList item.
- `DisplayListPlayer` groups consecutive commands that share a
`ClipFrame`, applying the clip once at the start of the group and
restoring it once at the end.
Going from 10 ms to 5 ms in rasterization on Discord might not sound
like much, but keep in mind that for 60fps we have 16 ms per frame and
there is a lot more work besides display list rasterization we do in
each frame.
* https://discord.com/channels/1247070541085671459/1247090064480014443
- DisplayList items: 81844 -> 3671
- rasterize time: 10 ms -> 5 ms
- record time: 5 ms -> 3 ms
* https://github.com/LadybirdBrowser/ladybird
- DisplayList items: 7902 -> 1176
- rasterize time: 4 ms -> 4 ms
- record time: 3 ms -> 2 ms
In the upcoming change, device pixel conversion of ClipFrame will
happen during display list replay, where PaintContext is not available,
so let’s move it out of PaintContext.
Initially ClippableAndScrollable was introduced, because we had
PaintableBox and InlinePaintable and both wanted to share clipping and
scrolling logic. Now, when InlinePaintable is gone, we could inline
ClippableAndScrollable implementation into PaintableBox.
Previously, we always applied the enclosing clip rectangle for all paint
phases except overlays, and the own clip rectangle for the background
and foreground phases. The problem is that applying a clip rectangle
means emitting an AddClipRect display list item for each clip rectangle
in the containing block. With this change, we choose whether to include
the own clip based on the paint phase and this way avoid emitting
AddClipRect for enclosing clip rectangles twice.
Own clip rect is alredy applied in `PaintableBox::before_paint()` for
all paintables with lines, so there's no need to do it once again in
`PaintableWithLines::paint()`.
We were always delegating hit tests to PaintableBox if a
PaintableWithLines has no fragments, which means that anonymous
containers could overlap with previous siblings and prioritize their
border box rect. Instead, the nearest non-anonymous ancestor should take
care of hit testing the children so the correct order is maintained.
To achieve this, we no longer do an early hit test in
PaintableWithLines::hit_test() if there are no fragments and default
to the later PaintableBox::hit_test() call that does take anonymous
containers into account.
Fixes the issue seen in #4864.
This way we can reuse the logic between PaintableWithLines and
PaintableBox. It also introduces the .is_positioned() check for the
children of a PaintableWithLines, which makes sure to skip positioned
child nodes since those are handled by the StackingContext.
A PaintableWithLines will first try to see if there are any fragments
that have a hit. If not, it falls back to hit testing against its border
box rect.
However, inline content is often hoisted out of its parent into an
anonymous container to maintain the invariant that all layout nodes
either have inline or block level children. If that's the case, we
should not check the border box rect of the anonymous container, because
we might trigger a hit too early if the node has previous siblings in
its original parent node that overlap with their bounds.
By ignoring anonymous nodes, we leave the border box hit testing to the
nearest non-anonymous ancestor, which correctly applies the hit testing
order to its children.
Note that the border box rect checks whether the _untransformed_ point
is inside of it, which mirrors the behavior of PaintableBox::hit_test().
