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().
We were calculating the scroll delta based on the last known mouse
position, even if that position ventured far beyond the scroll bar's
rect. This caused weird behavior such as scrolling when the mouse was
clearly not on the scrollbar.
This reworks the scrollbar logic to use the mouse's absolute position
instead of a delta, and to always calculate and set the absolute scroll
offset. This makes it much easier to reason about the scrollbar's
position, plus we don't need the last mouse position anymore.
As far as I can tell, our scroll bar behavior now closely resembles
Firefox' behavior.
We generated `PaintableFragment`s with a start and length represented in
UTF-8 byte offsets, but failed to consider that the offsets in a
`DOM::Range` are actually expressed in UTF-16 code units.
This is a bit of a mess: almost all web specs use UTF-16 code units as
the unit for indexing into text nodes, but we almost exclusively use
UTF-8 in our code base. Arguably the best thing would for us to use
UTF-16 everywhere as well: it prevents these mismatches in our
implementations for the price of a bit more memory usage - and even that
could potentially be optimized for.
But for now, try to do the correct thing and lazily allocate UTF-16 data
in a `PaintableFragment` whenever we need to index into it or if we're
asked to determine the code unit offset of a pixel position.
A scrollbar contains a mouse position only if its gutter rect contains
that position. We were incorrectly deciding a position was contained if
it fell to the right of a vertical scrollbar, or below a horizontal
scrollbar.
Currently, compute_scrollbar_data does not adjust the position of the
scrollbar thumb based on the actual scroll offset. This is because we
perform this offset in most cases inside the display list executor, in
order to allow us to avoid recomputing the display list.
However, there are cases where we do want the thumb rect with an offset
inside PaintableBox. We currently use scroll_thumb_rect to perform that
computation.
In an upcoming patch, we will need both this offset thumb rect and the
scrollbar gutter rect. So this patch moves the computation of the offset
to compute_scrollbar_data, performed behind an optional parameter.
When a scrollbar is not interacting with the mouse, we now draw the
scrollbar slightly slimmer. When the mouse enters the space occupied
by the scrollbar, we enlarge it for easier mouse interactivity.
Fixes underinvalidation caused by resolving text-decoration-thickness
during layout commit, while this property can be invalidated
independently of layout.
