When performing a hit test of type TextCursor, it would check if the
position is around each fragment and not just inside it. This resulted
in always selecting the first fragment checked.
This commit computes the distance of each hit test result, and picks the
closest one.
Calls to `Document::set_needs_display()` and
`Paintable::set_needs_display()` now invalidate the display list by
default. This behavior can be changed by passing
`InvalidateDisplayList::No` to the function where invalidating the
display list is not necessary.
Scroll offset of body does not affect position of fixed elements, so
nearest scrollable lookup should early return from ancestor scrollable
lookup loop once "position: fixed" box is encountered.
Fixes regression introduced in 866608532a
Sticky positioning is implemented by modifying the algorithm for
assigning and refreshing scroll frames. Now, elements with
"position: sticky" are assigned their own scroll frame, and their
position is refreshed independently from regular scroll boxes.
Refreshing the scroll offsets for sticky boxes does not require display
list invalidation.
A separate hash map is used for the scroll frames of sticky boxes. This
is necessary because a single paintable box can have two scroll frames
if it 1) has "position: sticky" and 2) contains scrollable overflow.
This allows the calculation of the cumulative scroll offset for a scroll
frame by adding its scroll offset to the parent’s scroll offset, rather
than traversing the containing block chain. While it doesn't greatly
simplify calculations for typical scroll frames, it serves as a
preparation for supporting "position: sticky".
This change is intended to insure that the thumb control on the dialog
will never be narrower than 50 pixels no matter how long the line it's
displaying.
We *could* even skip creating a paintable for hidden nodes, but that
means that dynamic updates to the CSS visibility property would require
mutating the paint tree, so let's keep it simple for now.
Instead, it could be applied directly as a clip path in Skia painter.
As a side bonus, we get rid of some DeprecatedPath and
AntiAliasingPainter usage.
A new display list item type named PaintScrollBar is introduced. Having
a dedicated type for scroll bars allows the thumb position to be updated
without rebuilding a display list. This was not possible with
FillRectWithRoundedCorners that does not allow to tell whether it
belongs to scroll thumb.
A display list should not contain coordinates shifted by scroll offset.
Instead, "scroll frame id" needs to be used. In the future it's going to
allow us reuse a display list in cases when only scroll offsets need to
be updated.
Before this change AddClipRect was a "special" because it didn't respect
scroll frame offset and was meant to be recorded using viewport-relative
coordinates. The motivation behind this was to record a "final" clip
rectangle computed by intersecting all clip rectangles used by a clip
frame. The disadvantage of this approach is that it blocks us from
implementing an optimisation to reuse display list if the only change is
in the scroll offset, because any scroll offset change leads to
invalidating all AddClipRect items within a list.
This change aligns AddClipRect with the rest of display list items by
making it account for scroll frame offset. It required discontinuing
the recording of the intersection of all clip rectangles within a clip
frame and instead producing an AddClipRect for each of them.
A nice side effect is the removal of code that shifts clip rectangle by
`enclosing_scroll_offset()` in a bunch of places, because now it happens
automatically in `DisplayList::apply_scroll_offsets()`.
This change causes the viewport to be treated as a "scroll frame,"
similar to how it already works for boxes with "overflow: scroll."
This means that, instead of encoding the viewport translation into a
display list, the items will be assigned the scroll frame id of the
viewport and then shifted by the scroll offset before execution. In the
future it will allow us to reuse a display list for repainting if only
scroll offset has changed.
As a side effect, it also removes the need for special handling of
"position: fixed" because compensating for the viewport offset while
painting or hit-testing is no longer necessary. Instead, anything
contained within a "position: fixed" element is simply not assigned
a scroll frame id, which means it is not shifted by the scroll offset.
This change fixes layering violation by moving to_px() calls to happen
before display list recording. Also it should make display list
recording a bit faster by resolving background properties beforehand.
Navigables are re-used for navigations within the same tab. Its current
ownership of the cursor position is a bit ad-hoc, so nothing in the spec
indicates when to reset the cursor, nor do we manually do so. So when a
cursor update happens on one page, that cursor is retained on the next
page.
Instead, let's have the document own the cursor. Each navigation results
in a new document, thus we don't need to worry about resetting cursors.
This also makes many of the callsites feel nicer. We were previously
often going from the node, to the document, to the navigable, to the
cursor. This patch removes the navigable hop.
Overflow clipping is currently implemented as:
1. Create clip frame for each box with hidden overflow
2. Calculate clip rect for each clip frame by intersecting padding boxes
of all boxes with hidden overflow in containing block chain
3. Assign enclosing clip frame (closest clip frame in containing block
chain) to each PaintableBox
4. Apply clip rect of enclosing clip frame in Paintable::before_paint()
It breaks when any CSS transform other than simple translation is lying
between box with hidden overflow and a clipped box, because clip
rectangle will be applied when transform has already changed.
The fix is implemented by relying on the following rule:
"For elements whose layout is governed by the CSS box model, any value
other than none for the transform also causes the element to establish
a containing block for all descendants."
It means everything nested into a stacking context with CSS transform
can't escape its clip, so it's safe to apply its clip for all children.
Moves paint_table_borders() call into PaintableBox::paint() to make
scroll offset and clip rectangle of enclosing scrollable be applied
in ::before_paint().
Contrary to LibGfx, where corner clipping was implemented by sampling
and blitting pixels under corners into a temporary bitmap, Skia allows
us to simply apply a mask. As a result, we no longer need the
BlitCornerClipping command, which has become a no-op.
- SampleUnderCorners is renamed to AddRoundedRectClip
- The optimization that skipped unnecessary blit and sample commands has
been removed. However, this should not result in a performance
regression because Skia seems to perform mask rasterization lazily.
Having resolution of all properties for all paintable types in a single
function was hard to iterate on, so this change separates it into
smaller functions per paintable type.
Previously calling `PaintableBox::set_scroll_offset()` with a
PaintableBox whose content size was larger than its scrollble overflow
rect would cause a crash.
Found by Domato.
Previously, the scrollbar thumbs were (almost) invisible, when the page
background color was similar to the scrollbar thumb color (DarkGray).
Now, in addition to the filled rounded rectangle, the scrollbar thumbs
are painted with a 1px solid LightGrey border. On a white or light color
background the border stays invisible.
The ChunkIterator now limits a chunk to using only one font (before, it
was possible to have a chunk with >1 font, when `unicode-range` CSS
property is used).
This change allows us to reduce some complexity in the text shaping and
painting code and makes us compatible with the APIs in Skia and
HarfBuzz.
The main intention of this change is to have a consistent look and
behavior across all scrollbars, including elements with
`overflow: scroll` and `overflow: auto`, iframes, and a page.
Before:
- Page's scrollbar is painted by Browser (Qt/AppKit) using the
corresponding UI framework style,
- Both WebContent and Browser know the scroll position offset.
- WebContent uses did_request_scroll_to() IPC call to send updates.
- Browser uses set_viewport_rect() to send updates.
After:
- Page's scrollbar is painted on WebContent side using the same style as
currently used for elements with `overflow: scroll` and
`overflow: auto`. A nice side effects: scrollbars are now painted for
iframes, and page's scrollbar respects scrollbar-width CSS property.
- Only WebContent knows scroll position offset.
- did_request_scroll_to() is no longer used.
- set_viewport_rect() is changed to set_viewport_size().
This adds a `--experimental-cpu-transforms` option to Ladybird and
WebContent (which defaults to false/off).
When enabled the AffineCommandExecutorCPU will be used to handle
painting transformed stacking contexts (i.e. stacking contexts where
the transform is something other than a simple translation). The regular
command executor will still handle the non-transformed cases.
This is hidden under a flag as the `AffineCommandExecutorCPU` is very
incomplete now. It missing support for clipping, text, and other basic
commands. Once most common commands have been implemented this flag
will be removed.
Although refreshing is cheap, it was performed before each hit-testing
and was 2-4% in profiles on Discord and Twitter.
Now clip and scroll states are refreshed only if scroll offset has
changed.
All painting commands except SetClipRect are shifted by scroll offset
before command list execution. This change removes scroll offset
translation for sample/blit corner commands in
`PaintableWithLines::paint` so it is only applied once in
`CommandList::apply_scroll_offsets()`.
Currently, these only work when there are no CSS transforms (as the
stacking context painting is not set up to handle that case yet). This
is still enough to get most chat/comment markers working on GitHub
though :^)
Changes compute_absolute_padding_rect_with_css_transform_applied() to
use cached absolute rect and CSS transform instead of doing expensive
containing block chain traversal.
Reduces refresh_clip_state() from 4% to 2% in Discord profiles.
