Previously, we were collapsing whitespace in Layout::TextNode and then
passed the resulting string for further processing through ChunkIterator
-> InlineLevelIterator -> InlineFormattingContext -> LineBuilder ->
LineBoxFragment -> PaintableFragment. Our painting tree is where we deal
with things like range offsets into the underlying text nodes, but since
we modified the original string, the offsets were wrong.
This changes the way we generate fragments:
* Layout::TextNode no longer collapses whitespace as part of its
stored "text for rendering", but moves this logic to ChunkIterator
which splits up this text into separate views whenever whitespace
needs to be collapsed.
* Layout::LineBox now only extends the last fragment if its end offset
is equal to the new fragment's start offset. Otherwise, there's a
gap caused by collapsing whitespace and we need to generate a
separate fragment for that in order to have a correct start offset.
Some tests need new baselines because of the fixed start offsets.
Fixes#566.
Previously, it was possible for an up/down arrow press to place the
cursor in the middle of a multi-code point grapheme cluster. We want to
prevent this in a way that matches the behavior of other browsers.
Both Chrome and Firefox will map the starting position to a visually
equivalent position in the target line with harfbuzz and ICU segmenters.
The need for this is explained in a code comment. The result is a much
more natural feeling of text navigation.
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.
This exposed a few bugs which caused the following tests to behave
incorrectly:
- `tab-size-text-wrap.html`: This previously relied on a bug where we
incorrectly treated `white-space: pre` as allowing text wrapping. The
fix here is to implement the text-wrap CSS shorthand property.
- `execCommand-preserveWhitespace.html`: We don't correctly serialize
shorthand properties. This is covered by an existing FIXME in
`CSSStyleProperties::serialized()`
- `white-space-shorthand.html`: The last 5 subtests here fail as we
don't correctly handle shorthand properties in
`CSSStyleProperties::remove_property()`. This is covered by an
existing FIXME in said function.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
This means that an `<input type=password>` will show the correct number
of *s in it when non-ASCII characters are entered.
We also don't need to perform text-transform on these as that doesn't
affect the output length, so I've moved it earlier.
Various whitespace-related issues have been fixed, and support for the
different CSS white-space values is improved enough that I think we can
stop doing the hack where we just prune whitespace nodes from the tree
and actually let them show up.
This is a nice step forward for correctness with the slight downside of
cluttering up layout tree dumps with tons of whitespace text nodes.
But hey, that's the web we know & love. :^)
Fixes#4427.
We were only pruning trailing whitespace on lines. This patch makes it
so we also don't add whitespace as the leading line box fragment on new
lines.
This logic is pretty crufty and I think we can do better, but for now
I've just made it handle this extra case so we can stop having lines
that start with a space character. :^)
The BFC "context box" is now the outer box of the block formatting
context. Previously the context box was always the current target box,
which made it hard to reason about who was really the containing block
of whom in various places.
Note that IFC still has the containing block as its context box, this
change only affects BFC. However, to clarify the situation in IFC,
I've added a containing_block() getter than returns the context_box().
Boxes can now be floated left or right, which makes text within the
same block formatting context flow around them.
We were creating way too many block formatting contexts. As it turns
out, we don't need one for every new block, but rather there's a set
of rules that determines whether a given block creates a new block
formatting context.
Each BFC keeps track of the floating boxes within it, and IFC's can
then query it to find the available space for line boxes.
There's a huge hack in here where we assume all lines are the exact
line-height. Making this work with vertically non-uniform lines will
require some architectural changes.
Fragment painting was very limited by only being called during the
foreground paint phase. We now paint fragments as part of every phase
(and the phase is passed to paint_fragment() of course!)
Bring the names of various boxes closer to spec language. This should
hopefully make things easier to understand and hack on. :^)
Some notable changes:
- LayoutNode -> Layout::Node
- LayoutBox -> Layout::Box
- LayoutBlock -> Layout::BlockBox
- LayoutReplaced -> Layout::ReplacedBox
- LayoutDocument -> Layout::InitialContainingBlockBox
- LayoutText -> Layout::TextNode
- LayoutInline -> Layout::InlineNode
Note that this is not strictly a "box tree" as we also hang inline/text
nodes in the same tree, and they don't generate boxes. (Instead, they
contribute line box fragments to their containing block!)
2020-11-22 15:56:27 +01:00
Renamed from Libraries/LibWeb/Layout/LayoutText.cpp (Browse further)
