Empty fragments may need to be layed out to draw borders, padding/background,
and insertion points. (Fragments that consist of discardable whitespace and
control characters, on the other hand, can still be discarded.)
This ends up preserving some useless empty fragments. It's possible we could
avoid this by storing some sort of flag on "important" empty fragments, so we
can discard the rest.
This fixes two problems that could cause scanned text fragments to end up with
incorrect LAST_FRAGMENT_OF_ELEMENT or FIRST_FRAGMENT_OF_ELEMENT flags:
1. If a single unscanned fragment was split into multiple scanned fragments,
then all of them would inherit its flags. We need to clear these flags,
except for the first and last scanned fragment.
2. When an unscanned fragment generated zero scanned fragments, we correctly
called `meld_with_next_inline_fragment` to transfer LAST_FRAGMENT flags to
the preceding fragment, but we didn't do anything to transfer
FIRST_FRAGMENT flags to the following fragment. We can fix this by calling
`meld_with_prev_inline_fragment` on the following fragment.
Before this fix, if a TextRun containing an insertion point was split into
multiple ScannedText fragments, text layout would draw an insertion point
inside of each of the fragments. This patch records the insertion point
position at most once per TextRun, and copies it only into the appropriate
ScannedText fragment.
Reduce size of layout::fragment::Fragment struct
This reduces the size of the SpecificFragmentInfo enum from 48 to 24.
r? @pcwalton
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This is the first part of #10185. More to follow. I have built this locally with both servo and geckolib without errors; let's see if it succeeds on all platforms as well.
Highlight selected text in input fields
Fixes#9993. This does not yet allow stylesheets to set the selection colors; instead it uses a hard-coded orange background and white foreground.
r? @pcwalton
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margins.
* The code that attempted to strip out borders that span multiple
fragments in the same element could go wrong if fragments were
stripped out due to text clumping or whitespace stripping. This patch
rewrites that code to maintain flags in the inline fragment context
specifying whether the node is the beginning or end of the element.
Not only is this easier to maintain, it's closer in spirit to what roc
originally suggested two years ago: it's isomorphic to "begin element,
end element" markers for inline layout.
* Padding and margins for spans containing inline-blocks are now
properly handled via a division of labor between the `InlineBlock`
fragment and the `BlockFlow` that represents the inline-block.
* Unscanned text fragments may not be joined together into a text run if
borders, padding, or margins separate them.
Because Servo now matches the rendering of Gecko and WebKit on the
`input_button_margins_a` reftest, I had to modify it to add some
vertical alignment.
The combined effect of all of these fixes places "Advertising" on the
right place on google.com.
This patch makes Servo unconditionally strip whitespace before text run
scanning (assuming that the `white-space` property allows it). Whitespace
stripping during reflow is now only used for handling whitespace at the ends of
lines; reflow now never attempts to handle ignorable whitespace.
Many CSS tests pass now. There are some new failures, however.
The following reference tests now fail due to a pre-existing bug whereby
whitespace is used to calculate the position of inline hypothetical boxes for
elements with `display: inline; position: absolute`:
* `absolute-replaced-height-036.htm`
* `vertical-align-sub-001.htm`
* `vertical-align-super-001.htm`
The following reference tests fail due to a pre-existing bug whereby we don't
handle `font-size: 0` properly in inline reflow:
* `font-size-zero-1.htm`
* `font-size-zero-2.htm`
The following reference test fails due to the fact that it relied on our
incorrect insertion of whitespace to make room for the black background:
* `inline-formatting-context-007.htm`
This removes an extraneous layer of indirection, without increasing the size
of the `SpecificFragmentInfo` enum (because `Box<str>` is a fat pointer, which
is the same size as the `FlowRef` trait object that is already stored in
`InlineAbsoluteHypotheticalFragmentInfo`)
wrapping on newlines rather than searching for a newline character.
Since the newline character might have been stripped out during
whitespace stripping, this was incorrect.
Fixes the "jumpiness" seen on the Google home page, Wikipedia, and many
other places.
text layout, and unify the inline layout paths for pre- and
normally-formatted text.
This fixes a lot of "jumpiness" and removes the `new_line_pos` stuff.
Closes#2260.
