Changeset 284678 in webkit

Timestamp:

Oct 22, 2021, 6:44:00 AM (5 years ago)

Author:

Alan Bujtas

Message:

[LFC][IFC] Add support for checking leading collapsible whitespace in InlineContentBreaker::processOverflowingContent
​https://bugs.webkit.org/show_bug.cgi?id=232091

Reviewed by Antti Koivisto.

This patch ensures that the leading collapsible whitespace on the continuous run is taken
into account when checking if the otherwise overflowing content may fit the line.
e.g.
<span style="white-space: nowrap">no_wrap </span><span> yes_wrap</span>
The " yes_wrap" content has a collapsible leading whitespace here.
(This is also a preparation for fixing a regression and a WPT test.)

• layout/formattingContexts/inline/InlineContentBreaker.cpp:

(WebCore::Layout::isVisuallyEmptyWhitespaceContent):
(WebCore::Layout::InlineContentBreaker::processOverflowingContent const):
(WebCore::Layout::InlineContentBreaker::ContinuousContent::append):
(WebCore::Layout::InlineContentBreaker::ContinuousContent::reset):

• layout/formattingContexts/inline/InlineContentBreaker.h:

(WebCore::Layout::InlineContentBreaker::ContinuousContent::leadingCollapsibleWidth const):
(WebCore::Layout::InlineContentBreaker::ContinuousContent::trailingCollapsibleWidth const):
(WebCore::Layout::InlineContentBreaker::ContinuousContent::hasCollapsibleContent const):
(WebCore::Layout::InlineContentBreaker::ContinuousContent::isFullyCollapsible const):
(WebCore::Layout::InlineContentBreaker::ContinuousContent::collapsibleLogicalWidth const): Deleted.
(WebCore::Layout::InlineContentBreaker::ContinuousContent::nonCollapsibleLogicalWidth const): Deleted.
(WebCore::Layout::InlineContentBreaker::ContinuousContent::hasTrailingCollapsibleContent const): Deleted.

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• layout/formattingContexts/inline/InlineContentBreaker.cpp (modified) (5 diffs)
• layout/formattingContexts/inline/InlineContentBreaker.h (modified) (3 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2021-10-22  Alan Bujtas  <zalan@apple.com>
+
+        [LFC][IFC] Add support for checking leading collapsible whitespace in InlineContentBreaker::processOverflowingContent
+        https://bugs.webkit.org/show_bug.cgi?id=232091
+
+        Reviewed by Antti Koivisto.
+
+        This patch ensures that the leading collapsible whitespace on the continuous run is taken
+        into account when checking if the otherwise overflowing content may fit the line.
+        e.g.
+        <span style="white-space: nowrap">no_wrap </span><span> yes_wrap</span>
+        The " yes_wrap" content has a collapsible leading whitespace here.
+        (This is also a preparation for fixing a regression and a WPT test.)
+
+        * layout/formattingContexts/inline/InlineContentBreaker.cpp:
+        (WebCore::Layout::isVisuallyEmptyWhitespaceContent):
+        (WebCore::Layout::InlineContentBreaker::processOverflowingContent const):
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::append):
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::reset):
+        * layout/formattingContexts/inline/InlineContentBreaker.h:
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::leadingCollapsibleWidth const):
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::trailingCollapsibleWidth const):
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::hasCollapsibleContent const):
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::isFullyCollapsible const):
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::collapsibleLogicalWidth const): Deleted.
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::nonCollapsibleLogicalWidth const): Deleted.
+        (WebCore::Layout::InlineContentBreaker::ContinuousContent::hasTrailingCollapsibleContent const): Deleted.
+
 2021-10-22  Alan Bujtas  <zalan@apple.com>
 

trunk/Source/WebCore/layout/formattingContexts/inline/InlineContentBreaker.cpp

@@ -98 +98 @@
     // [<span></span> ] [<span> </span>] [ <span style="padding: 0px;"></span>] are all considered visually empty whitespace content.
     // [<span style="border: 1px solid red"></span> ] while this is whitespace content only, it is not considered visually empty.
-    // Due to commit boundary rules, we just need to check the first non-typeless inline item (can't have both [img] and [text])
+    ASSERT(!continuousContent.runs().isEmpty());
+    auto hasWhitespace = false;
     for (auto& run : continuousContent.runs()) {
         auto& inlineItem = run.inlineItem;
-        // FIXME: check for padding border etc.
+        // FIXME: check if visual decoration makes a difference here e.g. padding border.
         if (inlineItem.isInlineBoxStart() || inlineItem.isInlineBoxEnd())
             continue;
-        return inlineItem.isText() && downcast<InlineTextItem>(inlineItem).isWhitespace();
-    }
-    return false;
+        auto isWhitespace = inlineItem.isText() && downcast<InlineTextItem>(inlineItem).isWhitespace();
+        if (!isWhitespace)
+            return false;
+        hasWhitespace = true;
+    }
+    return hasWhitespace;
 }
 
@@ -174 +178 @@
 
     ASSERT(continuousContent.logicalWidth() > lineStatus.availableWidth);
-    if (continuousContent.hasTrailingCollapsibleContent()) {
-        ASSERT(hasTrailingTextContent(overflowContent));
-        // First check if the content fits without the trailing collapsible part.
-        if (continuousContent.nonCollapsibleLogicalWidth() <= lineStatus.availableWidth)
-            return { Result::Action::Keep, IsEndOfLine::No };
-        // Now check if we can trim the line too.
-        if (lineStatus.hasFullyCollapsibleTrailingRun && continuousContent.isFullyCollapsible()) {
+    if (continuousContent.hasCollapsibleContent()) {
+        if (lineStatus.hasFullyCollapsibleTrailingContent && continuousContent.isFullyCollapsible()) {
             // If this new content is fully collapsible, it should surely fit.
             return { Result::Action::Keep, IsEndOfLine::No };
         }
+        // Check if the content fits if we collapsed it.
+        auto spaceRequired = continuousContent.logicalWidth() - continuousContent.trailingCollapsibleWidth();
+        if (lineStatus.hasFullyCollapsibleTrailingContent)
+            spaceRequired -= continuousContent.leadingCollapsibleWidth();
+        if (spaceRequired <= lineStatus.availableWidth)
+            return { Result::Action::Keep, IsEndOfLine::No };
     } else if (lineStatus.collapsibleWidth && isNonContentRunsOnly(continuousContent)) {
         // Let's see if the non-content runs fit when the line has trailing collapsible content.
@@ -650 +655 @@
 {
     ASSERT(inlineItem.isText() || inlineItem.isBox() || inlineItem.isInlineBoxStart() || inlineItem.isInlineBoxEnd());
+    auto isLeadingCollapsible = collapsibleWidth && (m_runs.isEmpty() || isFullyCollapsible());
     m_runs.append({ inlineItem, style, logicalWidth });
     m_logicalWidth = clampTo<InlineLayoutUnit>(m_logicalWidth + logicalWidth);
@@ -655 +661 @@
         if (inlineItem.isText() || inlineItem.isBox()) {
             // Inline boxes do not prevent the trailing content from getting collapsed.
-            m_collapsibleLogicalWidth = { };
+            m_trailingCollapsibleWidth = { };
         }
         return;
     }
     ASSERT(*collapsibleWidth <= logicalWidth);
-    if (*collapsibleWidth == logicalWidth) {
-        // Fully collapsible run.
-        m_collapsibleLogicalWidth += logicalWidth;
+    if (isLeadingCollapsible) {
+        ASSERT(!m_trailingCollapsibleWidth);
+        m_leadingCollapsibleWidth += *collapsibleWidth;
         return;
     }
-    // Partially collapsible run.
-    m_collapsibleLogicalWidth = *collapsibleWidth;
+    m_trailingCollapsibleWidth = *collapsibleWidth == logicalWidth ? m_trailingCollapsibleWidth + logicalWidth : *collapsibleWidth;
 }
 
@@ -672 +677 @@
 {
     m_logicalWidth = { };
-    m_collapsibleLogicalWidth = { };
+    m_leadingCollapsibleWidth = { };
+    m_trailingCollapsibleWidth = { };
     m_runs.clear();
 }

trunk/Source/WebCore/layout/formattingContexts/inline/InlineContentBreaker.h

@@ -78 +78 @@
     struct ContinuousContent {
         InlineLayoutUnit logicalWidth() const { return m_logicalWidth; }
-        InlineLayoutUnit collapsibleLogicalWidth() const { return m_collapsibleLogicalWidth; }
-        InlineLayoutUnit nonCollapsibleLogicalWidth() const { return logicalWidth() - collapsibleLogicalWidth(); }
-        bool hasTrailingCollapsibleContent() const { return !!collapsibleLogicalWidth(); }
-        bool isFullyCollapsible() const { return logicalWidth() == collapsibleLogicalWidth(); }
+        InlineLayoutUnit leadingCollapsibleWidth() const { return m_leadingCollapsibleWidth; }
+        InlineLayoutUnit trailingCollapsibleWidth() const { return m_trailingCollapsibleWidth; }
+        bool hasCollapsibleContent() const { return trailingCollapsibleWidth() > 0 || leadingCollapsibleWidth() > 0; }
+        bool isFullyCollapsible() const { return logicalWidth() == trailingCollapsibleWidth() + leadingCollapsibleWidth(); }
 
-        void append(const InlineItem&, const RenderStyle&, InlineLayoutUnit logicalWidth, std::optional<InlineLayoutUnit> collapsibleWidth);
+        void append(const InlineItem&, const RenderStyle&, InlineLayoutUnit logicalWidth, std::optional<InlineLayoutUnit> collapsibleWidth = std::nullopt);
         void reset();
 
@@ -101 +101 @@
         RunList m_runs;
         InlineLayoutUnit m_logicalWidth { 0 };
-        InlineLayoutUnit m_collapsibleLogicalWidth { 0 };
+        InlineLayoutUnit m_leadingCollapsibleWidth { 0 };
+        InlineLayoutUnit m_trailingCollapsibleWidth { 0 };
     };
 
@@ -109 +110 @@
         InlineLayoutUnit collapsibleWidth { 0 };
         std::optional<InlineLayoutUnit> trailingSoftHyphenWidth;
-        bool hasFullyCollapsibleTrailingRun { false };
+        bool hasFullyCollapsibleTrailingContent { false };
         bool hasContent { false };
         bool hasWrapOpportunityAtPreviousPosition { false };