Changeset 252924 in webkit

Timestamp:

Nov 28, 2019 6:49:54 AM (4 years ago)

Author:

Alan Bujtas

Message:

[LFC][IFC] Adjust the line's is-visually-empty status after trimming the trailing whitespace content
​https://bugs.webkit.org/show_bug.cgi?id=204660
<rdar://problem/57513035>

Reviewed by Antti Koivisto.

We need to check if the line is still visually empty after trimming the trailing content.

• layout/inlineformatting/InlineLineBox.h:

(WebCore::Layout::LineBox::setIsConsideredEmpty):

• layout/inlineformatting/InlineLineBuilder.cpp:

(WebCore::Layout::LineBuilder::removeTrailingTrimmableContent):
(WebCore::Layout::LineBuilder::appendTextContent):

• layout/inlineformatting/InlineLineBuilder.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• layout/inlineformatting/InlineLineBox.h (modified) (1 diff)
• layout/inlineformatting/InlineLineBuilder.cpp (modified) (3 diffs)
• layout/inlineformatting/InlineLineBuilder.h (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-11-28  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][IFC] Adjust the line's is-visually-empty status after trimming the trailing whitespace content
+        https://bugs.webkit.org/show_bug.cgi?id=204660
+        <rdar://problem/57513035>
+
+        Reviewed by Antti Koivisto.
+
+        We need to check if the line is still visually empty after trimming the trailing content.
+
+        * layout/inlineformatting/InlineLineBox.h:
+        (WebCore::Layout::LineBox::setIsConsideredEmpty):
+        * layout/inlineformatting/InlineLineBuilder.cpp:
+        (WebCore::Layout::LineBuilder::removeTrailingTrimmableContent):
+        (WebCore::Layout::LineBuilder::appendTextContent):
+        * layout/inlineformatting/InlineLineBuilder.h:
+
 2019-11-28  Zalan Bujtas  <zalan@apple.com>
 

trunk/Source/WebCore/layout/inlineformatting/InlineLineBox.h

@@ -116 +116 @@
     // Note that it does not necessarily mean visually non-empty line. <span style="font-size: 0px">this is still considered non-empty</span>
     bool isConsideredEmpty() const { return m_isConsideredEmpty; }
+    void setIsConsideredEmpty() { m_isConsideredEmpty = true; }
     void setIsConsideredNonEmpty() { m_isConsideredEmpty = false; }
 

trunk/Source/WebCore/layout/inlineformatting/InlineLineBuilder.cpp

@@ -235 +235 @@
     m_inlineItemRuns.clear();
     m_trimmableContent.clear();
+    m_lineIsVisuallyEmptyBeforeTrimmableContent = { };
 }
 
@@ -436 +437 @@
     m_lineBox.shrinkHorizontally(m_trimmableContent.width());
     m_trimmableContent.clear();
+    // If we trimmed the first visible run on the line, we need to re-check the visibility status.
+    ASSERT(m_lineIsVisuallyEmptyBeforeTrimmableContent.hasValue());
+    if (*m_lineIsVisuallyEmptyBeforeTrimmableContent) {
+        // Just because the line was visually empty before the trimmed content, it does not necessarily mean it is still visually empty.
+        // <span>  </span><span style="padding-left: 10px"></span>  <- non-empty
+        auto lineIsVisuallyEmpty = [&] {
+            for (auto& run : m_inlineItemRuns) {
+                if (isVisuallyNonEmpty(*run))
+                    return false;
+            }
+            return true;
+        };
+        // We could only go from visually non empty -> to visually empty. Trimming runs should never make the line visible.
+        if (lineIsVisuallyEmpty())
+            m_lineBox.setIsConsideredEmpty();
+        m_lineIsVisuallyEmptyBeforeTrimmableContent = { };
+    }
 }
 
@@ -541 +559 @@
     if (collapsedRun)
         lineRun->setIsCollapsed();
-    if (isTrimmable)
+    if (isTrimmable) {
+        // If we ever trim this content, we need to know if the line visibility state needs to be recomputed.
+        if (m_trimmableContent.isEmpty())
+            m_lineIsVisuallyEmptyBeforeTrimmableContent = isVisuallyEmpty();
         m_trimmableContent.append(*lineRun);
+    }
 
     m_lineBox.expandHorizontally(lineRun->logicalRect().width());

trunk/Source/WebCore/layout/inlineformatting/InlineLineBuilder.h

@@ -173 +173 @@
     bool m_hasIntrusiveFloat { false };
     LineBox m_lineBox;
+    Optional<bool> m_lineIsVisuallyEmptyBeforeTrimmableContent;
 };