RenderBox::hasHorizontalLayoutOverflow/hasVerticalLayoutOverflow use …

…incorrect coordinate space

https://bugs.webkit.org/show_bug.cgi?id=241796

Reviewed by Simon Fraser.

RenderBox::x() and y() are in the coordinate space of the containing block while layoutOverflowRect is relative to the box's border box. These functions would compute overflow true if the box happens to have some offset (through margin or positioning) even without actual overflow.

* LayoutTests/fast/overflow/horizontal-overflow-with-offset-expected.txt: Added.
* LayoutTests/fast/overflow/horizontal-overflow-with-offset.html: Added.
* LayoutTests/fast/overflow/vertical-overflow-with-offset-expected.txt: Added.
* LayoutTests/fast/overflow/vertical-overflow-with-offset.html: Added.
* Source/WebCore/rendering/RenderBox.h:
(WebCore::RenderBox::hasHorizontalLayoutOverflow const):
(WebCore::RenderBox::hasVerticalLayoutOverflow const):

Canonical link: https://commits.webkit.org/251720@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@295715 268f45cc-cd09-0410-ab3c-d52691b4dbfc

LayoutTests/fast/overflow/horizontal-overflow-with-offset-expected.txt

@@ -0,0 +1 @@
+PASS

LayoutTests/fast/overflow/horizontal-overflow-with-offset.html

@@ -0,0 +1,38 @@
+<style>
+#container {
+  position: absolute;
+  top: 100px;
+  left: 100px;
+
+  width: 100px;
+  height: 100px;
+  overflow: hidden;
+
+  background-color: green;
+}
+
+#child {
+  width: 10px;
+  height: 10px;
+  background-color: blue;
+}
+</style>
+<div id=container><div id=child></div></div>
+<pre id=result></pre>
+<script>
+if (window.testRunner) {
+  testRunner.dumpAsText();
+  testRunner.waitUntilDone();
+}
+
+function overflowChanged(event) {
+  result.innerText = !event.horizontalOverflow ? "PASS" : "FAIL";
+  if (window.testRunner)
+    testRunner.notifyDone();
+}
+container.addEventListener('overflowchanged', overflowChanged, false);
+
+document.body.offsetHeight;
+// This should not trigger horizontal overflow change.
+child.style.height = "120px";
+</script>

LayoutTests/fast/overflow/vertical-overflow-with-offset-expected.txt

@@ -0,0 +1 @@
+PASS

LayoutTests/fast/overflow/vertical-overflow-with-offset.html

@@ -0,0 +1,38 @@
+<style>
+#container {
+  position: absolute;
+  top: 100px;
+  left: 100px;
+
+  width: 100px;
+  height: 100px;
+  overflow: hidden;
+
+  background-color: green;
+}
+
+#child {
+  width: 10px;
+  height: 10px;
+  background-color: blue;
+}
+</style>
+<div id=container><div id=child></div></div>
+<pre id=result></pre>
+<script>
+if (window.testRunner) {
+  testRunner.dumpAsText();
+  testRunner.waitUntilDone();
+}
+
+function overflowChanged(event) {
+  result.innerText = !event.verticalOverflow ? "PASS" : "FAIL";
+  if (window.testRunner)
+    testRunner.notifyDone();
+}
+container.addEventListener('overflowchanged', overflowChanged, false);
+
+document.body.offsetHeight;
+// This should not trigger vertical overflow change.
+child.style.width = "120px";
+</script>

Source/WebCore/rendering/RenderBox.h

@@ -625,19 +625,19 @@ override;
         if (!m_overflow)
             return false;
 
-        LayoutRect layoutOverflowRect = m_overflow->layoutOverflowRect();
-        flipForWritingMode(layoutOverflowRect);
-        return layoutOverflowRect.x() < x() || layoutOverflowRect.maxX() > x() + logicalWidth();
+        auto layoutOverflowRect = m_overflow->layoutOverflowRect();
+        auto paddingBoxRect = flippedClientBoxRect();
+        return layoutOverflowRect.x() < paddingBoxRect.x() || layoutOverflowRect.maxX() > paddingBoxRect.maxX();
     }
 
     bool hasVerticalLayoutOverflow() const
     {
         if (!m_overflow)
             return false;
 
-        LayoutRect layoutOverflowRect = m_overflow->layoutOverflowRect();
-        flipForWritingMode(layoutOverflowRect);
-        return layoutOverflowRect.y() < y() || layoutOverflowRect.maxY() > y() + logicalHeight();
+        auto layoutOverflowRect = m_overflow->layoutOverflowRect();
+        auto paddingBoxRect = flippedClientBoxRect();
+        return layoutOverflowRect.y() < paddingBoxRect.y() || layoutOverflowRect.maxY() > paddingBoxRect.maxY();
     }
 
     virtual RenderPtr<RenderBox> createAnonymousBoxWithSameTypeAs(const RenderBox&) const