tor-browser

commit 1da35cc35d48f8552e80a045109f99840ef6e292
parent 643eec99211ba30e588908baaf8e73c52caba369
Author: Ting-Yu Lin <tlin@mozilla.com>
Date:   Sat, 22 Nov 2025 23:32:00 +0000

Bug 1994083 - Generate display items for frames in absolute child list. r=dholbert,layout-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D272401

Diffstat:
M
layout/forms/nsFieldSetFrame.cpp
 | 
1
+
M
layout/generic/nsBlockFrame.cpp
 | 
1
+
M
layout/generic/nsCanvasFrame.cpp
 | 
1
+
M
layout/generic/nsContainerFrame.cpp
 | 
9
+++++++++
M
layout/generic/nsContainerFrame.h
 | 
9
+++++++++
M
layout/generic/nsFlexContainerFrame.cpp
 | 
1
+
M
layout/generic/nsGridContainerFrame.cpp
 | 
1
+

7 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/layout/forms/nsFieldSetFrame.cpp b/layout/forms/nsFieldSetFrame.cpp
@@ -229,6 +229,7 @@ void nsFieldSetFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
 
   if (GetPrevInFlow()) {
     DisplayOverflowContainers(aBuilder, aLists);
+    DisplayAbsoluteContinuations(aBuilder, aLists);
   }
 
   nsDisplayListCollection contentDisplayItems(aBuilder);
diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
@@ -7764,6 +7764,7 @@ void nsBlockFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
 
   if (GetPrevInFlow()) {
     DisplayOverflowContainers(aBuilder, aLists);
+    DisplayAbsoluteContinuations(aBuilder, aLists);
     for (nsIFrame* f : GetChildList(FrameChildListID::Float)) {
       if (f->HasAnyStateBits(NS_FRAME_IS_PUSHED_FLOAT)) {
         BuildDisplayListForChild(aBuilder, f, aLists);
diff --git a/layout/generic/nsCanvasFrame.cpp b/layout/generic/nsCanvasFrame.cpp
@@ -219,6 +219,7 @@ void nsCanvasFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
              "::-moz-{scrolled-,}canvas doesn't have native appearance");
   if (GetPrevInFlow()) {
     DisplayOverflowContainers(aBuilder, aLists);
+    DisplayAbsoluteContinuations(aBuilder, aLists);
   }
 
   // Force a background to be shown. We may have a background propagated to us,
diff --git a/layout/generic/nsContainerFrame.cpp b/layout/generic/nsContainerFrame.cpp
@@ -1018,6 +1018,15 @@ void nsContainerFrame::DisplayOverflowContainers(
   }
 }
 
+void nsContainerFrame::DisplayAbsoluteContinuations(
+    nsDisplayListBuilder* aBuilder, const nsDisplayListSet& aLists) {
+  for (nsIFrame* frame : GetChildList(FrameChildListID::Absolute)) {
+    if (frame->GetPrevInFlow()) {
+      BuildDisplayListForChild(aBuilder, frame, aLists);
+    }
+  }
+}
+
 bool nsContainerFrame::TryRemoveFrame(FrameListPropertyDescriptor aProp,
                                       nsIFrame* aChildToRemove) {
   nsFrameList* list = GetProperty(aProp);
diff --git a/layout/generic/nsContainerFrame.h b/layout/generic/nsContainerFrame.h
@@ -437,6 +437,15 @@ class nsContainerFrame : public nsSplittableFrame {
                                  const nsDisplayListSet& aLists);
 
   /**
+   * Add absolute frame continuations to the display list.
+   *
+   * Note: for absolute frame's first-in-flow, it will be painted through its
+   * placeholder frame.
+   */
+  void DisplayAbsoluteContinuations(nsDisplayListBuilder* aBuilder,
+                                    const nsDisplayListSet& aLists);
+
+  /**
    * Builds display lists for the children. The background
    * of each child is placed in the Content() list (suitable for inline
    * children and other elements that behave like inlines,
diff --git a/layout/generic/nsFlexContainerFrame.cpp b/layout/generic/nsFlexContainerFrame.cpp
@@ -2987,6 +2987,7 @@ void nsFlexContainerFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
 
   if (GetPrevInFlow()) {
     DisplayOverflowContainers(aBuilder, tempLists);
+    DisplayAbsoluteContinuations(aBuilder, tempLists);
   }
 
   // Our children are all block-level, so their borders/backgrounds all go on
diff --git a/layout/generic/nsGridContainerFrame.cpp b/layout/generic/nsGridContainerFrame.cpp
@@ -10272,6 +10272,7 @@ void nsGridContainerFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
 
   if (GetPrevInFlow()) {
     DisplayOverflowContainers(aBuilder, aLists);
+    DisplayAbsoluteContinuations(aBuilder, aLists);
   }
 
   // Our children are all grid-level boxes, which behave the same as