Bug 1300611 - Move overflow rect into correct coordinate space when computing perspective overflows so that it's not affected by scroll position. r=dbaron
authorMatt Woodrow <mwoodrow@mozilla.com>
Wed, 14 Sep 2016 18:00:17 +1200
changeset 355167 442ca1f2745ec2689225c6c5254f58b3b0cb090f
parent 355166 b1cdea819863ad7e6721a5ef746f66d95eb0a3e7
child 355168 ce4e1e8aaa0e4a4ec25d33a46458f821499d8c25
push id6570
push userraliiev@mozilla.com
push dateMon, 14 Nov 2016 12:26:13 +0000
treeherdermozilla-beta@f455459b2ae5 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersdbaron
bugs1300611
milestone51.0a1
first release with
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nightly linux64
nightly mac
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nightly win64
Bug 1300611 - Move overflow rect into correct coordinate space when computing perspective overflows so that it's not affected by scroll position. r=dbaron
layout/generic/nsGfxScrollFrame.cpp
layout/generic/test/test_bug1198135.html
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -942,17 +942,17 @@ GetScrollableOverflowForPerspective(nsIF
         overhang.top /= bottomDelta;
         overhang.right /= rightDelta;
         overhang.bottom /= bottomDelta;
         overhang.left /= rightDelta;
 
         // Take the minimum overflow rect that would allow the current scroll
         // position, using the size of the scroll port and offset by the
         // inverse of the scroll position.
-        nsRect overflow(0, 0, aScrollPort.width, aScrollPort.height);
+        nsRect overflow = aScrollPort - scrollPos;
 
         // Expand it by our margins to get an overflow rect that would allow all
         // edges of our transformed content to be scrolled into view.
         overflow.Inflate(overhang);
 
         // Merge it with the combined overflow
         aScrolledFrameOverflowArea.UnionRect(aScrolledFrameOverflowArea,
                                              overflow);
--- a/layout/generic/test/test_bug1198135.html
+++ b/layout/generic/test/test_bug1198135.html
@@ -72,13 +72,18 @@ https://bugzilla.mozilla.org/show_bug.cg
   <div class="example__group">
     <div class="example__layer layer--c"></div>
     <div class="example__layer layer--e"></div>
   </div>
 </div>
 
 <script>
   is(document.getElementById("first").scrollHeight, 600, "Scroll height should be computed correctly");
+  document.getElementById("first").scrollTop = 150;
+  is(document.getElementById("first").scrollHeight, 600, "Scroll height should be a constant when scrolling");
+
   // The true height is 727.5 and we don't always snap the same direction.
   isfuzzy(document.getElementById("second").scrollHeight, 728, 1, "Scroll height should be computed correctly");
+  document.getElementById("second").scrollTop = 150;
+  isfuzzy(document.getElementById("second").scrollHeight, 728, 1, "Scroll height should be a constant when scrolling");
 </script>
 
 </body></html>