Bug 1412179 - implement fieldsets with nonempty legends. r=kats

Differential Revision: https://phabricator.services.mozilla.com/D27350 --HG-- extra : moz-landing-system : lando
dothq · Apr 15, 2019 · b4a27bb · b4a27bb
1 parent 99e4403
commit b4a27bb
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Showing 5 changed files with 36 additions and 8 deletions.
diff --git a/gfx/webrender_bindings/WebRenderAPI.h b/gfx/webrender_bindings/WebRenderAPI.h
@@ -654,6 +654,14 @@ class MOZ_RAII SpaceAndClipChainHelper final {
     aBuilder.mCurrentSpaceAndClipChain.space = aSpatialId;
     MOZ_GUARD_OBJECT_NOTIFIER_INIT;
   }
+  SpaceAndClipChainHelper(DisplayListBuilder& aBuilder,
+                          wr::WrClipChainId aClipChainId
+                              MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+      : mBuilder(aBuilder),
+        mOldSpaceAndClipChain(aBuilder.mCurrentSpaceAndClipChain) {
+    aBuilder.mCurrentSpaceAndClipChain.clip_chain = aClipChainId.id;
+    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+  }
 
   ~SpaceAndClipChainHelper() {
     mBuilder.mCurrentSpaceAndClipChain = mOldSpaceAndClipChain;

diff --git a/layout/forms/nsFieldSetFrame.cpp b/layout/forms/nsFieldSetFrame.cpp
@@ -167,15 +167,36 @@ bool nsDisplayFieldSetBorder::CreateWebRenderCommands(
   auto frame = static_cast<nsFieldSetFrame*>(mFrame);
   auto offset = ToReferenceFrame();
   nsRect rect;
+  Maybe<wr::SpaceAndClipChainHelper> clipOut;
 
   if (nsIFrame* legend = frame->GetLegend()) {
     rect = frame->VisualBorderRectRelativeToSelf() + offset;
 
-    // Legends require a "negative" clip around the text, which WR doesn't
-    // support yet.
     nsRect legendRect = legend->GetNormalRect() + offset;
+
+    // Make sure we clip all of the border in case the legend is smaller.
+    nscoord borderTopWidth = frame->GetUsedBorder().top;
+    if (legendRect.height < borderTopWidth) {
+      legendRect.height = borderTopWidth;
+      legendRect.y = offset.y;
+    }
+
     if (!legendRect.IsEmpty()) {
-      return false;
+      // We need to clip out the part of the border where the legend would go
+      auto appUnitsPerDevPixel = frame->PresContext()->AppUnitsPerDevPixel();
+      auto layoutRect = wr::ToRoundedLayoutRect(
+          LayoutDeviceRect::FromAppUnits(rect, appUnitsPerDevPixel));
+
+      wr::ComplexClipRegion region;
+      region.rect = wr::ToRoundedLayoutRect(
+          LayoutDeviceRect::FromAppUnits(legendRect, appUnitsPerDevPixel));
+      region.mode = wr::ClipMode::ClipOut;
+      region.radii = wr::EmptyBorderRadius();
+      nsTArray<mozilla::wr::ComplexClipRegion> array{region};
+
+      auto clip = aBuilder.DefineClip(Nothing(), layoutRect, &array, nullptr);
+      auto clipChain = aBuilder.DefineClipChain({clip});
+      clipOut.emplace(aBuilder, clipChain);
     }
   } else {
     rect = nsRect(offset, frame->GetRect().Size());

diff --git a/layout/reftests/box-shadow/reftest.list b/layout/reftests/box-shadow/reftest.list
@@ -40,7 +40,7 @@ fuzzy(0-13,0-9445) fuzzy-if(d2d,0-13,0-10926) fuzzy-if(webrender,14-15,11263-132
 == overflow-not-scrollable-2.html overflow-not-scrollable-2-ref.html
 fuzzy-if(webrender,0-1,0-655) == 611574-1.html 611574-1-ref.html
 fuzzy-if(webrender,0-4,0-144) == 611574-2.html 611574-2-ref.html
-fuzzy-if(winWidget,0-5,0-30) fuzzy-if(skiaContent,0-16,0-10) fuzzy-if(webrender,20-34,82-84) == fieldset.html fieldset-ref.html # minor anti-aliasing problem on Windows
+fuzzy-if(winWidget,0-5,0-30) fuzzy-if(skiaContent,0-16,0-10) == fieldset.html fieldset-ref.html # minor anti-aliasing problem on Windows
 fuzzy-if(winWidget,0-5,0-30) fuzzy-if(skiaContent,0-16,0-10) fails-if(webrender) == fieldset-inset.html fieldset-inset-ref.html # minor anti-aliasing problem on Windows
 == 1178575.html 1178575-ref.html
 == 1178575-2.html 1178575-2-ref.html

diff --git a/...ndering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-vertical.html.ini b/...ndering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-vertical.html.ini
diff --git a/...ering/non-replaced-elements/the-fieldset-and-legend-elements/legend-auto-margins.html.ini b/...ering/non-replaced-elements/the-fieldset-and-legend-elements/legend-auto-margins.html.ini
@@ -0,0 +1,3 @@
+[legend-auto-margins.html]
+  fuzzy:
+    if webrender and (os == "linux"): legend-auto-margins-ref.html:maxDifference=8;totalPixels=8-10