Bug 505115 - Part 10 - Implement the backface-visibility CSS property. r=dbaron

dom/interfaces/css/nsIDOMCSS2Properties.idl

@@ -51,7 +51,7 @@
  * http://www.w3.org/TR/DOM-Level-2-Style
  */
 
-[scriptable, uuid(1ca298f0-4eaf-4483-8aa2-587f392f84bb)]
+[scriptable, uuid(63a0afd0-b322-11e0-aff2-0800200c9a66)]
 interface nsIDOMCSS2Properties : nsISupports
 {
            attribute DOMString        background;
@@ -684,6 +684,9 @@ interface nsIDOMCSS2Properties : nsISupports
            attribute DOMString        MozPerspective;
                                         // raises(DOMException) on setting
 
+           attribute DOMString        MozBackfaceVisibility;
+                                        // raises(DOMException) on setting 
+
            attribute DOMString        MozWindowShadow;
                                         // raises(DOMException) on setting
 

gfx/thebes/gfx3DMatrix.cpp

@@ -392,3 +392,17 @@ gfxRect gfx3DMatrix::ProjectRectBounds(const gfxRect& aRect) const
   return gfxRect(min_x, min_y, max_x - min_x, max_y - min_y);
 }
 
+gfxPoint3D gfx3DMatrix::GetNormalVector() const
+{
+    // Define a plane in transformed space as the transformations
+    // of 3 points on the z=0 screen plane.
+    gfxPoint3D a = Transform3D(gfxPoint3D(0, 0, 0));
+    gfxPoint3D b = Transform3D(gfxPoint3D(0, 1, 0));
+    gfxPoint3D c = Transform3D(gfxPoint3D(1, 0, 0));
+
+    // Convert to two vectors on the surface of the plane.
+    gfxPoint3D ab = b - a;
+    gfxPoint3D ac = c - a;
+
+    return ac.CrossProduct(ab);
+}

gfx/thebes/gfx3DMatrix.h

@@ -134,6 +134,12 @@ public:
     return temp;
   }
 
+  /**
+   * Returns a unit vector that is perpendicular to the plane formed
+   * by transform the screen plane (z=0) by this matrix.
+   */
+  gfxPoint3D GetNormalVector() const;
+
   /**
    * Check if matrix is singular (no inverse exists).
    */

layout/base/nsDisplayList.cpp

@@ -2418,8 +2418,12 @@ already_AddRefed<Layer> nsDisplayTransform::BuildLayer(nsDisplayListBuilder *aBu
 {
   const gfx3DMatrix& newTransformMatrix = 
     GetTransform(mFrame->PresContext()->AppUnitsPerDevPixel());
-  if (newTransformMatrix.IsSingular())
+
+  if (newTransformMatrix.IsSingular() ||
+      (mFrame->GetStyleDisplay()->mBackfaceVisibility == NS_STYLE_BACKFACE_VISIBILITY_HIDDEN &&
+       newTransformMatrix.GetNormalVector().z <= 0.0)) {
     return nsnull;
+  }
 
   return aBuilder->LayerBuilder()->
     BuildContainerLayerFor(aBuilder, aManager, mFrame, this, *mStoredList.GetList(),
@@ -2487,8 +2491,12 @@ void nsDisplayTransform::HitTest(nsDisplayListBuilder *aBuilder,
   float factor = nsPresContext::AppUnitsPerCSSPixel();
   gfx3DMatrix matrix = GetTransform(factor);
 
-  if (matrix.IsSingular())
-    return;
+  /* If the matrix is singular, or a hidden backface is shown, we didn't hit anything. */
+  if (matrix.IsSingular() ||
+      (mFrame->GetStyleDisplay()->mBackfaceVisibility == NS_STYLE_BACKFACE_VISIBILITY_HIDDEN &&
+       matrix.GetNormalVector().z <= 0.0)) {
+          return;
+  }
 
   /* We want to go from transformed-space to regular space.
    * Thus we have to invert the matrix, which normally does

layout/base/nsStyleConsts.h

@@ -858,6 +858,10 @@ static inline mozilla::css::Side operator++(mozilla::css::Side& side, int) {
 #define NS_STYLE_COLOR_INTERPOLATION_SRGB           1
 #define NS_STYLE_COLOR_INTERPOLATION_LINEARRGB      2
 
+// 3d Transforms - Backface visibility
+#define NS_STYLE_BACKFACE_VISIBILITY_VISIBLE        1
+#define NS_STYLE_BACKFACE_VISIBILITY_HIDDEN         0
+
 /*****************************************************************************
  * Constants for media features.                                             *
  *****************************************************************************/

layout/style/nsCSSPropList.h

@@ -2267,6 +2267,15 @@ CSS_PROP_DISPLAY(
     nsnull,
     offsetof(nsStyleDisplay, mChildPerspective),
     eStyleAnimType_Coord)
+CSS_PROP_DISPLAY(
+    -moz-backface-visibility,
+    backface_visibility,
+    CSS_PROP_DOMPROP_PREFIXED(BackfaceVisibility),
+    CSS_PROPERTY_PARSE_VALUE,
+    VARIANT_HK,
+    kBackfaceVisibilityKTable,
+    offsetof(nsStyleDisplay, mBackfaceVisibility),
+    eStyleAnimType_None)
 CSS_PROP_POSITION(
     top,
     top,

layout/style/nsCSSProps.cpp

@@ -581,6 +581,11 @@ const PRInt32 nsCSSProps::kAppearanceKTable[] = {
   eCSSKeyword_UNKNOWN,-1
 };
 
+const PRInt32 nsCSSProps::kBackfaceVisibilityKTable[] = {
+  eCSSKeyword_visible, NS_STYLE_BACKFACE_VISIBILITY_VISIBLE,
+  eCSSKeyword_hidden, NS_STYLE_BACKFACE_VISIBILITY_HIDDEN
+};
+
 const PRInt32 nsCSSProps::kBackgroundAttachmentKTable[] = {
   eCSSKeyword_fixed, NS_STYLE_BG_ATTACHMENT_FIXED,
   eCSSKeyword_scroll, NS_STYLE_BG_ATTACHMENT_SCROLL,

layout/style/nsCSSProps.h

@@ -333,6 +333,7 @@ public:
   static const PRInt32 kAnimationTimingFunctionKTable[];
   static const PRInt32 kAppearanceKTable[];
   static const PRInt32 kAzimuthKTable[];
+  static const PRInt32 kBackfaceVisibilityKTable[];
   static const PRInt32 kBackgroundAttachmentKTable[];
   static const PRInt32 kBackgroundInlinePolicyKTable[];
   static const PRInt32 kBackgroundOriginKTable[];

layout/style/nsComputedDOMStyle.cpp

@@ -954,6 +954,16 @@ nsComputedDOMStyle::DoGetMozPerspective()
     return val;
 }
 
+nsIDOMCSSValue*
+nsComputedDOMStyle::DoGetMozBackfaceVisibility()
+{
+    nsROCSSPrimitiveValue* val = GetROCSSPrimitiveValue();
+    val->SetIdent(
+        nsCSSProps::ValueToKeywordEnum(GetStyleDisplay()->mBackfaceVisibility,
+                                       nsCSSProps::kBackfaceVisibilityKTable));
+    return val;
+}
+
 /* If the property is "none", hand back "none" wrapped in a value.
  * Otherwise, compute the aggregate transform matrix and hands it back in a
  * "matrix" wrapper.
@@ -4378,6 +4388,7 @@ nsComputedDOMStyle::GetQueryablePropertyMap(PRUint32* aLength)
     COMPUTED_STYLE_MAP_ENTRY(animation_play_state,          AnimationPlayState),
     COMPUTED_STYLE_MAP_ENTRY(animation_timing_function,     AnimationTimingFunction),
     COMPUTED_STYLE_MAP_ENTRY(appearance,                    Appearance),
+    COMPUTED_STYLE_MAP_ENTRY(backface_visibility,           MozBackfaceVisibility),
     COMPUTED_STYLE_MAP_ENTRY(_moz_background_inline_policy, BackgroundInlinePolicy),
     COMPUTED_STYLE_MAP_ENTRY(binding,                       Binding),
     COMPUTED_STYLE_MAP_ENTRY(border_bottom_colors,          BorderBottomColors),

layout/style/nsComputedDOMStyle.h

@@ -348,6 +348,7 @@ private:
   nsIDOMCSSValue* DoGetMozTransform();
   nsIDOMCSSValue* DoGetMozTransformOrigin();
   nsIDOMCSSValue* DoGetMozPerspective();
+  nsIDOMCSSValue* DoGetMozBackfaceVisibility();
   nsIDOMCSSValue* DoGetOrient();
 
   /* User interface properties */

layout/style/nsRuleNode.cpp

@@ -4489,6 +4489,11 @@ nsRuleNode::ComputeDisplayData(void* aStartStruct,
            SETCOORD_LAH | SETCOORD_INITIAL_ZERO | SETCOORD_NONE,
            aContext, mPresContext, canStoreInRuleTree);
 
+  SetDiscrete(*aRuleData->ValueForBackfaceVisibility(),
+              display->mBackfaceVisibility, canStoreInRuleTree,
+              SETDSC_ENUMERATED, parentDisplay->mBackfaceVisibility,
+              NS_STYLE_BACKFACE_VISIBILITY_VISIBLE, 0, 0, 0, 0);
+
   // orient: enum, inherit, initial
   SetDiscrete(*aRuleData->ValueForOrient(),
               display->mOrient, canStoreInRuleTree,

layout/style/nsStyleStruct.cpp

@@ -2034,6 +2034,7 @@ nsStyleDisplay::nsStyleDisplay()
   mTransformOrigin[0].SetPercentValue(0.5f); // Transform is centered on origin
   mTransformOrigin[1].SetPercentValue(0.5f); 
   mChildPerspective.SetCoordValue(0);
+  mBackfaceVisibility = NS_STYLE_BACKFACE_VISIBILITY_VISIBLE;
   mOrient = NS_STYLE_ORIENT_HORIZONTAL;
 
   mTransitions.AppendElement();
@@ -2100,6 +2101,7 @@ nsStyleDisplay::nsStyleDisplay(const nsStyleDisplay& aSource)
   mTransformOrigin[0] = aSource.mTransformOrigin[0];
   mTransformOrigin[1] = aSource.mTransformOrigin[1];
   mChildPerspective = aSource.mChildPerspective;
+  mBackfaceVisibility = aSource.mBackfaceVisibility;
 }
 
 nsChangeHint nsStyleDisplay::CalcDifference(const nsStyleDisplay& aOther) const
@@ -2165,6 +2167,9 @@ nsChangeHint nsStyleDisplay::CalcDifference(const nsStyleDisplay& aOther) const
     if (mChildPerspective != aOther.mChildPerspective)
       NS_UpdateHint(hint, NS_CombineHint(nsChangeHint_ReflowFrame,
                                          nsChangeHint_RepaintFrame));
+
+    if (mBackfaceVisibility != aOther.mBackfaceVisibility)
+      NS_UpdateHint(hint, nsChangeHint_RepaintFrame);
   }
 
   // Note:  Our current behavior for handling changes to the

layout/style/nsStyleStruct.h

@@ -1516,6 +1516,7 @@ struct nsStyleDisplay {
   const nsCSSValueList *mSpecifiedTransform; // [reset]
   nsStyleCoord mTransformOrigin[2]; // [reset] percent, coord, calc
   nsStyleCoord mChildPerspective; // [reset] coord
+  PRUint8 mBackfaceVisibility;
 
   nsAutoTArray<nsTransition, 1> mTransitions; // [reset]
   // The number of elements in mTransitions that are not from repeating

layout/style/test/property_database.js

@@ -975,6 +975,14 @@ var gCSSProperties = {
 		other_values: [ "1000px", "500.2px", "-100px", "-27.2em" ],
 		invalid_values: [ "pants", "200" ]
 	},
+    "-moz-backface-visibility": {
+        domProp: "MozBackfaceVisibility",
+        inherited: false,
+        type: CSS_TYPE_LONGHAND,
+        initial_values: [ "visible" ],
+        other_values: [ "hidden" ],
+        invalid_values: [ "collapse" ]
+    },
 	"-moz-user-focus": {
 		domProp: "MozUserFocus",
 		inherited: true,