Migrate from MathUtil::inverse() to gfx::Transform::GetInverse()

cc/layer_tree_host_common.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layer_tree_host_common.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "cc/layer.h"
@@ skipping 38 matching lines @@
     // If the layer doesn't fill up the entire surface, then find the part of
     // the surface rect where the layer could be visible. This avoids trying to
     // project surface rect points that are behind the projection point.
     gfx::Rect minimalSurfaceRect = targetSurfaceRect;
     minimalSurfaceRect.Intersect(layerRectInTargetSpace);
 
     // Project the corners of the target surface rect into the layer space.
     // This bounding rectangle may be larger than it needs to be (being
     // axis-aligned), but is a reasonable filter on the space to consider.
     // Non-invertible transforms will create an empty rect here.
-    const gfx::Transform surfaceToLayer = MathUtil::inverse(transform);
+    gfx::Transform surfaceToLayer(gfx::Transform::kSkipInitialization);
+    transform.GetInverse(&surfaceToLayer);

[danakj, 2012/12/19 05:23:06]

If it's not invertible, should we return layerBoundRect or something else? Or
should we DCHECK the return value here?

     gfx::Rect layerRect = gfx::ToEnclosingRect(MathUtil::projectClippedRect(surfaceToLayer, gfx::RectF(minimalSurfaceRect)));
     layerRect.Intersect(layerBoundRect);
     return layerRect;
 }
 
 gfx::Rect LayerTreeHostCommon::calculateVisibleRect(const gfx::Rect& targetSurfaceRect, const gfx::Rect& layerBoundRect, const gfx::Transform& transform)
 {
     gfx::Rect layerInSurfaceSpace = MathUtil::mapClippedRect(transform, layerBoundRect);
     return calculateVisibleRectWithCachedLayerRect(targetSurfaceRect, layerBoundRect, layerInSurfaceSpace, transform);
 }
@@ skipping 244 matching lines @@
     // These steps create a matrix that both start and end in targetSurfaceSpace. So this matrix can
     // pre-multiply any fixed-position layer's drawTransform to undo the scrollDeltas -- as long as
     // that fixed position layer is fixed onto the same renderTarget as this scrollingLayer.
     //
 
     gfx::Transform partialLayerOriginTransform = parentMatrix;
     partialLayerOriginTransform.PreconcatTransform(scrollingLayer->implTransform());
 
     gfx::Transform scrollCompensationForThisLayer = partialLayerOriginTransform; // Step 3
     scrollCompensationForThisLayer.Translate(scrollingLayer->scrollDelta().x(), scrollingLayer->scrollDelta().y()); // Step 2
-    scrollCompensationForThisLayer.PreconcatTransform(MathUtil::inverse(partialLayerOriginTransform)); // Step 1
+    gfx::Transform inversePartialLayerOriginTransform(gfx::Transform::kSkipInitialization);
+    partialLayerOriginTransform.GetInverse(&inversePartialLayerOriginTransform);

[danakj, 2012/12/19 05:23:06]

DCHECK the return value?

+    scrollCompensationForThisLayer.PreconcatTransform(inversePartialLayerOriginTransform); // Step 1
     return scrollCompensationForThisLayer;
 }
 
 gfx::Transform computeScrollCompensationMatrixForChildren(Layer* currentLayer, const gfx::Transform& currentParentMatrix, const gfx::Transform& currentScrollCompensation)
 {
     // The main thread (i.e. Layer) does not need to worry about scroll compensation.
     // So we can just return an identity matrix here.
     return gfx::Transform();
 }
 
@@ skipping 31 matching lines @@
     if (!layer->scrollDelta().IsZero()) {
         gfx::Transform scrollCompensationForThisLayer = computeScrollCompensationForThisLayer(layer, parentMatrix);
         nextScrollCompensationMatrix.PreconcatTransform(scrollCompensationForThisLayer);
     }
 
     // If the layer created its own renderSurface, we have to adjust nextScrollCompensationMatrix.
     // The adjustment allows us to continue using the scrollCompensation on the next surface.
     //  Step 1 (right-most in the math): transform from the new surface to the original ancestor surface
     //  Step 2: apply the scroll compensation
     //  Step 3: transform back to the new surface.
-    if (layer->renderSurface() && !nextScrollCompensationMatrix.IsIdentity())
-        nextScrollCompensationMatrix = MathUtil::inverse(layer->renderSurface()->drawTransform()) * nextScrollCompensationMatrix * layer->renderSurface()->drawTransform();
+    if (layer->renderSurface() && !nextScrollCompensationMatrix.IsIdentity()) {
+        gfx::Transform inverseSurfaceDrawTransform(gfx::Transform::kSkipInitialization);
+        layer->renderSurface()->drawTransform().GetInverse(&inverseSurfaceDrawTransform);

[danakj, 2012/12/19 05:23:06]

DCHECK the return value? Or should we do something else?

+        nextScrollCompensationMatrix = inverseSurfaceDrawTransform * nextScrollCompensationMatrix * layer->renderSurface()->drawTransform();
+    }
 
     return nextScrollCompensationMatrix;
 }
 
 static inline void updateLayerContentsScale(LayerImpl* layer, const gfx::Transform& combinedTransform, float deviceScaleFactor, float pageScaleFactor, bool animatingTransformToScreen)
 {
 }
 
 static inline void updateLayerContentsScale(Layer* layer, const gfx::Transform& combinedTransform, float deviceScaleFactor, float pageScaleFactor, bool animatingTransformToScreen)
 {
@@ skipping 341 matching lines @@
 
         // FIXME:  make this smarter for the SkImageFilter case (check for
         //         pixel-moving filters)
         if (layer->filters().hasFilterThatMovesPixels() || layer->filter())
             nearestAncestorThatMovesPixels = renderSurface;
 
         // The render surface clipRect is expressed in the space where this surface draws, i.e. the same space as clipRectFromAncestor.
         renderSurface->setIsClipped(ancestorClipsSubtree);
         if (ancestorClipsSubtree) {
             renderSurface->setClipRect(clipRectFromAncestor);
-            clipRectForSubtreeInDescendantSpace = gfx::ToEnclosingRect(MathUtil::projectClippedRect(MathUtil::inverse(renderSurface->drawTransform()), renderSurface->clipRect()));
+            gfx::Transform inverseSurfaceDrawTransform(gfx::Transform::kSkipInitialization);
+            renderSurface->drawTransform().GetInverse(&inverseSurfaceDrawTransform);

[danakj, 2012/12/19 05:23:06]

DCHECK the return value?

+            clipRectForSubtreeInDescendantSpace = gfx::ToEnclosingRect(MathUtil::projectClippedRect(inverseSurfaceDrawTransform, renderSurface->clipRect()));
         } else {
             renderSurface->setClipRect(gfx::Rect());
             clipRectForSubtreeInDescendantSpace = clipRectFromAncestorInDescendantSpace;
         }
 
         renderSurface->setNearestAncestorThatMovesPixels(nearestAncestorThatMovesPixels);
 
         // If the new render surface is drawn translucent or with a non-integral translation
         // then the subtree that gets drawn on this render surface cannot use LCD text.
         subtreeCanUseLCDText = layerCanUseLCDText;
@@ skipping 241 matching lines @@
 
     // The dummy layer list should not have been used.
     DCHECK(dummyLayerList.size() == 0);
     // A root layer renderSurface should always exist after calculateDrawProperties.
     DCHECK(rootLayer->renderSurface());
 }
 
 static bool pointHitsRect(const gfx::PointF& screenSpacePoint, const gfx::Transform& localSpaceToScreenSpaceTransform, gfx::RectF localSpaceRect)
 {
     // If the transform is not invertible, then assume that this point doesn't hit this rect.
-    if (!localSpaceToScreenSpaceTransform.IsInvertible())
+    gfx::Transform inverseLocalSpaceToScreenSpace(gfx::Transform::kSkipInitialization);
+    if (!localSpaceToScreenSpaceTransform.GetInverse(&inverseLocalSpaceToScreenSpace))
         return false;
 
     // Transform the hit test point from screen space to the local space of the given rect.
     bool clipped = false;
-    gfx::PointF hitTestPointInLocalSpace = MathUtil::projectPoint(MathUtil::inverse(localSpaceToScreenSpaceTransform), screenSpacePoint, clipped);
+    gfx::PointF hitTestPointInLocalSpace = MathUtil::projectPoint(inverseLocalSpaceToScreenSpace, screenSpacePoint, clipped);
 
     // If projectPoint could not project to a valid value, then we assume that this point doesn't hit this rect.
     if (clipped)
         return false;
 
     return localSpaceRect.Contains(hitTestPointInLocalSpace);
 }
 
 static bool pointHitsRegion(gfx::PointF screenSpacePoint, const gfx::Transform& screenSpaceTransform, const Region& layerSpaceRegion, float layerContentScaleX, float layerContentScaleY)
 {
     // If the transform is not invertible, then assume that this point doesn't hit this region.
-    if (!screenSpaceTransform.IsInvertible())
+    gfx::Transform inverseScreenSpaceTransform(gfx::Transform::kSkipInitialization);
+    if (!screenSpaceTransform.GetInverse(&inverseScreenSpaceTransform))
         return false;
 
     // Transform the hit test point from screen space to the local space of the given region.
     bool clipped = false;
-    gfx::PointF hitTestPointInContentSpace = MathUtil::projectPoint(MathUtil::inverse(screenSpaceTransform), screenSpacePoint, clipped);
+    gfx::PointF hitTestPointInContentSpace = MathUtil::projectPoint(inverseScreenSpaceTransform, screenSpacePoint, clipped);
     gfx::PointF hitTestPointInLayerSpace = gfx::ScalePoint(hitTestPointInContentSpace, 1 / layerContentScaleX, 1 / layerContentScaleY);
 
     // If projectPoint could not project to a valid value, then we assume that this point doesn't hit this region.
     if (clipped)
         return false;
 
     return layerSpaceRegion.Contains(gfx::ToRoundedPoint(hitTestPointInLayerSpace));
 }
 
 static bool pointIsClippedBySurfaceOrClipRect(const gfx::PointF& screenSpacePoint, LayerImpl* layer)
@@ skipping 84 matching lines @@
 
   // At this point, we think the point does hit the touch event handler region on the layer, but we need to walk up
   // the parents to ensure that the layer was not clipped in such a way that the
   // hit point actually should not hit the layer.
   if (pointIsClippedBySurfaceOrClipRect(screenSpacePoint, layerImpl))
      return false;
 
   return true;
 }
 }  // namespace cc