[PDF] If matrix inversion fails, use the identity matrix.

BUG=chrome:123078

Review URL: https://codereview.appspot.com/6007044

git-svn-id: http://skia.googlecode.com/svn/trunk@3676 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 15 insertions, 8 deletions

diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index f3aaa5efae..7e85afdcde 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -490,7 +490,9 @@ static inline SkBitmap makeContentBitmap(const SkISize& contentSize,
         SkMatrix inverse;
         drawingSize.set(SkIntToScalar(contentSize.fWidth),
                         SkIntToScalar(contentSize.fHeight));
-        initialTransform->invert(&inverse);
+        if (!initialTransform->invert(&inverse)) {
+            inverse.reset();
+        }
         inverse.mapVectors(&drawingSize, 1);
         SkISize size = SkSize::Make(drawingSize.fX, drawingSize.fY).toRound();
         bitmap.setConfig(SkBitmap::kNo_Config, abs(size.fWidth),
@@ -600,8 +602,9 @@ void SkPDFDevice::internalDrawPaint(const SkPaint& paint,
     SkMatrix totalTransform = fInitialTransform;
     totalTransform.preConcat(contentEntry->fState.fMatrix);
     SkMatrix inverse;
-    inverse.reset();
-    totalTransform.invert(&inverse);
+    if (!totalTransform.invert(&inverse)) {
+        inverse.reset();
+    }
     inverse.mapRect(&bbox);
 
     SkPDFUtils::AppendRectangle(bbox, &contentEntry->fContent);
diff --git a/src/pdf/SkPDFFormXObject.cpp b/src/pdf/SkPDFFormXObject.cpp
index fb8a9159cf..f368834938 100644
--- a/src/pdf/SkPDFFormXObject.cpp
+++ b/src/pdf/SkPDFFormXObject.cpp
@@ -36,8 +36,9 @@ SkPDFFormXObject::SkPDFFormXObject(SkPDFDevice* device) {
     // embedded in things like shaders and images.
     if (!device->initialTransform().isIdentity()) {
         SkMatrix inverse;
-        inverse.reset();
-        device->initialTransform().invert(&inverse);
+        if (!device->initialTransform().invert(&inverse)) {
+            inverse.reset();
+        }
         insert("Matrix", SkPDFUtils::MatrixToArray(inverse))->unref();
     }
 
diff --git a/src/pdf/SkPDFShader.cpp b/src/pdf/SkPDFShader.cpp
index 15acf67c72..3a559ba3d3 100644
--- a/src/pdf/SkPDFShader.cpp
+++ b/src/pdf/SkPDFShader.cpp
@@ -23,8 +23,9 @@
 
 static void transformBBox(const SkMatrix& matrix, SkRect* bbox) {
     SkMatrix inverse;
-    inverse.reset();
-    matrix.invert(&inverse);
+    if (!matrix.invert(&inverse)) {
+        inverse.reset();
+    }
     inverse.mapRect(bbox);
 }
 
@@ -488,7 +489,9 @@ SkPDFFunctionShader::SkPDFFunctionShader(SkPDFShader::State* state)
     if (fState.get()->fType == SkShader::kRadial2_GradientType) {
         SkShader::GradientInfo twoPointRadialInfo = *info;
         SkMatrix inverseMapperMatrix;
-        mapperMatrix.invert(&inverseMapperMatrix);
+        if (!mapperMatrix.invert(&inverseMapperMatrix)) {
+            inverseMapperMatrix.reset();
+        }
         inverseMapperMatrix.mapPoints(twoPointRadialInfo.fPoint, 2);
         twoPointRadialInfo.fRadius[0] =
             inverseMapperMatrix.mapRadius(info->fRadius[0]);