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[PDF] Handle failures of matrix inversion

Previously reviewed in https://codereview.appspot.com/6033047.  Rolled back
because of unrelated fixed-point bugs.

Review URL: https://codereview.appspot.com/6052051

git-svn-id: http://skia.googlecode.com/svn/trunk/src@3715 2bbb7eff-a529-9590-31e7-b0007b416f81
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vandebo@chromium.org
vandebo@chromium.org committed Apr 17, 2012
1 parent 091d321 commit 86edf7332417d0d7c80123f074f3e12a9128776d
Showing with 31 additions and 12 deletions.
  1. +3 −1 pdf/SkPDFDevice.cpp
  2. +2 −0 pdf/SkPDFFormXObject.cpp
  3. +24 −11 pdf/SkPDFShader.cpp
  4. +2 −0 pdf/SkPDFShader.h
View
@@ -491,6 +491,8 @@ static inline SkBitmap makeContentBitmap(const SkISize& contentSize,
drawingSize.set(SkIntToScalar(contentSize.fWidth),
SkIntToScalar(contentSize.fHeight));
if (!initialTransform->invert(&inverse)) {
+ // This shouldn't happen, initial transform should be invertible.
+ SkASSERT(false);
inverse.reset();
}
inverse.mapVectors(&drawingSize, 1);
@@ -603,7 +605,7 @@ void SkPDFDevice::internalDrawPaint(const SkPaint& paint,
totalTransform.preConcat(contentEntry->fState.fMatrix);
SkMatrix inverse;
if (!totalTransform.invert(&inverse)) {
- inverse.reset();
+ return;
}
inverse.mapRect(&bbox);
View
@@ -37,6 +37,8 @@ SkPDFFormXObject::SkPDFFormXObject(SkPDFDevice* device) {
if (!device->initialTransform().isIdentity()) {
SkMatrix inverse;
if (!device->initialTransform().invert(&inverse)) {
+ // The initial transform should be invertible.
+ SkASSERT(false);
inverse.reset();
}
insert("Matrix", SkPDFUtils::MatrixToArray(inverse))->unref();
View
@@ -21,12 +21,13 @@
#include "SkThread.h"
#include "SkTypes.h"
-static void transformBBox(const SkMatrix& matrix, SkRect* bbox) {
+static bool transformBBox(const SkMatrix& matrix, SkRect* bbox) {
SkMatrix inverse;
if (!matrix.invert(&inverse)) {
- inverse.reset();
+ return false;
}
inverse.mapRect(bbox);
+ return true;
}
static void unitToPointsMatrix(const SkPoint pts[2], SkMatrix* matrix) {
@@ -309,7 +310,7 @@ class SkPDFFunctionShader : public SkPDFDict, public SkPDFShader {
fResources.unrefAll();
}
- bool isValid() { return fResources.count() > 0; }
+ virtual bool isValid() { return fResources.count() > 0; }
void getResources(SkTDArray<SkPDFObject*>* resourceList) {
GetResourcesHelper(&fResources, resourceList);
@@ -332,6 +333,8 @@ class SkPDFImageShader : public SkPDFStream, public SkPDFShader {
fResources.unrefAll();
}
+ virtual bool isValid() { return size() > 0; }
+
void getResources(SkTDArray<SkPDFObject*>* resourceList) {
GetResourcesHelper(&fResources, resourceList);
}
@@ -367,18 +370,24 @@ SkPDFObject* SkPDFShader::GetPDFShader(const SkShader& shader,
result->ref();
return result;
}
+
+ bool valid = false;
// The PDFShader takes ownership of the shaderSate.
if (shaderState.get()->fType == SkShader::kNone_GradientType) {
- result = new SkPDFImageShader(shaderState.detach());
+ SkPDFImageShader* imageShader =
+ new SkPDFImageShader(shaderState.detach());
+ valid = imageShader->isValid();
+ result = imageShader;
} else {
SkPDFFunctionShader* functionShader =
new SkPDFFunctionShader(shaderState.detach());
- if (!functionShader->isValid()) {
- delete functionShader;
- return NULL;
- }
+ valid = functionShader->isValid();
result = functionShader;
}
+ if (!valid) {
+ delete result;
+ return NULL;
+ }
entry.fPDFShader = result;
CanonicalShaders().push(entry);
return result; // return the reference that came from new.
@@ -472,7 +481,9 @@ SkPDFFunctionShader::SkPDFFunctionShader(SkPDFShader::State* state)
finalMatrix.preConcat(fState.get()->fShaderTransform);
SkRect bbox;
bbox.set(fState.get()->fBBox);
- transformBBox(finalMatrix, &bbox);
+ if (!transformBBox(finalMatrix, &bbox)) {
+ return;
+ }
SkRefPtr<SkPDFArray> domain = new SkPDFArray;
domain->unref(); // SkRefPtr and new both took a reference.
@@ -490,7 +501,7 @@ SkPDFFunctionShader::SkPDFFunctionShader(SkPDFShader::State* state)
SkShader::GradientInfo twoPointRadialInfo = *info;
SkMatrix inverseMapperMatrix;
if (!mapperMatrix.invert(&inverseMapperMatrix)) {
- inverseMapperMatrix.reset();
+ return;
}
inverseMapperMatrix.mapPoints(twoPointRadialInfo.fPoint, 2);
twoPointRadialInfo.fRadius[0] =
@@ -525,7 +536,9 @@ SkPDFImageShader::SkPDFImageShader(SkPDFShader::State* state) : fState(state) {
finalMatrix.preConcat(fState.get()->fShaderTransform);
SkRect surfaceBBox;
surfaceBBox.set(fState.get()->fBBox);
- transformBBox(finalMatrix, &surfaceBBox);
+ if (!transformBBox(finalMatrix, &surfaceBBox)) {
+ return;
+ }
SkMatrix unflip;
unflip.setTranslate(0, SkScalarRoundToScalar(surfaceBBox.height()));
View
@@ -60,6 +60,8 @@ class SkPDFShader {
static void RemoveShader(SkPDFObject* shader);
SkPDFShader();
+
+ virtual bool isValid() = 0;
};
#endif

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