Fix SkAlphaThresholdFilter bounds handling.

src/effects/SkAlphaThresholdFilter.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAlphaThresholdFilter.h"
 #include "SkBitmap.h"
 #include "SkDevice.h"
@@ skipping 50 matching lines @@
 #include "GrTextureAccess.h"
 #include "effects/GrPorterDuffXferProcessor.h"
 
 #include "SkGr.h"
 
 #include "glsl/GrGLSLFragmentProcessor.h"
 #include "glsl/GrGLSLFragmentShaderBuilder.h"
 #include "glsl/GrGLSLProgramDataManager.h"
 #include "glsl/GrGLSLUniformHandler.h"
 
+namespace {
+
+SkMatrix make_div_and_translate_matrix(GrTexture* texture, int x, int y) {
+    SkMatrix matrix = GrCoordTransform::MakeDivByTextureWHMatrix(texture);
+    matrix.preTranslate(SkIntToScalar(x), SkIntToScalar(y));
+    return matrix;
+}
+
+};
+
 class AlphaThresholdEffect : public GrFragmentProcessor {
 
 public:
     static GrFragmentProcessor* Create(GrTexture* texture,
                                        GrTexture* maskTexture,
                                        float innerThreshold,
-                                       float outerThreshold) {
-        return new AlphaThresholdEffect(texture, maskTexture, innerThreshold, outerThreshold);
+                                       float outerThreshold,
+                                       const SkIRect& bounds) {
+        return new AlphaThresholdEffect(texture, maskTexture, innerThreshold, outerThreshold,
+                                        bounds);
     }
 
     virtual ~AlphaThresholdEffect() {};
 
     const char* name() const override { return "Alpha Threshold"; }
 
     float innerThreshold() const { return fInnerThreshold; }
     float outerThreshold() const { return fOuterThreshold; }
 
 private:
     AlphaThresholdEffect(GrTexture* texture,
                          GrTexture* maskTexture,
                          float innerThreshold,
-                         float outerThreshold)
+                         float outerThreshold,
+                         const SkIRect& bounds)
         : fInnerThreshold(innerThreshold)
         , fOuterThreshold(outerThreshold)
         , fImageCoordTransform(kLocal_GrCoordSet,
                                GrCoordTransform::MakeDivByTextureWHMatrix(texture), texture,
                                GrTextureParams::kNone_FilterMode)
         , fImageTextureAccess(texture)
         , fMaskCoordTransform(kLocal_GrCoordSet,
-                              GrCoordTransform::MakeDivByTextureWHMatrix(maskTexture), maskTexture,
+                              make_div_and_translate_matrix(maskTexture, -bounds.x(), -bounds.y()),
+                              maskTexture,
                               GrTextureParams::kNone_FilterMode)
         , fMaskTextureAccess(maskTexture) {
         this->initClassID<AlphaThresholdEffect>();
         this->addCoordTransform(&fImageCoordTransform);
         this->addTextureAccess(&fImageTextureAccess);
         this->addCoordTransform(&fMaskCoordTransform);
         this->addTextureAccess(&fMaskTextureAccess);
     }
 
     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
@@ skipping 87 matching lines @@
 
 /////////////////////////////////////////////////////////////////////
 
 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(AlphaThresholdEffect);
 
 const GrFragmentProcessor* AlphaThresholdEffect::TestCreate(GrProcessorTestData* d) {
     GrTexture* bmpTex = d->fTextures[GrProcessorUnitTest::kSkiaPMTextureIdx];
     GrTexture* maskTex = d->fTextures[GrProcessorUnitTest::kAlphaTextureIdx];
     float innerThresh = d->fRandom->nextUScalar1();
     float outerThresh = d->fRandom->nextUScalar1();
-    return AlphaThresholdEffect::Create(bmpTex, maskTex, innerThresh, outerThresh);
+    const int kMaxWidth = 1000;
+    const int kMaxHeight = 1000;
+    uint32_t width = d->fRandom->nextULessThan(kMaxWidth);
+    uint32_t height = d->fRandom->nextULessThan(kMaxHeight);
+    uint32_t x = d->fRandom->nextULessThan(kMaxWidth - width);
+    uint32_t y = d->fRandom->nextULessThan(kMaxHeight - height);
+    SkIRect bounds = SkIRect::MakeXYWH(x, y, width, height);
+    return AlphaThresholdEffect::Create(bmpTex, maskTex, innerThresh, outerThresh, bounds);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 void AlphaThresholdEffect::onGetGLSLProcessorKey(const GrGLSLCaps& caps,
                                                  GrProcessorKeyBuilder* b) const {
     GrGLAlphaThresholdEffect::GenKey(*this, caps, b);
 }
 
 GrGLSLFragmentProcessor* AlphaThresholdEffect::onCreateGLSLInstance() const {
@@ skipping 34 matching lines @@
     : INHERITED(1, &input)
     , fRegion(region)
     , fInnerThreshold(innerThreshold)
     , fOuterThreshold(outerThreshold) {
 }
 
 #if SK_SUPPORT_GPU
 bool SkAlphaThresholdFilterImpl::asFragmentProcessor(GrFragmentProcessor** fp,
                                                      GrTexture* texture,
                                                      const SkMatrix& inMatrix,
-                                                     const SkIRect&) const {
+                                                     const SkIRect& bounds) const {
     if (fp) {
         GrContext* context = texture->getContext();
         GrSurfaceDesc maskDesc;
         if (context->caps()->isConfigRenderable(kAlpha_8_GrPixelConfig, false)) {
             maskDesc.fConfig = kAlpha_8_GrPixelConfig;
         } else {
             maskDesc.fConfig = kRGBA_8888_GrPixelConfig;
         }
         maskDesc.fFlags = kRenderTarget_GrSurfaceFlag;
         // Add one pixel of border to ensure that clamp mode will be all zeros
         // the outside.
-        maskDesc.fWidth = texture->width();
-        maskDesc.fHeight = texture->height();
+        maskDesc.fWidth = bounds.width();
+        maskDesc.fHeight = bounds.height();
         SkAutoTUnref<GrTexture> maskTexture(
             context->textureProvider()->createApproxTexture(maskDesc));
         if (!maskTexture) {
             return false;
         }
 
         SkAutoTUnref<GrDrawContext> drawContext(
                                             context->drawContext(maskTexture->asRenderTarget()));
         if (drawContext) {
             GrPaint grPaint;
             grPaint.setPorterDuffXPFactory(SkXfermode::kSrc_Mode);
             SkRegion::Iterator iter(fRegion);
             drawContext->clear(nullptr, 0x0, true);
 
+            GrClip clip(SkRect::Make(SkIRect::MakeWH(bounds.width(), bounds.height())));
             while (!iter.done()) {
                 SkRect rect = SkRect::Make(iter.rect());
-                drawContext->drawRect(GrClip::WideOpen(), grPaint, inMatrix, rect);
+                drawContext->drawRect(clip, grPaint, inMatrix, rect);
                 iter.next();
             }
         }
 
         *fp = AlphaThresholdEffect::Create(texture,
                                            maskTexture,
                                            fInnerThreshold,
-                                           fOuterThreshold);
+                                           fOuterThreshold,
+                                           bounds);
     }
     return true;
 }
 #endif
 
 void SkAlphaThresholdFilterImpl::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writeScalar(fInnerThreshold);
     buffer.writeScalar(fOuterThreshold);
     buffer.writeRegion(fRegion);
@@ skipping 65 matching lines @@
 }
 
 #ifndef SK_IGNORE_TO_STRING
 void SkAlphaThresholdFilterImpl::toString(SkString* str) const {
     str->appendf("SkAlphaThresholdImageFilter: (");
     str->appendf("inner: %f outer: %f", fInnerThreshold, fOuterThreshold);
     str->append(")");
 }
 #endif