add ImageShader, sharing code with its Bitmap cousin

This is done by having abstracted the BitmapShaderContext to take a BitmapProvider, instead of just a bitmap. This allows us to share all of that code between SkBitmap and SkImage, since both are valid providers.

It also means that we can simplify SkImage_Base to not need a virtual for onNewShader, since ALL images can uniformly be turned into a shader now.

BUG=skia:

Review URL: https://codereview.chromium.org/1342113002

8 files changed, 191 insertions, 40 deletions

diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index 6f4655758e..975d7ba803 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -11,6 +11,7 @@
 #include "SkData.h"
 #include "SkImageGenerator.h"
 #include "SkImagePriv.h"
+#include "SkImageShader.h"
 #include "SkImage_Base.h"
 #include "SkNextID.h"
 #include "SkPixelRef.h"
@@ -69,7 +70,7 @@ void SkImage::preroll(GrContext* ctx) const {
 SkShader* SkImage::newShader(SkShader::TileMode tileX,
                              SkShader::TileMode tileY,
                              const SkMatrix* localMatrix) const {
-    return as_IB(this)->onNewShader(tileX, tileY, localMatrix);
+    return SkImageShader::Create(this, tileX, tileY, localMatrix);
 }
 
 SkData* SkImage::encode(SkImageEncoder::Type type, int quality) const {
diff --git a/src/image/SkImageShader.cpp b/src/image/SkImageShader.cpp
new file mode 100644
index 0000000000..58eddf3f7d
--- /dev/null
+++ b/src/image/SkImageShader.cpp
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkBitmapProcShader.h"
+#include "SkBitmapProvider.h"
+#include "SkImage_Base.h"
+#include "SkImageShader.h"
+#include "SkReadBuffer.h"
+#include "SkWriteBuffer.h"
+
+SkImageShader::SkImageShader(const SkImage* img, TileMode tmx, TileMode tmy, const SkMatrix* matrix)
+    : INHERITED(matrix)
+    , fImage(SkRef(img))
+    , fTileModeX(tmx)
+    , fTileModeY(tmy)
+{}
+
+SkFlattenable* SkImageShader::CreateProc(SkReadBuffer& buffer) {
+    const TileMode tx = (TileMode)buffer.readUInt();
+    const TileMode ty = (TileMode)buffer.readUInt();
+    SkMatrix matrix;
+    buffer.readMatrix(&matrix);
+    SkAutoTUnref<SkImage> img(buffer.readImage());
+    if (!img) {
+        return nullptr;
+    }
+    return new SkImageShader(img, tx, ty, &matrix);
+}
+
+void SkImageShader::flatten(SkWriteBuffer& buffer) const {
+    buffer.writeUInt(fTileModeX);
+    buffer.writeUInt(fTileModeY);
+    buffer.writeMatrix(this->getLocalMatrix());
+    buffer.writeImage(fImage);
+}
+
+bool SkImageShader::isOpaque() const {
+    return fImage->isOpaque();
+}
+
+size_t SkImageShader::contextSize() const {
+    return SkBitmapProcShader::ContextSize();
+}
+
+SkShader::Context* SkImageShader::onCreateContext(const ContextRec& rec, void* storage) const {
+    return SkBitmapProcShader::MakeContext(*this, fTileModeX, fTileModeY,
+                                           SkBitmapProvider(fImage), rec, storage);
+}
+
+SkShader* SkImageShader::Create(const SkImage* image, TileMode tx, TileMode ty,
+                                const SkMatrix* localMatrix) {
+    if (!image) {
+        return nullptr;
+    }
+    return new SkImageShader(image, tx, ty, localMatrix);
+}
+
+#ifndef SK_IGNORE_TO_STRING
+void SkImageShader::toString(SkString* str) const {
+    const char* gTileModeName[SkShader::kTileModeCount] = {
+        "clamp", "repeat", "mirror"
+    };
+
+    str->appendf("ImageShader: ((%s %s) ", gTileModeName[fTileModeX], gTileModeName[fTileModeY]);
+    fImage->toString(str);
+    this->INHERITED::toString(str);
+    str->append(")");
+}
+#endif
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+#if SK_SUPPORT_GPU
+
+#include "GrTextureAccess.h"
+#include "SkGr.h"
+#include "effects/GrSimpleTextureEffect.h"
+#include "effects/GrBicubicEffect.h"
+#include "effects/GrExtractAlphaFragmentProcessor.h"
+#include "effects/GrSimpleTextureEffect.h"
+
+const GrFragmentProcessor* SkImageShader::asFragmentProcessor(GrContext* context,
+                                                              const SkMatrix& viewM,
+                                                              const SkMatrix* localMatrix,
+                                                              SkFilterQuality filterQuality,
+                                                              GrProcessorDataManager* mgr) const {
+    SkMatrix matrix;
+    matrix.setIDiv(fImage->width(), fImage->height());
+
+    SkMatrix lmInverse;
+    if (!this->getLocalMatrix().invert(&lmInverse)) {
+        return nullptr;
+    }
+    if (localMatrix) {
+        SkMatrix inv;
+        if (!localMatrix->invert(&inv)) {
+            return nullptr;
+        }
+        lmInverse.postConcat(inv);
+    }
+    matrix.preConcat(lmInverse);
+
+    SkShader::TileMode tm[] = { fTileModeX, fTileModeY };
+
+    // Must set wrap and filter on the sampler before requesting a texture. In two places below
+    // we check the matrix scale factors to determine how to interpret the filter quality setting.
+    // This completely ignores the complexity of the drawVertices case where explicit local coords
+    // are provided by the caller.
+    bool doBicubic;
+    GrTextureParams::FilterMode textureFilterMode =
+    GrSkFilterQualityToGrFilterMode(filterQuality, viewM, this->getLocalMatrix(), &doBicubic);
+    GrTextureParams params(tm, textureFilterMode);
+
+    SkImageUsageType usageType;
+    if (kClamp_TileMode == fTileModeX && kClamp_TileMode == fTileModeY) {
+        usageType = kUntiled_SkImageUsageType;
+    } else if (GrTextureParams::kNone_FilterMode == textureFilterMode) {
+        usageType = kTiled_Unfiltered_SkImageUsageType;
+    } else {
+        usageType = kTiled_Filtered_SkImageUsageType;
+    }
+
+    SkAutoTUnref<GrTexture> texture(as_IB(fImage)->asTextureRef(context, usageType));
+    if (!texture) {
+        return nullptr;
+    }
+
+    SkAutoTUnref<GrFragmentProcessor> inner;
+    if (doBicubic) {
+        inner.reset(GrBicubicEffect::Create(mgr, texture, matrix, tm));
+    } else {
+        inner.reset(GrSimpleTextureEffect::Create(mgr, texture, matrix, params));
+    }
+
+    if (GrPixelConfigIsAlphaOnly(texture->config())) {
+        return SkRef(inner.get());
+    }
+    return GrExtractAlphaFragmentProcessor::Create(inner);
+}
+
+#endif
diff --git a/src/image/SkImageShader.h b/src/image/SkImageShader.h
new file mode 100644
index 0000000000..fdd7976aad
--- /dev/null
+++ b/src/image/SkImageShader.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkImageShader_DEFINED
+#define SkImageShader_DEFINED
+
+#include "SkImage.h"
+#include "SkShader.h"
+
+class SkImageShader : public SkShader {
+public:
+    static SkShader* Create(const SkImage*, TileMode tx, TileMode ty, const SkMatrix* localMatrix);
+
+    bool isOpaque() const override;
+    size_t contextSize() const override;
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkImageShader)
+
+#if SK_SUPPORT_GPU
+    const GrFragmentProcessor* asFragmentProcessor(GrContext*, const SkMatrix& viewM,
+                                                   const SkMatrix*, SkFilterQuality,
+                                                   GrProcessorDataManager*) const override;
+#endif
+
+protected:
+    void flatten(SkWriteBuffer&) const override;
+    Context* onCreateContext(const ContextRec&, void* storage) const override;
+
+    SkAutoTUnref<const SkImage> fImage;
+    const TileMode              fTileModeX;
+    const TileMode              fTileModeY;
+
+private:
+    SkImageShader(const SkImage*, TileMode tx, TileMode ty, const SkMatrix* localMatrix);
+
+    typedef SkShader INHERITED;
+};
+
+#endif
diff --git a/src/image/SkImage_Base.h b/src/image/SkImage_Base.h
index d0cb8d5840..bbe70a7e4a 100644
--- a/src/image/SkImage_Base.h
+++ b/src/image/SkImage_Base.h
@@ -56,10 +56,6 @@ public:
     // Caller must call unref when they are done.
     virtual GrTexture* asTextureRef(GrContext*, SkImageUsageType) const = 0;
 
-    virtual SkShader* onNewShader(SkShader::TileMode,
-                                  SkShader::TileMode,
-                                  const SkMatrix* localMatrix) const { return nullptr; }
-
     // newWidth > 0, newHeight > 0, subset either nullptr or a proper subset of this bounds
     virtual SkImage* onNewImage(int newWidth, int newHeight, const SkIRect* subset,
                                 SkFilterQuality) const;
diff --git a/src/image/SkImage_Generator.cpp b/src/image/SkImage_Generator.cpp
index 0f1fa3692c..f0bf7e3641 100644
--- a/src/image/SkImage_Generator.cpp
+++ b/src/image/SkImage_Generator.cpp
@@ -28,11 +28,6 @@ public:
 
     bool getROPixels(SkBitmap*) const override;
     GrTexture* asTextureRef(GrContext*, SkImageUsageType) const override;
-
-    SkShader* onNewShader(SkShader::TileMode,
-                          SkShader::TileMode,
-                          const SkMatrix* localMatrix) const override;
-
     bool onIsLazyGenerated() const override { return true; }
 
 private:
@@ -43,17 +38,6 @@ private:
 
 ///////////////////////////////////////////////////////////////////////////////
 
-SkShader* SkImage_Generator::onNewShader(SkShader::TileMode tileX, SkShader::TileMode tileY,
-                                         const SkMatrix* localMatrix) const {
-    // TODO: need a native Shader that takes Cacherator (or this image) so we can natively return
-    // textures as output from the shader.
-    SkBitmap bm;
-    if (this->getROPixels(&bm)) {
-        return SkShader::CreateBitmapShader(bm, tileX, tileY, localMatrix);
-    }
-    return nullptr;
-}
-
 SkSurface* SkImage_Generator::onNewSurface(const SkImageInfo& info,
                                            const SkSurfaceProps& props) const {
     return SkSurface::NewRaster(info, &props);
diff --git a/src/image/SkImage_Gpu.cpp b/src/image/SkImage_Gpu.cpp
index 163e62e02d..527bcc3ef5 100644
--- a/src/image/SkImage_Gpu.cpp
+++ b/src/image/SkImage_Gpu.cpp
@@ -49,13 +49,6 @@ extern void SkTextureImageApplyBudgetedDecision(SkImage* image) {
     }
 }
 
-SkShader* SkImage_Gpu::onNewShader(SkShader::TileMode tileX, SkShader::TileMode tileY,
-                                   const SkMatrix* localMatrix) const {
-    SkBitmap bm;
-    GrWrapTextureInBitmap(fTexture, this->width(), this->height(), this->isOpaque(), &bm);
-    return SkShader::CreateBitmapShader(bm, tileX, tileY, localMatrix);
-}
-
 bool SkImage_Gpu::getROPixels(SkBitmap* dst) const {
     if (SkBitmapCache::Find(this->uniqueID(), dst)) {
         SkASSERT(dst->getGenerationID() == this->uniqueID());
diff --git a/src/image/SkImage_Gpu.h b/src/image/SkImage_Gpu.h
index d168fb6853..cc576c499c 100644
--- a/src/image/SkImage_Gpu.h
+++ b/src/image/SkImage_Gpu.h
@@ -40,9 +40,6 @@ public:
     GrTexture* asTextureRef(GrContext* ctx, SkImageUsageType usage) const override;
 
     GrTexture* peekTexture() const override { return fTexture; }
-    SkShader* onNewShader(SkShader::TileMode,
-                          SkShader::TileMode,
-                          const SkMatrix* localMatrix) const override;
     bool isOpaque() const override;
     SkSurface* onNewSurface(const SkImageInfo&, const SkSurfaceProps&) const override;
     bool onReadPixels(const SkImageInfo&, void* dstPixels, size_t dstRowBytes,
diff --git a/src/image/SkImage_Raster.cpp b/src/image/SkImage_Raster.cpp
index 67498f0e11..18d6ba6fd7 100644
--- a/src/image/SkImage_Raster.cpp
+++ b/src/image/SkImage_Raster.cpp
@@ -80,10 +80,6 @@ public:
 
     SkPixelRef* getPixelRef() const { return fBitmap.pixelRef(); }
 
-    SkShader* onNewShader(SkShader::TileMode,
-                          SkShader::TileMode,
-                          const SkMatrix* localMatrix) const override;
-
     bool isOpaque() const override;
     bool onAsLegacyBitmap(SkBitmap*, LegacyBitmapMode) const override;
 
@@ -144,11 +140,6 @@ SkImage_Raster::SkImage_Raster(const Info& info, SkPixelRef* pr, const SkIPoint&
 
 SkImage_Raster::~SkImage_Raster() {}
 
-SkShader* SkImage_Raster::onNewShader(SkShader::TileMode tileX, SkShader::TileMode tileY,
-                                      const SkMatrix* localMatrix) const {
-    return SkShader::CreateBitmapShader(fBitmap, tileX, tileY, localMatrix);
-}
-
 SkSurface* SkImage_Raster::onNewSurface(const SkImageInfo& info, const SkSurfaceProps& props) const {
     return SkSurface::NewRaster(info, &props);
 }