Add SkSpecialImage & SkSpecialSurface classes

src/core/SkSpecialImage.cpp

Index: src/core/SkSpecialImage.cpp
diff --git a/src/core/SkSpecialImage.cpp b/src/core/SkSpecialImage.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..50447fc1e964ade4fe65bf42930e4e462c5ce735
--- /dev/null
+++ b/src/core/SkSpecialImage.cpp
@@ -0,0 +1,224 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file
+ */
+
+#include "SkCanvas.h"
+#include "SkSpecialImage.h"
+#include "SkSpecialSurface.h"
+
+///////////////////////////////////////////////////////////////////////////////
+class SkSpecialImage_Base : public SkSpecialImage {
+public:
+    SkSpecialImage_Base(const SkIRect& subset) : INHERITED(subset) { }
+    virtual ~SkSpecialImage_Base() { }
+
+    virtual void onDraw(SkCanvas*, int x, int y, const SkPaint*) const = 0;
+
+    virtual bool onPeekPixels(SkPixmap*) const { return false; }
+
+    virtual GrTexture* onPeekTexture() const { return nullptr; }
+
+    virtual SkSpecialSurface* onNewSurface(const SkImageInfo& info) const { return nullptr; }
+
+private:
+    typedef SkSpecialImage INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+static inline const SkSpecialImage_Base* as_IB(const SkSpecialImage* image) {
+    return static_cast<const SkSpecialImage_Base*>(image);
+}
+
+void SkSpecialImage::draw(SkCanvas* canvas, int x, int y, const SkPaint* paint) const {
+    return as_IB(this)->onDraw(canvas, x, y, paint);
+}
+
+bool SkSpecialImage::peekPixels(SkPixmap* pixmap) const {
+    return as_IB(this)->onPeekPixels(pixmap);
+}
+
+GrTexture* SkSpecialImage::peekTexture() const {
+    return as_IB(this)->onPeekTexture();
+}
+
+SkSpecialSurface* SkSpecialImage::newSurface(const SkImageInfo& info) const {
+    return as_IB(this)->onNewSurface(info);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+#include "SkImage.h"
+#if SK_SUPPORT_GPU
+#include "SkGr.h"
+#include "SkGrPriv.h"
+#endif
+
+class SkSpecialImage_Image : public SkSpecialImage_Base {
+public:
+    SkSpecialImage_Image(const SkIRect& subset, const SkImage* image)
+        : INHERITED(subset)
+        , fImage(SkRef(image)) {
+    }
+
+    ~SkSpecialImage_Image() override { }
+
+    void onDraw(SkCanvas* canvas, int x, int y, const SkPaint* paint) const override {
+        SkRect dst = SkRect::MakeXYWH(x, y, this->subset().width(), this->subset().height());
+
+        canvas->drawImageRect(fImage, this->subset(),
+                              dst, paint, SkCanvas::kStrict_SrcRectConstraint);
+    }
+
+    bool onPeekPixels(SkPixmap* pixmap) const override {
+        return fImage->peekPixels(pixmap);
+    }
+
+    GrTexture* onPeekTexture() const override { return fImage->getTexture(); }
+
+    SkSpecialSurface* onNewSurface(const SkImageInfo& info) const override {
+#if SK_SUPPORT_GPU
+        GrTexture* texture = fImage->getTexture();
+        if (texture) {
+            GrSurfaceDesc desc = GrImageInfoToSurfaceDesc(info);
+            desc.fFlags = kRenderTarget_GrSurfaceFlag;
+
+            return SkSpecialSurface::NewRenderTarget(texture->getContext(), desc);
+        }
+#endif
+        return SkSpecialSurface::NewRaster(info, nullptr);
+    }
+
+private:
+    SkAutoTUnref<const SkImage> fImage;
+
+    typedef SkSpecialImage_Base INHERITED;
+};
+
+#ifdef SK_DEBUG
+static bool rect_fits(const SkIRect& rect, int width, int height) {
+    return rect.fLeft >= 0 && rect.fLeft < width && rect.fLeft < rect.fRight &&
+           rect.fRight >= 0 && rect.fRight <= width &&
+           rect.fTop >= 0 && rect.fTop < height && rect.fTop < rect.fBottom &&
+           rect.fBottom >= 0 && rect.fBottom <= height;
+}
+#endif
+
+SkSpecialImage* SkSpecialImage::NewFromImage(const SkIRect& subset, const SkImage* image) {
+    SkASSERT(rect_fits(subset, image->width(), image->height()));
+    return new SkSpecialImage_Image(subset, image);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+#include "SkBitmap.h"
+#include "SkImageInfo.h"
+#include "SkPixelRef.h"
+
+class SkSpecialImage_Raster : public SkSpecialImage_Base {
+public:
+    SkSpecialImage_Raster(const SkIRect& subset, const SkBitmap& bm)
+        : INHERITED(subset)
+        , fBitmap(bm) {
+        if (bm.pixelRef()->isPreLocked()) {
+            // we only preemptively lock if there is no chance of triggering something expensive
+            // like a lazy decode or imagegenerator. PreLocked means it is flat pixels already.
+            fBitmap.lockPixels();
+        }
+    }
+
+    ~SkSpecialImage_Raster() override { }
+
+    void onDraw(SkCanvas* canvas, int x, int y, const SkPaint* paint) const override {
+        SkRect dst = SkRect::MakeXYWH(x, y,
+                                      this->subset().width(), this->subset().height());
+
+        canvas->drawBitmapRect(fBitmap, this->subset(),
+                               dst, paint, SkCanvas::kStrict_SrcRectConstraint);
+    }
+
+    bool onPeekPixels(SkPixmap* pixmap) const override {
+        const SkImageInfo info = fBitmap.info();
+        if ((kUnknown_SkColorType == info.colorType()) || !fBitmap.getPixels()) {
+            return false;
+        }
+        const void* pixels = fBitmap.getPixels();
+        if (pixels) {
+            if (pixmap) {
+                pixmap->reset(info, pixels, fBitmap.rowBytes());
+            }
+            return true;
+        }
+        return false;
+    }
+
+    SkSpecialSurface* onNewSurface(const SkImageInfo& info) const override {
+        return SkSpecialSurface::NewRaster(info, nullptr);
+    }
+
+private:
+    SkBitmap fBitmap;
+
+    typedef SkSpecialImage_Base INHERITED;
+};
+
+SkSpecialImage* SkSpecialImage::NewFromRaster(const SkIRect& subset, const SkBitmap& bm) {
+    SkASSERT(nullptr == bm.getTexture());
+    SkASSERT(rect_fits(subset, bm.width(), bm.height()));
+    return new SkSpecialImage_Raster(subset, bm);
+}
+
+#if SK_SUPPORT_GPU
+///////////////////////////////////////////////////////////////////////////////
+#include "GrTexture.h"
+
+class SkSpecialImage_Gpu : public SkSpecialImage_Base {
+public:
+    SkSpecialImage_Gpu(const SkIRect& subset, GrTexture* tex)
+        : INHERITED(subset)
+        , fTexture(SkRef(tex)) {
+    }
+
+    ~SkSpecialImage_Gpu() override { }
+
+    void onDraw(SkCanvas* canvas, int x, int y, const SkPaint* paint) const override {
+        SkRect dst = SkRect::MakeXYWH(x, y,
+                                      this->subset().width(), this->subset().height());
+
+        SkBitmap bm;
+
+        static const bool kUnknownOpacity = false;
+        GrWrapTextureInBitmap(fTexture,
+                              fTexture->width(), fTexture->height(), kUnknownOpacity, &bm);
+
+        canvas->drawBitmapRect(bm, this->subset(),
+                               dst, paint, SkCanvas::kStrict_SrcRectConstraint);
+    }
+
+    GrTexture* onPeekTexture() const override { return fTexture; }
+
+    SkSpecialSurface* onNewSurface(const SkImageInfo& info) const override {
+        GrSurfaceDesc desc = GrImageInfoToSurfaceDesc(info);
+        desc.fFlags = kRenderTarget_GrSurfaceFlag;
+
+        return SkSpecialSurface::NewRenderTarget(fTexture->getContext(), desc);
+    }
+
+private:
+    SkAutoTUnref<GrTexture> fTexture;
+
+    typedef SkSpecialImage_Base INHERITED;
+};
+
+SkSpecialImage* SkSpecialImage::NewFromGpu(const SkIRect& subset, GrTexture* tex) {
+    SkASSERT(rect_fits(subset, tex->width(), tex->height()));
+    return new SkSpecialImage_Gpu(subset, tex);
+}
+
+#else
+
+SkSpecialImage* SkSpecialImage::NewFromGpu(const SkIRect& subset, GrTexture* tex) {
+    return nullptr;
+}
+
+#endif