diff --git a/src/pdf/SkBitmapKey.h b/src/pdf/SkBitmapKey.h
index 53d4d64..a640468 100644
--- a/src/pdf/SkBitmapKey.h
+++ b/src/pdf/SkBitmapKey.h
@@ -11,57 +11,67 @@
 #include "SkImage.h"
 #include "SkCanvas.h"
 
-class SkBitmapKey {
-public:
-    SkBitmapKey() : fSubset(SkIRect::MakeEmpty()), fID(0) {}
-    explicit SkBitmapKey(const SkBitmap& bm)
-        : fSubset(bm.getSubset()), fID(bm.getGenerationID()) {}
-    explicit SkBitmapKey(const SkImage* img)
-        : fSubset(img ? img->bounds() : SkIRect::MakeEmpty())
-        , fID(img ? img->uniqueID() : 0) {}
-    explicit SkBitmapKey(const sk_sp<SkImage> img)
-        : fSubset(img->bounds()), fID(img->uniqueID()) {}
+struct SkBitmapKey {
+    SkIRect fSubset;
+    uint32_t fID;
     bool operator==(const SkBitmapKey& rhs) const {
         return fID == rhs.fID && fSubset == rhs.fSubset;
     }
     bool operator!=(const SkBitmapKey& rhs) const { return !(*this == rhs); }
-    uint32_t id() const { return fID; }
-
-private:
-    SkIRect fSubset;
-    uint32_t fID;
 };
 
 /**
-   This wraps a thing that could either be a bitmap or a image and
-   abstracts out some common tasks.
+   This class has all the advantages of SkBitmaps and SkImages.
  */
-class SkImageBitmap {
+class SkImageSubset {
 public:
-    explicit SkImageBitmap(const SkBitmap& b) : fBitmap(b), fImage(nullptr) {}
-    explicit SkImageBitmap(SkImage* i) : fImage(i) { SkASSERT(fImage); }
-    SkIRect bounds() const { return fImage ? fImage->bounds() : fBitmap.bounds(); }
-    SkISize dimensions() const {
-        return fImage ? fImage->dimensions() : fBitmap.dimensions();
-    }
-    sk_sp<SkImage> makeImage() const {
-        return fImage ? sk_ref_sp(fImage) : SkImage::MakeFromBitmap(fBitmap);
-    }
-    SkBitmapKey getKey() const {
-        return fImage ? SkBitmapKey(fImage) : SkBitmapKey(fBitmap);
-    }
-    void draw(SkCanvas* canvas, SkPaint* paint) const {
-        if (fImage) {
-            canvas->drawImage(fImage, 0, 0, paint);
+    SkImageSubset(sk_sp<SkImage> i, SkIRect subset = {0, 0, 0, 0})
+        : fImage(std::move(i)) {
+        if (!fImage) {
+            fSubset = {0, 0, 0, 0};
+            fID = 0;
+            return;
+        }
+        fID = fImage->uniqueID();
+        if (subset.isEmpty()) {
+            fSubset = fImage->bounds();
+            // SkImage always has a non-zero dimensions.
+            SkASSERT(!fSubset.isEmpty());
         } else {
-            canvas->drawBitmap(fBitmap, 0, 0, paint);
+            fSubset = subset;
+            if (!fSubset.intersect(fImage->bounds())) {
+                fImage = nullptr;
+                fSubset = {0, 0, 0, 0};
+                fID = 0;
+            }
         }
     }
 
+    void setID(uint32_t id) { fID = id; }
+
+    bool isValid() const { return fImage != nullptr; }
+
+    SkIRect bounds() const { return SkIRect::MakeSize(this->dimensions()); }
+
+    SkISize dimensions() const { return fSubset.size(); }
+
+    sk_sp<SkImage> makeImage() const {
+        return fSubset == fImage->bounds() ? fImage : fImage->makeSubset(fSubset);
+    }
+
+    SkBitmapKey getKey() const { return SkBitmapKey{fSubset, fID}; }
+
+    void draw(SkCanvas* canvas, SkPaint* paint) const {
+        SkASSERT(this->isValid());
+        SkRect src = SkRect::Make(fSubset),
+               dst = SkRect::Make(this->bounds());
+        canvas->drawImageRect(fImage.get(), src, dst, paint);
+    }
+
 private:
-    SkBitmap fBitmap;
-    SkImage* fImage; // non-owning; when drawImage starts passing a sk_sp<>,
-                     // we can take a const ref to that sk_sp<>.
+    SkIRect fSubset;
+    sk_sp<SkImage> fImage;
+    uint32_t fID;
 };
 
 #endif  // SkBitmapKey_DEFINED
diff --git a/src/pdf/SkPDFCanvas.cpp b/src/pdf/SkPDFCanvas.cpp
index 0fc242b..13fcb55 100644
--- a/src/pdf/SkPDFCanvas.cpp
+++ b/src/pdf/SkPDFCanvas.cpp
@@ -54,35 +54,23 @@
 }
 
 void SkPDFCanvas::onDrawImageRect(const SkImage* image,
-                                  const SkRect* srcPtr,
+                                  const SkRect* src,
                                   const SkRect& dst,
                                   const SkPaint* paint,
                                   SkCanvas::SrcRectConstraint constraint) {
-    SkRect bounds = SkRect::Make(image->bounds());
-    SkRect src = srcPtr ? *srcPtr : bounds;
     SkAutoCanvasRestore autoCanvasRestore(this, true);
-    if (src != bounds) {
-        this->clipRect(dst);
-    }
-    this->concat(SkMatrix::MakeRectToRect(src, dst,
-                                 SkMatrix::kFill_ScaleToFit));
-    this->drawImage(image, 0, 0, paint);
+    this->clipRect(dst);
+    this->SkCanvas::onDrawImageRect(image, src, dst, paint, constraint);
 }
 
 void SkPDFCanvas::onDrawBitmapRect(const SkBitmap& bitmap,
-                                   const SkRect* srcPtr,
+                                   const SkRect* src,
                                    const SkRect& dst,
                                    const SkPaint* paint,
                                    SkCanvas::SrcRectConstraint constraint) {
-    SkRect bounds = SkRect::Make(bitmap.bounds());
-    SkRect src = srcPtr ? *srcPtr : bounds;
     SkAutoCanvasRestore autoCanvasRestore(this, true);
-    if (src != bounds) {
-        this->clipRect(dst);
-    }
-    this->concat(SkMatrix::MakeRectToRect(src, dst,
-                                 SkMatrix::kFill_ScaleToFit));
-    this->drawBitmap(bitmap, 0, 0, paint);
+    this->clipRect(dst);
+    this->SkCanvas::onDrawBitmapRect(bitmap, src, dst, paint, constraint);
 }
 
 void SkPDFCanvas::onDrawImageLattice(const SkImage* image,
diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index eed4992..4065235 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -31,6 +31,7 @@
 #include "SkPDFShader.h"
 #include "SkPDFTypes.h"
 #include "SkPDFUtils.h"
+#include "SkPixelRef.h"
 #include "SkRasterClip.h"
 #include "SkRRect.h"
 #include "SkScopeExit.h"
@@ -83,6 +84,27 @@
     return result;
 }
 
+static SkImageSubset make_image_subset(const SkBitmap& bitmap) {
+    SkASSERT(!bitmap.drawsNothing());
+    SkIRect subset = bitmap.getSubset();
+    SkAutoLockPixels autoLockPixels(bitmap);
+    SkASSERT(bitmap.pixelRef());
+    SkBitmap tmp;
+    tmp.setInfo(bitmap.pixelRef()->info(), bitmap.rowBytes());
+    tmp.setPixelRef(bitmap.pixelRef());
+    tmp.lockPixels();
+    auto img = SkImage::MakeFromBitmap(tmp);
+    if (img) {
+        SkASSERT(!bitmap.isImmutable() || img->uniqueID() == bitmap.getGenerationID());
+        SkASSERT(img->bounds().contains(subset));
+    }
+    SkImageSubset imageSubset(std::move(img), subset);
+    // SkImage::MakeFromBitmap only preserves genID for immutable
+    // bitmaps.  Use the bitmap's original ID for de-duping.
+    imageSubset.setID(bitmap.getGenerationID());
+    return imageSubset;
+}
+
 SkPDFDevice::GraphicStateEntry::GraphicStateEntry()
     : fColor(SK_ColorBLACK)
     , fTextScaleX(SK_Scalar1)
@@ -772,33 +794,98 @@
                           &content.entry()->fContent);
 }
 
-void SkPDFDevice::drawBitmapRect(const SkDraw& draw,
+
+void SkPDFDevice::drawImageRect(const SkDraw& d,
+                                const SkImage* image,
+                                const SkRect* src,
+                                const SkRect& dst,
+                                const SkPaint& srcPaint,
+                                SkCanvas::SrcRectConstraint) {
+    if (!image) {
+        return;
+    }
+    SkIRect bounds = image->bounds();
+    SkPaint paint = srcPaint;
+    if (image->isOpaque()) {
+        replace_srcmode_on_opaque_paint(&paint);
+    }
+    SkRect srcRect = src ? *src : SkRect::Make(bounds);
+    SkMatrix transform;
+    transform.setRectToRect(srcRect, dst, SkMatrix::kFill_ScaleToFit);
+    if (src) {
+        if (!srcRect.intersect(SkRect::Make(bounds))) {
+            return;
+        }
+        srcRect.roundOut(&bounds);
+        transform.preTranslate(SkIntToScalar(bounds.x()),
+                               SkIntToScalar(bounds.y()));
+    }
+    SkImageSubset imageSubset(sk_ref_sp(const_cast<SkImage*>(image)), bounds);
+    if (!imageSubset.isValid()) {
+        return;
+    }
+    transform.postConcat(*d.fMatrix);
+    this->internalDrawImage(transform, d.fClipStack, d.fRC->bwRgn(),
+                            std::move(imageSubset), paint);
+}
+
+void SkPDFDevice::drawBitmapRect(const SkDraw& d,
                                  const SkBitmap& bitmap,
                                  const SkRect* src,
                                  const SkRect& dst,
-                                 const SkPaint& srcPaint,
-                                 SkCanvas::SrcRectConstraint constraint) {
-    SkASSERT(false);
+                                const SkPaint& srcPaint,
+                                SkCanvas::SrcRectConstraint) {
+    if (bitmap.drawsNothing()) {
+        return;
+    }
+    SkIRect bounds = bitmap.bounds();
+    SkPaint paint = srcPaint;
+    if (bitmap.isOpaque()) {
+        replace_srcmode_on_opaque_paint(&paint);
+    }
+    SkRect srcRect = src ? *src : SkRect::Make(bounds);
+    SkMatrix transform;
+    transform.setRectToRect(srcRect, dst, SkMatrix::kFill_ScaleToFit);
+    if (src) {
+        if (!srcRect.intersect(SkRect::Make(bounds))) {
+            return;
+        }
+        srcRect.roundOut(&bounds);
+        transform.preTranslate(SkIntToScalar(bounds.x()),
+                               SkIntToScalar(bounds.y()));
+    }
+    SkBitmap bitmapSubset;
+    if (!bitmap.extractSubset(&bitmapSubset, bounds)) {
+        return;
+    }
+    SkImageSubset imageSubset = make_image_subset(bitmapSubset);
+    if (!imageSubset.isValid()) {
+        return;
+    }
+    transform.postConcat(*d.fMatrix);
+    this->internalDrawImage(transform, d.fClipStack, d.fRC->bwRgn(),
+                            std::move(imageSubset), paint);
 }
 
 void SkPDFDevice::drawBitmap(const SkDraw& d,
                              const SkBitmap& bitmap,
                              const SkMatrix& matrix,
                              const SkPaint& srcPaint) {
+    if (bitmap.drawsNothing() || d.fRC->isEmpty()) {
+        return;
+    }
     SkPaint paint = srcPaint;
     if (bitmap.isOpaque()) {
         replace_srcmode_on_opaque_paint(&paint);
     }
-
-    if (d.fRC->isEmpty()) {
+    SkImageSubset imageSubset = make_image_subset(bitmap);
+    if (!imageSubset.isValid()) {
         return;
     }
-
     SkMatrix transform = matrix;
     transform.postConcat(*d.fMatrix);
-    SkImageBitmap imageBitmap(bitmap);
     this->internalDrawImage(
-            transform, d.fClipStack, d.fRC->bwRgn(), imageBitmap, paint);
+            transform, d.fClipStack, d.fRC->bwRgn(), std::move(imageSubset), paint);
 }
 
 void SkPDFDevice::drawSprite(const SkDraw& d,
@@ -806,20 +893,20 @@
                              int x,
                              int y,
                              const SkPaint& srcPaint) {
+    if (bitmap.drawsNothing() || d.fRC->isEmpty()) {
+        return;
+    }
     SkPaint paint = srcPaint;
     if (bitmap.isOpaque()) {
         replace_srcmode_on_opaque_paint(&paint);
     }
-
-    if (d.fRC->isEmpty()) {
+    SkImageSubset imageSubset = make_image_subset(bitmap);
+    if (!imageSubset.isValid()) {
         return;
     }
-
-    SkMatrix matrix;
-    matrix.setTranslate(SkIntToScalar(x), SkIntToScalar(y));
-    SkImageBitmap imageBitmap(bitmap);
+    SkMatrix transform = SkMatrix::MakeTrans(SkIntToScalar(x), SkIntToScalar(y));
     this->internalDrawImage(
-            matrix, d.fClipStack, d.fRC->bwRgn(), imageBitmap, paint);
+            transform, d.fClipStack, d.fRC->bwRgn(), std::move(imageSubset), paint);
 }
 
 void SkPDFDevice::drawImage(const SkDraw& draw,
@@ -837,20 +924,14 @@
     if (draw.fRC->isEmpty()) {
         return;
     }
+    SkImageSubset imageSubset(sk_ref_sp(const_cast<SkImage*>(image)));
+    if (!imageSubset.isValid()) {
+        return;
+    }
     SkMatrix transform = SkMatrix::MakeTrans(x, y);
     transform.postConcat(*draw.fMatrix);
-    SkImageBitmap imageBitmap(const_cast<SkImage*>(image));
     this->internalDrawImage(
-            transform, draw.fClipStack, draw.fRC->bwRgn(), imageBitmap, paint);
-}
-
-void SkPDFDevice::drawImageRect(const SkDraw& draw,
-                                const SkImage* image,
-                                const SkRect* src,
-                                const SkRect& dst,
-                                const SkPaint& srcPaint,
-                                SkCanvas::SrcRectConstraint constraint) {
-    SkASSERT(false);
+            transform, draw.fClipStack, draw.fRC->bwRgn(), std::move(imageSubset), paint);
 }
 
 namespace {
@@ -2109,16 +2190,16 @@
     return SkSize::Make(r.width(), r.height());
 }
 
-static sk_sp<SkImage> color_filter(const SkImageBitmap& imageBitmap,
+static sk_sp<SkImage> color_filter(const SkImageSubset& imageSubset,
                                    SkColorFilter* colorFilter) {
     auto surface =
-        SkSurface::MakeRaster(SkImageInfo::MakeN32Premul(imageBitmap.dimensions()));
+        SkSurface::MakeRaster(SkImageInfo::MakeN32Premul(imageSubset.dimensions()));
     SkASSERT(surface);
     SkCanvas* canvas = surface->getCanvas();
     canvas->clear(SK_ColorTRANSPARENT);
     SkPaint paint;
     paint.setColorFilter(sk_ref_sp(colorFilter));
-    imageBitmap.draw(canvas, &paint);
+    imageSubset.draw(canvas, &paint);
     canvas->flush();
     return surface->makeImageSnapshot();
 }
@@ -2127,9 +2208,9 @@
 void SkPDFDevice::internalDrawImage(const SkMatrix& origMatrix,
                                     const SkClipStack* clipStack,
                                     const SkRegion& origClipRegion,
-                                    SkImageBitmap imageBitmap,
+                                    SkImageSubset imageSubset,
                                     const SkPaint& paint) {
-    if (imageBitmap.dimensions().isZero()) {
+    if (imageSubset.dimensions().isZero()) {
         return;
     }
     #ifdef SK_PDF_IMAGE_STATS
@@ -2138,7 +2219,6 @@
     SkMatrix matrix = origMatrix;
     SkRegion perspectiveBounds;
     const SkRegion* clipRegion = &origClipRegion;
-    sk_sp<SkImage> autoImageUnref;
 
     // Rasterize the bitmap using perspective in a new bitmap.
     if (origMatrix.hasPerspective()) {
@@ -2148,7 +2228,7 @@
         // Transform the bitmap in the new space, without taking into
         // account the initial transform.
         SkPath perspectiveOutline;
-        SkRect imageBounds = SkRect::Make(imageBitmap.bounds());
+        SkRect imageBounds = SkRect::Make(imageSubset.bounds());
         perspectiveOutline.addRect(imageBounds);
         perspectiveOutline.transform(origMatrix);
 
@@ -2182,7 +2262,7 @@
 
         SkISize wh = rect_to_size(physicalPerspectiveBounds).toCeil();
 
-        auto surface(SkSurface::MakeRaster(SkImageInfo::MakeN32Premul(wh)));
+        auto surface = SkSurface::MakeRaster(SkImageInfo::MakeN32Premul(wh));
         if (!surface) {
             return;
         }
@@ -2199,7 +2279,7 @@
         // Translate the draw in the new canvas, so we perfectly fit the
         // shape in the bitmap.
         canvas->setMatrix(offsetMatrix);
-        imageBitmap.draw(canvas, nullptr);
+        imageSubset.draw(canvas, nullptr);
         // Make sure the final bits are in the bitmap.
         canvas->flush();
 
@@ -2211,8 +2291,7 @@
         perspectiveBounds.setRect(bounds.roundOut());
         clipRegion = &perspectiveBounds;
 
-        autoImageUnref = surface->makeImageSnapshot();
-        imageBitmap = SkImageBitmap(autoImageUnref.get());
+        imageSubset = SkImageSubset(surface->makeImageSnapshot());
     }
 
     SkMatrix scaled;
@@ -2220,9 +2299,9 @@
     scaled.setScale(SK_Scalar1, -SK_Scalar1);
     scaled.postTranslate(0, SK_Scalar1);
     // Scale the image up from 1x1 to WxH.
-    SkIRect subset = imageBitmap.bounds();
-    scaled.postScale(SkIntToScalar(imageBitmap.dimensions().width()),
-                     SkIntToScalar(imageBitmap.dimensions().height()));
+    SkIRect subset = imageSubset.bounds();
+    scaled.postScale(SkIntToScalar(imageSubset.dimensions().width()),
+                     SkIntToScalar(imageSubset.dimensions().height()));
     scaled.postConcat(matrix);
     ScopedContentEntry content(this, clipStack, *clipRegion, scaled, paint);
     if (!content.entry()) {
@@ -2244,16 +2323,16 @@
         // drawBitmap*()/drawImage*() calls amd ImageFilters (which
         // rasterize a layer on this backend).  Fortuanely, this seems
         // to be how Chromium impements most color-filters.
-        autoImageUnref = color_filter(imageBitmap, colorFilter);
-        imageBitmap = SkImageBitmap(autoImageUnref.get());
+        sk_sp<SkImage> img = color_filter(imageSubset, colorFilter);
+        imageSubset = SkImageSubset(std::move(img));
         // TODO(halcanary): de-dupe this by caching filtered images.
         // (maybe in the resource cache?)
     }
 
-    SkBitmapKey key = imageBitmap.getKey();
+    SkBitmapKey key = imageSubset.getKey();
     sk_sp<SkPDFObject> pdfimage = fDocument->canon()->findPDFBitmap(key);
     if (!pdfimage) {
-        sk_sp<SkImage> img = imageBitmap.makeImage();
+        sk_sp<SkImage> img = imageSubset.makeImage();
         if (!img) {
             return;
         }
diff --git a/src/pdf/SkPDFDevice.h b/src/pdf/SkPDFDevice.h
index db6f9b2..be0a277 100644
--- a/src/pdf/SkPDFDevice.h
+++ b/src/pdf/SkPDFDevice.h
@@ -21,7 +21,7 @@
 #include "SkTDArray.h"
 #include "SkTextBlob.h"
 
-class SkImageBitmap;
+class SkImageSubset;
 class SkPath;
 class SkPDFArray;
 class SkPDFCanon;
@@ -285,7 +285,7 @@
     void internalDrawImage(const SkMatrix& origMatrix,
                            const SkClipStack* clipStack,
                            const SkRegion& origClipRegion,
-                           SkImageBitmap imageBitmap,
+                           SkImageSubset imageSubset,
                            const SkPaint& paint);
 
     bool handleInversePath(const SkDraw& d, const SkPath& origPath,
diff --git a/src/pdf/SkPDFShader.cpp b/src/pdf/SkPDFShader.cpp
index d44f10b..82b5b34 100644
--- a/src/pdf/SkPDFShader.cpp
+++ b/src/pdf/SkPDFShader.cpp
@@ -958,7 +958,8 @@
                                             SkScalar dpi,
                                             const SkPDFShader::State& state,
                                             SkBitmap image) {
-    SkASSERT(state.fBitmapKey == SkBitmapKey(image));
+    SkASSERT(state.fBitmapKey ==
+             (SkBitmapKey{image.getSubset(), image.getGenerationID()}));
     SkAutoLockPixels SkAutoLockPixels(image);
 
     // The image shader pattern cell will be drawn into a separate device
@@ -1167,7 +1168,7 @@
 
     if (fType == SkShader::kNone_GradientType) {
         if (fBitmapKey != b.fBitmapKey ||
-                fBitmapKey.id() == 0 ||
+                fBitmapKey.fID == 0 ||
                 fImageTileModes[0] != b.fImageTileModes[0] ||
                 fImageTileModes[1] != b.fImageTileModes[1]) {
             return false;
@@ -1223,6 +1224,7 @@
     fType = shader->asAGradient(&fInfo);
 
     if (fType != SkShader::kNone_GradientType) {
+        fBitmapKey = SkBitmapKey{{0, 0, 0, 0}, 0};
         fShaderTransform = shader->getLocalMatrix();
         this->allocateGradientInfoStorage();
         shader->asAGradient(&fInfo);
@@ -1231,7 +1233,7 @@
     if (SkImage* skimg = shader->isAImage(&fShaderTransform, fImageTileModes)) {
         // TODO(halcanary): delay converting to bitmap.
         if (skimg->asLegacyBitmap(imageDst, SkImage::kRO_LegacyBitmapMode)) {
-            fBitmapKey = SkBitmapKey(*imageDst);
+            fBitmapKey = SkBitmapKey{imageDst->getSubset(), imageDst->getGenerationID()};
             return;
         }
     }
@@ -1276,7 +1278,7 @@
 
     fShaderTransform.setTranslate(shaderRect.x(), shaderRect.y());
     fShaderTransform.preScale(1 / scale.width(), 1 / scale.height());
-    fBitmapKey = SkBitmapKey(*imageDst);
+    fBitmapKey = SkBitmapKey{imageDst->getSubset(), imageDst->getGenerationID()};
 }
 
 SkPDFShader::State::State(const SkPDFShader::State& other)
@@ -1305,7 +1307,7 @@
  * Only valid for gradient states.
  */
 SkPDFShader::State SkPDFShader::State::MakeAlphaToLuminosityState() const {
-    SkASSERT(fBitmapKey == SkBitmapKey());
+    SkASSERT(fBitmapKey == (SkBitmapKey{{0, 0, 0, 0}, 0}));
     SkASSERT(fType != SkShader::kNone_GradientType);
 
     SkPDFShader::State newState(*this);
@@ -1323,7 +1325,7 @@
  * Only valid for gradient states.
  */
 SkPDFShader::State SkPDFShader::State::MakeOpaqueState() const {
-    SkASSERT(fBitmapKey == SkBitmapKey());
+    SkASSERT(fBitmapKey == (SkBitmapKey{{0, 0, 0, 0}, 0}));
     SkASSERT(fType != SkShader::kNone_GradientType);
 
     SkPDFShader::State newState(*this);