Add onDrawBitmapLattice(), avoid unnecessary bitmap->image copy

src/image/SkImage_Raster.h

+/*
+ * 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 "SkImage_Base.h"
+#include "SkPixelRef.h"
+
+// fixes https://bug.skia.org/5096
+static bool is_not_subset(const SkBitmap& bm) {
+    SkASSERT(bm.pixelRef());
+    SkISize dim = bm.pixelRef()->info().dimensions();
+    SkASSERT(dim != bm.dimensions() || bm.pixelRefOrigin().isZero());
+    return dim == bm.dimensions();
+}
+
+class SkImage_Raster : public SkImage_Base {
+public:
+    static bool ValidArgs(const Info& info, size_t rowBytes, bool hasColorTable,
+                          size_t* minSize) {
+        const int maxDimension = SK_MaxS32 >> 2;
+
+        if (info.width() <= 0 || info.height() <= 0) {
+            return false;
+        }
+        if (info.width() > maxDimension || info.height() > maxDimension) {
+            return false;
+        }
+        if ((unsigned)info.colorType() > (unsigned)kLastEnum_SkColorType) {
+            return false;
+        }
+        if ((unsigned)info.alphaType() > (unsigned)kLastEnum_SkAlphaType) {
+            return false;
+        }
+
+        if (kUnknown_SkColorType == info.colorType()) {
+            return false;
+        }
+
+        const bool needsCT = kIndex_8_SkColorType == info.colorType();
+        if (needsCT != hasColorTable) {
+            return false;
+        }
+
+        if (rowBytes < info.minRowBytes()) {
+            return false;
+        }
+
+        size_t size = info.getSafeSize(rowBytes);
+        if (0 == size) {
+            return false;
+        }
+
+        if (minSize) {
+            *minSize = size;
+        }
+        return true;
+    }
+
+    SkImage_Raster(const SkImageInfo&, sk_sp<SkData>, size_t rb, SkColorTable*);
+    virtual ~SkImage_Raster();
+
+    SkImageInfo onImageInfo() const override {
+        return fBitmap.info();
+    }
+
+    bool onReadPixels(const SkImageInfo&, void*, size_t, int srcX, int srcY, CachingHint) const override;
+    bool onPeekPixels(SkPixmap*) const override;
+    const SkBitmap* onPeekBitmap() const override { return &fBitmap; }
+
+    SkData* onRefEncoded(GrContext*) const override;
+    bool getROPixels(SkBitmap*, CachingHint) const override;
+    GrTexture* asTextureRef(GrContext*, const GrTextureParams&,
+                            SkSourceGammaTreatment) const override;
+    sk_sp<SkImage> onMakeSubset(const SkIRect&) const override;
+
+    // exposed for SkSurface_Raster via SkNewImageFromPixelRef
+    SkImage_Raster(const SkImageInfo&, SkPixelRef*, const SkIPoint& origin, size_t rowBytes);
+
+    SkPixelRef* getPixelRef() const { return fBitmap.pixelRef(); }
+
+    bool isOpaque() const override;
+    bool onAsLegacyBitmap(SkBitmap*, LegacyBitmapMode) const override;
+
+    SkImage_Raster(const SkBitmap& bm, bool bitmapMayBeMutable = false)
+        : INHERITED(bm.width(), bm.height(),
+                    is_not_subset(bm) ? bm.getGenerationID()
+                                      : (uint32_t)kNeedNewImageUniqueID)
+        , 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();
+        }
+        SkASSERT(bitmapMayBeMutable || fBitmap.isImmutable());
+    }
+
+    bool onIsLazyGenerated() const override {
+        return fBitmap.pixelRef() && fBitmap.pixelRef()->isLazyGenerated();
+    }
+
+private:
+    SkBitmap fBitmap;
+
+    typedef SkImage_Base INHERITED;
+};