images with offset bitmap don't share genid

tests/image-bitmap.cpp

Index: tests/image-bitmap.cpp
diff --git a/tests/image-bitmap.cpp b/tests/image-bitmap.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..fee5f0d7a6de92203fb7862059b42a2b1bf90613
--- /dev/null
+++ b/tests/image-bitmap.cpp
@@ -0,0 +1,75 @@
+/*
+ * 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 "Test.h"
+
+#include "SkBitmap.h"
+#include "SkImage.h"
+
+namespace {
+class BitmapKey {
+public:
+    BitmapKey() : fSubset(SkIRect::MakeEmpty()), fID(0) {}
+    explicit BitmapKey(const SkBitmap& bm)
+        : fSubset(bm.getSubset()), fID(bm.getGenerationID()) {}
+    explicit BitmapKey(const SkImage* img)
+        : fSubset(img->bounds()), fID(img->uniqueID()) {}
+    explicit BitmapKey(const sk_sp<SkImage> img)
+        : fSubset(img->bounds()), fID(img->uniqueID()) {}
+    bool operator==(const BitmapKey& rhs) const {
+        return fID == rhs.fID && fSubset == rhs.fSubset;
+    }
+    bool operator!=(const BitmapKey& rhs) const { return !(*this == rhs); }
+
+private:
+    SkIRect fSubset;
+    uint32_t fID;
+};
+}
+static SkBitmap makebitmap() {
+    SkBitmap bm;
+    bm.allocN32Pixels(32, 64);
+    bm.eraseColor(SK_ColorBLACK);
+    bm.setImmutable();
+    return bm;
+}
+

[reed1, 2016/03/17 17:34:15]

// Test that when we make an image from a subset of a bitmap, that it has a diff
ID from an image made from the entire bitmap (see bug#...)

[hal.canary, 2016/03/17 17:57:02]

Done.

+DEF_TEST(ImageBitmapIdentity, r) {
+    SkBitmap bm = makebitmap();
+    auto img = SkImage::MakeFromBitmap(bm);
+    if (img) {

[reed1, 2016/03/17 17:34:15]

Not sure these runtime checks are needed, unless its defined that these
(MakeFromBitmap, extractSubset) are allowed to fail sometimes. Definitely makes
reading the test harder

[hal.canary, 2016/03/17 17:57:02]

Done.

+        REPORTER_ASSERT(r, BitmapKey(img) == BitmapKey(bm));
+    } else {
+        ERRORF(r, "SkImage::MakeFromBitmap failed");
+    }
+    SkBitmap a, b;
+    if (!bm.extractSubset(&a, SkIRect::MakeXYWH(0, 0, 32, 32))) {
+        ERRORF(r, "SkBitmap::extractSubset failed.");
+        return;
+    }
+    REPORTER_ASSERT(r, a.dimensions() == SkISize::Make(32, 32));
+    if (!bm.extractSubset(&b, SkIRect::MakeXYWH(0, 32, 32, 32))) {
+        ERRORF(r, "SkBitmap::extractSubset failed.");
+        return;
+    }
+    REPORTER_ASSERT(r, b.dimensions() == SkISize::Make(32, 32));
+    auto imgA = SkImage::MakeFromBitmap(a);
+    if (!imgA) {
+        ERRORF(r, "SkImage::MakeFromBitmap failed.");
+        return;
+    }
+    auto imgB = SkImage::MakeFromBitmap(b);
+    if (!imgB) {
+        ERRORF(r, "SkImage::MakeFromBitmap failed.");
+        return;
+    }
+    REPORTER_ASSERT(r, imgA->uniqueID() != imgB->uniqueID());
+    REPORTER_ASSERT(r, BitmapKey(imgA) != BitmapKey(imgB));
+    REPORTER_ASSERT(r, BitmapKey(imgA) == BitmapKey(a));
+    REPORTER_ASSERT(r, BitmapKey(imgB) != BitmapKey(b));
+    REPORTER_ASSERT(r, BitmapKey(a) != BitmapKey(b));
+}