Make SkNewImageFromBitmap take pixel ref origin into account

tests/SkImageTest.cpp

Index: tests/SkImageTest.cpp
diff --git a/tests/SkImageTest.cpp b/tests/SkImageTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..80ba776af106ae85b827332b97f253f8195ce078
--- /dev/null
+++ b/tests/SkImageTest.cpp
@@ -0,0 +1,49 @@
+/*
+ * 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 "SkBitmapDevice.h"
+#include "SkImagePriv.h"
+#include "Test.h"
+
+static const int gWidth = 20;
+static const int gHeight = 20;
+
+// Tests that SkNewImageFromBitmap obeys pixelref origin.
+DEF_TEST(SkImageFromBitmap_extractSubset, reporter) {
+    SkAutoTUnref<SkImage> image;
+    {
+        SkBitmap srcBitmap;
+        srcBitmap.allocN32Pixels(gWidth, gHeight);
+        srcBitmap.eraseColor(SK_ColorRED);
+        SkBitmapDevice dev(srcBitmap);
+        SkCanvas canvas(&dev);
+        SkIRect r = SkIRect::MakeXYWH(5, 5, gWidth - 5, gWidth - 5);
+        SkPaint p;
+        p.setColor(SK_ColorGREEN);
+        canvas.drawIRect(r, p);
+        SkBitmap dstBitmap;
+        srcBitmap.extractSubset(&dstBitmap, r);
+        image.reset(SkNewImageFromBitmap(dstBitmap, true, NULL));
+    }
+
+    SkBitmap tgt;
+    tgt.allocN32Pixels(gWidth, gHeight);
+    SkBitmapDevice dev(tgt);
+    SkCanvas canvas(&dev);
+    canvas.clear(SK_ColorTRANSPARENT);
+    canvas.drawImage(image, 0, 0, NULL);
+
+    uint32_t pixel = 0;
+    SkImageInfo info = SkImageInfo::MakeN32Premul(1, 1);
+    canvas.readPixels(info, &pixel, 4, 0, 0);
+    REPORTER_ASSERT(reporter, pixel == SK_ColorGREEN);
+    canvas.readPixels(info, &pixel, 4, gWidth - 6, gWidth - 6);
+    REPORTER_ASSERT(reporter, pixel == SK_ColorGREEN);
+
+    canvas.readPixels(info, &pixel, 4, gWidth - 5, gWidth - 5);
+    REPORTER_ASSERT(reporter, pixel == SK_ColorTRANSPARENT);
+}