Fix WIC encoder to support kJPEG_Type

tests/EncodeTest.cpp

+/*
+ * 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 "Resources.h"
+#include "SkCodec.h"
+#include "SkImageEncoder.h"
+#include "Test.h"
+
+static inline bool almost_equal(uint8_t a, uint8_t b) {
+    return SkTAbs((int) a - (int) b) <= 30;

[mtklein_C, 2016/08/15 15:11:37]

That's a pretty generous definition of almost equal...

[msarett, 2016/08/15 19:31:08]

Acknowledged.

+}
+
+DEF_TEST(Encode, r) {
+    SkBitmap orig;
+    bool result = GetResourceAsBitmap("mandrill_512_q075.jpg", &orig);
+    REPORTER_ASSERT(r, result);
+    sk_sp<SkData> pngData(SkImageEncoder::EncodeData(orig, SkImageEncoder::kPNG_Type, 100));
+    sk_sp<SkData> jpegData(SkImageEncoder::EncodeData(orig, SkImageEncoder::kJPEG_Type, 100));

[mtklein_C, 2016/08/15 15:11:37]

Does the quality setting cause us to go down any different code paths when
encoding a JPEG?  That is, should we test more quality settings?

[msarett, 2016/08/15 19:31:08]

The jpeg library handles the quality, so the code path is the same for us.  I
think this is fine.

+    SkAutoTDelete<SkCodec> pngCodec = SkCodec::NewFromData(pngData.get());
+    SkAutoTDelete<SkCodec> jpegCodec = SkCodec::NewFromData(jpegData.get());
+
+    SkImageInfo info = pngCodec->getInfo().makeColorType(kN32_SkColorType);
+    SkBitmap pngBitmap, jpegBitmap;
+    pngBitmap.allocPixels(info);
+    jpegBitmap.allocPixels(info);
+    pngCodec->getPixels(info, pngBitmap.getPixels(), pngBitmap.rowBytes());
+    jpegCodec->getPixels(info, jpegBitmap.getPixels(), jpegBitmap.rowBytes());
+
+    for (int y = 0; y < pngBitmap.height(); y++) {
+        for (int x = 0; x < pngBitmap.width(); x++) {
+            SkPMColor pngPixel = *pngBitmap.getAddr32(x, y);
+            SkPMColor jpegPixel = *jpegBitmap.getAddr32(x, y);
+            REPORTER_ASSERT(r, almost_equal(SkGetPackedR32(pngPixel), SkGetPackedR32(jpegPixel)));
+            REPORTER_ASSERT(r, almost_equal(SkGetPackedG32(pngPixel), SkGetPackedG32(jpegPixel)));
+            REPORTER_ASSERT(r, almost_equal(SkGetPackedB32(pngPixel), SkGetPackedB32(jpegPixel)));
+            REPORTER_ASSERT(r, almost_equal(SkGetPackedA32(pngPixel), SkGetPackedA32(jpegPixel)));

[mtklein_C, 2016/08/15 15:11:37]

Sort of silly to test JPEG's alpha?

[msarett, 2016/08/15 19:31:08]

Acknowledged.

+        }
+    }
+}