***Disables swizzles to 565.

We may want to enable swizzles to 565
for images that are encoded in a format
similar to 565, however, we do not want
to take images that decode naturally to
kN32 and then convert them to 565.

***Enable swizzles to kIndex_8.  For images
encoded in a color table format, we suggest
that they be decoded to kIndex_8.  When we
decode, we only allow conversion to kIndex_8
if it matches the suggested color type (except
wbmp which seems good as is).

***Modify dm to test images that decode to
kIndex_8.

BUG=skia:3257
BUG=skia:3440

Review URL: https://codereview.chromium.org/1055743003

3 files changed, 90 insertions, 15 deletions

diff --git a/dm/DM.cpp b/dm/DM.cpp
index 296b7c88d7..2a71500605 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -178,6 +178,46 @@ static void push_src(const char* tag, const char* options, Src* s) {
     }
 }
 
+static void push_codec_srcs(Path path) {
+    SkAutoTUnref<SkData> encoded(SkData::NewFromFileName(path.c_str()));
+    if (!encoded) {
+        SkDebugf("Couldn't read %s.", path.c_str());
+        return;
+    }
+    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(encoded));
+    if (NULL == codec.get()) {
+        SkDebugf("Couldn't create codec for %s.", path.c_str());
+        return;
+    }
+
+    // Build additional test cases for images that decode natively to non-canvas types
+    switch(codec->getInfo().colorType()) {
+        case kGray_8_SkColorType:
+            push_src("image", "codec kGray8", new CodecSrc(path, CodecSrc::kNormal_Mode,
+                    CodecSrc::kGrayscale_Always_DstColorType));
+            push_src("image", "scanline kGray8", new CodecSrc(path, CodecSrc::kScanline_Mode,
+                    CodecSrc::kGrayscale_Always_DstColorType));
+            // Intentional fall through
+            // FIXME: Is this a long term solution for testing wbmps decodes to kIndex8?
+            // Further discussion on this topic is at skbug.com/3683
+      case kIndex_8_SkColorType:
+          push_src("image", "codec kIndex8", new CodecSrc(path, CodecSrc::kNormal_Mode,
+                  CodecSrc::kIndex8_Always_DstColorType));
+          push_src("image", "scanline kIndex8", new CodecSrc(path, CodecSrc::kScanline_Mode,
+                  CodecSrc::kIndex8_Always_DstColorType));
+        break;
+      default:
+        // Do nothing
+        break;
+    }
+
+    // Decode all images to the canvas color type
+    push_src("image", "codec", new CodecSrc(path, CodecSrc::kNormal_Mode,
+            CodecSrc::kGetFromCanvas_DstColorType));
+    push_src("image", "scanline", new CodecSrc(path, CodecSrc::kScanline_Mode,
+            CodecSrc::kGetFromCanvas_DstColorType));
+}
+
 static bool codec_supported(const char* ext) {
     // FIXME: Once other versions of SkCodec are available, we can add them to this
     // list (and eventually we can remove this check once they are all supported).
@@ -223,8 +263,7 @@ static void gather_srcs() {
                     push_src("image", "decode", new ImageSrc(path)); // Decode entire image
                     push_src("image", "subset", new ImageSrc(path, 2)); // Decode into 2x2 subsets
                     if (codec_supported(exts[j])) {
-                        push_src("image", "codec", new CodecSrc(path, CodecSrc::kNormal_Mode));
-                        push_src("image", "scanline", new CodecSrc(path, CodecSrc::kScanline_Mode));
+                        push_codec_srcs(path);
                     }
                 }
             }
@@ -232,8 +271,7 @@ static void gather_srcs() {
             // assume that FLAGS_images[i] is a valid image if it is a file.
             push_src("image", "decode", new ImageSrc(flag)); // Decode entire image.
             push_src("image", "subset", new ImageSrc(flag, 2)); // Decode into 2 x 2 subsets
-            push_src("image", "codec", new CodecSrc(flag, CodecSrc::kNormal_Mode));
-            push_src("image", "scanline", new CodecSrc(flag, CodecSrc::kScanline_Mode));
+            push_codec_srcs(flag);
         }
     }
 }
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index de9ee76c80..9e9a77c271 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -52,7 +52,11 @@ Name GMSrc::name() const {
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
-CodecSrc::CodecSrc(Path path, Mode mode) : fPath(path), fMode(mode) {}
+CodecSrc::CodecSrc(Path path, Mode mode, DstColorType dstColorType)
+    : fPath(path)
+    , fMode(mode)
+    , fDstColorType(dstColorType)
+{}
 
 Error CodecSrc::draw(SkCanvas* canvas) const {
     SkImageInfo canvasInfo;
@@ -66,27 +70,53 @@ Error CodecSrc::draw(SkCanvas* canvas) const {
     if (!encoded) {
         return SkStringPrintf("Couldn't read %s.", fPath.c_str());
     }
-
     SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(encoded));
-    if (!codec) {
-        return SkStringPrintf("Couldn't decode %s.", fPath.c_str());
+    if (NULL == codec.get()) {
+        return SkStringPrintf("Couldn't create codec for %s.", fPath.c_str());
+    }
+
+    // Choose the color type to decode to
+    SkImageInfo decodeInfo = codec->getInfo();
+    SkColorType canvasColorType = canvasInfo.colorType();
+    switch (fDstColorType) {
+        case kIndex8_Always_DstColorType:
+        case kGrayscale_Always_DstColorType:
+            if (kRGB_565_SkColorType == canvasColorType) {
+                return Error::Nonfatal("Testing non-565 to 565 is uninteresting.");
+            }
+            break;
+        default:
+            decodeInfo = decodeInfo.makeColorType(canvasColorType);
+            break;
+    }
+
+    // Construct a color table for the decode if necessary
+    SkAutoTUnref<SkColorTable> colorTable(NULL);
+    SkPMColor* colorPtr = NULL;
+    int* colorCountPtr = NULL;
+    int maxColors = 256;
+    if (kIndex_8_SkColorType == decodeInfo.colorType()) {
+        SkPMColor colors[256];
+        colorTable.reset(SkNEW_ARGS(SkColorTable, (colors, maxColors)));
+        colorPtr = const_cast<SkPMColor*>(colorTable->readColors());
+        colorCountPtr = &maxColors;
     }
 
-    SkImageInfo decodeInfo = codec->getInfo().makeColorType(canvasInfo.colorType());
+    // FIXME: Currently we cannot draw unpremultiplied sources.
     if (decodeInfo.alphaType() == kUnpremul_SkAlphaType) {
-        // FIXME: Currently we cannot draw unpremultiplied sources.
         decodeInfo = decodeInfo.makeAlphaType(kPremul_SkAlphaType);
     }
 
     SkBitmap bitmap;
-    if (!bitmap.tryAllocPixels(decodeInfo)) {
+    if (!bitmap.tryAllocPixels(decodeInfo, NULL, colorTable.get())) {
         return SkStringPrintf("Image(%s) is too large (%d x %d)\n", fPath.c_str(),
                               decodeInfo.width(), decodeInfo.height());
     }
 
     switch (fMode) {
         case kNormal_Mode:
-            switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes())) {
+            switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes(), NULL,
+                    colorPtr, colorCountPtr)) {
                 case SkImageGenerator::kSuccess:
                     // We consider incomplete to be valid, since we should still decode what is
                     // available.
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index 57af911062..0807cb6644 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -13,6 +13,7 @@
 #include "SkBBoxHierarchy.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
+#include "SkCodec.h"
 #include "SkData.h"
 #include "SkGPipe.h"
 #include "SkPicture.h"
@@ -94,14 +95,20 @@ public:
         kNormal_Mode,
         kScanline_Mode,
     };
-    CodecSrc(Path, Mode);
+    enum DstColorType {
+        kGetFromCanvas_DstColorType,
+        kIndex8_Always_DstColorType,
+        kGrayscale_Always_DstColorType,
+    };
+    CodecSrc(Path, Mode, DstColorType);
 
     Error draw(SkCanvas*) const override;
     SkISize size() const override;
     Name name() const override;
 private:
-    Path fPath;
-    Mode fMode;
+    Path                   fPath;
+    Mode                   fMode;
+    DstColorType           fDstColorType;
 };