SkImageEncoder: simplify API

  - Hide SkImageEncoder class in private header.
  - SkImageEncoder::Type becomes SkEncodedImageFormat
  - SkEncodedFormat becomes SkEncodedImageFormat
  - SkImageEncoder static functions replaced with
    single function EncodeImage()
  - utility wrappers for EncodeImage() are in
    sk_tool_utils.h

TODO: remove link-time registration mechanism.
TODO: clean up clients use of API and flip the flag.
TODO: implement EncodeImage() in chromeium/skia/ext

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4909

Change-Id: Ib48b31fdc05cf23cda7f56ebfd67c841c149ce70
Reviewed-on: https://skia-review.googlesource.com/4909
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>

8 files changed, 91 insertions, 92 deletions

diff --git a/src/images/SkForceLinking.cpp b/src/images/SkForceLinking.cpp
index 81d485c882..dfed6b4b57 100644
--- a/src/images/SkForceLinking.cpp
+++ b/src/images/SkForceLinking.cpp
@@ -5,7 +5,7 @@
  * found in the LICENSE file.
  */
 
-#include "SkImageEncoder.h"
+#include "SkImageEncoderPriv.h"
 #include "SkForceLinking.h"
 
 // This method is required to fool the linker into not discarding the pre-main
@@ -30,10 +30,10 @@ int SkForceLinking(bool doNotPassTrue) {
 #endif
 
 #if defined (SK_USE_CG_ENCODER)
-        CreateImageEncoder_CG(SkImageEncoder::kPNG_Type);
+        CreateImageEncoder_CG(SkEncodedImageFormat::kPNG);
 #endif
 #if defined (SK_USE_WIC_ENCODER)
-        CreateImageEncoder_WIC(SkImageEncoder::kPNG_Type);
+        CreateImageEncoder_WIC(SkEncodedImageFormat::kPNG);
 #endif
         return -1;
     }
diff --git a/src/images/SkImageEncoder.cpp b/src/images/SkImageEncoder.cpp
index 787ff8ef62..fc5f1267a5 100644
--- a/src/images/SkImageEncoder.cpp
+++ b/src/images/SkImageEncoder.cpp
@@ -5,84 +5,15 @@
  * found in the LICENSE file.
  */
 
-#include "SkImageEncoder.h"
-#include "SkBitmap.h"
-#include "SkPixelSerializer.h"
-#include "SkPixmap.h"
-#include "SkStream.h"
-#include "SkTemplates.h"
+#include "SkImageEncoderPriv.h"
 
-SkImageEncoder::~SkImageEncoder() {}
-
-bool SkImageEncoder::encodeStream(SkWStream* stream, const SkBitmap& bm,
-                                  int quality) {
-    quality = SkMin32(100, SkMax32(0, quality));
-    return this->onEncode(stream, bm, quality);
-}
-
-bool SkImageEncoder::encodeFile(const char file[], const SkBitmap& bm,
-                                int quality) {
-    quality = SkMin32(100, SkMax32(0, quality));
-    SkFILEWStream   stream(file);
-    return this->onEncode(&stream, bm, quality);
-}
-
-SkData* SkImageEncoder::encodeData(const SkBitmap& bm, int quality) {
-    SkDynamicMemoryWStream stream;
-    quality = SkMin32(100, SkMax32(0, quality));
-    if (this->onEncode(&stream, bm, quality)) {
-        return stream.detachAsData().release();
-    }
-    return nullptr;
-}
-
-bool SkImageEncoder::EncodeFile(const char file[], const SkBitmap& bm, Type t,
-                                int quality) {
-    std::unique_ptr<SkImageEncoder> enc(SkImageEncoder::Create(t));
-    return enc.get() && enc.get()->encodeFile(file, bm, quality);
-}
-
-bool SkImageEncoder::EncodeStream(SkWStream* stream, const SkBitmap& bm, Type t,
-                                  int quality) {
-    std::unique_ptr<SkImageEncoder> enc(SkImageEncoder::Create(t));
-    return enc.get() && enc.get()->encodeStream(stream, bm, quality);
-}
-
-SkData* SkImageEncoder::EncodeData(const SkBitmap& bm, Type t, int quality) {
-    std::unique_ptr<SkImageEncoder> enc(SkImageEncoder::Create(t));
-    return enc.get() ? enc.get()->encodeData(bm, quality) : nullptr;
-}
-
-SkData* SkImageEncoder::EncodeData(const SkImageInfo& info, const void* pixels, size_t rowBytes,
-                                   Type t, int quality) {
-    SkBitmap bm;
-    if (!bm.installPixels(info, const_cast<void*>(pixels), rowBytes)) {
-        return nullptr;
-    }
-    bm.setImmutable();
-    return SkImageEncoder::EncodeData(bm, t, quality);
-}
-
-SkData* SkImageEncoder::EncodeData(const SkPixmap& pixmap,
-                                   Type t, int quality) {
+bool SkEncodeImage(SkWStream* dst, const SkPixmap& src,
+                   SkEncodedImageFormat format, int quality) {
     SkBitmap bm;
-    if (!bm.installPixels(pixmap)) {
+    if (!bm.installPixels(src)) {
         return nullptr;
     }
     bm.setImmutable();
-    return SkImageEncoder::EncodeData(bm, t, quality);
-}
-
-namespace {
-class ImageEncoderPixelSerializer final : public SkPixelSerializer {
-protected:
-    bool onUseEncodedData(const void*, size_t) override { return true; }
-    SkData* onEncode(const SkPixmap& pmap) override {
-        return SkImageEncoder::EncodeData(pmap, SkImageEncoder::kPNG_Type, 100);
-    }
-};
-} // namespace
-
-SkPixelSerializer* SkImageEncoder::CreatePixelSerializer() {
-    return new ImageEncoderPixelSerializer;
+    std::unique_ptr<SkImageEncoder> enc(SkImageEncoder::Create((SkImageEncoder::Type)format));
+    return enc && enc->encodeStream(dst, bm, quality);
 }
diff --git a/src/images/SkImageEncoderPriv.h b/src/images/SkImageEncoderPriv.h
new file mode 100644
index 0000000000..9b632f5a5b
--- /dev/null
+++ b/src/images/SkImageEncoderPriv.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkImageEncoderPriv_DEFINED
+#define SkImageEncoderPriv_DEFINED
+
+#include "SkImageEncoder.h"
+#include "SkTRegistry.h"
+
+#ifndef SK_SUPPORT_LEGACY_IMAGE_ENCODER_CLASS
+
+    // TODO(halcanary): replace this class and registry system with something simpler.
+    class SkImageEncoder {
+    public:
+        typedef SkEncodedImageFormat Type;
+        static SkImageEncoder* Create(SkEncodedImageFormat);
+
+        virtual ~SkImageEncoder() {}
+
+        bool encodeStream(SkWStream* dst, const SkBitmap& src, int quality) {
+            return this->onEncode(dst, src, SkMin32(100, SkMax32(0, quality)));
+        }
+
+    protected:
+        /**
+         * Encode bitmap 'bm' in the desired format, writing results to
+         * stream 'stream', at quality level 'quality' (which can be in
+         * range 0-100).
+         */
+        virtual bool onEncode(SkWStream* stream, const SkBitmap& bm, int quality) = 0;
+    };
+
+#endif  // SK_SUPPORT_LEGACY_IMAGE_ENCODER_CLASS
+
+// This macro declares a global (i.e., non-class owned) creation entry point
+// for each encoder (e.g., CreateJPEGImageEncoder)
+#define DECLARE_ENCODER_CREATOR(codec)          \
+    SK_API SkImageEncoder *Create ## codec ();
+
+// This macro defines the global creation entry point for each encoder. Each
+// encoder implementation that registers with the encoder factory must call it.
+#define DEFINE_ENCODER_CREATOR(codec) \
+    SkImageEncoder* Create##codec() { return new Sk##codec; }
+
+// All the encoders known by Skia. Note that, depending on the compiler settings,
+// not all of these will be available
+DECLARE_ENCODER_CREATOR(JPEGImageEncoder);
+DECLARE_ENCODER_CREATOR(PNGImageEncoder);
+DECLARE_ENCODER_CREATOR(KTXImageEncoder);
+DECLARE_ENCODER_CREATOR(WEBPImageEncoder);
+
+#if defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
+SkImageEncoder* CreateImageEncoder_CG(SkImageEncoder::Type type);
+#endif
+
+#if defined(SK_BUILD_FOR_WIN)
+SkImageEncoder* CreateImageEncoder_WIC(SkImageEncoder::Type type);
+#endif
+
+// Typedef to make registering encoder callback easier
+// This has to be defined outside SkImageEncoder. :(
+typedef SkTRegistry<SkImageEncoder*(*)(SkImageEncoder::Type)> SkImageEncoder_EncodeReg;
+
+#endif // SkImageEncoderPriv_DEFINED
diff --git a/src/images/SkImageEncoder_Factory.cpp b/src/images/SkImageEncoder_Factory.cpp
index 887ce55dda..a5ae8d0560 100644
--- a/src/images/SkImageEncoder_Factory.cpp
+++ b/src/images/SkImageEncoder_Factory.cpp
@@ -5,11 +5,11 @@
  * found in the LICENSE file.
  */
 
-#include "SkImageEncoder.h"
+#include "SkImageEncoderPriv.h"
 
 template SkImageEncoder_EncodeReg* SkImageEncoder_EncodeReg::gHead;
 
-SkImageEncoder* SkImageEncoder::Create(Type t) {
+SkImageEncoder* SkImageEncoder::Create(SkImageEncoder::Type t) {
     SkImageEncoder* codec = nullptr;
     const SkImageEncoder_EncodeReg* curr = SkImageEncoder_EncodeReg::Head();
     while (curr) {
diff --git a/src/images/SkJPEGImageEncoder.cpp b/src/images/SkJPEGImageEncoder.cpp
index 66b2440c20..97b8bbc30d 100644
--- a/src/images/SkJPEGImageEncoder.cpp
+++ b/src/images/SkJPEGImageEncoder.cpp
@@ -5,20 +5,20 @@
  * found in the LICENSE file.
  */
 
+#include "SkImageEncoderPriv.h"
 
-#include "SkImageEncoder.h"
+#include "SkCanvas.h"
 #include "SkColorPriv.h"
 #include "SkDither.h"
+#include "SkJPEGWriteUtility.h"
+#include "SkRect.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
 #include "SkTime.h"
 #include "SkUtils.h"
-#include "SkRect.h"
-#include "SkCanvas.h"
-
 
 #include <stdio.h>
-#include "SkJPEGWriteUtility.h"
+
 extern "C" {
     #include "jpeglib.h"
     #include "jerror.h"
@@ -178,7 +178,7 @@ DEFINE_ENCODER_CREATOR(JPEGImageEncoder);
 ///////////////////////////////////////////////////////////////////////////////
 
 static SkImageEncoder* sk_libjpeg_efactory(SkImageEncoder::Type t) {
-    return (SkImageEncoder::kJPEG_Type == t) ? new SkJPEGImageEncoder : nullptr;
+    return (SkEncodedImageFormat::kJPEG == (SkEncodedImageFormat)t) ? new SkJPEGImageEncoder : nullptr;
 }
 
 static SkImageEncoder_EncodeReg gEReg(sk_libjpeg_efactory);
diff --git a/src/images/SkKTXImageEncoder.cpp b/src/images/SkKTXImageEncoder.cpp
index 078cec6b4d..7a0ccb3a85 100644
--- a/src/images/SkKTXImageEncoder.cpp
+++ b/src/images/SkKTXImageEncoder.cpp
@@ -6,7 +6,7 @@
  */
 
 #include "SkColorPriv.h"
-#include "SkImageEncoder.h"
+#include "SkImageEncoderPriv.h"
 #include "SkImageGenerator.h"
 #include "SkPixelRef.h"
 #include "SkStream.h"
@@ -91,7 +91,7 @@ DEFINE_ENCODER_CREATOR(KTXImageEncoder);
 /////////////////////////////////////////////////////////////////////////////////////////
 
 SkImageEncoder* sk_libktx_efactory(SkImageEncoder::Type t) {
-    return (SkImageEncoder::kKTX_Type == t) ? new SkKTXImageEncoder : nullptr;
+    return (SkEncodedImageFormat::kKTX == (SkEncodedImageFormat)t) ? new SkKTXImageEncoder : nullptr;
 }
 
 static SkImageEncoder_EncodeReg gEReg(sk_libktx_efactory);
diff --git a/src/images/SkPNGImageEncoder.cpp b/src/images/SkPNGImageEncoder.cpp
index 69a53fb2a4..4fc3a10272 100644
--- a/src/images/SkPNGImageEncoder.cpp
+++ b/src/images/SkPNGImageEncoder.cpp
@@ -5,7 +5,7 @@
  * found in the LICENSE file.
  */
 
-#include "SkImageEncoder.h"
+#include "SkImageEncoderPriv.h"
 #include "SkColor.h"
 #include "SkColorPriv.h"
 #include "SkDither.h"
@@ -356,7 +356,7 @@ DEFINE_ENCODER_CREATOR(PNGImageEncoder);
 ///////////////////////////////////////////////////////////////////////////////
 
 SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type t) {
-    return (SkImageEncoder::kPNG_Type == t) ? new SkPNGImageEncoder : nullptr;
+    return (SkEncodedImageFormat::kPNG == (SkEncodedImageFormat)t) ? new SkPNGImageEncoder : nullptr;
 }
 
 static SkImageEncoder_EncodeReg gEReg(sk_libpng_efactory);
diff --git a/src/images/SkWEBPImageEncoder.cpp b/src/images/SkWEBPImageEncoder.cpp
index 116608a253..27c984ac1b 100644
--- a/src/images/SkWEBPImageEncoder.cpp
+++ b/src/images/SkWEBPImageEncoder.cpp
@@ -15,7 +15,7 @@
  */
 
 #include "SkBitmap.h"
-#include "SkImageEncoder.h"
+#include "SkImageEncoderPriv.h"
 #include "SkColorPriv.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
@@ -241,7 +241,7 @@ DEFINE_ENCODER_CREATOR(WEBPImageEncoder);
 ///////////////////////////////////////////////////////////////////////////////
 
 static SkImageEncoder* sk_libwebp_efactory(SkImageEncoder::Type t) {
-    return (SkImageEncoder::kWEBP_Type == t) ? new SkWEBPImageEncoder : nullptr;
+    return (SkEncodedImageFormat::kWEBP == (SkEncodedImageFormat)t) ? new SkWEBPImageEncoder : nullptr;
 }
 
 static SkImageEncoder_EncodeReg gEReg(sk_libwebp_efactory);