add colortable support to imagegenerator

BUG=skia:
R=halcanary@google.com, scroggo@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/304443003

git-svn-id: http://skia.googlecode.com/svn/trunk@14916 2bbb7eff-a529-9590-31e7-b0007b416f81

9 files changed, 174 insertions, 63 deletions

diff --git a/gyp/images.gyp b/gyp/images.gyp
index 0062f24f1d..18a18be7e1 100644
--- a/gyp/images.gyp
+++ b/gyp/images.gyp
@@ -71,6 +71,7 @@
         '../src/images/SkImageEncoder.cpp',
         '../src/images/SkImageEncoder_Factory.cpp',
         '../src/images/SkImageEncoder_argb.cpp',
+        '../src/images/SkImageGenerator.cpp',
         '../src/images/SkImageRef.cpp',
         '../src/images/SkImageRefPool.cpp',
         '../src/images/SkImageRefPool.h',
diff --git a/gyp/skia_for_chromium_defines.gypi b/gyp/skia_for_chromium_defines.gypi
index c114b7142e..a47b391c3c 100644
--- a/gyp/skia_for_chromium_defines.gypi
+++ b/gyp/skia_for_chromium_defines.gypi
@@ -16,6 +16,7 @@
       'SK_SUPPORT_LEGACY_GETTOPDEVICE',
       'SK_SUPPORT_LEGACY_ASIMAGEINFO',
       'SK_SUPPORT_LEGACY_N32_NAME',
+      'SK_SUPPORT_LEGACY_IMAGEGENERATORAPI',
     ],
   },
 }
diff --git a/include/core/SkImageGenerator.h b/include/core/SkImageGenerator.h
index f399ab538e..21ebcbb3f2 100644
--- a/include/core/SkImageGenerator.h
+++ b/include/core/SkImageGenerator.h
@@ -9,6 +9,7 @@
 #define SkImageGenerator_DEFINED
 
 #include "SkImageInfo.h"
+#include "SkColor.h"
 
 class SkBitmap;
 class SkData;
@@ -47,6 +48,13 @@ public:
      */
     virtual ~SkImageGenerator() { }
 
+#ifdef SK_SUPPORT_LEGACY_IMAGEGENERATORAPI
+    virtual bool refEncodedData() { return this->onRefEncodedData(); }
+    virtual bool getInfo(SkImageInfo* info) { return this->onGetInfo(info); }
+    virtual bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes) {
+        return this->onGetPixels(info, pixels, rowBytes, NULL, NULL);
+    }
+#else
     /**
      *  Return a ref to the encoded (i.e. compressed) representation,
      *  of this data.
@@ -54,7 +62,7 @@ public:
      *  If non-NULL is returned, the caller is responsible for calling
      *  unref() on the data when it is finished.
      */
-    virtual SkData* refEncodedData() { return NULL; }
+    SkData* refEncodedData() { return this->onRefEncodedData(); }
 
     /**
      *  Return some information about the image, allowing the owner of
@@ -65,7 +73,7 @@ public:
      *
      *  @return false if anything goes wrong.
      */
-    virtual bool getInfo(SkImageInfo* info) = 0;
+    bool getInfo(SkImageInfo* info);
 
     /**
      *  Decode into the given pixels, a block of memory of size at
@@ -83,12 +91,31 @@ public:
      *         different output-configs, which the implementation can
      *         decide to support or not.
      *
+     *  If info is kIndex8_SkColorType, then the caller must provide storage for up to 256
+     *  SkPMColor values in ctable. On success the generator must copy N colors into that storage,
+     *  (where N is the logical number of table entries) and set ctableCount to N.
+     *
+     *  If info is not kIndex8_SkColorType, then the last two parameters may be NULL. If ctableCount
+     *  is not null, it will be set to 0.
+     *
      *  @return false if anything goes wrong or if the image info is
      *          unsupported.
      */
-    virtual bool getPixels(const SkImageInfo& info,
-                           void* pixels,
-                           size_t rowBytes) = 0;
+    bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
+                   SkPMColor ctable[], int* ctableCount);
+
+    /**
+     *  Simplified version of getPixels() that asserts that info is NOT kIndex8_SkColorType.
+     */
+    bool getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes);
+#endif
+
+protected:
+    virtual SkData* onRefEncodedData();
+    virtual bool onGetInfo(SkImageInfo* info);
+    virtual bool onGetPixels(const SkImageInfo& info,
+                             void* pixels, size_t rowBytes,
+                             SkPMColor ctable[], int* ctableCount);
 };
 
 #endif  // SkImageGenerator_DEFINED
diff --git a/src/images/SkDecodingImageGenerator.cpp b/src/images/SkDecodingImageGenerator.cpp
index b3924a7daa..1f0f706ede 100644
--- a/src/images/SkDecodingImageGenerator.cpp
+++ b/src/images/SkDecodingImageGenerator.cpp
@@ -23,12 +23,6 @@ bool equal_modulo_alpha(const SkImageInfo& a, const SkImageInfo& b) {
 class DecodingImageGenerator : public SkImageGenerator {
 public:
     virtual ~DecodingImageGenerator();
-    virtual SkData* refEncodedData() SK_OVERRIDE;
-    // This implementaion of getInfo() always returns true.
-    virtual bool getInfo(SkImageInfo* info) SK_OVERRIDE;
-    virtual bool getPixels(const SkImageInfo& info,
-                           void* pixels,
-                           size_t rowBytes) SK_OVERRIDE;
 
     SkData*                fData;
     SkStreamRewindable*    fStream;
@@ -41,6 +35,18 @@ public:
                            const SkImageInfo& info,
                            int sampleSize,
                            bool ditherImage);
+
+protected:
+    virtual SkData* onRefEncodedData() SK_OVERRIDE;
+    virtual bool onGetInfo(SkImageInfo* info) SK_OVERRIDE {
+        *info = fInfo;
+        return true;
+    }
+    virtual bool onGetPixels(const SkImageInfo& info,
+                             void* pixels, size_t rowBytes,
+                             SkPMColor ctable[], int* ctableCount) SK_OVERRIDE;
+
+private:
     typedef SkImageGenerator INHERITED;
 };
 
@@ -123,14 +129,7 @@ DecodingImageGenerator::~DecodingImageGenerator() {
     fStream->unref();
 }
 
-bool DecodingImageGenerator::getInfo(SkImageInfo* info) {
-    if (info != NULL) {
-        *info = fInfo;
-    }
-    return true;
-}
-
-SkData* DecodingImageGenerator::refEncodedData() {
+SkData* DecodingImageGenerator::onRefEncodedData() {
     // This functionality is used in `gm --serialize`
     // Does not encode options.
     if (fData != NULL) {
@@ -151,22 +150,15 @@ SkData* DecodingImageGenerator::refEncodedData() {
     return SkSafeRef(fData);
 }
 
-bool DecodingImageGenerator::getPixels(const SkImageInfo& info,
-                                         void* pixels,
-                                         size_t rowBytes) {
-    if (NULL == pixels) {
-        return false;
-    }
+bool DecodingImageGenerator::onGetPixels(const SkImageInfo& info,
+                                         void* pixels, size_t rowBytes,
+                                         SkPMColor ctableEntries[], int* ctableCount) {
     if (fInfo != info) {
         // The caller has specified a different info.  This is an
         // error for this kind of SkImageGenerator.  Use the Options
         // to change the settings.
         return false;
     }
-    if (info.minRowBytes() > rowBytes) {
-        // The caller has specified a bad rowBytes.
-        return false;
-    }
 
     SkAssertResult(fStream->rewind());
     SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(fStream));
@@ -202,6 +194,20 @@ bool DecodingImageGenerator::getPixels(const SkImageInfo& info,
     } else {
         SkASSERT(check_alpha(info.alphaType(), bitmap.alphaType()));
     }
+
+    if (kIndex_8_SkColorType == info.colorType()) {
+        if (kIndex_8_SkColorType != bitmap.colorType()) {
+            return false;   // they asked for Index8, but we didn't receive that from decoder
+        }
+        SkColorTable* ctable = bitmap.getColorTable();
+        if (NULL == ctable) {
+            return false;
+        }
+        const int count = ctable->count();
+        memcpy(ctableEntries, ctable->lockColors(), count * sizeof(SkPMColor));
+        ctable->unlockColors();
+        *ctableCount = count;
+    }
     return true;
 }
 
@@ -214,11 +220,6 @@ SkImageGenerator* CreateDecodingImageGenerator(
         const SkDecodingImageGenerator::Options& opts) {
     SkASSERT(stream);
     SkAutoTUnref<SkStreamRewindable> autoStream(stream);  // always unref this.
-    if (opts.fUseRequestedColorType &&
-        (kIndex_8_SkColorType == opts.fRequestedColorType)) {
-        // We do not support indexed color with SkImageGenerators,
-        return NULL;
-    }
     SkAssertResult(autoStream->rewind());
     SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(autoStream));
     if (NULL == decoder.get()) {
@@ -227,24 +228,16 @@ SkImageGenerator* CreateDecodingImageGenerator(
     SkBitmap bitmap;
     decoder->setSampleSize(opts.fSampleSize);
     decoder->setRequireUnpremultipliedColors(opts.fRequireUnpremul);
-    if (!decoder->decode(stream, &bitmap,
-                         SkImageDecoder::kDecodeBounds_Mode)) {
+    if (!decoder->decode(stream, &bitmap, SkImageDecoder::kDecodeBounds_Mode)) {
         return NULL;
     }
-    if (bitmap.config() == SkBitmap::kNo_Config) {
+    if (kUnknown_SkColorType == bitmap.colorType()) {
         return NULL;
     }
 
     SkImageInfo info = bitmap.info();
 
-    if (!opts.fUseRequestedColorType) {
-        // Use default
-        if (kIndex_8_SkColorType == bitmap.colorType()) {
-            // We don't support kIndex8 because we don't support
-            // colortables in this workflow.
-            info.fColorType = kN32_SkColorType;
-        }
-    } else {
+    if (opts.fUseRequestedColorType && (opts.fRequestedColorType != info.colorType())) {
         if (!bitmap.canCopyTo(opts.fRequestedColorType)) {
             SkASSERT(bitmap.colorType() != opts.fRequestedColorType);
             return NULL;  // Can not translate to needed config.
diff --git a/src/images/SkImageGenerator.cpp b/src/images/SkImageGenerator.cpp
new file mode 100644
index 0000000000..b898764f0c
--- /dev/null
+++ b/src/images/SkImageGenerator.cpp
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkImageGenerator.h"
+
+#ifndef SK_SUPPORT_LEGACY_IMAGEGENERATORAPI
+bool SkImageGenerator::getInfo(SkImageInfo* info) {
+    SkImageInfo dummy;
+    if (NULL == info) {
+        info = &dummy;
+    }
+    return this->onGetInfo(info);
+}
+
+bool SkImageGenerator::getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
+                                 SkPMColor ctable[], int* ctableCount) {
+    // Dummy (out-of-range) value to catch subclasses that forgot to respect ctable params.
+    int localCTableCount = -1;
+    int* localCTableCountPtr = NULL;
+
+    if (kIndex_8_SkColorType == info.colorType()) {
+        if (NULL == ctable || NULL == ctableCount) {
+            return false;
+        }
+    } else {
+        if (ctableCount) {
+            *ctableCount = 0;
+        }
+        ctableCount = NULL;
+        ctable = NULL;
+    }
+
+    if (kUnknown_SkColorType == info.colorType()) {
+        return false;
+    }
+    if (NULL == pixels) {
+        return false;
+    }
+    if (rowBytes < info.minRowBytes()) {
+        return false;
+    }
+
+    bool success = this->onGetPixels(info, pixels, rowBytes, ctable, localCTableCountPtr);
+
+    if (success && localCTableCountPtr) {
+        SkASSERT(localCTableCount >= 0 && localCTableCount <= 256);
+        if (ctableCount) {
+            *ctableCount = localCTableCount;
+        }
+    }
+    return success;
+}
+
+bool SkImageGenerator::getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes) {
+    SkASSERT(kIndex_8_SkColorType != info.colorType());
+    if (kIndex_8_SkColorType == info.colorType()) {
+        return false;
+    }
+    return this->getPixels(info, pixels, rowBytes, NULL, NULL);
+}
+#endif
+
+/////////////////////////////////////////////////////////////////////////////////////////////
+
+SkData* SkImageGenerator::onRefEncodedData() {
+    return NULL;
+}
+
+bool SkImageGenerator::onGetInfo(SkImageInfo*) {
+    return false;
+}
+
+bool SkImageGenerator::onGetPixels(const SkImageInfo&, void*, size_t, SkPMColor*, int*) {
+    return false;
+}
diff --git a/src/lazy/SkDiscardablePixelRef.cpp b/src/lazy/SkDiscardablePixelRef.cpp
index ccf812ce6f..b0bbd27e3a 100644
--- a/src/lazy/SkDiscardablePixelRef.cpp
+++ b/src/lazy/SkDiscardablePixelRef.cpp
@@ -60,15 +60,30 @@ bool SkDiscardablePixelRef::onNewLockPixels(LockRec* rec) {
     }
 
     void* pixels = fDiscardableMemory->data();
-    if (!fGenerator->getPixels(this->info(), pixels, fRowBytes)) {
+    const SkImageInfo& info = this->info();
+    SkPMColor colors[256];
+    int colorCount = 0;
+
+    if (!fGenerator->getPixels(info, pixels, fRowBytes, colors, &colorCount)) {
         fDiscardableMemory->unlock();
         SkDELETE(fDiscardableMemory);
         fDiscardableMemory = NULL;
         return false;
     }
 
+    // Note: our ctable is not purgable, as it is not stored in the discardablememory block.
+    // This is because SkColorTable is refcntable, and therefore our caller could hold onto it
+    // beyond the scope of a lock/unlock. If we change the API/lifecycle for SkColorTable, we
+    // could move it into the block, but then again perhaps it is small enough that this doesn't
+    // really matter.
+    if (colorCount > 0) {
+        fCTable.reset(SkNEW_ARGS(SkColorTable, (colors, colorCount)));
+    } else {
+        fCTable.reset(NULL);
+    }
+
     rec->fPixels = pixels;
-    rec->fColorTable = NULL;
+    rec->fColorTable = fCTable.get();
     rec->fRowBytes = fRowBytes;
     return true;
 }
diff --git a/src/lazy/SkDiscardablePixelRef.h b/src/lazy/SkDiscardablePixelRef.h
index e5e1c9f0e1..52a1d6ce37 100644
--- a/src/lazy/SkDiscardablePixelRef.h
+++ b/src/lazy/SkDiscardablePixelRef.h
@@ -17,10 +17,6 @@
  *  A PixelRef backed by SkDiscardableMemory, with the ability to
  *  re-generate the pixels (via a SkImageGenerator) if the DM is
  *  purged.
- *
- *  Since SkColorTable is reference-counted, we do not support indexed
- *  color with this class; there would be no way for the discardable
- *  memory system to unref the color table.
  */
 class SkDiscardablePixelRef : public SkPixelRef {
 public:
@@ -46,6 +42,7 @@ private:
     // PixelRef, since the SkBitmap doesn't expect them to change.
 
     SkDiscardableMemory* fDiscardableMemory;
+    SkAutoTUnref<SkColorTable> fCTable;
 
     /* Takes ownership of SkImageGenerator. */
     SkDiscardablePixelRef(const SkImageInfo&, SkImageGenerator*,
diff --git a/tests/CachedDecodingPixelRefTest.cpp b/tests/CachedDecodingPixelRefTest.cpp
index 10e33ba841..eff77e215d 100644
--- a/tests/CachedDecodingPixelRefTest.cpp
+++ b/tests/CachedDecodingPixelRefTest.cpp
@@ -183,7 +183,9 @@ public:
         SkASSERT((fType <= kLast_TestType) && (fType >= 0));
     }
     virtual ~TestImageGenerator() { }
-    virtual bool getInfo(SkImageInfo* info) SK_OVERRIDE {
+
+protected:
+    virtual bool onGetInfo(SkImageInfo* info) SK_OVERRIDE {
         REPORTER_ASSERT(fReporter, NULL != info);
         if ((NULL == info) || (kFailGetInfo_TestType == fType)) {
             return false;
@@ -194,9 +196,9 @@ public:
         info->fAlphaType = kOpaque_SkAlphaType;
         return true;
     }
-    virtual bool getPixels(const SkImageInfo& info,
-                           void* pixels,
-                           size_t rowBytes) SK_OVERRIDE {
+
+    virtual bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
+                             SkPMColor ctable[], int* ctableCount) SK_OVERRIDE {
         REPORTER_ASSERT(fReporter, pixels != NULL);
         size_t minRowBytes
             = static_cast<size_t>(info.fWidth * info.bytesPerPixel());
diff --git a/tests/DrawBitmapRectTest.cpp b/tests/DrawBitmapRectTest.cpp
index f294ae7e6e..aa69de4bd4 100644
--- a/tests/DrawBitmapRectTest.cpp
+++ b/tests/DrawBitmapRectTest.cpp
@@ -22,20 +22,16 @@ class FailureImageGenerator : public SkImageGenerator {
 public:
     FailureImageGenerator() { }
     virtual ~FailureImageGenerator() { }
-    virtual bool getInfo(SkImageInfo* info) SK_OVERRIDE {
+    
+protected:
+    virtual bool onGetInfo(SkImageInfo* info) SK_OVERRIDE {
         info->fWidth = 100;
         info->fHeight = 100;
         info->fColorType = kN32_SkColorType;
         info->fAlphaType = kPremul_SkAlphaType;
         return true;
     }
-    virtual bool getPixels(const SkImageInfo& info,
-                           void* pixels,
-                           size_t rowBytes) SK_OVERRIDE {
-        // this will deliberately return false if they are asking us
-        // to decode into pixels.
-        return false;
-    }
+    // default onGetPixels() returns false, which is what we want.
 };
 
 // crbug.com/295895