add colortable support to imagegenerator

src/images/SkDecodingImageGenerator.cpp

Index: src/images/SkDecodingImageGenerator.cpp
diff --git a/src/images/SkDecodingImageGenerator.cpp b/src/images/SkDecodingImageGenerator.cpp
index b3924a7daa4d2b342cb6ea29f333ce93aa4b7390..e55af85a7dcdffcb3299a462325f3bf2384c83c5 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 +35,16 @@ public:
                            const SkImageInfo& info,
                            int sampleSize,
                            bool ditherImage);
+
+protected:
+    virtual SkData* onRefEncodedData() SK_OVERRIDE;
+    // This implementaion of getInfo() always returns true.
+    virtual bool onGetInfo(SkImageInfo* info) SK_OVERRIDE;
+    virtual bool onGetPixels(const SkImageInfo& info,
+                             void* pixels, size_t rowBytes,
+                             SkPMColor ctable[], int* ctableCount) SK_OVERRIDE;
+
+private:
     typedef SkImageGenerator INHERITED;
 };
 
@@ -123,14 +127,12 @@ DecodingImageGenerator::~DecodingImageGenerator() {
     fStream->unref();
 }
 
-bool DecodingImageGenerator::getInfo(SkImageInfo* info) {
-    if (info != NULL) {
-        *info = fInfo;
-    }
+bool DecodingImageGenerator::onGetInfo(SkImageInfo* info) {
+    *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 +153,15 @@ 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 +197,20 @@ 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;
 }