add colortable support to imagegenerator

src/images/SkImageGenerator.cpp

+/*
+ * 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;
+}