add new readPixels with direct memory parameters

tools/sk_tool_utils.cpp

 #include "sk_tool_utils.h"
 
 namespace sk_tool_utils {
 
+const char* colortype_name(SkColorType ct) {
+    switch (ct) {
+        case kUnknown_SkColorType:      return "Unknown";
+        case kAlpha_8_SkColorType:      return "Alpha_8";
+        case kIndex_8_SkColorType:      return "Index_8";
+        case kARGB_4444_SkColorType:    return "ARGB_4444";
+        case kRGB_565_SkColorType:      return "RGB_565";
+        case kRGBA_8888_SkColorType:    return "RGBA_8888";
+        case kBGRA_8888_SkColorType:    return "BGRA_8888";
+        default:
+            SkASSERT(false);
+            return "unexpected colortype";
+    }
+}
+
 void config8888_to_imagetypes(SkCanvas::Config8888 config, SkColorType* ct, SkAlphaType* at) {
     switch (config) {
         case SkCanvas::kNative_Premul_Config8888:
             *ct = kPMColor_SkColorType;
             *at = kPremul_SkAlphaType;
             break;
         case SkCanvas::kNative_Unpremul_Config8888:
             *ct = kPMColor_SkColorType;
             *at = kUnpremul_SkAlphaType;
             break;
@@ skipping 24 matching lines @@
     tmp.lockPixels();
 
     SkImageInfo info = tmp.info();
     info.fColorType = colorType;
     info.fAlphaType = alphaType;
 
     canvas->writePixels(info, tmp.getPixels(), tmp.rowBytes(), x, y);
 }
 
 }