Added 3-color gradient scraper for detecting symmetrical gradients.

src/utils/SkLua.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLua.h"
 #include "SkCanvas.h"
 #include "SkData.h"
@@ skipping 694 matching lines @@
         }
     }
     return 0;
 }
 
 static int lshader_asAGradient(lua_State* L) {
     SkShader* shader = get_ref<SkShader>(L, 1);
     if (shader) {
         SkShader::GradientInfo info;
         sk_bzero(&info, sizeof(info));
+
+        SkColor colors[3];  // hacked in for extracting info on 3 color case.
+        SkScalar pos[3];    
+
+        info.fColorCount = 3;
+        info.fColors = &colors[0];
+        info.fColorOffsets = &pos[0];
+        
         SkShader::GradientType t = shader->asAGradient(&info);
+
         if (SkShader::kNone_GradientType != t) {
             lua_newtable(L);
             setfield_string(L, "type", gradtype2string(t));
             setfield_number(L, "colorCount", info.fColorCount);
             setfield_string(L, "tile", mode2string(info.fTileMode));
+
+            if (info.fColorCount == 3){

[reed1, 2013/08/01 16:23:26]

nit: 3 == info.fColorCount

This ordering ensures you can't accidentally type 3 = info.fColorCount, which
would be assigning to a literal.

+                setfield_number(L, "midPos", pos[1]);
+            }
+            
             return 1;
         }
     }
     return 0;
 }
 
 static int lshader_gc(lua_State* L) {
     get_ref<SkShader>(L, 1)->unref();
     return 0;
 }
@@ skipping 375 matching lines @@
     REG_CLASS(L, SkShader);
     REG_CLASS(L, SkTypeface);
     REG_CLASS(L, SkMatrix);
 }
 
 extern "C" int luaopen_skia(lua_State* L);
 extern "C" int luaopen_skia(lua_State* L) {
     SkLua::Load(L);
     return 0;
 }