use macro to encapsulate building get_mtname() specializations

samplecode/SampleLua.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 "SampleCode.h"
 #include "SkView.h"
 #include "SkLua.h"
 #include "SkCanvas.h"
 
 extern "C" {
 #include "lua.h"
 #include "lualib.h"
 #include "lauxlib.h"
 }
 
 static const char gDrawName[] = "onDrawContent";
 
 static const char gCode[] = ""
+    "require \"math\" "
+    ""
     "local r = { left = 10, top = 10, right = 100, bottom = 80 } "
     "local x = 0;"
     ""
     "local paint = Sk.newPaint();"
     "paint:setAntiAlias(true);"
     ""
     "local color = {a = 1, r = 1, g = 0, b = 0};"
     ""
+    "function rnd(range) "
+    "   return math.random() * range;"
+    "end "
+    ""
+    "rndX = function () return rnd(640) end "
+    "rndY = function () return rnd(480) end "
+    ""
+    "function draw_rand_path(canvas);"
+    "   if not path_paint then "
+    "       path_paint = Sk.newPaint();"
+    "       path_paint:setAntiAlias(true);"
+    "   end "
+    "   path_paint:setColor({a = 1, r = math.random(), g = math.random(), b = math.random() });"
+    ""
+    "   local path = Sk.newPath();"
+    "   path:moveTo(rndX(), rndY());"
+    "   for i = 0, 50 do "
+    "       path:quadTo(rndX(), rndY(), rndX(), rndY());"
+    "   end "
+    "   canvas:drawPath(path, path_paint);"
+    "end "
+    ""
     "function onDrawContent(canvas) "
+    "   draw_rand_path(canvas);"
     "   color.g = x / 100;"
     "   paint:setColor(color) "
     "   canvas:translate(x, 0);"
     "   canvas:drawOval(r, paint) "
     "   x = x + 1;"
     "   if x > 100 then x = 0 end;"
     "end";
 
 class LuaView : public SampleView {
 public:
@@ skipping 60 matching lines @@
 private:
     SkLua* fLua;
 
     typedef SampleView INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static SkView* MyFactory() { return new LuaView; }
 static SkViewRegister reg(MyFactory);