Factor out checkerboard function in gm and sampleapp into tools.

gm/displacement.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 "Checkerboard.h"
+#include "SkBitmapSource.h"
+#include "SkDisplacementMapEffect.h"
 #include "gm.h"
-#include "SkDisplacementMapEffect.h"
-#include "SkBitmapSource.h"
 
 namespace skiagm {
 
 class DisplacementMapGM : public GM {
 public:
     DisplacementMapGM() : fInitialized(false) {
         this->setBGColor(0xFF000000);
     }
 
 protected:
@@ skipping 19 matching lines @@
         sk_tool_utils::set_portable_typeface(&paint);
         paint.setColor(0xFF884422);
         paint.setTextSize(SkIntToScalar(96));
         const char* str = "g";
         canvas.drawText(str, strlen(str), SkIntToScalar(15), SkIntToScalar(55), paint);
     }
 
     void make_checkerboard(SkBitmap* bitmap, int w, int h) {
         bitmap->allocN32Pixels(w, h);
         SkCanvas canvas(*bitmap);
-        canvas.clear(0x00000000);
-        SkPaint darkPaint;
-        darkPaint.setColor(0xFF804020);
-        SkPaint lightPaint;
-        lightPaint.setColor(0xFF244484);
-        for (int y = 0; y < h; y += 16) {
-          for (int x = 0; x < w; x += 16) {
-            canvas.save();
-            canvas.translate(SkIntToScalar(x), SkIntToScalar(y));
-            canvas.drawRect(SkRect::MakeXYWH(0, 0, 8, 8), darkPaint);
-            canvas.drawRect(SkRect::MakeXYWH(8, 0, 8, 8), lightPaint);
-            canvas.drawRect(SkRect::MakeXYWH(0, 8, 8, 8), lightPaint);
-            canvas.drawRect(SkRect::MakeXYWH(8, 8, 8, 8), darkPaint);
-            canvas.restore();
-          }
-        }
+        sk_tools::DrawCheckerboard(&canvas, 0xFF244484, 0xFF804020, 8);
     }
 
     virtual SkISize onISize() {
         return SkISize::Make(500, 500);
     }
 
     void drawClippedBitmap(SkCanvas* canvas, int x, int y, const SkPaint& paint) {
         canvas->save();
         canvas->translate(SkIntToScalar(x), SkIntToScalar(y));
         canvas->clipRect(SkRect::MakeWH(SkIntToScalar(fBitmap.width()), SkIntToScalar(fBitmap.height())));
@@ skipping 145 matching lines @@
     SkBitmap fBitmap, fCheckerboard, fSmall, fLarge, fLargeW, fLargeH;
     bool fInitialized;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new DisplacementMapGM; }
 static GMRegistry reg(MyFactory);
 
 }