Factor code to rotate a canvas about a point.

tools/sk_tool_utils.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 "sk_tool_utils.h"
 #include "sk_tool_utils_flags.h"
 
 #include "Resources.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkCommonFlags.h"
 #include "SkFontMgr.h"
 #include "SkFontStyle.h"
 #include "SkPoint3.h"
 #include "SkShader.h"
 #include "SkTestScalerContext.h"
 #include "SkTextBlob.h"
 
 DEFINE_bool(portableFonts, false, "Use portable fonts");
 
 namespace sk_tool_utils {
 
+void rotate_about(SkCanvas* canvas, SkScalar degrees, SkScalar px, SkScalar py) {
+    canvas->translate(px, py);
+    canvas->rotate(degrees);
+    canvas->translate(-px, -py);
+}
+
 /* these are the default fonts chosen by Chrome for serif, sans-serif, and monospace */
 static const char* gStandardFontNames[][3] = {
     { "Times", "Helvetica", "Courier" }, // Mac
     { "Times New Roman", "Helvetica", "Courier" }, // iOS
     { "Times New Roman", "Arial", "Courier New" }, // Win
     { "Times New Roman", "Arial", "Monospace" }, // Ubuntu
     { "serif", "sans-serif", "monospace" }, // Android
     { "Tinos", "Arimo", "Cousine" } // ChromeOS
 };
 
@@ skipping 421 matching lines @@
     for (int y = 0; y < src.height(); ++y) {
         for (int x = 0; x < src.width(); ++x) {
             *dst.getAddr32(x, y) = blur_pixel(src, x, y, kernel.get(), wh);
         }
     }
 
     return dst;
 }
 
 }  // namespace sk_tool_utils