Factor code to rotate a canvas about a point.

gm/typeface.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "Resources.h"
 #include "SkCanvas.h"
 #include "SkString.h"
 #include "SkSurfaceProps.h"
 #include "SkTypeface.h"
 #include "SkTypes.h"
+#include "sk_tool_utils.h"
 
 static void getGlyphPositions(const SkPaint& paint, const uint16_t glyphs[],
                              int count, SkScalar x, SkScalar y, SkPoint pos[]) {
     SkASSERT(SkPaint::kGlyphID_TextEncoding == paint.getTextEncoding());
 
     SkAutoSTMalloc<128, SkScalar> widthStorage(count);
     SkScalar* widths = widthStorage.get();
     paint.getTextWidths(glyphs, count * sizeof(uint16_t), widths);
 
     for (int i = 0; i < count; ++i) {
@@ skipping 122 matching lines @@
                 drawKernText(canvas, text, textLen, x + 240, y, paint);
             }
             y += dy;
         }
     }
 
 private:
     typedef skiagm::GM INHERITED;
 };
 
-static void rotate_about(SkCanvas* canvas,
-                         SkScalar degrees,
-                         SkScalar px, SkScalar py) {
-    canvas->translate(px, py);
-    canvas->rotate(degrees);
-    canvas->translate(-px, -py);
-}
-
 class TypefaceRenderingGM : public skiagm::GM {
     sk_sp<SkTypeface> fFace;
 
-public:
-    TypefaceRenderingGM() { }
-
 protected:
     void onOnceBeforeDraw() override {
         fFace = MakeResourceAsTypeface("/fonts/hintgasp.ttf");
     }
 
     SkString onShortName() override {
         SkString name("typefacerendering");
         name.append(sk_tool_utils::major_platform_os_name());
         return name;
     }
@@ skipping 68 matching lines @@
                     paint.setTextSize(textSize);
 
                     SkScalar dy = SkScalarCeilToScalar(paint.getFontMetrics(nullptr));
                     y += dy;
                     for (const SkPaint::Hinting& hinting : hintingTypes) {
                         paint.setHinting(hinting);
 
                         for (const bool& rotateABit : rotateABitTypes) {
                             SkAutoCanvasRestore acr(canvas, true);
                             if (rotateABit) {
-                                rotate_about(canvas, 2, x + subpixel.offset.x(),
-                                                        y + subpixel.offset.y());
+                                sk_tool_utils::rotate_about(canvas, 2, x + subpixel.offset.x(),
+                                                                       y + subpixel.offset.y());
                             }
                             canvas->drawText("A", 1, x + subpixel.offset.x(),
                                                      y + subpixel.offset.y(), paint);
 
                             SkScalar dx = SkScalarCeilToScalar(paint.measureText("A", 1)) + 5;
                             x += dx;
                             xMax = SkTMax(x, xMax);
                         }
                     }
                 }
                 y += 10;
             }
             xBase = xMax;
         }
     }
 
 private:
     typedef skiagm::GM INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 DEF_GM( return new TypefaceStylesGM(false); )
 DEF_GM( return new TypefaceStylesGM(true); )
 DEF_GM( return new TypefaceRenderingGM(); )