xref: /aosp_15_r20/external/skia/docs/examples/Canvas_drawTextRSXform.cpp (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1 // Copyright 2019 Google LLC.
2 // Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
3 #include "tools/fiddle/examples.h"
4 REG_FIDDLE(Canvas_drawTextRSXform, 256, 256, false, 0) {
draw(SkCanvas * canvas)5 void draw(SkCanvas* canvas) {
6     const int iterations = 26;
7     SkRSXform transforms[iterations];
8     char alphabet[iterations];
9     SkScalar angle = 0;
10     SkScalar scale = 1;
11     for (size_t i = 0; i < std::size(transforms); ++i) {
12         const SkScalar s = SkScalarSin(angle) * scale;
13         const SkScalar c = SkScalarCos(angle) * scale;
14         transforms[i] = SkRSXform::Make(-c, -s, -s * 16, c * 16);
15         angle += .45f;
16         scale += .2f;
17         alphabet[i] = 'A' + i;
18     }
19     SkPaint paint;
20     SkFont font(fontMgr->matchFamilyStyle(nullptr, {}), 20);
21     auto spiral = SkTextBlob::MakeFromRSXform(alphabet, sizeof(alphabet), transforms, font);
22     canvas->drawTextBlob(spiral, 110, 138, paint);
23 }
24 }  // END FIDDLE
25