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 // HASH=fad6b92b21b1e1deeae61978cec2d232
5 REG_FIDDLE(Matrix_fixedStepInX, 256, 256, false, 3) {
draw(SkCanvas * canvas)6 void draw(SkCanvas* canvas) {
7 SkMatrix matrix;
8 const SkPoint center = { 128, 128 };
9 matrix.setScale(20, 25, center.fX, center.fY);
10 matrix.postRotate(75, center.fX, center.fY);
11 {
12 SkAutoCanvasRestore acr(canvas, true);
13 canvas->concat(matrix);
14 canvas->drawBitmap(source, 0, 0);
15 }
16 if (matrix.isFixedStepInX()) {
17 SkPaint paint;
18 paint.setAntiAlias(true);
19 SkVector step = matrix.fixedStepInX(128);
20 SkVector end = center + step;
21 canvas->drawLine(center, end, paint);
22 SkVector arrow = { step.fX + step.fY, step.fY - step.fX};
23 arrow = arrow * .25f;
24 canvas->drawLine(end, end - arrow, paint);
25 canvas->drawLine(end, {end.fX + arrow.fY, end.fY - arrow.fX}, paint);
26 }
27 }
28 } // END FIDDLE
29