skia2/docs/examples/Matrix_fixedStepInX.cpp
Hal Canary d88c2e8e09 Docs: rename examples files to match names
Change-Id: I9a6b2780cfdd91cdd16d5a08eb9ba1214492cb7e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201982
Commit-Queue: Hal Canary <halcanary@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
2019-03-19 18:49:22 +00:00

29 lines
1.0 KiB
C++

// Copyright 2019 Google LLC.
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
#include "fiddle/examples.h"
// HASH=fad6b92b21b1e1deeae61978cec2d232
REG_FIDDLE(Matrix_fixedStepInX, 256, 256, false, 3) {
void draw(SkCanvas* canvas) {
SkMatrix matrix;
const SkPoint center = { 128, 128 };
matrix.setScale(20, 25, center.fX, center.fY);
matrix.postRotate(75, center.fX, center.fY);
{
SkAutoCanvasRestore acr(canvas, true);
canvas->concat(matrix);
canvas->drawBitmap(source, 0, 0);
}
if (matrix.isFixedStepInX()) {
SkPaint paint;
paint.setAntiAlias(true);
SkVector step = matrix.fixedStepInX(128);
SkVector end = center + step;
canvas->drawLine(center, end, paint);
SkVector arrow = { step.fX + step.fY, step.fY - step.fX};
arrow = arrow * .25f;
canvas->drawLine(end, end - arrow, paint);
canvas->drawLine(end, {end.fX + arrow.fY, end.fY - arrow.fX}, paint);
}
}
} // END FIDDLE