skia2/gm/crbug_938592.cpp
Ben Wagner 7fde8e1728 IWYU for gms.
This almost gets gms to be iwyu clean. The last bit is around gm.cpp
and the tracing framework and its use of atomic. Will also need a way
of keeping things from regressing, which is difficult due to needing to
do this outside-in.

Change-Id: I1393531e99da8b0f1a29f55c53c86d53f459af7d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/211593
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
2019-05-02 17:48:53 +00:00

50 lines
1.9 KiB
C++

/*
* Copyright 2019 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm/gm.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPoint.h"
#include "include/core/SkScalar.h"
#include "include/core/SkShader.h"
#include "include/core/SkTileMode.h"
#include "include/effects/SkGradientShader.h"
// This draws a hard stop gradient applied to a rectangle. The hard stops fall at half pixel
// boundaries in y. On some GPUs we've found that the winding of the two triangles that make up the
// rectangle can affect whether the interpolants for local coords wind up agreeing across a row.
// When they disagree the hard stop gradient appears jagged. We draw the rectangle four times:
// no-mirroring, mirror in x, mirror in y, and mirror in x and y.
DEF_SIMPLE_GM(crbug_938592, canvas, 500, 300) {
static constexpr SkPoint pts[] = {{0, 0}, {0, 30}};
static constexpr SkScalar pos[] = {0.f, 9.f / 20, 9.f / 20, 11.f / 20, 11.f / 20, 20.f / 20};
static constexpr SkColor c0 = SK_ColorBLUE;
static constexpr SkColor c1 = SK_ColorRED;
static constexpr SkColor c2 = SK_ColorGREEN;
static constexpr SkColor colors[] = {c0, c0, c1, c1, c2, c2};
auto grad = SkGradientShader::MakeLinear(pts, colors, pos, 6, SkTileMode::kClamp);
SkPaint paint;
paint.setShader(grad);
static constexpr int kMirrorX = 400;
static constexpr int kMirrorY = 200;
canvas->translate(50, 50);
for (int i = 0; i < 4; ++i) {
canvas->save();
if (i & 0b01) {
canvas->translate(0, kMirrorY);
canvas->scale(1.f, -1.f);
}
if (i & 0b10) {
canvas->translate(kMirrorX, 0);
canvas->scale(-1.f, 1.f);
}
canvas->drawRect({0, 0, 150, 30}, paint);
canvas->restore();
}
}