1 /*
2 * Copyright 2020 Google LLC
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "gm/gm.h"
9 #include "include/core/SkCanvas.h"
10 #include "include/core/SkPaint.h"
11 #include "include/core/SkRect.h"
12 #include "include/effects/SkImageFilters.h"
13
drawOne(SkCanvas * canvas,SkRect rect,float saveBorder,float sigma,SkColor c)14 static void drawOne(SkCanvas* canvas, SkRect rect, float saveBorder, float sigma, SkColor c) {
15 SkRect borderRect = rect.makeOutset(saveBorder, saveBorder);
16
17 SkPaint p;
18 p.setColor(c);
19 p.setImageFilter(
20 SkImageFilters::Blur(sigma, sigma,
21 // The blur's input is forced to have transparent padding because 'borderRect' is outset
22 // from the non-transparent content ('rect') that's drawn into the layer.
23 SkImageFilters::Crop(borderRect, SkTileMode::kClamp, nullptr),
24 // The blur's output crop visually won't affect the output because the transparent
25 // padding is blurred out by the edge of 3*sigma.
26 borderRect.makeOutset(3 * sigma, 3 * sigma)));
27 p.setAntiAlias(true);
28
29 canvas->drawRect(rect, p);
30 }
31
32 DEF_SIMPLE_GM(crbug_1156804, canvas, 250, 250) {
33 drawOne(canvas, SkRect::MakeXYWH( 64, 64, 25, 25), 1, 3, SK_ColorGREEN);
34 drawOne(canvas, SkRect::MakeXYWH(164, 64, 25, 25), 30, 3, SK_ColorGREEN);
35 // This one would draw incorrectly because the large sigma causes downscaling of the source
36 // and the one-pixel border would make the downscaled image not contain trans-black at the
37 // edges. Combined with the clamp mode on the blur filter it would "harden" the edge.
38 drawOne(canvas, SkRect::MakeXYWH( 64, 164, 25, 25), 1, 20, SK_ColorRED);
39 drawOne(canvas, SkRect::MakeXYWH(164, 164, 25, 25), 30, 20, SK_ColorGREEN);
40 }
41