| /* |
| * 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/effects/SkBlurImageFilter.h" |
| #include "include/effects/SkColorFilterImageFilter.h" |
| #include "include/core/SkPaint.h" |
| |
| // This draws correctly if there's a small cyan rectangle above a much larger magenta rectangle. |
| // There should be no red around the cyan rectangle and no green within the magenta rectangle. |
| |
| DEF_SIMPLE_GM(backdrop_imagefilter_croprect, canvas, 600, 500) { |
| // CTM translates to (150, 150) |
| SkPoint origin = SkPoint::Make(150.f, 150.f); |
| // The save layer specified after the CTM has negative coordinates, but |
| // means that (100, 100) to (500, 250) in device-space will be saved |
| SkRect clip = SkRect::MakeXYWH(-50.f, -50.f, 400.f, 150.f); |
| // The image-filter crop relative to the CTM, which will map to |
| // (200, 160) to (400, 190) in device space, or (100, 600) to (300, 90) in |
| // the layer's image space. |
| SkRect cropInLocal = SkRect::MakeLTRB(50.f, 10.f, 250.f, 40.f); |
| |
| SkImageFilter::CropRect cropRect(cropInLocal); |
| float matrix[20] = {-1.f, 0.f, 0.f, 0.f, 1.f, |
| 0.f, -1.f, 0.f, 0.f, 1.f, |
| 0.f, 0.f, -1.f, 0.f, 1.f, |
| 0.f, 0.f, 0.f, 1.f, 0.f}; |
| sk_sp<SkColorFilter> colorFilter = SkColorFilters::Matrix(matrix); |
| sk_sp<SkImageFilter> imageFilter = SkColorFilterImageFilter::Make(colorFilter, nullptr, |
| &cropRect); |
| |
| SkPaint p; |
| SkPaint l; |
| l.setStyle(SkPaint::kStroke_Style); |
| l.setStrokeWidth(0.f); |
| |
| for (int i = 0; i < 2; ++i) { |
| canvas->save(); |
| canvas->translate(origin.fX, origin.fY); |
| |
| canvas->clipRect(clip); |
| |
| if (i == 0) { |
| // Primary save layer mode, so save layer before drawing the content |
| SkPaint imfPaint; |
| imfPaint.setImageFilter(imageFilter); |
| canvas->saveLayer(nullptr, &imfPaint); |
| } // else backdrop mode, so the content is drawn first |
| |
| // Fill the clip with one color (cyan for i == 0 (inverse = red), and |
| // magenta for i == 1 (inverse = green)) |
| p.setColor(i == 0 ? SK_ColorCYAN : SK_ColorMAGENTA); |
| canvas->drawPaint(p); |
| |
| // Then an inner rectangle with a color meant to be inverted by the image filter |
| p.setColor(i == 0 ? SK_ColorRED : SK_ColorGREEN); |
| canvas->drawRect(cropInLocal, p); |
| |
| if (i == 1) { |
| // Backdrop mode, so save a layer using the image filter as the backdrop to filter |
| // content on initialization. |
| canvas->saveLayer({nullptr, nullptr, imageFilter.get(), nullptr, nullptr, |
| SkCanvas::kInitWithPrevious_SaveLayerFlag}); |
| } |
| |
| // Restore the saved layer (either a main layer that was just drawn into and needs to be |
| // filtered, or an "empty" layer initialized with the previously filtered backdrop) |
| canvas->restore(); |
| |
| // Move down |
| canvas->restore(); |
| origin.fY += 150.f; |
| } |
| } |