1 /* 2 * Copyright 2020 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #pragma once 18 19 #include <SkCanvas.h> 20 #include <SkImage.h> 21 #include <SkRuntimeEffect.h> 22 #include <SkSurface.h> 23 24 using namespace std; 25 26 namespace android { 27 namespace renderengine { 28 namespace skia { 29 30 class BlurFilter { 31 public: 32 // Downsample FBO to improve performance 33 static constexpr float kInputScale = 0.25f; 34 // Downsample scale factor used to improve performance 35 static constexpr float kInverseInputScale = 1.0f / kInputScale; 36 37 explicit BlurFilter(float maxCrossFadeRadius = 10.0f); ~BlurFilter()38 virtual ~BlurFilter(){} 39 40 // Execute blur, saving it to a texture 41 virtual sk_sp<SkImage> generate(GrRecordingContext* context, const uint32_t radius, 42 const sk_sp<SkImage> blurInput, const SkRect& blurRect) const = 0; 43 44 /** 45 * Draw the blurred content (from the generate method) into the canvas. 46 * @param canvas is the destination/output for the blur 47 * @param effectRegion the RoundRect in canvas coordinates that determines the blur coverage 48 * @param blurRadius radius of the blur used to determine the intensity of the crossfade effect 49 * @param blurAlpha alpha value applied to the effectRegion when the blur is drawn 50 * @param blurRect bounds of the blurredImage translated into canvas coordinates 51 * @param blurredImage down-sampled blurred content that was produced by the generate() method 52 * @param input original unblurred input that is used to crossfade with the blurredImage 53 */ 54 void drawBlurRegion(SkCanvas* canvas, const SkRRect& effectRegion, 55 const uint32_t blurRadius, const float blurAlpha, 56 const SkRect& blurRect, sk_sp<SkImage> blurredImage, 57 sk_sp<SkImage> input); 58 59 float getMaxCrossFadeRadius() const; 60 61 private: 62 // To avoid downscaling artifacts, we interpolate the blurred fbo with the full composited 63 // image, up to this radius. 64 const float mMaxCrossFadeRadius; 65 66 // Optional blend used for crossfade only if mMaxCrossFadeRadius > 0 67 const sk_sp<SkRuntimeEffect> mMixEffect; 68 }; 69 70 } // namespace skia 71 } // namespace renderengine 72 } // namespace android 73