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      1 /*
      2  * Copyright (C) 2014 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 #ifndef PAINT_UTILS_H
     17 #define PAINT_UTILS_H
     18 
     19 #include <GLES2/gl2.h>
     20 #include <utils/Blur.h>
     21 
     22 #include <SkColorFilter.h>
     23 #include <SkDrawLooper.h>
     24 #include <SkPaint.h>
     25 #include <SkShader.h>
     26 
     27 namespace android {
     28 namespace uirenderer {
     29 
     30 /**
     31  * Utility methods for accessing data within SkPaint, and providing defaults
     32  * with optional SkPaint pointers.
     33  */
     34 class PaintUtils {
     35 public:
     36     static inline GLenum getFilter(const SkPaint* paint) {
     37         if (!paint || paint->getFilterQuality() != kNone_SkFilterQuality) {
     38             return GL_LINEAR;
     39         }
     40         return GL_NEAREST;
     41     }
     42 
     43     static bool isOpaquePaint(const SkPaint* paint) {
     44         if (!paint) return true;  // default (paintless) behavior is SrcOver, black
     45 
     46         if (paint->getAlpha() != 0xFF || PaintUtils::isBlendedShader(paint->getShader()) ||
     47             PaintUtils::isBlendedColorFilter(paint->getColorFilter())) {
     48             return false;
     49         }
     50 
     51         // Only let simple srcOver / src blending modes declare opaque, since behavior is clear.
     52         SkBlendMode mode = paint->getBlendMode();
     53         return mode == SkBlendMode::kSrcOver || mode == SkBlendMode::kSrc;
     54     }
     55 
     56     static bool isBlendedShader(const SkShader* shader) {
     57         if (shader == nullptr) {
     58             return false;
     59         }
     60         return !shader->isOpaque();
     61     }
     62 
     63     static bool isBlendedColorFilter(const SkColorFilter* filter) {
     64         if (filter == nullptr) {
     65             return false;
     66         }
     67         return (filter->getFlags() & SkColorFilter::kAlphaUnchanged_Flag) == 0;
     68     }
     69 
     70     struct TextShadow {
     71         SkScalar radius;
     72         float dx;
     73         float dy;
     74         SkColor color;
     75     };
     76 
     77     static inline bool getTextShadow(const SkPaint* paint, TextShadow* textShadow) {
     78         SkDrawLooper::BlurShadowRec blur;
     79         if (paint && paint->getLooper() && paint->getLooper()->asABlurShadow(&blur)) {
     80             if (textShadow) {
     81                 textShadow->radius = Blur::convertSigmaToRadius(blur.fSigma);
     82                 textShadow->dx = blur.fOffset.fX;
     83                 textShadow->dy = blur.fOffset.fY;
     84                 textShadow->color = blur.fColor;
     85             }
     86             return true;
     87         }
     88         return false;
     89     }
     90 
     91     static inline bool hasTextShadow(const SkPaint* paint) { return getTextShadow(paint, nullptr); }
     92 
     93     static inline SkBlendMode getBlendModeDirect(const SkPaint* paint) {
     94         return paint ? paint->getBlendMode() : SkBlendMode::kSrcOver;
     95     }
     96 
     97     static inline int getAlphaDirect(const SkPaint* paint) {
     98         return paint ? paint->getAlpha() : 255;
     99     }
    100 
    101 };  // class PaintUtils
    102 
    103 } /* namespace uirenderer */
    104 } /* namespace android */
    105 
    106 #endif /* PAINT_UTILS_H */
    107