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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 <utils/Blur.h>
     20 
     21 #include <SkColorFilter.h>
     22 #include <SkDrawLooper.h>
     23 #include <SkShader.h>
     24 
     25 namespace android {
     26 namespace uirenderer {
     27 
     28 /**
     29  * Utility methods for accessing data within SkPaint, and providing defaults
     30  * with optional SkPaint pointers.
     31  */
     32 class PaintUtils {
     33 public:
     34 
     35     static inline GLenum getFilter(const SkPaint* paint) {
     36         if (!paint || paint->getFilterQuality() != kNone_SkFilterQuality) {
     37             return GL_LINEAR;
     38         }
     39         return GL_NEAREST;
     40     }
     41 
     42     static bool isOpaquePaint(const SkPaint* paint) {
     43         if (!paint) return true; // default (paintless) behavior is SrcOver, black
     44 
     45         if (paint->getAlpha() != 0xFF
     46                 || 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
     54                 || mode == SkBlendMode::kSrc;
     55     }
     56 
     57     static bool isBlendedShader(const SkShader* shader) {
     58         if (shader == nullptr) {
     59             return false;
     60         }
     61         return !shader->isOpaque();
     62     }
     63 
     64     static bool isBlendedColorFilter(const SkColorFilter* filter) {
     65         if (filter == nullptr) {
     66             return false;
     67         }
     68         return (filter->getFlags() & SkColorFilter::kAlphaUnchanged_Flag) == 0;
     69     }
     70 
     71     struct TextShadow {
     72         SkScalar radius;
     73         float dx;
     74         float dy;
     75         SkColor color;
     76     };
     77 
     78     static inline bool getTextShadow(const SkPaint* paint, TextShadow* textShadow) {
     79         SkDrawLooper::BlurShadowRec blur;
     80         if (paint && paint->getLooper() && paint->getLooper()->asABlurShadow(&blur)) {
     81             if (textShadow) {
     82                 textShadow->radius = Blur::convertSigmaToRadius(blur.fSigma);
     83                 textShadow->dx = blur.fOffset.fX;
     84                 textShadow->dy = blur.fOffset.fY;
     85                 textShadow->color = blur.fColor;
     86             }
     87             return true;
     88         }
     89         return false;
     90     }
     91 
     92     static inline bool hasTextShadow(const SkPaint* paint) {
     93         return getTextShadow(paint, nullptr);
     94     }
     95 
     96     static inline SkBlendMode getBlendModeDirect(const SkPaint* paint) {
     97         return paint ? paint->getBlendMode() : SkBlendMode::kSrcOver;
     98     }
     99 
    100     static inline int getAlphaDirect(const SkPaint* paint) {
    101         return paint ? paint->getAlpha() : 255;
    102     }
    103 
    104 }; // class PaintUtils
    105 
    106 } /* namespace uirenderer */
    107 } /* namespace android */
    108 
    109 #endif /* PAINT_UTILS_H */
    110