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:
getFilter(const SkPaint * paint)34     static inline GLenum getFilter(const SkPaint* paint) {
35         if (!paint || paint->getFilterQuality() != kNone_SkFilterQuality) {
36             return GL_LINEAR;
37         }
38         return GL_NEAREST;
39     }
40 
isOpaquePaint(const SkPaint * paint)41     static bool isOpaquePaint(const SkPaint* paint) {
42         if (!paint) return true;  // default (paintless) behavior is SrcOver, black
43 
44         if (paint->getAlpha() != 0xFF || PaintUtils::isBlendedShader(paint->getShader()) ||
45             PaintUtils::isBlendedColorFilter(paint->getColorFilter())) {
46             return false;
47         }
48 
49         // Only let simple srcOver / src blending modes declare opaque, since behavior is clear.
50         SkBlendMode mode = paint->getBlendMode();
51         return mode == SkBlendMode::kSrcOver || mode == SkBlendMode::kSrc;
52     }
53 
isBlendedShader(const SkShader * shader)54     static bool isBlendedShader(const SkShader* shader) {
55         if (shader == nullptr) {
56             return false;
57         }
58         return !shader->isOpaque();
59     }
60 
isBlendedColorFilter(const SkColorFilter * filter)61     static bool isBlendedColorFilter(const SkColorFilter* filter) {
62         if (filter == nullptr) {
63             return false;
64         }
65         return (filter->getFlags() & SkColorFilter::kAlphaUnchanged_Flag) == 0;
66     }
67 
68     struct TextShadow {
69         SkScalar radius;
70         float dx;
71         float dy;
72         SkColor color;
73     };
74 
getTextShadow(const SkPaint * paint,TextShadow * textShadow)75     static inline bool getTextShadow(const SkPaint* paint, TextShadow* textShadow) {
76         SkDrawLooper::BlurShadowRec blur;
77         if (paint && paint->getLooper() && paint->getLooper()->asABlurShadow(&blur)) {
78             if (textShadow) {
79                 textShadow->radius = Blur::convertSigmaToRadius(blur.fSigma);
80                 textShadow->dx = blur.fOffset.fX;
81                 textShadow->dy = blur.fOffset.fY;
82                 textShadow->color = blur.fColor;
83             }
84             return true;
85         }
86         return false;
87     }
88 
hasTextShadow(const SkPaint * paint)89     static inline bool hasTextShadow(const SkPaint* paint) { return getTextShadow(paint, nullptr); }
90 
getBlendModeDirect(const SkPaint * paint)91     static inline SkBlendMode getBlendModeDirect(const SkPaint* paint) {
92         return paint ? paint->getBlendMode() : SkBlendMode::kSrcOver;
93     }
94 
getAlphaDirect(const SkPaint * paint)95     static inline int getAlphaDirect(const SkPaint* paint) {
96         return paint ? paint->getAlpha() : 255;
97     }
98 
99 };  // class PaintUtils
100 
101 } /* namespace uirenderer */
102 } /* namespace android */
103 
104 #endif /* PAINT_UTILS_H */
105