1 /*
2  * Copyright (C) 2013 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 #ifndef ANDROID_HWUI_BLUR_H
18 #define ANDROID_HWUI_BLUR_H
19 
20 #include <cutils/compiler.h>
21 #include <stdint.h>
22 
23 namespace android {
24 namespace uirenderer {
25 
26 class Blur {
27 public:
28     // If radius > 0, return the corresponding sigma, else return 0
29     ANDROID_API static float convertRadiusToSigma(float radius);
30     // If sigma > 0.5, return the corresponding radius, else return 0
31     ANDROID_API static float convertSigmaToRadius(float sigma);
32     // If the original radius was on an integer boundary then after the sigma to
33     // radius conversion a small rounding error may be introduced. This function
34     // accounts for that error and snaps to the appropriate integer boundary.
35     static uint32_t convertRadiusToInt(float radius);
36 
37     static void generateGaussianWeights(float* weights, float radius);
38     static void horizontal(float* weights, int32_t radius, const uint8_t* source, uint8_t* dest,
39                            int32_t width, int32_t height);
40     static void vertical(float* weights, int32_t radius, const uint8_t* source, uint8_t* dest,
41                          int32_t width, int32_t height);
42 };
43 
44 }  // namespace uirenderer
45 }  // namespace android
46 
47 #endif  // ANDROID_HWUI_BLUR_H
48