1 /*
2  * Copyright (c) 2021-2023 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef SCALAR_H
17 #define SCALAR_H
18 
19 #include <cmath>
20 #include <limits>
21 
22 namespace OHOS {
23 namespace Rosen {
24 namespace Drawing {
25 typedef float scalar;
26 static const scalar SCALAR_ONE = 1.0f;
27 static const scalar BLUR_SIGMA_SCALE = 0.57735f;
28 static const scalar FLOAT_PI = 3.14159265f;
29 
IsScalarAlmostEqual(scalar a,scalar b)30 inline bool IsScalarAlmostEqual(scalar a, scalar b)
31 {
32     return fabs(a - b) < std::numeric_limits<scalar>::min();
33 }
34 
ConvertRadiusToSigma(scalar radius)35 inline scalar ConvertRadiusToSigma(scalar radius)
36 {
37     return radius > 0 ? BLUR_SIGMA_SCALE * radius + 0.5f : 0.0f;
38 }
39 
ConvertSigmaToRadius(scalar sigma)40 inline scalar ConvertSigmaToRadius(scalar sigma)
41 {
42     return sigma > 0.5f ? (sigma - 0.5f) / BLUR_SIGMA_SCALE : 0.0f;
43 }
44 
45 /**
46  * @param radians Radians values.
47  * @return Return degrees values.
48  */
ConvertRadiansToDegrees(scalar radians)49 inline scalar ConvertRadiansToDegrees(scalar radians)
50 {
51     return radians * (180 / FLOAT_PI);
52 }
53 } // namespace Drawing
54 } // namespace Rosen
55 } // namespace OHOS
56 #endif
57