1 /*
2  * Copyright 2021 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 #include "ColorSpaces.h"
18 
19 namespace android {
20 namespace renderengine {
21 namespace skia {
22 
23 // please keep in sync with hwui/utils/Color.cpp
24 // TODO: Scale by the dimming ratio here instead of in a generic 3x3 transform
25 // Otherwise there may be luminance shift for e.g., HLG.
toSkColorSpace(ui::Dataspace dataspace)26 sk_sp<SkColorSpace> toSkColorSpace(ui::Dataspace dataspace) {
27     skcms_Matrix3x3 gamut;
28     switch (dataspace & HAL_DATASPACE_STANDARD_MASK) {
29         case HAL_DATASPACE_STANDARD_BT709:
30             gamut = SkNamedGamut::kSRGB;
31             break;
32         case HAL_DATASPACE_STANDARD_BT2020:
33             gamut = SkNamedGamut::kRec2020;
34             break;
35         case HAL_DATASPACE_STANDARD_DCI_P3:
36             gamut = SkNamedGamut::kDisplayP3;
37             break;
38         case HAL_DATASPACE_STANDARD_ADOBE_RGB:
39             gamut = SkNamedGamut::kAdobeRGB;
40             break;
41         case HAL_DATASPACE_STANDARD_BT601_625:
42         case HAL_DATASPACE_STANDARD_BT601_625_UNADJUSTED:
43         case HAL_DATASPACE_STANDARD_BT601_525:
44         case HAL_DATASPACE_STANDARD_BT601_525_UNADJUSTED:
45         case HAL_DATASPACE_STANDARD_BT2020_CONSTANT_LUMINANCE:
46         case HAL_DATASPACE_STANDARD_BT470M:
47         case HAL_DATASPACE_STANDARD_FILM:
48         case HAL_DATASPACE_STANDARD_UNSPECIFIED:
49         default:
50             gamut = SkNamedGamut::kSRGB;
51             break;
52     }
53 
54     switch (dataspace & HAL_DATASPACE_TRANSFER_MASK) {
55         case HAL_DATASPACE_TRANSFER_LINEAR:
56             return SkColorSpace::MakeRGB(SkNamedTransferFn::kLinear, gamut);
57         case HAL_DATASPACE_TRANSFER_SRGB:
58             return SkColorSpace::MakeRGB(SkNamedTransferFn::kSRGB, gamut);
59         case HAL_DATASPACE_TRANSFER_GAMMA2_2:
60             return SkColorSpace::MakeRGB({2.2f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut);
61         case HAL_DATASPACE_TRANSFER_GAMMA2_6:
62             return SkColorSpace::MakeRGB({2.6f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut);
63         case HAL_DATASPACE_TRANSFER_GAMMA2_8:
64             return SkColorSpace::MakeRGB({2.8f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f}, gamut);
65         case HAL_DATASPACE_TRANSFER_ST2084:
66             return SkColorSpace::MakeRGB({-2.f, -1.55522297832f, 1.86045365631f, 32 / 2523.0f,
67                                           2413 / 128.0f, -2392 / 128.0f, 8192 / 1305.0f},
68                                          gamut);
69         case HAL_DATASPACE_TRANSFER_SMPTE_170M:
70             return SkColorSpace::MakeRGB(SkNamedTransferFn::kRec2020, gamut);
71         case HAL_DATASPACE_TRANSFER_HLG:
72             skcms_TransferFunction hlgFn;
73             if (skcms_TransferFunction_makeScaledHLGish(&hlgFn, 0.314509843, 2.f, 2.f,
74                                                         1.f / 0.17883277f, 0.28466892f,
75                                                         0.55991073f)) {
76                 return SkColorSpace::MakeRGB(hlgFn, gamut);
77             } else {
78                 return SkColorSpace::MakeRGB(SkNamedTransferFn::kSRGB, gamut);
79             }
80         case HAL_DATASPACE_TRANSFER_UNSPECIFIED:
81         default:
82             return SkColorSpace::MakeRGB(SkNamedTransferFn::kSRGB, gamut);
83     }
84 }
85 
86 } // namespace skia
87 } // namespace renderengine
88 } // namespace android