1 // Copyright 2019 The Amber Authors.
2 //
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 #include "samples/png.h"
16
17 #include <cassert>
18
19 #include "amber/result.h"
20 #include "amber/value.h"
21
22 #pragma clang diagnostic push
23 #pragma clang diagnostic ignored "-Wweak-vtables"
24 #include "third_party/lodepng/lodepng.h"
25 #pragma clang diagnostic pop
26
27 namespace png {
28
29 namespace {
30
byte0(uint32_t word)31 unsigned char byte0(uint32_t word) {
32 return static_cast<unsigned char>(word);
33 }
34
byte1(uint32_t word)35 unsigned char byte1(uint32_t word) {
36 return static_cast<unsigned char>(word >> 8);
37 }
38
byte2(uint32_t word)39 unsigned char byte2(uint32_t word) {
40 return static_cast<unsigned char>(word >> 16);
41 }
42
byte3(uint32_t word)43 unsigned char byte3(uint32_t word) {
44 return static_cast<unsigned char>(word >> 24);
45 }
46
47 } // namespace
48
ConvertToPNG(uint32_t width,uint32_t height,const std::vector<amber::Value> & values,std::vector<uint8_t> * buffer)49 amber::Result ConvertToPNG(uint32_t width,
50 uint32_t height,
51 const std::vector<amber::Value>& values,
52 std::vector<uint8_t>* buffer) {
53 assert(values.size() == (width * height) &&
54 "Buffer values != width * height");
55 assert(!values.empty() && "Buffer empty");
56
57 std::vector<uint8_t> data;
58
59 // Prepare data as lodepng expects it
60 for (const amber::Value& value : values) {
61 const uint32_t pixel = value.AsUint32();
62 data.push_back(byte2(pixel)); // R
63 data.push_back(byte1(pixel)); // G
64 data.push_back(byte0(pixel)); // B
65 data.push_back(byte3(pixel)); // A
66 }
67
68 lodepng::State state;
69
70 // Force RGBA color type, otherwise many PNG decoders will ignore the alpha
71 // channel.
72 state.encoder.auto_convert = 0;
73 state.info_raw.colortype = LodePNGColorType::LCT_RGBA;
74 state.info_raw.bitdepth = 8;
75 state.info_png.color.colortype = LodePNGColorType::LCT_RGBA;
76 state.info_png.color.bitdepth = 8;
77
78 if (lodepng::encode(*buffer, data, width, height, state) != 0)
79 return amber::Result("lodepng::encode() returned non-zero");
80
81 return {};
82 }
83
LoadPNG(const std::string file_name,uint32_t * width,uint32_t * height,std::vector<amber::Value> * values)84 amber::Result LoadPNG(const std::string file_name,
85 uint32_t* width,
86 uint32_t* height,
87 std::vector<amber::Value>* values) {
88 std::vector<uint8_t> decoded_buffer;
89 if (lodepng::decode(decoded_buffer, *width, *height, file_name,
90 LodePNGColorType::LCT_RGBA, 8) != 0) {
91 return amber::Result("lodepng::decode() returned non-zero");
92 }
93
94 for (auto d : decoded_buffer) {
95 amber::Value v;
96 v.SetIntValue(d);
97 values->push_back(v);
98 }
99
100 return {};
101 }
102
103 } // namespace png
104