1 //
2 // Copyright 2020 The ANGLE Project Authors. All rights reserved.
3 // Use of this source code is governed by a BSD-style license that can be
4 // found in the LICENSE file.
5 //
6 // png_utils: Wrapper around libpng.
7 //
8
9 #include "util/png_utils.h"
10
11 #include <array>
12 #include <cstring>
13
14 #include <png.h>
15
16 namespace angle
17 {
18 namespace
19 {
20 class ScopedFILE
21 {
22 public:
ScopedFILE(FILE * fp)23 ScopedFILE(FILE *fp) : mFP(fp) {}
~ScopedFILE()24 ~ScopedFILE() { close(); }
25
get() const26 FILE *get() const { return mFP; }
27
close()28 void close()
29 {
30 if (mFP)
31 {
32 fclose(mFP);
33 mFP = nullptr;
34 }
35 }
36
37 private:
38 FILE *mFP;
39 };
40 } // namespace
41
SavePNGRGB(const char * fileName,const char * title,uint32_t width,uint32_t height,const std::vector<uint8_t> & data)42 bool SavePNGRGB(const char *fileName,
43 const char *title,
44 uint32_t width,
45 uint32_t height,
46 const std::vector<uint8_t> &data)
47 {
48 ScopedFILE fp(fopen(fileName, "wb"));
49 if (!fp.get())
50 {
51 fprintf(stderr, "Error opening '%s'.\n", fileName);
52 return false;
53 }
54
55 png_struct *writeStruct =
56 png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
57 if (!writeStruct)
58 {
59 fprintf(stderr, "Error on png_create_write_struct.\n");
60 return false;
61 }
62
63 png_info *infoStruct = png_create_info_struct(writeStruct);
64 if (!infoStruct)
65 {
66 fprintf(stderr, "Error on png_create_info_struct.\n");
67 return false;
68 }
69
70 if (setjmp(png_jmpbuf(writeStruct)))
71 {
72 fp.close();
73 png_free_data(writeStruct, infoStruct, PNG_FREE_ALL, -1);
74 png_destroy_write_struct(&writeStruct, &infoStruct);
75 return false;
76 }
77
78 png_init_io(writeStruct, fp.get());
79
80 // Write header (8 bit colour depth)
81 png_set_IHDR(writeStruct, infoStruct, width, height, 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
82 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
83
84 // Set title
85 if (title != nullptr && strlen(title) > 0)
86 {
87 std::array<char, 50> mutableKey = {};
88 strcpy(mutableKey.data(), "Title");
89 std::array<char, 200> mutableText = {};
90 strncpy(mutableText.data(), title, 199);
91
92 png_text titleText;
93 titleText.compression = PNG_TEXT_COMPRESSION_NONE;
94 titleText.key = mutableKey.data();
95 titleText.text = mutableText.data();
96 png_set_text(writeStruct, infoStruct, &titleText, 1);
97 }
98
99 png_write_info(writeStruct, infoStruct);
100
101 // RGB 3-byte stride.
102 const uint32_t rowStride = width * 3;
103 for (uint32_t row = 0; row < height; ++row)
104 {
105 uint32_t rowOffset = row * rowStride;
106 png_write_row(writeStruct, &data[rowOffset]);
107 }
108
109 png_write_end(writeStruct, infoStruct);
110
111 fp.close();
112 png_free_data(writeStruct, infoStruct, PNG_FREE_ALL, -1);
113 png_destroy_write_struct(&writeStruct, &infoStruct);
114 return true;
115 }
116 } // namespace angle
117