1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
|
#include <llmr/util/image.hpp>
#include <png.h>
std::string llmr::util::compress_png(int width, int height, void *rgba, bool flip) {
png_voidp error_ptr = 0;
png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, error_ptr, NULL, NULL);
if (!png_ptr) {
fprintf(stderr, "Couldn't create png_ptr\n");
return "";
}
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!png_ptr) {
png_destroy_write_struct(&png_ptr, (png_infopp)0);
fprintf(stderr, "Couldn't create info_ptr\n");
return "";
}
png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
jmp_buf *jmp_context = (jmp_buf *)png_get_error_ptr(png_ptr);
if (jmp_context) {
png_destroy_write_struct(&png_ptr, &info_ptr);
return "";
}
std::string result;
png_set_write_fn(png_ptr, &result, [](png_structp png_ptr, png_bytep data, png_size_t length) {
std::string *out = static_cast<std::string *>(png_get_io_ptr(png_ptr));
out->append(reinterpret_cast<char *>(data), length);
}, NULL);
struct ptrs {
ptrs(size_t count) : rows(new png_bytep[count]) {}
~ptrs() { delete[] rows; }
png_bytep *rows = nullptr;
} pointers(height);
for (int i = 0; i < height; i++) {
pointers.rows[flip ? height - 1 - i : i] = (png_bytep)((png_bytep)rgba + width * 4 * i);
}
png_set_rows(png_ptr, info_ptr, pointers.rows);
png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
png_destroy_write_struct(&png_ptr, &info_ptr);
return result;
}
|
