51 lines
1.6 KiB
C++
51 lines
1.6 KiB
C++
#include <llmr/util/image.hpp>
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#include <png.h>
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std::string llmr::util::compress_png(int width, int height, void *rgba) {
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png_voidp error_ptr = 0;
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png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, error_ptr, NULL, NULL);
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if (!png_ptr) {
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fprintf(stderr, "Couldn't create png_ptr\n");
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return "";
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}
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png_infop info_ptr = png_create_info_struct(png_ptr);
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if (!png_ptr) {
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png_destroy_write_struct(&png_ptr, (png_infopp)0);
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fprintf(stderr, "Couldn't create info_ptr\n");
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return "";
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}
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png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
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PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
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jmp_buf *jmp_context = (jmp_buf *)png_get_error_ptr(png_ptr);
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if (jmp_context) {
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png_destroy_write_struct(&png_ptr, &info_ptr);
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return "";
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}
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std::string result;
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png_set_write_fn(png_ptr, &result, [](png_structp png_ptr, png_bytep data, png_size_t length) {
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std::string *out = static_cast<std::string *>(png_get_io_ptr(png_ptr));
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out->append(reinterpret_cast<char *>(data), length);
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}, NULL);
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struct ptrs {
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ptrs(size_t count) : rows(new png_bytep[count]) {}
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~ptrs() { delete[] rows; }
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png_bytep *rows = nullptr;
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} pointers(height);
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for (int i = 0; i < height; i++) {
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pointers.rows[i] = (png_bytep)((png_bytep)rgba + width * 4 * i);
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}
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png_set_rows(png_ptr, info_ptr, pointers.rows);
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png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
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png_destroy_write_struct(&png_ptr, &info_ptr);
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return result;
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}
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