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#include "pngfile.h"
#include <stdexcept>
PngFile::PngFile(const std::string& filename, size_t width, size_t height)
: _filename(filename), _width(width), _height(height), _pixelSize(4) {}
PngFile::~PngFile() {}
void PngFile::BeginWrite() {
_fp = fopen(_filename.c_str(), "wb");
if (!_fp) throw std::runtime_error("Can not open file");
_png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, (png_voidp) nullptr,
nullptr, nullptr);
if (!_png_ptr) {
fclose(_fp);
throw std::runtime_error("Can not create png write structure");
}
_info_ptr = png_create_info_struct(_png_ptr);
if (!_info_ptr) {
png_destroy_write_struct(&_png_ptr, (png_infopp) nullptr);
fclose(_fp);
throw std::runtime_error("Can not write info structure to file");
}
if (setjmp(png_jmpbuf(_png_ptr))) {
png_destroy_write_struct(&_png_ptr, &_info_ptr);
fclose(_fp);
throw std::runtime_error(
"Unknown error occured during writing of png file");
}
png_init_io(_png_ptr, _fp);
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);
_row_pointers = (png_bytep*)png_malloc(_png_ptr, _height * sizeof(png_bytep));
for (size_t i = 0; i < _height; i++)
_row_pointers[i] = (png_bytep)png_malloc(_png_ptr, _width * _pixelSize);
}
void PngFile::Close() {
png_set_rows(_png_ptr, _info_ptr, _row_pointers);
png_write_png(_png_ptr, _info_ptr, PNG_TRANSFORM_IDENTITY, nullptr);
png_write_end(_png_ptr, _info_ptr);
for (unsigned i = 0; i < _height; i++) png_free(_png_ptr, _row_pointers[i]);
png_free(_png_ptr, _row_pointers);
png_destroy_write_struct(&_png_ptr, &_info_ptr);
fclose(_fp);
}
void PngFile::Clear(int colorR, int colorG, int colorB, int colorA) {
for (size_t y = 0; y < _height; y++) {
int xa = 0;
for (unsigned x = 0; x < _width; x++) {
_row_pointers[y][xa++] = colorR;
_row_pointers[y][xa++] = colorG;
_row_pointers[y][xa++] = colorB;
_row_pointers[y][xa++] = colorA;
}
}
}
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