#include #include #include #include "images/PNGReader.h" PNGReader::PNGReader(const char* path) : path(path), width(0), height(0), channels(0), bitDepth(0), rowBytes(0), file(fopen(path, "r")), read(nullptr), info(nullptr), rowPointers(nullptr) { if(file == nullptr) { std::cout << "file '" << path << "' cannot be read: " << strerror(errno) << "\n"; return; } if(checkSignature()) { return; } read = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr); if(read == nullptr) { std::cout << "cannot create png read data structure\n"; return; } info = png_create_info_struct(read); if(info == nullptr) { std::cout << "cannot create png info structure\n"; return; } if(setjmp(png_jmpbuf(read))) { std::cout << "png file '" << path << "' has used error callback\n"; return; } png_init_io(read, file); png_set_sig_bytes(read, 8); png_read_info(read, info); png_set_expand(read); width = png_get_image_width(read, info); height = png_get_image_height(read, info); channels = png_get_channels(read, info); bitDepth = png_get_bit_depth(read, info); if(png_get_bit_depth(read, info) == 16) { png_set_strip_16(read); } rowBytes = png_get_rowbytes(read, info); } PNGReader::~PNGReader() { if(file != nullptr) { fclose(file); } if(rowPointers != nullptr) { png_free(read, rowPointers); } png_destroy_read_struct(&read, &info, nullptr); } int PNGReader::getWidth() const { return width; } int PNGReader::getHeight() const { return height; } int PNGReader::getChannels() const { return channels; } int PNGReader::getBufferSize() const { return width * height * channels; } bool PNGReader::hasError() const { if(channels < 1 || channels > 4) { std::cout << "'" << path << "' has unsupported number of channels: " << channels << "\n"; return true; } else if(width < 1 || width > 2048 || height < 1 || height > 2048) { std::cout << "width and height of '" << path << "' are too big\n"; return true; } else if(bitDepth != 8 && bitDepth != 16) { std::cout << "bit depth of '" << path << "' is neither 8 or 16\n"; return true; } else if(getBufferSize() != (rowBytes * height * 8 / bitDepth)) { std::cout << "'" << path << "' needs an unexpected buffer size\n"; return true; } return false; } bool PNGReader::checkSignature() { png_byte buffer[8]; if(fread(buffer, sizeof(png_byte), 8, file) != 8) { std::cout << "cannot read signature of file '" << path << "'\n"; return true; } if(png_sig_cmp(buffer, 0, 8)) { std::cout << "file '" << path << "' is not a png\n"; return true; } return false; } bool PNGReader::readData(ColorChannel* buffer) { if(setjmp(png_jmpbuf(read))) { std::cout << "png file '" << path << "' has used error callback\n"; return true; } rowPointers = static_cast( png_malloc(read, height * sizeof(ColorChannel*))); for(int i = 0; i < height; i++) { rowPointers[i] = (buffer + i * width * channels); } png_set_rows(read, info, reinterpret_cast(rowPointers)); png_read_image(read, reinterpret_cast(rowPointers)); return false; }