2024-11-06 06:46:35 +08:00

288 lines
13 KiB
C++

#pragma once
#pragma pack(push, 1)
struct BMPFileHeader {
uint16_t file_type{ 0x4D42 }; // File type always BM which is 0x4D42 (stored as hex uint16_t in little endian)
uint32_t file_size{ 0 }; // Size of the file (in bytes)
uint16_t reserved1{ 0 }; // Reserved, always 0
uint16_t reserved2{ 0 }; // Reserved, always 0
uint32_t offset_data{ 0 }; // Start position of pixel data (bytes from the beginning of the file)
};
struct BMPInfoHeader {
uint32_t size{ 0 }; // Size of this header (in bytes)
int32_t width{ 0 }; // width of bitmap in pixels
int32_t height{ 0 }; // width of bitmap in pixels
// (if positive, bottom-up, with origin in lower left corner)
// (if negative, top-down, with origin in upper left corner)
uint16_t planes{ 1 }; // No. of planes for the target device, this is always 1
uint16_t bit_count{ 0 }; // No. of bits per pixel
uint32_t compression{ 0 }; // 0 or 3 - uncompressed. THIS PROGRAM CONSIDERS ONLY UNCOMPRESSED BMP images
uint32_t size_image{ 0 }; // 0 - for uncompressed images
int32_t x_pixels_per_meter{ 0 };
int32_t y_pixels_per_meter{ 0 };
uint32_t colors_used{ 0 }; // No. color indexes in the color table. Use 0 for the max number of colors allowed by bit_count
uint32_t colors_important{ 0 }; // No. of colors used for displaying the bitmap. If 0 all colors are required
};
struct BMPColorHeader {
uint32_t red_mask{ 0x00ff0000 }; // Bit mask for the red channel
uint32_t green_mask{ 0x0000ff00 }; // Bit mask for the green channel
uint32_t blue_mask{ 0x000000ff }; // Bit mask for the blue channel
uint32_t alpha_mask{ 0xff000000 }; // Bit mask for the alpha channel
uint32_t color_space_type{ 0x73524742 }; // Default "sRGB" (0x73524742)
uint32_t unused[16]{ 0 }; // Unused data for sRGB color space
};
#pragma pack(pop)
struct BMP {
BMPFileHeader file_header;
BMPInfoHeader bmp_info_header;
BMPColorHeader bmp_color_header;
std::vector<uint8_t> data;
BMP(const char *fname) {
read(fname);
}
void read(const char *fname) {
std::ifstream inp{ fname, std::ios_base::binary };
if (inp) {
inp.read((char*)&file_header, sizeof(file_header));
if(file_header.file_type != 0x4D42) {
throw std::runtime_error("Error! Unrecognized file format.");
}
inp.read((char*)&bmp_info_header, sizeof(bmp_info_header));
// The BMPColorHeader is used only for transparent images
if(bmp_info_header.bit_count == 32) {
// Check if the file has bit mask color information
if(bmp_info_header.size >= (sizeof(BMPInfoHeader) + sizeof(BMPColorHeader))) {
inp.read((char*)&bmp_color_header, sizeof(bmp_color_header));
// Check if the pixel data is stored as BGRA and if the color space type is sRGB
check_color_header(bmp_color_header);
} else {
std::cerr << "Error! The file \"" << fname << "\" does not seem to contain bit mask information\n";
throw std::runtime_error("Error! Unrecognized file format.");
}
}
// Jump to the pixel data location
inp.seekg(file_header.offset_data, inp.beg);
// Adjust the header fields for output.
// Some editors will put extra info in the image file, we only save the headers and the data.
if(bmp_info_header.bit_count == 32) {
bmp_info_header.size = sizeof(BMPInfoHeader) + sizeof(BMPColorHeader);
file_header.offset_data = sizeof(BMPFileHeader) + sizeof(BMPInfoHeader) + sizeof(BMPColorHeader);
} else {
bmp_info_header.size = sizeof(BMPInfoHeader);
file_header.offset_data = sizeof(BMPFileHeader) + sizeof(BMPInfoHeader);
}
file_header.file_size = file_header.offset_data;
if (bmp_info_header.height < 0) {
throw std::runtime_error("The program can treat only BMP images with the origin in the bottom left corner!");
}
data.resize(bmp_info_header.width * bmp_info_header.height * bmp_info_header.bit_count / 8);
// Here we check if we need to take into account row padding
if (bmp_info_header.width % 4 == 0) {
inp.read((char*)data.data(), data.size());
file_header.file_size += static_cast<uint32_t>(data.size());
}
else {
row_stride = bmp_info_header.width * bmp_info_header.bit_count / 8;
uint32_t new_stride = make_stride_aligned(4);
std::vector<uint8_t> padding_row(new_stride - row_stride);
for (int y = 0; y < bmp_info_header.height; ++y) {
inp.read((char*)(data.data() + row_stride * y), row_stride);
inp.read((char*)padding_row.data(), padding_row.size());
}
file_header.file_size += static_cast<uint32_t>(data.size()) + bmp_info_header.height * static_cast<uint32_t>(padding_row.size());
}
}
else {
throw std::runtime_error("Unable to open the input image file.");
}
}
BMP(int32_t width, int32_t height, bool has_alpha = true) {
if (width <= 0 || height <= 0) {
throw std::runtime_error("The image width and height must be positive numbers.");
}
bmp_info_header.width = width;
bmp_info_header.height = height;
if (has_alpha) {
bmp_info_header.size = sizeof(BMPInfoHeader) + sizeof(BMPColorHeader);
file_header.offset_data = sizeof(BMPFileHeader) + sizeof(BMPInfoHeader) + sizeof(BMPColorHeader);
bmp_info_header.bit_count = 32;
bmp_info_header.compression = 3;
row_stride = width * 4;
data.resize(row_stride * height);
file_header.file_size = file_header.offset_data + data.size();
}
else {
bmp_info_header.size = sizeof(BMPInfoHeader);
file_header.offset_data = sizeof(BMPFileHeader) + sizeof(BMPInfoHeader);
bmp_info_header.bit_count = 24;
bmp_info_header.compression = 0;
row_stride = width * 3;
data.resize(row_stride * height);
uint32_t new_stride = make_stride_aligned(4);
file_header.file_size = file_header.offset_data + static_cast<uint32_t>(data.size()) + bmp_info_header.height * (new_stride - row_stride);
}
}
void write_tomem(std::string &of) {
if (bmp_info_header.bit_count == 32) {
write_headers_and_data_tomem(of);
}
else if (bmp_info_header.bit_count == 24) {
if (bmp_info_header.width % 4 == 0) {
write_headers_and_data_tomem(of);
}
else {
uint32_t new_stride = make_stride_aligned(4);
std::vector<uint8_t> padding_row(new_stride - row_stride);
write_headers_tomem(of);
for (int y = 0; y < bmp_info_header.height; ++y) {
of.append(std::move(std::string((const char*)(data.data() + row_stride * y), row_stride)));
of.append(std::move(std::string((const char*)padding_row.data(), padding_row.size())));
}
}
}
}
void write(const char *fname) {
std::ofstream of{ fname, std::ios_base::binary };
if (of) {
if (bmp_info_header.bit_count == 32) {
write_headers_and_data(of);
}
else if (bmp_info_header.bit_count == 24) {
if (bmp_info_header.width % 4 == 0) {
write_headers_and_data(of);
}
else {
uint32_t new_stride = make_stride_aligned(4);
std::vector<uint8_t> padding_row(new_stride - row_stride);
write_headers(of);
for (int y = 0; y < bmp_info_header.height; ++y) {
of.write((const char*)(data.data() + row_stride * y), row_stride);
of.write((const char*)padding_row.data(), padding_row.size());
}
}
}
else {
throw std::runtime_error("The program can treat only 24 or 32 bits per pixel BMP files");
}
}
else {
throw std::runtime_error("Unable to open the output image file.");
}
}
void fill_region(uint32_t x0, uint32_t y0, uint32_t w, uint32_t h, uint8_t B, uint8_t G, uint8_t R, uint8_t A) {
if (x0 + w > (uint32_t)bmp_info_header.width || y0 + h > (uint32_t)bmp_info_header.height) {
throw std::runtime_error("The region does not fit in the image!");
}
uint32_t channels = bmp_info_header.bit_count / 8;
for (uint32_t y = y0; y < y0 + h; ++y) {
for (uint32_t x = x0; x < x0 + w; ++x) {
data[channels * (y * bmp_info_header.width + x) + 0] = B;
data[channels * (y * bmp_info_header.width + x) + 1] = G;
data[channels * (y * bmp_info_header.width + x) + 2] = R;
if (channels == 4) {
data[channels * (y * bmp_info_header.width + x) + 3] = A;
}
}
}
}
void set_pixel(uint32_t x0, uint32_t y0, uint8_t B, uint8_t G, uint8_t R, uint8_t A) {
if (x0 >= (uint32_t)bmp_info_header.width || y0 >= (uint32_t)bmp_info_header.height || x0 < 0 || y0 < 0) {
throw std::runtime_error("The point is outside the image boundaries!");
}
uint32_t channels = bmp_info_header.bit_count / 8;
data[channels * (y0 * bmp_info_header.width + x0) + 0] = B;
data[channels * (y0 * bmp_info_header.width + x0) + 1] = G;
data[channels * (y0 * bmp_info_header.width + x0) + 2] = R;
if (channels == 4) {
data[channels * (y0 * bmp_info_header.width + x0) + 3] = A;
}
}
void draw_rectangle(uint32_t x0, uint32_t y0, uint32_t w, uint32_t h,
uint8_t B, uint8_t G, uint8_t R, uint8_t A, uint8_t line_w) {
if (x0 + w > (uint32_t)bmp_info_header.width || y0 + h > (uint32_t)bmp_info_header.height) {
throw std::runtime_error("The rectangle does not fit in the image!");
}
fill_region(x0, y0, w, line_w, B, G, R, A); // top line
fill_region(x0, (y0 + h - line_w), w, line_w, B, G, R, A); // bottom line
fill_region((x0 + w - line_w), (y0 + line_w), line_w, (h - (2 * line_w)), B, G, R, A); // right line
fill_region(x0, (y0 + line_w), line_w, (h - (2 * line_w)), B, G, R, A); // left line
}
private:
uint32_t row_stride{ 0 };
void write_headers_tomem(std::string& of) {
of.append(std::move(std::string((const char*)&file_header, sizeof(file_header))));
of.append(std::move(std::string((const char*)&bmp_info_header, sizeof(bmp_info_header))));
if (bmp_info_header.bit_count == 32) {
of.append(std::move(std::string((const char*)&bmp_color_header, sizeof(bmp_color_header))));
}
}
void write_headers(std::ofstream &of) {
of.write((const char*)&file_header, sizeof(file_header));
of.write((const char*)&bmp_info_header, sizeof(bmp_info_header));
if(bmp_info_header.bit_count == 32) {
of.write((const char*)&bmp_color_header, sizeof(bmp_color_header));
}
}
void write_headers_and_data_tomem(std::string& of) {
write_headers_tomem(of);
of.append(std::move(std::string((const char*)data.data(), data.size())));
}
void write_headers_and_data(std::ofstream &of) {
write_headers(of);
of.write((const char*)data.data(), data.size());
}
// Add 1 to the row_stride until it is divisible with align_stride
uint32_t make_stride_aligned(uint32_t align_stride) {
uint32_t new_stride = row_stride;
while (new_stride % align_stride != 0) {
new_stride++;
}
return new_stride;
}
// Check if the pixel data is stored as BGRA and if the color space type is sRGB
void check_color_header(BMPColorHeader &bmp_color_header) {
BMPColorHeader expected_color_header;
if(expected_color_header.red_mask != bmp_color_header.red_mask ||
expected_color_header.blue_mask != bmp_color_header.blue_mask ||
expected_color_header.green_mask != bmp_color_header.green_mask ||
expected_color_header.alpha_mask != bmp_color_header.alpha_mask) {
throw std::runtime_error("Unexpected color mask format! The program expects the pixel data to be in the BGRA format");
}
if(expected_color_header.color_space_type != bmp_color_header.color_space_type) {
throw std::runtime_error("Unexpected color space type! The program expects sRGB values");
}
}
};