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/*
* Copyright (c) 2020, Ben Jilks <benjyjilks@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibGfx/BMPWriter.h>
#include <LibGfx/Bitmap.h>
namespace Gfx {
class OutputStreamer {
public:
OutputStreamer(u8* data)
: m_data(data)
{
}
void write_u8(u8 i)
{
*(m_data++) = i;
}
void write_u16(u16 i)
{
*(m_data++) = i & 0xFF;
*(m_data++) = (i >> 8) & 0xFF;
}
void write_u32(u32 i)
{
write_u16(i & 0xFFFF);
write_u16((i >> 16) & 0xFFFF);
}
void write_i32(i32 i)
{
write_u32(static_cast<u32>(i));
}
private:
u8* m_data;
};
static ByteBuffer write_pixel_data(RefPtr<Bitmap> const bitmap, int pixel_row_data_size, int bytes_per_pixel, bool include_alpha_channel)
{
int image_size = pixel_row_data_size * bitmap->height();
auto buffer_result = ByteBuffer::create_uninitialized(image_size);
if (buffer_result.is_error())
return {};
auto buffer = buffer_result.release_value();
int current_row = 0;
for (int y = bitmap->physical_height() - 1; y >= 0; --y) {
auto* row = buffer.data() + (pixel_row_data_size * current_row++);
for (int x = 0; x < bitmap->physical_width(); x++) {
auto pixel = bitmap->get_pixel(x, y);
row[x * bytes_per_pixel + 0] = pixel.blue();
row[x * bytes_per_pixel + 1] = pixel.green();
row[x * bytes_per_pixel + 2] = pixel.red();
if (include_alpha_channel)
row[x * bytes_per_pixel + 3] = pixel.alpha();
}
}
return buffer;
}
static ByteBuffer compress_pixel_data(ByteBuffer const& pixel_data, BMPWriter::Compression compression)
{
switch (compression) {
case BMPWriter::Compression::BI_BITFIELDS:
case BMPWriter::Compression::BI_RGB:
return pixel_data;
}
VERIFY_NOT_REACHED();
}
ByteBuffer BMPWriter::dump(RefPtr<Bitmap> const bitmap, DibHeader dib_header)
{
switch (dib_header) {
case DibHeader::Info:
m_compression = Compression::BI_RGB;
m_bytes_per_pixel = 3;
m_include_alpha_channel = false;
break;
case DibHeader::V3:
case DibHeader::V4:
m_compression = Compression::BI_BITFIELDS;
m_bytes_per_pixel = 4;
m_include_alpha_channel = true;
}
const size_t file_header_size = 14;
size_t pixel_data_offset = file_header_size + (u32)dib_header;
int pixel_row_data_size = (m_bytes_per_pixel * 8 * bitmap->width() + 31) / 32 * 4;
int image_size = pixel_row_data_size * bitmap->height();
auto buffer_result = ByteBuffer::create_uninitialized(pixel_data_offset);
if (buffer_result.is_error())
return {};
auto buffer = buffer_result.release_value();
auto pixel_data = write_pixel_data(bitmap, pixel_row_data_size, m_bytes_per_pixel, m_include_alpha_channel);
pixel_data = compress_pixel_data(pixel_data, m_compression);
size_t file_size = pixel_data_offset + pixel_data.size();
OutputStreamer streamer(buffer.data());
streamer.write_u8('B');
streamer.write_u8('M');
streamer.write_u32(file_size);
streamer.write_u32(0);
streamer.write_u32(pixel_data_offset);
streamer.write_u32((u32)dib_header); // Header size
streamer.write_i32(bitmap->width()); // ImageWidth
streamer.write_i32(bitmap->height()); // ImageHeight
streamer.write_u16(1); // Planes
streamer.write_u16(m_bytes_per_pixel * 8); // BitsPerPixel
streamer.write_u32((u32)m_compression); // Compression
streamer.write_u32(image_size); // ImageSize
streamer.write_i32(0); // XpixelsPerMeter
streamer.write_i32(0); // YpixelsPerMeter
streamer.write_u32(0); // TotalColors
streamer.write_u32(0); // ImportantColors
if (dib_header == DibHeader::V3 || dib_header == DibHeader::V4) {
streamer.write_u32(0x00ff0000); // Red bitmask
streamer.write_u32(0x0000ff00); // Green bitmask
streamer.write_u32(0x000000ff); // Blue bitmask
streamer.write_u32(0xff000000); // Alpha bitmask
}
if (dib_header == DibHeader::V4) {
streamer.write_u32(0); // Colorspace
for (int i = 0; i < 12; i++) {
streamer.write_u32(0); // Endpoints
}
}
if (auto result = buffer.try_append(pixel_data.data(), pixel_data.size()); result.is_error())
dbgln("Failed to write {} bytes of pixel data to buffer: {}", pixel_data.size(), result.error());
return buffer;
}
}
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