public void ToFile(string fileName)
{
BITMAPFILEHEADER bmfh;
bmfh.bfType = 0x4D42;
int fileSize = Marshal.SizeOf(typeof(BITMAPFILEHEADER));
fileSize += Marshal.SizeOf(typeof(BITMAPINFOHEADER));
fileSize += Marshal.SizeOf(typeof(RGBQUAD)) * colorTable.Count();
bmfh.bfOffBits = (uint)fileSize;
fileSize += imageData.Count();
bmfh.bfSize = (uint)fileSize;
bmfh.bfReserved1 = 0;
bmfh.bfReserved2 = 0;
using (var writer = new BinaryWriter(File.Open(fileName, FileMode.Create)))
{
ReadWriteStructWithAllocGCHandle.WriteTo <BITMAPFILEHEADER>(writer, bmfh);
ReadWriteStructWithAllocGCHandle.WriteTo <BITMAPINFOHEADER>(writer, bmih);
foreach (var c in colorTable)
{
ReadWriteStructWithAllocGCHandle.WriteTo <RGBQUAD>(writer, c);
}
writer.Write(imageData);
}
}
public static Bmp FromFile(string fileName)
{
Bmp bmp = new Bmp();
using (BinaryReader reader = new BinaryReader(File.Open(fileName, FileMode.Open)))
{
BITMAPFILEHEADER bmfh;
bmfh = ReadWriteStructWithAllocGCHandle.ReadFrom <BITMAPFILEHEADER>(reader);
if (bmfh.bfType != 0x4D42)
{
throw new FileFormatException();
}
bmp.bmih = ReadWriteStructWithAllocGCHandle.ReadFrom <BITMAPINFOHEADER>(reader);
uint numQuads;
if (bmp.bmih.biClrUsed == 0)
{
switch (bmp.bmih.biBitCount)
{
case 1:
case 4:
case 8:
numQuads = (uint)(1 << bmp.bmih.biBitCount);
break;
default:
throw new FileFormatException();
}
}
else
{
numQuads = bmp.bmih.biClrUsed;
}
if (bmp.bmih.biHeight < 0)
{
// TODO: TopDown 形式のサポート
throw new NotImplementedException();
}
bmp.colorTable = new RGBQUAD[numQuads];
for (int i = 0; i < numQuads; ++i)
{
bmp.colorTable[i] = ReadWriteStructWithAllocGCHandle.ReadFrom <RGBQUAD>(reader);
}
if (reader.BaseStream.Position != bmfh.bfOffBits)
{
throw new FileFormatException();
}
// https://stackoverflow.com/a/10038017/4699324
using (var ms = new MemoryStream())
{
reader.BaseStream.CopyTo(ms);
bmp.imageData = ms.ToArray();
}
}
return(bmp);
} // FromFile
