private static Size DecodeBitmap(SequentialBinaryReader reader)
{
var magicNumber = reader.ReadUInt16();
// skip past the rest of the file header
reader.Skip(4 + 2 + 2 + 4);
int headerSize = reader.ReadInt32();
int width, height;
// We expect the header size to be either 40 (BITMAPINFOHEADER) or 12 (BITMAPCOREHEADER)
if (headerSize == 40)
{
// BITMAPINFOHEADER
width = reader.ReadInt32();
height = Math.Abs(reader.ReadInt32());
}
else if (headerSize == 12)
{
width = reader.ReadInt16();
height = reader.ReadInt16();
}
else
{
// Unexpected DIB header size
return(Size.Empty);
}
return(new Size(width, height));
}
private static Size DecodePng(SequentialBinaryReader reader)
{
reader.IsBigEndian = true;
reader.ReadBytes(pngSignatureBytes.Length);
reader.Skip(8);
int width = reader.ReadInt32();
int height = reader.ReadInt32();
return(new Size(width, height));
}
private static Size DecodeEmf(SequentialBinaryReader reader)
{
// EMR_HEADER: Type + Size + Bounds
reader.Skip(4 + 4 + 16);
// Frame: specify the rectangular inclusive-inclusive dimensions,
// in .01 millimeter units, of a rectangle that surrounds the image stored in the metafile.
int left = reader.ReadInt32();
int top = reader.ReadInt32();
int right = reader.ReadInt32();
int bottom = reader.ReadInt32();
// Skip other headers:
// Signature (4) + Version (4) + Size (4) + Records (4) + Handles (2)
// + nReserved (2) + nDescription (4) + offDescription (4) + PalEntries (4)
reader.Skip(32);
// Next 8 bytes specify the size of the reference device, in pixels
int deviceSizeInPixelX = reader.ReadInt32();
int deviceSizeInPixelY = reader.ReadInt32();
// Then 8 more to specify the size of the reference device, in millimeters
int deviceSizeInMlmX = reader.ReadInt32();
int deviceSizeInMlmY = reader.ReadInt32();
int widthInPixel = (int)Math.Round(0.5 + ((right - left + 1.0) * deviceSizeInPixelX / deviceSizeInMlmX) / 100.0);
int heightInPixel = (int)Math.Round(0.5 + ((bottom - top + 1.0) * deviceSizeInPixelY / deviceSizeInMlmY) / 100.0);
return(new Size(widthInPixel, heightInPixel));
}