static byte[] GetHeader(uint fileSize, PDFiumBitmap bitmap, double dpiX, double dpiY)
{
const double MetersPerInch = 0.0254;
byte[] header = new byte[BmpHeaderSize + DibHeaderSize];
using (var ms = new MemoryStream(header))
using (var writer = new BinaryWriter(ms))
{
writer.Write((byte)'B');
writer.Write((byte)'M');
writer.Write(fileSize);
writer.Write(0u);
writer.Write(PixelArrayOffset);
writer.Write(DibHeaderSize);
writer.Write(bitmap.Width);
writer.Write(-bitmap.Height); // top-down image
writer.Write((ushort)1);
writer.Write((ushort)(bitmap.BytesPerPixel * 8));
writer.Write(CompressionMethod);
writer.Write(0);
writer.Write((int)Math.Round(dpiX / MetersPerInch));
writer.Write((int)Math.Round(dpiY / MetersPerInch));
writer.Write(0L);
writer.Write(MaskR);
writer.Write(MaskG);
writer.Write(MaskB);
if (bitmap.Format == BitmapFormats.FPDFBitmap_BGRA)
{
writer.Write(MaskA);
}
}
return(header);
}
public BmpStream(PDFiumBitmap bitmap, double dpiX, double dpiY)
{
if (bitmap.Format == BitmapFormats.FPDFBitmap_Gray)
{
throw new NotSupportedException($"Bitmap format {bitmap.Format} is not yet supported.");
}
_bitmap = bitmap;
_rowLength = (uint)bitmap.BytesPerPixel * (uint)bitmap.Width;
_stride = (((uint)bitmap.BytesPerPixel * 8 * (uint)bitmap.Width + 31) / 32) * 4;
_length = PixelArrayOffset + _stride * (uint)bitmap.Height;
_header = GetHeader(_length, _bitmap, dpiX, dpiY);
_pos = 0;
}
protected virtual void Dispose(bool disposing)
{
if (IsDisposed)
{
return;
}
if (_bitmap != null)
{
_bitmap.Dispose();
}
_bitmap = null;
IsDisposed = true;
if (disposing)
{
GC.SuppressFinalize(this);
}
}