/// <summary>
/// Encodes the image to the specified stream from the <see cref="ImageFrame{TPixel}"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="ImageFrame{TPixel}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TPixel>(Image <TPixel> image, Stream stream)
where TPixel : unmanaged, IPixel <TPixel>
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
this.configuration = image.GetConfiguration();
ImageMetadata metadata = image.Metadata;
BmpMetadata bmpMetadata = metadata.GetBmpMetadata();
this.bitsPerPixel = this.bitsPerPixel ?? bmpMetadata.BitsPerPixel;
short bpp = (short)this.bitsPerPixel;
int bytesPerLine = 4 * (((image.Width * bpp) + 31) / 32);
this.padding = bytesPerLine - (int)(image.Width * (bpp / 8F));
// Set Resolution.
int hResolution = 0;
int vResolution = 0;
if (metadata.ResolutionUnits != PixelResolutionUnit.AspectRatio)
{
if (metadata.HorizontalResolution > 0 && metadata.VerticalResolution > 0)
{
switch (metadata.ResolutionUnits)
{
case PixelResolutionUnit.PixelsPerInch:
hResolution = (int)Math.Round(UnitConverter.InchToMeter(metadata.HorizontalResolution));
vResolution = (int)Math.Round(UnitConverter.InchToMeter(metadata.VerticalResolution));
break;
case PixelResolutionUnit.PixelsPerCentimeter:
hResolution = (int)Math.Round(UnitConverter.CmToMeter(metadata.HorizontalResolution));
vResolution = (int)Math.Round(UnitConverter.CmToMeter(metadata.VerticalResolution));
break;
case PixelResolutionUnit.PixelsPerMeter:
hResolution = (int)Math.Round(metadata.HorizontalResolution);
vResolution = (int)Math.Round(metadata.VerticalResolution);
break;
}
}
}
int infoHeaderSize = this.writeV4Header ? BmpInfoHeader.SizeV4 : BmpInfoHeader.SizeV3;
var infoHeader = new BmpInfoHeader(
headerSize: infoHeaderSize,
height: image.Height,
width: image.Width,
bitsPerPixel: bpp,
planes: 1,
imageSize: image.Height * bytesPerLine,
clrUsed: 0,
clrImportant: 0,
xPelsPerMeter: hResolution,
yPelsPerMeter: vResolution);
if (this.writeV4Header && this.bitsPerPixel == BmpBitsPerPixel.Pixel32)
{
infoHeader.AlphaMask = Rgba32AlphaMask;
infoHeader.RedMask = Rgba32RedMask;
infoHeader.GreenMask = Rgba32GreenMask;
infoHeader.BlueMask = Rgba32BlueMask;
infoHeader.Compression = BmpCompression.BitFields;
}
int colorPaletteSize = this.bitsPerPixel == BmpBitsPerPixel.Pixel8 ? ColorPaletteSize8Bit : 0;
var fileHeader = new BmpFileHeader(
type: BmpConstants.TypeMarkers.Bitmap,
fileSize: BmpFileHeader.Size + infoHeaderSize + infoHeader.ImageSize,
reserved: 0,
offset: BmpFileHeader.Size + infoHeaderSize + colorPaletteSize);
Span <byte> buffer = stackalloc byte[infoHeaderSize];
fileHeader.WriteTo(buffer);
stream.Write(buffer, 0, BmpFileHeader.Size);
if (this.writeV4Header)
{
infoHeader.WriteV4Header(buffer);
}
else
{
infoHeader.WriteV3Header(buffer);
}
stream.Write(buffer, 0, infoHeaderSize);
this.WriteImage(stream, image.Frames.RootFrame);
stream.Flush();
}
