/// <summary>
/// Reads the <see cref="BmpInfoHeader"/> from the stream.
/// </summary>
private void ReadInfoHeader()
{
#if NETCOREAPP2_1
Span <byte> buffer = stackalloc byte[BmpInfoHeader.MaxHeaderSize];
#else
byte[] buffer = new byte[BmpInfoHeader.MaxHeaderSize];
#endif
this.stream.Read(buffer, 0, BmpInfoHeader.HeaderSizeSize); // read the header size
int headerSize = BinaryPrimitives.ReadInt32LittleEndian(buffer);
if (headerSize < BmpInfoHeader.CoreSize)
{
throw new NotSupportedException($"ImageSharp does not support this BMP file. HeaderSize: {headerSize}.");
}
int skipAmount = 0;
if (headerSize > BmpInfoHeader.MaxHeaderSize)
{
skipAmount = headerSize - BmpInfoHeader.MaxHeaderSize;
headerSize = BmpInfoHeader.MaxHeaderSize;
}
// read the rest of the header
this.stream.Read(buffer, BmpInfoHeader.HeaderSizeSize, headerSize - BmpInfoHeader.HeaderSizeSize);
if (headerSize == BmpInfoHeader.CoreSize)
{
// 12 bytes
this.infoHeader = BmpInfoHeader.ParseCore(buffer);
}
else if (headerSize >= BmpInfoHeader.Size)
{
// >= 40 bytes
this.infoHeader = BmpInfoHeader.Parse(buffer);
}
else
{
throw new NotSupportedException($"ImageSharp does not support this BMP file. HeaderSize: {headerSize}.");
}
// Resolution is stored in PPM.
var meta = new ImageMetaData();
meta.ResolutionUnits = PixelResolutionUnit.PixelsPerMeter;
if (this.infoHeader.XPelsPerMeter > 0 && this.infoHeader.YPelsPerMeter > 0)
{
meta.HorizontalResolution = this.infoHeader.XPelsPerMeter;
meta.VerticalResolution = this.infoHeader.YPelsPerMeter;
}
else
{
// Convert default metadata values to PPM.
meta.HorizontalResolution = Math.Round(UnitConverter.InchToMeter(ImageMetaData.DefaultHorizontalResolution));
meta.VerticalResolution = Math.Round(UnitConverter.InchToMeter(ImageMetaData.DefaultVerticalResolution));
}
this.metaData = meta;
// skip the remaining header because we can't read those parts
this.stream.Skip(skipAmount);
}
/// <summary>
/// Reads the <see cref="BmpInfoHeader"/> from the stream.
/// </summary>
private void ReadInfoHeader()
{
#if NETCOREAPP2_1
Span <byte> buffer = stackalloc byte[BmpInfoHeader.MaxHeaderSize];
#else
byte[] buffer = new byte[BmpInfoHeader.MaxHeaderSize];
#endif
this.stream.Read(buffer, 0, BmpInfoHeader.HeaderSizeSize); // read the header size
int headerSize = BinaryPrimitives.ReadInt32LittleEndian(buffer);
if (headerSize < BmpInfoHeader.CoreSize)
{
throw new NotSupportedException($"ImageSharp does not support this BMP file. HeaderSize: {headerSize}.");
}
int skipAmount = 0;
if (headerSize > BmpInfoHeader.MaxHeaderSize)
{
skipAmount = headerSize - BmpInfoHeader.MaxHeaderSize;
headerSize = BmpInfoHeader.MaxHeaderSize;
}
// read the rest of the header
this.stream.Read(buffer, BmpInfoHeader.HeaderSizeSize, headerSize - BmpInfoHeader.HeaderSizeSize);
if (headerSize == BmpInfoHeader.CoreSize)
{
// 12 bytes
this.infoHeader = BmpInfoHeader.ParseCore(buffer);
}
else if (headerSize >= BmpInfoHeader.Size)
{
// >= 40 bytes
this.infoHeader = BmpInfoHeader.Parse(buffer);
}
else
{
throw new NotSupportedException($"ImageSharp does not support this BMP file. HeaderSize: {headerSize}.");
}
// skip the remaining header because we can't read those parts
this.stream.Skip(skipAmount);
}
/// <summary>
/// Reads the <see cref="BmpInfoHeader"/> from the stream.
/// </summary>
private void ReadInfoHeader()
{
byte[] buffer = new byte[BmpInfoHeader.MaxHeaderSize];
// read header size
this.stream.Read(buffer, 0, BmpInfoHeader.HeaderSizeSize);
int headerSize = BitConverter.ToInt32(buffer, 0);
if (headerSize < BmpInfoHeader.CoreSize)
{
throw new NotSupportedException($"ImageSharp does not support this BMP file. HeaderSize: {headerSize}.");
}
int skipAmount = 0;
if (headerSize > BmpInfoHeader.MaxHeaderSize)
{
skipAmount = headerSize - BmpInfoHeader.MaxHeaderSize;
headerSize = BmpInfoHeader.MaxHeaderSize;
}
// read the rest of the header
this.stream.Read(buffer, BmpInfoHeader.HeaderSizeSize, headerSize - BmpInfoHeader.HeaderSizeSize);
if (headerSize == BmpInfoHeader.CoreSize)
{
// 12 bytes
this.infoHeader = BmpInfoHeader.ParseCore(buffer);
}
else if (headerSize >= BmpInfoHeader.Size)
{
// >= 40 bytes
this.infoHeader = BmpInfoHeader.Parse(buffer.AsSpan(0, 40));
}
else
{
throw new NotSupportedException($"ImageSharp does not support this BMP file. HeaderSize: {headerSize}.");
}
// skip the remaining header because we can't read those parts
this.stream.Skip(skipAmount);
}