/// <summary>
/// Decompress a JPEG image to an RGB, grayscale, or CMYK image.
/// </summary>
/// <param name="jpegBuf">Pointer to a buffer containing the JPEG image to decompress. This buffer is not modified.</param>
/// <param name="outBuf">The buffer into which to store the decompressed JPEG image.</param>
/// <param name="destPixelFormat">Pixel format of the destination image (see <see cref="TJPixelFormat"/> "Pixel formats".)</param>
/// <param name="flags">The bitwise OR of one or more of the <see cref="TJFlags"/> "flags".</param>
/// <param name="width">Width of image in pixels.</param>
/// <param name="height">Height of image in pixels.</param>
/// <param name="stride">Bytes per line in the destination image.</param>
public unsafe void Decompress(Span <byte> jpegBuf, Span <byte> outBuf, TJPixelFormat destPixelFormat, TJFlags flags, out int width, out int height, out int stride)
{
Verify.NotDisposed(this);
fixed(byte *jpegBufPtr = jpegBuf)
fixed(byte *outBufPtr = outBuf)
{
int subsampl;
int colorspace;
var funcResult = TurboJpegImport.TjDecompressHeader(
this.decompressorHandle,
jpegBufPtr,
(nuint)jpegBuf.Length,
out width,
out height,
out subsampl,
out colorspace);
TJUtils.ThrowOnError(funcResult);
var targetFormat = destPixelFormat;
stride = TurboJpegImport.TJPAD(width * TurboJpegImport.PixelSizes[targetFormat]);
var bufSize = stride * height;
if (outBuf.Length < bufSize)
{
throw new ArgumentOutOfRangeException(nameof(outBuf));
}
funcResult = TurboJpegImport.TjDecompress(
this.decompressorHandle,
jpegBufPtr,
(nuint)jpegBuf.Length,
outBufPtr,
width,
stride,
height,
(int)targetFormat,
(int)flags);
TJUtils.ThrowOnError(funcResult);
}
}
/// <summary>
/// Retrieve information about a JPEG image without decompressing it.
/// </summary>
/// <param name="jpegBuf">
/// Pointer to a buffer containing a JPEG image. This buffer is not modified.
/// </param>
/// <param name="destPixelFormat">
/// The pixel format of the uncompressed image.
/// </param>
/// <param name="width">
/// Pointer to an integer variable that will receive the width (in pixels) of the JPEG image.
/// </param>
/// <param name="height">
/// Pointer to an integer variable that will receive the height (in pixels) of the JPEG image.
/// </param>
/// <param name="stride">
/// Pointer to an integer variable that will receive the stride (in bytes) of the JPEG image.
/// </param>
/// <param name="bufSize">
/// The size of a buffer that can receive the uncompressed JPEG image.
/// </param>
public void GetImageInfo(Span <byte> jpegBuf, TJPixelFormat destPixelFormat, out int width, out int height, out int stride, out int bufSize)
{
Verify.NotDisposed(this);
int subsampl;
int colorspace;
fixed(byte *jpegBufPtr = jpegBuf)
{
var funcResult = TurboJpegImport.TjDecompressHeader(
this.decompressorHandle,
jpegBufPtr,
(nuint)jpegBuf.Length,
out width,
out height,
out subsampl,
out colorspace);
stride = TurboJpegImport.TJPAD(width * TurboJpegImport.PixelSizes[destPixelFormat]);
bufSize = stride * height;
}
}
/// <summary>Transforms input image into one or several destinations.</summary>
/// <param name="jpegBuf">Pointer to a buffer containing the JPEG image to decompress. This buffer is not modified.</param>
/// <param name="transforms">Array of transform descriptions to be applied to the source image. </param>
/// <param name="flags">The bitwise OR of one or more of the <see cref="TJFlags"/> "flags".</param>
/// <returns>Array of transformed jpeg images.</returns>
/// <exception cref="ArgumentNullException"><paramref name="transforms"/> is <see langword="null" />.</exception>
/// <exception cref="ArgumentException">Transforms can not be empty.</exception>
/// <exception cref="TJException"> Throws if low level turbo jpeg function fails. </exception>
public byte[][] Transform(Span <byte> jpegBuf, TJTransformDescription[] transforms, TJFlags flags)
{
Verify.NotDisposed(this);
if (transforms == null)
{
throw new ArgumentNullException(nameof(transforms));
}
if (transforms.Length == 0)
{
throw new ArgumentException("Transforms can not be empty", nameof(transforms));
}
fixed(byte *jpegBufPtr = jpegBuf)
{
var count = transforms.Length;
var destBufs = new IntPtr[count];
var destSizes = new uint[count];
int subsampl;
int colorspace;
int width;
int height;
var funcResult = TurboJpegImport.TjDecompressHeader(
this.transformHandle,
jpegBufPtr,
(nuint)jpegBuf.Length,
out width,
out height,
out subsampl,
out colorspace);
TJUtils.ThrowOnError(funcResult);
Size mcuSize;
if (!TurboJpegImport.MCUSizes.TryGetValue((TJSubsamplingOption)subsampl, out mcuSize))
{
throw new TJException("Unable to read Subsampling Options from jpeg header");
}
var tjTransforms = new TJTransform[count];
for (var i = 0; i < count; i++)
{
var x = CorrectRegionCoordinate(transforms[i].Region.X, mcuSize.Width);
var y = CorrectRegionCoordinate(transforms[i].Region.Y, mcuSize.Height);
var w = CorrectRegionSize(transforms[i].Region.X, x, transforms[i].Region.W, width);
var h = CorrectRegionSize(transforms[i].Region.Y, y, transforms[i].Region.H, height);
tjTransforms[i] = new TJTransform
{
Op = (int)transforms[i].Operation,
Options = (int)transforms[i].Options,
R = new TJRegion
{
X = x,
Y = y,
W = w,
H = h,
},
Data = transforms[i].CallbackData,
CustomFilter = transforms[i].CustomFilter,
};
}
var transformsPtr = TJUtils.StructArrayToIntPtr(tjTransforms);
try
{
funcResult = TurboJpegImport.TjTransform(
this.transformHandle,
jpegBufPtr,
(nuint)jpegBuf.Length,
count,
destBufs,
destSizes,
transformsPtr,
(int)flags);
TJUtils.ThrowOnError(funcResult);
var result = new List <byte[]>();
for (var i = 0; i < destBufs.Length; i++)
{
var ptr = destBufs[i];
var size = destSizes[i];
var item = new byte[size];
Marshal.Copy(ptr, item, 0, (int)size);
result.Add(item);
TurboJpegImport.TjFree(ptr);
}
return(result.ToArray());
}
finally
{
TJUtils.FreePtr(transformsPtr);
}
}
}