/// <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="jpegBufSize">Size of the JPEG image (in bytes)</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(IntPtr jpegBuf, ulong jpegBufSize, TJTransformDescription[] transforms, TJFlags flags)
{
if (transforms == null)
{
throw new ArgumentNullException("transforms");
}
if (transforms.Length == 0)
{
throw new ArgumentException("Transforms can not be empty", "transforms");
}
// ReSharper disable once ExceptionNotDocumented
var count = transforms.Length;
var destBufs = new IntPtr[count];
var destSizes = new ulong[count];
int subsampl;
int colorspace;
int width;
int height;
var funcResult = TurboJpegImport.tjDecompressHeader(_transformHandle, jpegBuf, jpegBufSize,
out width, out height, out subsampl, out colorspace);
if (funcResult == -1)
{
TJUtils.GetErrorAndThrow();
}
Size mcuSize;
if (!TurboJpegImport.MCUSizes.TryGetValue((TJSubsamplingOptions)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(_transformHandle, jpegBuf, jpegBufSize, count, destBufs,
destSizes, transformsPtr, (int)flags);
if (funcResult == -1)
{
TJUtils.GetErrorAndThrow();
}
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);
}
}