/// <summary>
/// Compresses input image to the jpeg format with specified quality.
/// </summary>
/// <param name="srcBuf">
/// Image buffer containing RGB, grayscale, or CMYK pixels to be compressed.
/// This buffer is not modified.
/// </param>
/// <param name="stride">
/// Bytes per line in the source image.
/// Normally, this should be <c>width * BytesPerPixel</c> if the image is unpadded,
/// or <c>TJPAD(width * BytesPerPixel</c> if each line of the image
/// is padded to the nearest 32-bit boundary, as is the case for Windows bitmaps.
/// You can also be clever and use this parameter to skip lines, etc.
/// Setting this parameter to 0 is the equivalent of setting it to
/// <c>width * BytesPerPixel</c>.
/// </param>
/// <param name="width">Width (in pixels) of the source image.</param>
/// <param name="height">Height (in pixels) of the source image.</param>
/// <param name="pixelFormat">Pixel format of the source image (see <see cref="PixelFormat"/> "Pixel formats").</param>
/// <param name="subSamp">
/// The level of chrominance subsampling to be used when
/// generating the JPEG image (see <see cref="TJSubsamplingOption"/> "Chrominance subsampling options".)
/// </param>
/// <param name="quality">The image quality of the generated JPEG image (1 = worst, 100 = best).</param>
/// <param name="flags">The bitwise OR of one or more of the <see cref="TJFlags"/> "flags".</param>
/// <returns>
/// A <see cref="byte"/> array containing the compressed image.
/// </returns>
/// <exception cref="TJException">
/// Throws if compress function failed.
/// </exception>
/// <exception cref="ObjectDisposedException">Object is disposed and can not be used anymore.</exception>
/// <exception cref="NotSupportedException">
/// Some parameters' values are incompatible:
/// <list type="bullet">
/// <item><description>Subsampling not equals to <see cref="TJSubsamplingOption.Gray"/> and pixel format <see cref="TJPixelFormat.Gray"/></description></item>
/// </list>
/// </exception>
public unsafe byte[] Compress(byte[] srcBuf, int stride, int width, int height, PixelFormat pixelFormat, TJSubsamplingOption subSamp, int quality, TJFlags flags)
{
if (this.isDisposed)
{
throw new ObjectDisposedException("this");
}
var tjPixelFormat = TJUtils.ConvertPixelFormat(pixelFormat);
CheckOptionsCompatibilityAndThrow(subSamp, tjPixelFormat);
var buf = IntPtr.Zero;
ulong bufSize = 0;
try
{
fixed(byte *srcBufPtr = srcBuf)
{
var result = TurboJpegImport.TjCompress2(
this.compressorHandle,
(IntPtr)srcBufPtr,
width,
stride,
height,
(int)tjPixelFormat,
ref buf,
ref bufSize,
(int)subSamp,
quality,
(int)flags);
if (result == -1)
{
TJUtils.GetErrorAndThrow();
}
}
var jpegBuf = new byte[bufSize];
Marshal.Copy(buf, jpegBuf, 0, (int)bufSize);
return(jpegBuf);
}
finally
{
TurboJpegImport.TjFree(buf);
}
}
/// <summary> /// Free an image buffer previously allocated by TurboJPEG. /// </summary> /// <param name="buffer">Address of the buffer to free.</param> /// <seealso cref="Alloc"/> public static void Free(IntPtr buffer) => TurboJpegImport.TjFree(buffer);
/// <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(nameof(transforms));
}
if (transforms.Length == 0)
{
throw new ArgumentException("Transforms can not be empty", nameof(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(
this.transformHandle,
jpegBuf,
jpegBufSize,
out width,
out height,
out subsampl,
out colorspace);
if (funcResult == -1)
{
TJUtils.GetErrorAndThrow();
}
TjSize tjSize;
if (!TurboJpegImport.MCUSizes.TryGetValue((TJSubsamplingOption)subsampl, out tjSize))
{
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, tjSize.Width);
var y = CorrectRegionCoordinate(transforms[i].Region.Y, tjSize.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,
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);
}
}
