/// <summary>
/// Given the size of an image, determines the size of a decompressed image.
/// </summary>
/// <param name="height">
/// The height of the image.
/// </param>
/// <param name="width">
/// The width of the image.
/// </param>
/// <param name="destPixelFormat">
/// The pixel format of the uncompressed image.
/// </param>
/// <returns>
/// The size of a buffer that can hold the uncompressed image.
/// </returns>
public int GetBufferSize(int height, int width, TJPixelFormat destPixelFormat)
{
Verify.NotDisposed(this);
int stride = TurboJpegImport.TJPAD(width * TurboJpegImport.PixelSizes[destPixelFormat]);
return(stride * height);
}
/// <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;
}
}
