/// <summary>Creates a Bitmap object from a libtiff handle.</summary>
/// <param name="tiff">Source image handle, 16 bit grayscale</param>
/// <param name="min">Min source histogram value => mapped to 0</param>
/// <param name="max">Max source histogram value => mapped to 255</param>
/// <returns>The Bitmap object. Remember to dispose the bitmap data
/// before abandoning the object!</returns>
private Bitmap GetBitmapFromTIFFHandle(IntPtr tiff, ushort min, ushort max)
{
UInt32 imageWidth, imageLength;
UInt16 bitsPerSample, samplesPerPixel;
int scanlineSize = LibTIFF.ScanlineSize(tiff);
Bitmap bmp;
// get image parameters
LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_IMAGEWIDTH, out imageWidth);
LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_IMAGELENGTH, out imageLength);
LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_BITSPERSAMPLE, out bitsPerSample);
LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_SAMPLESPERPIXEL, out samplesPerPixel);
if (bitsPerSample != 16 || samplesPerPixel != 1)
{
// this is not a 16bit grayscale TIFF file -- return
return(null);
}
// allocate memory for bitmap
IntPtr bmpData = LibTIFF._malloc((int)(scanlineSize / 2 * imageLength));
tbInitialScan0Ptr.Text = bmpData.ToString();
// read scanline by scanline
IntPtr pScanline = LibTIFF._malloc(scanlineSize);
for (UInt32 row = 0; row < imageLength; row++)
{
LibTIFF.ReadScanline(tiff, pScanline, row);
unsafe
{
ushort *srcBits16bit = (ushort *)pScanline; // source: 16bit grayscale bitmap
byte * dstBitsPalette = (byte *)bmpData; // dest.: 8bit palette bitmap
for (int i = 0; i < imageWidth; i++)
{
// scale each pixel's color according to given limits
if (srcBits16bit[i] <= min)
{
dstBitsPalette[i + row * imageWidth] = 0;
}
else if (srcBits16bit[i] >= max)
{
dstBitsPalette[i + row * imageWidth] = 255;
}
else
{
dstBitsPalette[i + row * imageWidth] =
(byte)(((long)srcBits16bit[i] - (long)min) * (long)255 / ((long)max - min));
}
}
}
}
LibTIFF._free(pScanline);
// create the Bitmap object using the read bitmap data
bmp = new Bitmap((int)imageWidth, (int)imageLength, scanlineSize / 2,
PixelFormat.Format8bppIndexed, bmpData);
// setup grayscale palette
ColorPalette palette = bmp.Palette;
for (int i = 0; i < 256; i++)
{
Color c = Color.FromArgb(i, i, i);
palette.Entries[i] = c;
}
bmp.Palette = palette;
return(bmp);
}
private void btnOpenTIFF_Click(object sender, System.EventArgs e)
{
if (ofdOpenTIFF.ShowDialog() != DialogResult.OK)
{
return;
}
// open TIFF file
string filename = ofdOpenTIFF.FileName;
tiff = LibTIFF.Open(filename, "r");
if (tiff == IntPtr.Zero)
{
MessageBox.Show("Failed to open " + filename);
return;
}
// report some file info
tbTIFFPtr.Text = tiff.ToString();
tbRasterScanlineSize.Text = LibTIFF.RasterScanlineSize(tiff).ToString();
tbScanlineSize.Text = LibTIFF.ScanlineSize(tiff).ToString();
UInt32 width, length;
if (LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_IMAGEWIDTH, out width) &&
LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_IMAGELENGTH, out length))
{
tbImageDimensions.Text = width.ToString() + "x" + length.ToString();
}
if (LibTIFF.IsTiled(tiff))
{
if (LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_TILEWIDTH, out width) &&
LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_TILELENGTH, out length))
{
tbTileDimensions.Text = width.ToString() + "x" + length.ToString();
}
}
else
{
tbTileDimensions.Text = "not tiled";
UInt32 rows;
if (LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_ROWSPERSTRIP, out rows))
{
tbRowsPerStrip.Text = rows.ToString();
}
}
UInt16 bps;
if (LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_BITSPERSAMPLE, out bps))
{
tbBitsPerSample.Text = bps.ToString();
}
UInt16 spp;
if (LibTIFF.GetField(tiff, (int)TIFFTags.TIFFTAG_SAMPLESPERPIXEL, out spp))
{
tbSamplesPerPixel.Text = spp.ToString();
}
// place TIFF content in the picture box
pbPicture.SizeMode = PictureBoxSizeMode.StretchImage;
pbPicture.Image = GetBitmapFromTIFFHandle(tiff, 0, 65535);
System.Console.WriteLine("System.GC.GetTotalMemory: " + System.GC.GetTotalMemory(true));
}
