How to split multipage Tiff using LibTiff.Net

Question

In the LibTiff.Net documentation I've found that it is possible to get a specific page of the Tiff document.

But, if it is possible to split multipage Tiff (using LibTiff.Net) without knowing how many pages are there? How?

Using this example it returns only the first page.

Btw, the main problem is that Windows XP can't handle different tiff images, so I want to split it into jpeg ones.

Answer 1

//open tif file
var tif = Tiff.Open(@"file", "r");

//get number of pages
var num = tif.NumberOfDirectories();

for (short i = 0; i < num; i++)
{
    //set current page
    tif.SetDirectory(i); 

    Bitmap bmp = GetBitmapFormTiff(tif);
    bmp.Save(string.Format(@"newfile{0}.bmp", i));
}

The code of GetBitmapFormTiff is from example:

private static Bitmap GetBitmapFormTiff(Tiff tif)
        {
            FieldValue[] value = tif.GetField(TiffTag.IMAGEWIDTH);
            int width = value[0].ToInt();

            value = tif.GetField(TiffTag.IMAGELENGTH);
            int height = value[0].ToInt();

            //Read the image into the memory buffer
            var raster = new int[height * width];
            if (!tif.ReadRGBAImage(width, height, raster))
            {
                return null;
            }

            var bmp = new Bitmap(width, height, PixelFormat.Format32bppRgb);

            var rect = new Rectangle(0, 0, bmp.Width, bmp.Height);

            BitmapData bmpdata = bmp.LockBits(rect, ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);
            var bits = new byte[bmpdata.Stride * bmpdata.Height];

            for (int y = 0; y < bmp.Height; y++)
            {
                int rasterOffset = y * bmp.Width;
                int bitsOffset = (bmp.Height - y - 1) * bmpdata.Stride;

                for (int x = 0; x < bmp.Width; x++)
                {
                    int rgba = raster[rasterOffset++];
                    bits[bitsOffset++] = (byte)((rgba >> 16) & 0xff);
                    bits[bitsOffset++] = (byte)((rgba >> 8) & 0xff);
                    bits[bitsOffset++] = (byte)(rgba & 0xff);
                    bits[bitsOffset++] = (byte)((rgba >> 24) & 0xff);
                }
            }

            System.Runtime.InteropServices.Marshal.Copy(bits, 0, bmpdata.Scan0, bits.Length);
            bmp.UnlockBits(bmpdata);

            return bmp;
        }