`Tiff.rewriteDirectory`

Updates the current directory of a file with changed tags.

Category: Data Import and Analysis > Data Import and Export

Syntax

rewriteDirectory(t)

Writes the changed tags of the current directory back to the file.

Description

The method acts on a Tiff object created with Tiff(filename, mode). Open the file with 'r+', move to the directory you want with setDirectory, change a tag with setTag, then call rewriteDirectory. Only metadata is rewritten, and the pixel data stays as it is.

Input arguments

t: Tiff object opened in 'r+' mode.

Example

Add a description to an existing file

tag.ImageLength = 2; tag.ImageWidth = 2;
tag.Photometric = Tiff.Photometric.MinIsBlack;
tag.BitsPerSample = 8; tag.SamplesPerPixel = 1; tag.RowsPerStrip = 2;
tag.PlanarConfiguration = Tiff.PlanarConfiguration.Chunky;
w = Tiff('m.tif', 'w');
w.setTag(tag); w.write(uint8([1 2; 3 4])); w.writeDirectory();
w.setTag(tag); w.write(uint8([5 6; 7 8])); w.close();
t = Tiff('m.tif', 'r+');
t.setDirectory(2);
t.setTag('ImageDescription', 'second image');
t.rewriteDirectory();
t.close();
r = Tiff('m.tif', 'r');
r.setDirectory(2);
r.getTag('ImageDescription')
r.close();

Output

ans = 'second image'

See also

Tiff.setTag Tiff.setDirectory Tiff.getTag Tiff.close