[OctDev] Image package (imread problem)

[Lucas Sá <luc...@gm...>]

Today I noticed that the image package treats indexed images differently in
functions within the module.

Using [X, map] = *imread *will give me a matrix X with values from 0 to
n-1, while all other image package functions expect index mapping from 1 to
n, such as *imshow*, *ind2rgb*, *ind2gray*.

This fact makes the execution of a simple *imshow('some_file.gif') *to show
something different from the original image. imshow(*X+1*, map) would show
it fine as well.

The function ind2rgb, for example, even has a validation for indices less
than 1 in line 43 of ind2rgb.m:

  ## Check if X is an indexed image.
  if (ndims (x) != 2 || any (x(:) != fix (x(:))) || *min (x(:)) < 1*)
    error ("ind2rgb: X must be an indexed image");


Is it normal that I am receving 0 values in X matrix? I am using octave
3.6.2 and graphicsmagick 1.3.16.