Re: need a test in matlab to implement imformats in Octave

[Laurent Hoeltgen]

On 07/05/2013 04:50 PM, Carnë Draug wrote:
> On 5 July 2013 08:22, PhilipNienhuis <address@hidden> wrote:
> > Carnë Draug-4 wrote
> > > Hi
> > >
> > > could someone with matlab run a test for me in. I'm trying to
> > > understand how the image IO functions work after messing up with
> > > imformats. The test is the following:
> > This contains quite a bit of invalid ML syntax. [...]
> Sorry. I always get caught in Octave's incompatibility bugs. It's not
> like Octave changes that fast, Mathworks should have already fixed
> this by now :p
>
> > Error using testreadjpg
> > Too many output arguments.
> >
> > Error in imread (line 415)
> >      [X, map] = feval(fmt_s.read, filename, extraArgs{:});
> >
> > ... so I think testreadjpg.m contains additional errors. It doesn't even get
> > called as there's no 'im initialized' message.
> Could you please try again and define testreadjpg as
>
> function [out, m] = testreadjpg (filename)
>    persistent im;
>    if (isempty (im)); im = 1; fprintf ('im initialized\n'); end
>    disp (im)
>    if (im > 3), error ('stuck in a loop\n'); end
>    im = im + 1;
>    [out, m] = imread (filename);
> end
>
>  From their documentation, the test should either print 1, 2, 3 and
> then give an error, or return the image. Unless, there's another
> interpretation that I'm missing :(
>
> Thank you,
> Carnë

Hi,

Matlab R2012a output:

>> fmt = imformats ('jpg')

fmt =

            ext: {'jpg'  'jpeg'}
            isa: @isjpg
           info: @imjpginfo
           read: @readjpg
          write: @writejpg
          alpha: 0
    description: 'Joint Photographic Experts Group (JPEG)'

>> fmt.read = @testreadjpg;
>> imformats ('update', 'jpg', fmt);
>> img = imread ('lena.jpg');
im initialized
     1

     2

     3

     4

Error using testreadjpg (line 5)
stuck in a loop\n

Error in imread (line 435)
    [X, map] = feval(fmt_s.read, filename, extraArgs{:});

Error in testreadjpg (line 7)
  [out, m] = imread (filename);

Error in imread (line 435)
    [X, map] = feval(fmt_s.read, filename, extraArgs{:});

Error in testreadjpg (line 7)
  [out, m] = imread (filename);

Error in imread (line 435)
    [X, map] = feval(fmt_s.read, filename, extraArgs{:});

Error in testreadjpg (line 7)
  [out, m] = imread (filename);

Error in imread (line 435)
    [X, map] = feval(fmt_s.read, filename, extraArgs{:});

>> image (img)
Undefined function or variable 'img'.

>>