Re: Replacing default.img by default image 'cdata'

[Pantxo Diribarne]

>> > Hi,
>>
>>       >
>>
>>
>>       > Currently, the call to "image ()" without argument builds an
>>       image object using data loaded from file (default.img). For
>>       consistency with other graphics primitives (and for matlab
>>       compatibility if it is of any importance here), I think octave
>>       should use the default image "cdata" instead.
>>
>>
>>       >
>>
>>
>>       > Do people have an opinion against this modification in
>>       image.m behavior?
>>
>>
>>       >
>>
>>
>>       > Pantxo
>>
>>
>> The default cdata does not appear to be the same as that in 
default.img?  Should the two be made the same?  Matlab compatible 
behavior is to display a default image for the function call image().  
Is their cdata equivalent to their default image?
>>
>> cimg = get (0, 'defaultimagecdata');
>> hi = image ();
>> dimg = get (hi, 'cdata');
>> isequal (cimg, dimg)
>>
>> --Rik
>
>from R2014b
>
>cimg = get (0, 'defaultimagecdata');
>hi = image ();
>dimg = get (hi, 'cdata');
>isequal (cimg, dimg)
>
>ans =
>
>     1
>
>Ben

Hi,

The attached minimal changeset brings Octave in line with Matlab for the 
above behavior. Is it ok to push it?

Then if we want to change the default image "cdata" it is as easy as 
changing the data in octave-default-image.h and eventually the 
dimensions in graphics.cc (see default_image_cdata  function). The image 
data should be indexes in the default colormap, which is "jet".

The current default "cdata" represent Octave logo dithered and exported 
to header file using Gimp. Its dimensions are 64-by-64 as in Matlab. We 
could eventually use default.img data, even though dimensions (53-by-40) 
are a bit weird.

Pantxo

load_image_cdata.patch
Description: Text Data