Re: Anybody have a prgram to write a .bmp file?

[Robert A. Macy]

Forgot to mention that on the WinXP machine, where imshow
works, that 
>> imshow(r,256);
produces perfect gray scale images.

Somehow it makes two files
 1 internet explorer file 
 2 .bmp file
the .bmp file is stored as 256 color 113K size

and note
the range of r is 0 <= r <= 1
and does NOT have to be reduced at the top end as I have to
do with gray2ind before bmpwrite.

            - Robert -

On Sun, 04 Feb 2007 05:44:33 -0800
 "Robert A. Macy" <address@hidden> wrote:
> color doesn't seem to work almost at all
> 
> if I do
> >> [X,map]=rgb2ind(r,g,b);
> >> saveimage("Xtest.ppm",X,"ppm",map);
> I almost get something of interest
> 
> if I do 
> >> [X,map]=gray2ind(r,256);
> >> bmpwrite(X,map,"Xtest.bmp");
> I get a proper gray scaled image EXCEPT...
> r cannot be in this range 0 <= r <= 1 
> it must be in this range 0 <= r <= 255/256
> or else wherever the image is near 1 becomes black as if
> 0
> 
> Using Paint:
> just a note, the Xtest.bmp in gray scale is stored as 256
> color at a size of 113K. If I save the image as 24 bit
> color, the stored file enlarges to 334K.  
> 
> octave:
> Converting the r,g,b to indexed image and then bmpwrite
> that image is also stored also as 256 color, not 24 bit
> color?!  and the size is too large at 556K?! Not the
> proper
> 24 bit color size of 334K.  Note .ppm was 334K.
> 
>         - Robrt-
> 
> interestingly, the command
> >> saveimage("Xtest.ppm",X,"ppm",map);
> produces a 334K size file.  
> 
>