Baslinux mailing list

[sindi keesan <keesan AT sdf.lonestar.org>]

On Mon, 26 Dec 2005, David Moberg wrote:

> On 12/26/05, sindi keesan <keesan AT sdf.lonestar.org> wrote:
> > Rather than upload megabytes of 200K 1280 res photos, I am using netpbm
> > programs to cut the size to 50K.  pamscale reduces X and Y by the same
> > factor as a default (.5 in my case).
> > I called my script halve.
> >
> > jpegtopnm $1 > temp1.pnm
> > pamscale .5 temp1.pnm > temp2.pnm (or big.pnm and small.pnm if you prefer)
>
> Are you sure that it is pamscale? I do not have pamscale here, (not
> sure what version of netpbm I have) but I do have pnmscale, which
> appears to work with this script.

pnmscale (it replaced pamscale a while ago).

> > I have tried various changes to my script and they all produce 0 length
> > files.  I don't think I can output > $1 to end up with the same name file
> > I started with.
> >
> > How can I at least avoid the step of renaming temp.jpg, and if possible,
> > how can I shrink all the files in a directory with one command or script?
> >
> > For i in .... ?
>
> jpegtopnm infile.jpg | pnmscale .5 | pnmtojpeg >outfile.jpg
>
> You need to put this in a 'for' loop in order to process multiple files
> at once.

I got this far but I don't want all the files to end up with the same name 
(outfile.jpg).  Can I generate a new name based on the old one somehow? 
infile.jpg converted to infile2.jpg ?  I tried with $1.jpg but it added 
another .jpg (file.jpg.jpg) and with $1 but then $1scale would be 
infile.jpg.scale.   Most of my experiments gave 0 length files.

To use netpbm, first I converted jpeg to pnm, then shrank the pnms, then I 
combined (with pamcat -lr and then -tb -white) 6 images into one, after 
trimming them all to 1200x960 so I could print 6 on a page, letter size 
with 1/4" margins left and right. 8"x 300 dpi = 2400 (2 photos wide).
I could already fit three photos high (3x960 is less than 10.5x300).

I converted the pnm to ps with pnmtops (netpbm) and it told me
Warning:  image too large for page, rescaling to 0.255'
(What did this do?) but produced one 42MB file.  (This should only be done 
on a fast computer with lots of hard drive - 99.8% cpu use on my 600MHz).

My HP 870cse printed (without red, and with thin white horizontal 
stripes) K-Mart can do better for 20 cents.  Use cdjcolor (not cdeskjet - 
'unable to open the initial device' is what printed that way).

The Epson stylus (stcolor) says it is 'out of paper' (so does my HP LJ6L 
-- wrong cables, or do they need something other than SPP/normal in CMOS?) 
and the black is clogged (Epson, nozzles not part of cartridge) so I 
converted back from pnm to jpeg to put on a floppy disk and take to 
K-mart.

pnmtojpeg produced a file that was just over 1.457K (floppy disk size).

pnmtojpeg2k makes smaller files but it 'failed to encode the JPEG 2000 
image Rc=-1'

pnmtojpeg -optimize produced a 1.452K file, same quality, in a few more 
seconds.  This is larger than my 6 original 200-210K jpg images and the 
(default) conversion was only 75%.  (100% produced a 5MB file).  Is there 
some way to combine 6 jpegs losslessly?

> > Pamscale is taking 5-10 seconds per photo and uses 99.8% of cpu but very
> > little memory to scale down (reduce).  It must be averaging out the colors
> > of two pixels to make one.
>
> > Don't try this on a 486.  Rotating images takes more memory and crashes a
> > 486 with 24MB RAM and no swap file.

> Does it use less memory if you use a smaller image?

I think it worked with a 640K photo when I shrank the image from 1280 
before rotating.  I won't try rotating anything on a slow computer again.

> David