[Image-SIG] Creating HUGE images...

[Kevin Cazabon]

Well, huge is 1.2GB or so... a full-res 50x50" image at 406.4dpi (for output on a
LightJet laser photoplotter, using photographic paper).

I know I could PROBABLY thrash an NT box around overnight with such an image and a
whack of VM, but I figured that if I could simply create a "dummy" file on the hard
drive, and re-write the data portion line-by-line manually it would be MUCH faster.

Alternatively, is there an easy way to create the header and trailer portions of a
standard TIFF file (I'd know the size and details of the final image before I
started) so that I could do all this manually?  My alternative is to just write a RAW
file to the HD, and open it as such in my imaging program (which does support RAW). 
That's the ugly way to do it.

Thanks,

Kevin.

>>> "Barry A. Scott" <barry@scottb.demon.co.uk> 07/29/99 02:48PM >>>
How HUGE is HUGE? Can you use virtual memory to get the memory size you
need?
Limits would depend on your OS of course. Apart from LInux (limit of 128MB
swap
partition last I played) most OS seem to let you get 1GB to 3GB of VM on a
Pentium powered box.

  BArry

-----Original Message-----
From: image-sig-admin@python.org [mailto:image-sig-admin@python.org]On 
Behalf Of Kevin Cazabon
Sent: Friday, July 23, 1999 8:28 PM
To: image-sig@python.org 
Subject: [Image-SIG] Creating HUGE images...


I'm trying to develop an easy method to create images much larger than the
memory
available on the host computer, and have one big question:

-Is there any way to create a NEW image on the hard drive (with blank
background)
without first creating it in memory?  This way, I can create the 'canvas' as
large as
I want, and paste in small chunks of data manually as I go, staying within
the memory
limits of the machine.  (Writing to an existing file shouldn't be a problem,
just
creating the blank file in the first place is causing me problems)

I know I can read small sections of an image file at a time, using Fred's
earlier
suggestion of modifying the .tile attribute.  What I really need now is same
thing
for writing to a file.

Thanks,

Kevin Cazabon.











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