Re: JPEG support for backgrounds - XPM.GZ

sashav (sashav@sprintmail.com)
Sat, 22 Aug 1998 10:42:52 -0500


Rob Foehl wrote:
> 
> On Fri, 21 Aug 1998 Sasha_Vasko@osca.state.mo.us wrote:
> 
> > Here is another idea :
> >
> > I've been checking  libXPM sources and found that it can read .Z-ed and
> > .GZ-ed files
> > if compiled with proper options. Those options are set by default.
> >
> > Therefor it is possible to GZ you large XPM files to save up space.
> > You need to have 'gunzip' for .GZ and 'uncompress' for .Z as far as it is
> > only running
> > those uncompressors and pipe out result.
> >
> > Catch : file needs to have .GZ or .Z at the end.
> >
> > I had no time to check it so far.
> > Could somebody try it, please ???

Don't try!  Pager needs to be fixed to be able to do this.

> 
> Reading a 2-12 meg XPM off the disk isnt the problem; Keeping it on the
> screen is. Keeping a file that large displayed takes a hellacious amount
> of system resources, not to mention user's time and patience.

Image size in memory is exactly the same for JPEG and XPM and any other
format.
When you load it you decompress it and convert to XImage or Pixmap that
takes exactly 
the same system resources and so forth.

Only advantage of JPEG is that it takes less space on disk.
Disadvantages are lesser
image quality ( depends on compression level ) and CPU time for
decompression (for
fast HDD it should be greater then difference in expences for reading
bigger XPM of disk.)

> 
> -Rob
>

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