Re: Re: Re: Which graphics format can Perl alter easier and more?

Resizing in any format will lose detail!

However, a highly-compressed JPEG that looks OK in normal use will go very wrong very quick if you start manipulating it. The compression artifacts, just below your visibility threshhold originally, really mess things up.

Zoom in on a JPEG and you'll see the artifacts I'm talking about. It's called "scambled eggs" or "mosqueto legs".

—John

Comment on Re: Re: Re: Which graphics format can Perl alter easier and more?

Replies are listed 'Best First'.
Re(4): Which graphics format can Perl alter easier and more? by FoxtrotUniform (Prior) on Aug 13, 2001 at 19:31 UTC
JPEG was originally intended to compress photos, which are pretty noisy in high frequencies. The compression artifacts don't really show if you're compressing suitable images (most of your pr0n collection, for instance :-), but if you're dealing with images with sharp high-frequency detail (especially sharp edges, I find) you'll get a bunch of crap in the high band. PNG, on the other hand, was designed as a replacement for GIF, and had to handle all sorts of sharp-edged, computer generated web content, so it don't do that. (Neither is vector-based, so if you zoom in far enough you'll naturally get a huge mess of pixels.) PNG also has great alpha-channel support, much better than GIF's "ignore this palette entry" crap. `-- :wq`	[reply]

Replies are listed 'Best First'.

Re(4): Which graphics format can Perl alter easier and more?
by FoxtrotUniform (Prior) on Aug 13, 2001 at 19:31 UTC

JPEG was originally intended to compress photos, which are pretty noisy in high frequencies. The compression artifacts don't really show if you're compressing suitable images (most of your pr0n collection, for instance :-), but if you're dealing with images with sharp high-frequency detail (especially sharp edges, I find) you'll get a bunch of crap in the high band.

PNG, on the other hand, was designed as a replacement for GIF, and had to handle all sorts of sharp-edged, computer generated web content, so it don't do that. (Neither is vector-based, so if you zoom in far enough you'll naturally get a huge mess of pixels.) PNG also has great alpha-channel support, much better than GIF's "ignore this palette entry" crap.

-- :wq

[reply]