I've used GD (in PHP) for plotting graphs. It's not too bad . There are put-pixel and draw-line type functions.

I've only used GnuPlot once and that involved feeding it a text file of values to plot if I recall correctly. Read the docs though because I don't know how else you can use it.

Also maybe check out imagemagick.

Update: OH right the whole reason I posted.
1) check the quality settings in GD's JPEG functions (also maybe use PNG instead).
2) I did a contract that involved generating thumbnails. The client wasn't impressed with GD's or ImageMagick's results even with sharpen and unsharp filters. In the end he generated them via a script in Photoshop. If you're on Linux maybe check out the GIMP which can be scripted in Scheme (maybe perl, I'm not sure).

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.