[thelist] banding in jpegs using mozilla in 16 bit display

Adrian Simmons adrinux at ntlworld.com
Wed Jul 3 10:22:01 CDT 2002


I'm working on a new home page for myself, heavily 'inspired' by Eric
Meyer's complex spiral demo. This is XHTML and CSS but my question
concerns something else - mozilla's rendering of jpeg images.

If you take a look at my prototype page in a modern standards compliant
You'll see I've place a jpeg in the bottom left of the viewport. This is
a greyscale jpeg of a telegraph pole.

Everything looks fine in Mozilla1.0 IE5.2 and Opera5 on OS X at millions
of colours, but at thousands (65000 odd colours?) mozilla1 has banding
in the grey trunk area of the telegraph pole.

Mozilla seems to be reserving colours for something else. Which is
disappointing. I note that the shell picture in Eric's demo has a
similar problem:
So I presume this is a general problem with the jpeg display code in gecko.

Despite googling the web and the evolt archives I can't find any mention
of this sort of behaviour.
Is this limited to OS X or a general feature of mozilla/gecko?

I assume the only way round this is to avoid images with gentle
gradients between colours?

I'd be inclined to dismiss it and say that moz users are few and far
between and probably run in millions of colours anyway - but then there
is that looming AOL gecko changeover, 30 million users who probably
don't know how to alter the display prefs on their computers...

My apologies if all that was a bit fuzzy, I'm coming down with a sore
throat/cold thingy and that's the way my brain feels today.


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