Re: Style sheet misuse advice

On Mon Feb 03 22:13:33 1997, in <Pine.SOL.3.91.970203121217.10258h-100000@koa.iolani.honolulu.hi.us>, Joel N. Weber II wrote:
>On Wed, 29 Jan 1997, John Pozadzides wrote:
>> Raising one other interesting yet off topic point.  Why haven't browser
>> manufacturers implemented a little "warning system" if you will, which
>> warns a user that text or link colors are set to the same color as a
>> background.  Then they would at least be aware of the fact that they are
>> looking at a page that might have hidden text...
>If you have the logic to detect sane colors, you might as well also 
>change the foreground to something sane so the text will be readable.
>But how should a browser behave if you have #000000 and #000100
>                                                 http://www.cyclic.com/~nemo
><nemo@koa.iolani.honolulu.hi.us>                    <devnull@gnu.ai.mit.edu>
>"...For I have not come to call the righteous, but sinners." -- Matthew 9:13

If the browser is at all smart, it will detect colors that are "too similar"
rather than only exact matches.  I would guess that (RF-RB)**2 + (GF-GB)**2
+(BF-BB)**2 would be a decent metric, where the first letter refers to the
color and the second to Foreground or Background, and users could either
take a default minimum or be allowed to set their own.  If the colors are
too close, the browser could first reset the background color to XB = 255 -
XF, where X = R, G, or B.  If that's still too close (e.g., when
RF=GF=BF=128), it could use XB=0 or XB=255, depending on user preference.

You would probably also want some slightly smarter algorithms to deal with
the various types of color blindness, but these would obviously be provided
only on user request.  Dealing with authors who forget to use good page
design principles is fairly easy.  On the other hand, there also may not be
very much useful information on their pages if they are that careless, so
the effort to present the pages reasonably well may not be worthwhile.