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distance colour gradient: highlight as indicator of focus by contrast.

From: Jonathan Chetwynd <j.chetwynd@btinternet.com>
Date: Wed, 29 Oct 2003 21:16:39 +0000
To: www-style@w3.org
Message-Id: <2FC31F2A-0A55-11D8-9FC4-0003939B5AD0@btinternet.com>

Is there a way to easily mimic distance colour gradient?

		highlight onmouseover or onfocus is a relatively crude method of 
indicating focus by contrast*.
		(normally colour contrast is dramatically enhanced in the foreground.)

thanks!

Jonathan Chetwynd
http://www.peepo.co.uk
"A web by people with learning difficulties"

*Could we introduce a feature 'fecolormatrix: neutralise', if another 
solution is not to hand?

http://www.peepo.co.uk/test/neutralise.svg has many artefacts, but is a 
marker.
It uses complementary colours underneath the original, so that as 
opacity decreases, everything moves towards #777.
However opacity melds this with the background colour.
For an item, one could set the value of neutralise at 0.7 say, which 
would mean 0.7 opacity as well, but perhaps provide an option to 
specify a bg colour, which would allow hue to be regularised, and also 
maintain an apparent opacity of 1.0 in case of overlapping items.

essentially  'fecolormatrix:saturate' appears or attempts to maintain 
luminance, this is very clear when printed in B+W
The result is that hue is easily distinguished, because of relative 
luminance at minimal saturation, even when opacity is used to dull it.
without opacity, the luminance is startlingly bright, for distance, and 
hence the contrast pronounced.
(nb 'stroke' seems unaffected, not sure if this is my coding, or 
design.)
http://www.peepo.co.uk/test/saturate.svg.

http://www.peepo.co.uk uses opacity rather than either of these 
solutions, and isn't quite right. The blacks are too hard.
Received on Wednesday, 29 October 2003 16:11:33 GMT

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