Colour by depth in HEAD: survey viewing blues.

[Olly Betts]

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On Mon, Nov 24, 2003 at 07:25:03PM +0000, John P N Pybus wrote:
> I've built the pre-1.0.26 code from CVS head.  I like the new depth 
> gradient in aven!  However the tones are considerably darker than the 
> previous version.  The oranges/yellows are ok, but the blue is now 
> pretty hard to see against the black background.

It's not bad for me, but I can believe it'll depend on the monitor
and how it's set.

> I think that ideally a gradient which is uniformly bright (in a 
> perceptual sense) should be chosen.  For extra points it should be 
> linear in perceived colour difference.

I've just tried scaling the gradient by perceived luminosity
(brightness) but it doesn't work.

I tried weighting (as the eye is most sensitive to green and least
sensitive to blue) and just summing red, green, and blue unweighted.
Neither looks right - the middle colours of the gradient look too dull.

> At the very least, can we brighten up those blues a little though?
 
I've tried to do that, and it worked better.  Try copying the attached
gradient.pov into src and rebuilding.

> On an unrelated note, I noticed screen shots of a colour by year 
> version.

That's not currently in CVS - the changes were just too nasty so I
put them to one side pending some restructuring of the code.  That's
mostly done, but of course now the changes won't automatically apply!
But this will be in properly soon.

> I'd currently like to produce colour by survey grade.  No doubt 
> I'll find a way to hack it in as is

The survey grade/loop closure information really needs to be in the 3d
file.  Once that's done, adding "colour by survey grade" or "colour
by survey error" will be pretty easy with the new code structure.

> have you thought of creating general 'stylesheets' which could be used
> to specify all of the viewing parameters

I think this another aspect of the "presentation" code - that allows
you to save a series of "views" and animate between them.

> (and let you choose any depth gradient you fancy, of course)?

That's easy enough.  Currently you can do this but you have to rebuild.
But it's not hard to sort that out.

Cheers,
    Olly

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