Re: cvs: log cb broken

[Petr M. <mi...@ph...>]

> >   "bug_logcb.gp", line 4: color axis has cb coord of -10; must be above 0 
> >   for log scale!
> > 
> > plot 'matrix.dat' matrix with image
> >
> > What has broken in cvs?
> 
> But the error message is correct.  
> The cb values go negative and therefore log scale cannot work.
> 
> I see that 4.2 does draw something, but I don't understand 
> what it is drawing.  I'd say that 4.2 fails to detect the
> error, while CVS is doing the right thing by reporting it.

No, the error message is not correct, it should autoscale the cb-value to a 
lower positive value, as it does in the same case for "with image" for 
logged y or z axes. There must have been some change in cvs which broke this 
for "matrix with image".

Gnuplot has been always excellent in handling negative ranges in log scales. 
For example,

	gnuplot> set xrange [-10:10]; set log y; plot 1/x

---
PM