Re: with image and reversed x-axis

[Ethan M. <merritt@u.washington.edu>]

On Thursday 02 November 2006 09:01 am, Petr Mikulik wrote:
> >> In the following script, the map (for a 3D file) is shifted in the
> >> opposite (wrong) direction in the png output file compared to
> >> other terminals
> >
> > wxt and pdf give the same output as png
> > x11 and postscript give a different result, as you noted.
>
> The data are fixed once read from the datafile. Then they are
> plotted. If the x-axis is set to be reversed, the drawing should be
> reversed as well.

*None* of the drivers I have tested reversed the drawing.
The PostScript and x11 driver shift it over to the left, but
do not reverse it.

The wxt, png, and pdf driver neither shift nor reverse.

My test command was
   set xrange [140:-20]
   plot 'blutux.rgb' binary array=128x128 flipy \
       format='%uchar%uchar%uchar' using ($1+$2+$3) with image


> Using 'binary1' file from demo/, try:
>
> reset
> set autoscale fix
>
> set xrange [3:-3]
> #set xrange [-3:3]
>
> plot 'binary1' binary u 1:2:($3+$1*0.1+$2*0.3) w image
>
> set terminal png; set output "s.png"
> replot
> set term postscript color; set out 'a.ps'; replot
> set term fig color; set out 'a.fig'; replot
> set out; set term pop
>
>
> There, only the postscript file gives an expected drawing, while x11
> and png drawings are wrong.

Huh?  I get identical results in postscript and x11.

But you are correct that in this case the image is reversed in addition
to being shifted.  So the various sub-modes of "with image" are 
inconsistent as to whether they reverse or do not reverse the image,
even for the *same* output driver.


-- 
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle WA