gnuplot-beta

post.trm image max colors patch

[Daniel J S. <dan...@ie...>]

Attached is a bug fix for the PostScript image using the five operand form (i.e., no palette).  The bug was that the max colors was not set to 2^N, where N is 1, 2, 4, 8, or 12.  So if the gray scale max was 128 (2^7) the brightness was lower than it should have been.

Dan

Re: post.trm image max colors patch

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

On Thursday 09 February 2006 09:44 pm, Daniel J Sebald wrote:
> Attached is a bug fix for the PostScript image using the five operand
> form (i.e., no palette).  The bug was that the max colors was not set
> to 2^N, where N is 1, 2, 4, 8, or 12.  So if the gray scale max was
> 128 (2^7) the brightness was lower than it should have been.

Could you please provide a demo script that shows the difference
between before/after this patch?

	thanks,

		Ethan

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

Re: post.trm image max colors patch

[Daniel J S. <dan...@ie...>]

Ethan Merritt wrote:
> On Thursday 09 February 2006 09:44 pm, Daniel J Sebald wrote:
> 
>>Attached is a bug fix for the PostScript image using the five operand
>>form (i.e., no palette).  The bug was that the max colors was not set
>>to 2^N, where N is 1, 2, 4, 8, or 12.  So if the gray scale max was
>>128 (2^7) the brightness was lower than it should have been.
> 
> 
> Could you please provide a demo script that shows the difference
> between before/after this patch?

Sure, from the demo directory:

set palette gray maxcolors 128
plot 'blutux.rgb' binary array=128x128 flipy format='%uchar%uchar%uchar' using ($1+$2+$3)/3 with image
set output
set term post monochrome eps
set output 'test.eps'
replot
set output
# To illustrate other terms work
set term png
set output 'test.png'
replot
set output

The EPS appears too dark without the patch when maxcolors is 2 4 16 256 or 4096.

Dan

Re: post.trm image max colors patch

[Daniel J S. <dan...@ie...>]

Daniel J Sebald wrote:

> The EPS appears too dark without the patch when maxcolors is 2 4 16 256 
> or 4096.

That should be NOT 2 4 16 256 or 4096.

Dan

Re: post.trm image max colors patch

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

> Attached is a bug fix for the PostScript image using the five operand form 
> (i.e., no palette).  The bug was that the max colors was not set to 2^N, 
> where N is 1, 2, 4, 8, or 12.  So if the gray scale max was 128 (2^7) the 
> brightness was lower than it should have been.

The patch seems OK for me.

---
PM