Re: How to generate a graph image of specific size without labels?

[Anthony T. <A.T...@gr...>]

On Tue, 23 Mar 2010 14:57:00 -0700
Ethan Merritt <merritt@u.washington.edu> wrote:

| On Monday 22 March 2010 23:34:34 Anthony Thyssen wrote:
| > | How to generate a graph image of specific size without labels?
| > | 
| > | that is I what the 'border' of the plot to be the 'border' of the
| > | final image that is of specific size.  It is vital for including
| > | the plot results into other image mosaics.
| > | 
| > 
| > With suggestions from   Daniel J Sebald  I am posting the method
| > which I used with gnuplot v4.2.3-1 under Fedora 10.
| > 
| > The script broke with a OS version upgrade to gnuplot v4.2.6-1
| > under fedora 12
| > 
| > 
| >    set terminal png size 340,210
| >    unset key
| >    set format ""
| >    set xtics ( 75, 150, 225 ) scale 2
| >    set ytics ( 0.25, 0.5, 0.75 ) scale 2
| >    set xrange [0:300]
| >    set yrange [0:1]
| > 
| > The 'size' was designed to actually generate a 'graph' that was
| > exactly 300x184 pixels in size after it is 'autocroped' using
| > ImageMagick.
| 
| Your script is not doing what you stated that you wanted to do.
| If you want to guarantee that the plot boundary is a particular
| size, you should do that directly.  You can't rely on auto-crop
| because the size will change depending on at least the font size, 
| if not the phase of the moon.
| 
Yes I know, that is because I was NOT able to figure out how to get an
exact sized image, and had to fudge it.  I am not suprised it broke!
But that is why I asked the mail list.

| If you really have no labels or other plot decorations outside
| of the plot borders, then you want:
| 
|   set term png size 340,210
|   set lmargin at screen 0
|   set rmargin at screen 1
|   set bmargin at screen 0
|   set tmargin at screen 1
| 
| If for some reason you want to work with some white space around it,
| and then later crop to final size:
| 
|   set term png size 374,231    # NB: 10% bigger than the final size
|   set lmargin at screen 0.05
|   set rmargin at screen 0.95
|   set bmargin at screen 0.05
|   set tmargin at screen 0.95
| 
I remember trying to use the 'margin' settings, but without success.

however I'll try again now.  -- YES it is now working!!!
The first block is what I was needing.

Perhaps this should be in the FAQ :-)



| > Now both versions generate a image 340x210 pixels but the
| > graph area which was 300x184 pixels
| > is now under gnuplot v4.2.6-1  producing   292x171  pixels
| > 
| > In another example  a gnuplot "png size" of 
| > was producing     150x89  pixel graph
| > is now producing  142x76
| 
| Right. That method was never reliable.
| That's why we added a mechanism for specifying the boundaries
| precisely.
|
It worked, but I didn't think it was reliable.


| -- 
| Ethan A Merritt
| Biomolecular Structure Center
| University of Washington, Seattle 98195-7742



  Anthony Thyssen ( System Programmer )    <A.T...@gr...>
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