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RE: White border in plots

  • To: mathgroup at smc.vnet.net
  • Subject: [mg35431] RE: [mg35404] White border in plots
  • From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
  • Date: Fri, 12 Jul 2002 04:28:48 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

> -----Original Message-----
> From: Thomas Manz [mailto:thomas.manz at physik.uni-regensburg.de]
To: mathgroup at smc.vnet.net
> Sent: Thursday, July 11, 2002 11:24 AM
> Subject: [mg35431] [mg35404] White border in plots
> 
> 
> Hello!
> 
> I want to calculate some patterns but I always get artifacts. 
> The reason
> seems to be the white border around the plots. If I calculate 
> 100 x 100 points
> and plot or export them (see example below), the picture is 
> really 100 x 100
> pixels but with a white border. So my calculations are 
> 'squeezed' (some lines
> and rows are missing!).
> Does anyone have an idea how to get rid of this white border or will I
> really have to export my tables to a textfile and use another 
> software zu produce
> a bitmap-file??
> 
> 
> Example:
> t = Table[Sin[(x + y)], {x, 0, 100}, {y, 0, 100}];
> Export["test.tif", 
>   ListDensityPlot[t, Frame -> False, Mesh -> False, ImageSize -> {100,
> 100}]]
> 
> Thanks a lot for your help!
> 
> Best regards
> Thomas Manz
> 
> 
> 

Thomas,

I don't know whether this is of any help. The white margin you see is the
rest of the plot region not filled by your density plot. You may recognize
this, when you specify Background -> Hue[0] (now beeing red).

Deplorably the Option Background -> None is only effective for Text objects.
So I played for a while  with the option PlotRange to have filled all of the
range but nothing cut off from your plot, e.g.

In[91]:=
graph2 = ListDensityPlot[t, Frame -> False, Mesh -> False, 
        PlotRegion -> {{0 - #1, 1 + #2}, {0 - #3, 1 + #4}}, 
        Background -> Hue[0]] &[0.019, 0.019, 0.3, 0.3]

The effects where not predictable (to me), especially I couldn't get rid off
a small margin at the top or at the bottom. If #3 and #4 are great enough
and equal (you can make them arbitrarily great) there remains a small margin
at top and bottom as seen from Mathematica rendering. Exporting this as a
.tif and looking at that from Microsoft Photo Editor, I saw the margins at
bottom and right.

Exporting to .eps and displaying with Ghostview gave a similar appearance to
rendering within Mathematica . A short inspection of the .eps file makes me
guess that there is some slight imprecision with the calculation of the
bounding box and/or the scaling factor. Perhaps it is possible to fix the
postscript and convert it to another format. But then it may appear to be
easier to extract the gray values form the RasterGraphics and generate your
graphic file by different means (perhaps not too difficult in your case).

Possibly you will be content with the smallest margin possible (when you
color it white, or better adapt it to the background of you final
application).

--
Hartmut


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