Hi all
Interesting - I've seen the smoothing in SVG. I don't think there's any
way to switch it off in the file format. I don't think there are options
to disable compression Qt's PDF export. I should file a bug report about
the Pdf, as I don't think it's the correct default behaviour (if anyone
else has time please feel free to do this).
As you suggest, using rectangles mostly works, though in practice, you
get annoying light lines between the rectangles due to anti-aliasing in
PDF viewers, etc.
One solution is to resample the image to a higher resolution - this
should reduce the effect of the smoothing and the compression. In fact
the default image widget will do this if the image x and y grid is not
regular. The downside is the extra space used in the output file.
So Michael, you could try making the 2D dataset slightly irregular in
its gridding. This should force veusz to resample the image to higher
resolution. I can't remember how it chooses the resampled image size,
but I think it takes the smallest difference between bin widths and
resamples to that (with some limit).
I should add an option to resample to XXX DPI.
Chers
Jeremy
On 05/12/2016 12:23 PM, Gromov, Sergey wrote:
Hi all,
I have the same issue on Windows, up to the latest version.
My guess it has to do with extensive bitmap compression (it looks like jpg with
colour compression), through which the colours indeed change sometimes
substantially (read I cannot use this PDF for publication). SVG blurs the
bitmap, which is also bad.
See the example (pdf vs. png vs. svg) attached.
I wonder if it is possible to produce PDFs with bitmaps replaced with
primitives (i.e. matrices of boxes) of given colour... I did this trick when I
had to produce a vector output with image, i.e. reading the matrix and plotting
it as 'xy' with given coordinates and square symbol emulating pixels. But that
is usually a lot of work...
Sergey
-----Original Message-----
From: Veusz-discuss [mailto:veusz-discuss-boun...@gna.org] On Behalf Of
Jeremy Sanders
Sent: 12 May 2016 10:31
To: Michael Clerx <c...@michaelclerx.com>; veusz-discuss@gna.org
Subject: Re: [Veusz-discuss] Image to pdf conversion
On 11/05/16 23:24, Michael Clerx wrote:
I've used Veusz to create some nice 2d-density plots using the "image"
widget.
However, when I export my graph to PDF the colours change considerably.
I'm using the bluegreen colormap (inverted).
Has anybody else experienced similar problems?
I don't see the problem with the mandelbrot example with bluegreen on linux,
after exporting to PDF. There is some smoothing introduced, but the colours look
ok.
What version and platform are you using?
Thanks
Jeremy
_______________________________________________
Veusz-discuss mailing list
Veusz-discuss@gna.org
https://mail.gna.org/listinfo/veusz-discuss
_______________________________________________
Veusz-discuss mailing list
Veusz-discuss@gna.org
https://mail.gna.org/listinfo/veusz-discuss
_______________________________________________
Veusz-discuss mailing list
Veusz-discuss@gna.org
https://mail.gna.org/listinfo/veusz-discuss
