Re: smooth shading & terminal specialities

[<tim...@en...>]

>> I don't quite understand what you mean by that.
>> How does a "vector graphic format" avoid having to draw filled
>> rectangles?  Do you mean there is native support for gradient fill?
>> In any case...
>
> Yes, native support for gradient fill.

Starting from Postscript level 3, which has been released in 1999
according to the date in the Adobe documentation. I don't know much about
the capabilities of printers regarding Postscript level 3.

However, the rendering is good for me with Ghostscript.

> OK. Let me try to explain, For drawing the "plotting area" in this
> image (http://gnuplot.sourceforge.net/demo_4.1/pm3d.8.png), which is
> nothing else but a bitmap image, gnuplot calls my terminal
>     term->set_color(...)
>     term->fillbox(...)
> 49 x 49 times. For bitmap teminal this doesn't really matter, but for
> my terminal it means constructing 49x49 paths and fill each one of
> them separately (bot at compile time of the image and when displaying
> it in GhostView or Acrobat), not to mention aliasing-artefacts (I
> don't know how they are called, but GhostView shows white stripes all
> over the plot).

This kind of artifacts due to antialiasing can sometimes be worked around
when you know that paths are adjacent. For the wxWidgets terminal which
uses Cairo to render, I had to use a different operator
(CAIRO_OPERATOR_SATURATE) to composite what you want to paint with what
already exists on the surface, so that the fill algorithm won't produce
white seams between adjacent polygons. There have been multiple threads i=
n
the cairo mailing list about that.
However, in postscript no such concept seem to exist, at least I can't
find any by looking quickly in the Adobe doc, but that may be worth
looking for.

By the way, the aquaterm terminal seems to have the same problem : see th=
e
pm3d plot on http://aquaterm.sourceforge.net/index.shtml?page=3Ds1

Finally, if gradient fills are to be used, Cairo can also do that, so it
should definitely go into a new terminal entry instead of a direct call.

Regards,

Timoth=E9e