[pstricks] Hatch angles

[Denis Girou]

>>>>> "Vincent.Guirardel" == vincent  <vin.gui at laposte.net> writes:

    Vincent.Guirardel> ...

    Vincent.Guirardel> So I use hatchangle=56.3, but the line and the hatches dont look really 
    Vincent.Guirardel> parallel.

    Vincent.Guirardel> ...

    Vincent.Guirardel> Actually, I noticed that while I zooming with ghostview, the defect
    Vincent.Guirardel> seems to decrease (but it remains noticeable). So I looked at 600dpi
    Vincent.Guirardel> resolution, and then the result looked fine. Is it related to what the 
    Vincent.Guirardel> doc says about ``funny patterns at low resolution'' p28 while talking 
    Vincent.Guirardel> about cross-hatches ?

  I thought that 600 dpi was the default resolution value on "modern" systems
since many years... For instance, it was already the case in the config.ps
configuration file for dvips from the teTeX 1.0 branch in 1999 (and perhaps
before!)

  Anyway, I rather think that the problem that you submit is an artefact
introduced by GhostScript (at least with the X11 device). The effect that you
speak about is still visible on screens at normal resolutions, and both with
the versions 7.05 and 8.10 that I tested. The appearance is correct only for
magnifications of 16, 32 and 64. But you can also verify that converting the
PostScript file to PDF and viewving this resulting file with Acroread or xpdf
give the correct behavior, even without magnification.

D.G.