Re: Problem/bug with ends of thick lines in graphics
- To: mathgroup at smc.vnet.net
- Subject: [mg88472] Re: Problem/bug with ends of thick lines in graphics
- From: David Reiss <dbreiss at gmail.com>
- Date: Tue, 6 May 2008 06:40:40 -0400 (EDT)
- References: <fvhe27$3t8$1@smc.vnet.net> <fvmmuc$8gt$1@smc.vnet.net>
Good try Jens! Alas it creates a series of points that create a
jagged outer boundary where the disks of the points undulate. But an
approach like this may work for the end points.
I have communicated with the folks at WRI about this and the bug is
known.
--David
On May 5, 6:18 am, Jens-Peer Kuska <ku... at informatik.uni-leipzig.de>
wrote:
> Hi,
>
> Plot[x, {x, 1/3, 3/4}, PlotRange -> {{0, 1}, {0, 1}},
> PlotStyle -> {AbsoluteThickness[20]}] /.
> Line[pnts_] :> {AbsolutePointSize[20], Point[pnts]}
>
> may help in this case. But AFAIK Mathematica has no directive
> to set the line ends.
>
> Regards
> Jens
>
> David Reiss wrote:
> > In a quick search of things I haven't found a mention of the following
> > simple graphics issue and I'm checking in with the group to see if
> > there is a memory of its mention and if there is a simple fix (and
> > which is not a complicated hack) that I've not been able to come up
> > with.
>
> > Consider the following graph:
>
> > Plot[x, {x, 1/3, 3/4}, PlotRange -> {{0, 1}, {0, 1}},
> > PlotStyle -> {AbsoluteThickness[20]}]
>
> > When you plot it you will see that the line's ends are not
> > rectangular, whereas you would certainly want them to be so. (An
> > alternative would be to have them be rounded, for example, but the
> > question will remain the same whatever your preference is.) Rather
> > they appear as polygonal in a way inconsistent with the line itself.
>
> > One assums that this is an artifact of how the line is rendered based
> > on the individual line segments, and that that segmental rendering has
> > to do something with how a segment relates to the segments on either
> > side of it. The lack of a segment beyond the end segment presumably
> > runes the algorithm for rendering in a way that leads to this
> > appearance.
>
> > I have two related questions here. The first is how, if at all
> > possible, to fix this in a general way through some specific options
> > settings for the graphics function.
>
> > The second is how, when exporting this graphic as, say, a PDF, to make
> > it behave properly.
>
> > There was a trick in pre version-6 Mathematica that would involve
> > adding an explicit postscript command to the PlotStyle option. Though=
> > this would not (I think) correct the screen appearance of the graphic,
> > it would properly fix it when the graphic was exported to PDF or EPS.
> > Here is an example of how it was done:
>
> > Plot[x, {x, 1/3, 3/4}, PlotRange -> {{0, 1}, {0, 1}},
> > PlotStyle -> {{ PostScript["0 setlinecap"],AbsoluteThickness[20]}}]
>
> > This, however, no longer works in Mathematica 6+ presumably because of
> > the new way that graphics rendering is handled.
>
> > Does anyone have any solutions to either or both of these issues?
>
> > Thanks!
>
> > --David