Re: [Matplotlib-users] Overlapping labels in pie charts

[Rune V. S. <rv...@gm...>]

Hello again, and thanks.

I did not have a chance to look at this until now but using arc instead of
angle worked out great.

2010/3/24 Jae-Joon Lee <lee...@gm...>

> You should not use "angle" style if you change the x,y position (this
> is due to the algorithm of how the line connecting two points are
> create).
>
> Try something like below instead.
>
>   if foo:
>       if theta - foo < 10:
>           print >>sys.stderr, "Overlapping, offsetting a little bit"
>           y1 = y1 + 0.1
>            if x1 > 0 :
>               cstyle="arc,angleA=180,armA=30,armB=10,angleB=%f"%(-theta,)
>           else:
>               cstyle="arc,angleA=0,armA=30,armB=10,angleB=%f"%(theta,)
>
> There is not much documentation of how each algorithm works (it is
> beyond my english skill). They are loosely based on the latex pstrick
> package and the screenshot in the following link may be useful to get
> some idea though.
>
>
> http://matplotlib.sourceforge.net/users/annotations_guide.html#annotating-with-arrow
>
> Regards,
>
> -JJ
>
>
> 2010/3/24 Rune V. Sjøen <rv...@gm...>:
> > Hello again, and thank you very much for the answer, suddenly it all got
> > much clearer to me. The only 'issue' I am having is (from screenshot)
> what
> > happens to the line pointing to Logs when I try to offset it a little bit
> on
> > the Y axis. It looks like either the angleA or angleB is wrong, but I
> don't
> > see and reason why it would be as the X coordinates does not change.
> >
> > Another thing I do not quite understand is what that patchB does.
> >
> >         figure(1, figsize=(6,6))
> >         ax = axes([0.1, 0.1, 0.8, 0.8])
> >
> >         labels = 'Frogs', 'Hogs', 'Dogs', 'Logs'
> >         fracs = [45, 135 ,1, 1]
> >
> >         p = pie(fracs)
> >
> >         foo = None
> >         for p1, l1 in zip(p[0], labels):
> >
> >            r = p1.r
> >            dr = r*0.1
> >            t1, t2 = p1.theta1, p1.theta2
> >            theta = (t1+t2)/2.
> >
> >            xc = cos(theta/180.*pi)*r
> >            yc = sin(theta/180.*pi)*r
> >            x1 = cos(theta/180.*pi)*(r+dr)
> >            y1 = sin(theta/180.*pi)*(r+dr)
> >
> >            if x1 > 0 :
> >                x1 = r+2*dr
> >                ha, va = "left", "center"
> >                cstyle="angle,angleA=180,angleB=%f"%(-theta,)
> >                print >> sys.stderr, ha, ",A,", va
> >            else:
> >                x1 = -(r+2*dr)
> >                ha, va = "right", "center"
> >                cstyle="angle,angleA=0,angleB=%f"%(theta,)
> >                print >> sys.stderr, ha, ",B,", va
> >
> >            if foo:
> >                if theta - foo < 10:
> >                    print >>sys.stderr, "Overlapping, offsetting a little
> > bit"
> >                    y1 = y1 + 0.1
> >            foo = theta
> >
> >            annotate(l1,
> >                     (xc, yc), xycoords="data",
> >                     xytext=(x1, y1), textcoords="data", ha=ha, va=va,
> >                     arrowprops=dict(arrowstyle="-",
> >                                     connectionstyle=cstyle,
> >                                     patchB=p1))
> >
> > - Rune
> >
> > 2010/3/23 Jae-Joon Lee <lee...@gm...>
> >>
> >> This should be doable using the annotation. Here is a simple cook-up I
> >> just did. it uses a  naive algorithm to place the labels, but I guess
> >> it gives you an idea how things work.
> >> a screenshot is attached.
> >>
> >> Regards,
> >>
> >> -JJ
> >>
> >>
> >> from pylab import *
> >>
> >> # make a square figure and axes
> >> figure(1, figsize=(6,6))
> >> ax = axes([0.1, 0.1, 0.8, 0.8])
> >>
> >> labels = 'Frogs', 'Hogs', 'Dogs', 'Logs'
> >> fracs = [15,30,45, 10]
> >>
> >> explode=(0, 0.05, 0, 0)
> >> p = pie(fracs, explode=explode, shadow=True)
> >> title('Raining Hogs and Dogs', bbox={'facecolor':'0.8', 'pad':5})
> >>
> >> for p1, l1 in zip(p[0], labels):
> >>    r = p1.r
> >>    dr = r*0.1
> >>    t1, t2 = p1.theta1, p1.theta2
> >>    theta = (t1+t2)/2.
> >>
> >>    xc, yc = r/2.*cos(theta/180.*pi), r/2.*sin(theta/180.*pi)
> >>    x1, y1 = (r+dr)*cos(theta/180.*pi), (r+dr)*sin(theta/180.*pi)
> >>    if x1 > 0 :
> >>        x1 = r+2*dr
> >>        ha, va = "left", "center"
> >>        tt = -180
> >>        cstyle="angle,angleA=0,angleB=%f"%(theta,)
> >>    else:
> >>        x1 = -(r+2*dr)
> >>        ha, va = "right", "center"
> >>        tt = 0
> >>        cstyle="angle,angleA=0,angleB=%f"%(theta,)
> >>
> >>    annotate(l1,
> >>             (xc, yc), xycoords="data",
> >>             xytext=(x1, y1), textcoords="data", ha=ha, va=va,
> >>             arrowprops=dict(arrowstyle="-",
> >>                             connectionstyle=cstyle,
> >>                             patchB=p1))
> >>
> >> show()
> >
> >
>