matplotlib-users

[Matplotlib-users] Postscript problem

[Carol L. <car...@sr...>]

I am trying to overlay a polar grid on a previously plotted axis.

The plot looks fine on the screen and in a png file.  However, I get an 
error message when making a postscript file.


Basically, I drew one set of axes in rectangular coordinates and then 
tried to overlay a polar grid with:
	# Save current axes
	ax = gca()
	l, b, w, h = ax.get_position()	# Normalized
	axp = axes([l, b, w, h], polar=True, frameon=False)
	theta = arange(0,1,0.001) * 2*2*pi
	r = array([1.0 for i in range(len(theta))])
	polar(theta, r, color='k')
	angles = arange(0,360,45)
	labels = ('','NE','','NW','','SW', '','SE' '')
	thetalines, thetatext = thetagrids(angles, labels)
	# Restore previous axes
	axes(ax)

I am using a version of the CVS code that I downloaded today, Nov. 30, 
2004.  I have source code I could send, but I doubt you want an 
attachment sent to the list.

Here are the messages that appear:
   File "testoverlay.py", line 90, in ?
     savefig('overlay.ps')
   File "/usr/lib/python2.3/site-packages/matplotlib/matlab.py", line 
1008, in savefig
     manager.canvas.print_figure(*args, **kwargs)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_gtkagg.py", 
line 66, in print_figure
     agg.print_figure(filename, dpi, facecolor, edgecolor, orientation)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_agg.py", 
line 385, in print_figure
     ps.print_figure(filename, dpi, facecolor, edgecolor, orientation)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 570, in print_figure
     self.figure.draw(renderer)
   File "/usr/lib/python2.3/site-packages/matplotlib/figure.py", line 
254, in draw
     for a in self.axes: a.draw(renderer)
   File "/usr/lib/python2.3/site-packages/matplotlib/axes.py", line 
3125, in draw
     l.draw(renderer)
   File "/usr/lib/python2.3/site-packages/matplotlib/lines.py", line 
257, in draw
     lineFunc(renderer, gc, xt, yt)
   File "/usr/lib/python2.3/site-packages/matplotlib/lines.py", line 
513, in _draw_dotted
     renderer.draw_lines(gc, xt, yt)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 275, in draw_lines
     self._draw_lines(gc,points[0:1000])
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 264, in _draw_lines
     self._draw_ps("\n".join(ps), gc, None)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 375, in _draw_ps
     self.set_linedash(*gc.get_dashes())
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 103, in set_linedash
     if seq:
   File "/usr/lib/python2.3/site-packages/numarray/generic.py", line 
477, in __nonzero__
     raise RuntimeError("An array doesn't make sense as a truth value. 
Use sometrue(a) or alltrue(a).")
RuntimeError: An array doesn't make sense as a truth value.  Use 
sometrue(a) or alltrue(a).


-- 
Ms. Carol A. Leger
SRI International			Phone: (650) 859-4114
333 Ravenswood Avenue G-273
Menlo Park, CA 94025                    e-mail: le...@sr...

[Matplotlib-users] Postscript problem

[Carol L. <car...@sr...>]

> Yep, this is a bug.  In backend_ps in the the set_linedashes function
> on line 103, replace the line
> 
>     if seq: 
> 
> with 
> 
>     if seq is not None and len(seq):
> 
> My guess is you are using numarray, and if memory serves numarray but
> not Numeric fails on using an array as a boolean, which is what
> backend ps is doing here.
> 
>
Yes, I am using numarray.  I made the change to line 103 and now line 
102 is reporting a similar error.

Traceback (most recent call last):
   File "testoverlay.py", line 91, in ?
     savefig('overlay.ps')
   File "/usr/lib/python2.3/site-packages/matplotlib/matlab.py", line 
1008, in savefig
     manager.canvas.print_figure(*args, **kwargs)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_gtkagg.py", 
line 66, in print_figure
     agg.print_figure(filename, dpi, facecolor, edgecolor, orientation)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_agg.py", 
line 385, in print_figure
     ps.print_figure(filename, dpi, facecolor, edgecolor, orientation)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 570, in print_figure
     self.figure.draw(renderer)
   File "/usr/lib/python2.3/site-packages/matplotlib/figure.py", line 
254, in draw
     for a in self.axes: a.draw(renderer)
   File "/usr/lib/python2.3/site-packages/matplotlib/axes.py", line 
3125, in draw
     l.draw(renderer)
   File "/usr/lib/python2.3/site-packages/matplotlib/lines.py", line 
257, in draw
     lineFunc(renderer, gc, xt, yt)
   File "/usr/lib/python2.3/site-packages/matplotlib/lines.py", line 
513, in _draw_dotted
     renderer.draw_lines(gc, xt, yt)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 275, in draw_lines
     self._draw_lines(gc,points[0:1000])
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 264, in _draw_lines
     self._draw_ps("\n".join(ps), gc, None)
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 375, in _draw_ps
     self.set_linedash(*gc.get_dashes())
   File 
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_ps.py", 
line 102, in set_linedash
     if (offset,seq) != self.linedash:
   File "/usr/lib/python2.3/site-packages/numarray/generic.py", line 
477, in __nonzero__
     raise RuntimeError("An array doesn't make sense as a truth value. 
Use sometrue(a) or alltrue(a).")
RuntimeError: An array doesn't make sense as a truth value.  Use 
sometrue(a) or alltrue(a).
-- 
Ms. Carol A. Leger
SRI International			Phone: (650) 859-4114
333 Ravenswood Avenue G-273
Menlo Park, CA 94025                    e-mail: le...@sr...

Re: [Matplotlib-users] Postscript problem

[John H. <jdh...@ac...>]

>>>>> "Carol" == Carol Leger <car...@sr...> writes:

    >> Yep, this is a bug.  In backend_ps in the the set_linedashes
    >> function on line 103, replace the line if seq: with if seq is
    >> not None and len(seq): My guess is you are using numarray, and
    >> if memory serves numarray but not Numeric fails on using an
    >> array as a boolean, which is what backend ps is doing here.
    >> 
    Carol> Yes, I am using numarray.  I made the change to line 103
    Carol> and now line 102 is reporting a similar error.

Sorry for all the troubles here.  Try this function for set_linedash
in backend_ps

    def set_linedash(self, offset, seq):        
        if self.linedash is not None:
            oldo, oldseq = self.linedash
            if offset==oldo and seq==oldseq: return        
            
        if seq is not None and len(seq):
            s="[%s] %d setdash\n"%(_nums_to_str(*seq), offset)
            self._pswriter.write(s)
        else:
            self._pswriter.write("[] 0 setdash\n")
        self.linedash = (offset,seq)

Re: [Matplotlib-users] Postscript problem

[John H. <jdh...@ac...>]

>>>>> "Carol" == Carol Leger <car...@sr...> writes:

    >> Yep, this is a bug.  In backend_ps in the the set_linedashes
    >> function on line 103, replace the line if seq: with if seq is
    >> not None and len(seq): My guess is you are using numarray, and
    >> if memory serves numarray but not Numeric fails on using an
    >> array as a boolean, which is what backend ps is doing here.
    >> 
    Carol> Yes, I am using numarray.  I made the change to line 103
    Carol> and now line 102 is reporting a similar error.

Ignore my last post - the solution I posted was as buggy as before.  I
think I finally nailed this down.  Basically, we are comparing seq1
and seq2, either are possibly None, or general sequences, or arrays.
I wrote a little function

def seq_allequal(seq1, seq2):
    """
    seq1 and seq2 are either None or sequences or numerix arrays
    Return True if both are None or both are seqs with identical
    elements
    """
    if seq1 is None:
        return seq2 is None

    if seq2 is None:
        return False
    #ok, neither are None:, assuming iterable
        
    if len(seq1) != len(seq2): return False
    return alltrue(equal(seq1, seq2))

You should import alltrue and equal from the numerix module at the top
of backend_ps, add this function to backend_ps and then replace
set_linedash with

    def set_linedash(self, offset, seq):        
        if self.linedash is not None:
            oldo, oldseq = self.linedash
            if seq_allequal(seq, oldseq): return
            
        if seq is not None and len(seq):
            s="[%s] %d setdash\n"%(_nums_to_str(*seq), offset)
            self._pswriter.write(s)
        else:
            self._pswriter.write("[] 0 setdash\n")
        self.linedash = (offset,seq)


I think this is finally coherent.  At least it passes my tests now...

JDH

[Matplotlib-users] Semi transparent boxes around text and Postscript

[Carol L. <car...@sr...>]

The that the polar plot overlayed on a rectangular plot is working in 
Postscipt, I am having trouble with the semi-transparent boxes around 
the text.

The png file looks fine, but the postcript file does not show the 
differences in the alpha value.

Since the code is short, I'll supply it here:

#!/usr/bin python
from matplotlib.matlab import *

def OverlayText(xmax):
	x=0
	y = 0.65*xmax
	ystep = 0.2*xmax
	alpha = arange(0.0,1.2,0.2)

	
	for a in alpha:
		stext = 'Alpha = %.1f' % a
		t = text(x,y,stext)
		set(t,bbox={'edgecolor':'w','facecolor':'w','alpha':a})
		y = y - ystep


if __name__ == "__main__":
	# Make some kind of plot

	xmin = -750
	xmax = 750
	ymin = xmin
	ymax = xmax
	x = [xmin,xmax,xmax,xmin]
	y = [ymin,ymin,ymax,ymax]
	fill(x,y,'g',edgecolor='b')
	a = gca()
	a.set_xlim([xmin,xmax])
	a.set_ylim([ymin,ymax])


	OverlayText(xmax)

	savefig('overlay2.png')
	savefig('overlay2.ps')

	show()


-- 
Ms. Carol A. Leger
SRI International			Phone: (650) 859-4114
333 Ravenswood Avenue G-273
Menlo Park, CA 94025                    e-mail: le...@sr...

Re: [Matplotlib-users] Semi transparent boxes around text and Postscript

[John H. <jdh...@ac...>]

>>>>> "Carol" == Carol Leger <car...@sr...> writes:

    Carol> The that the polar plot overlayed on a rectangular plot is
    Carol> working in Postscipt, I am having trouble with the
    Carol> semi-transparent boxes around the text.

postscript doesn't support the alpha channel and there is nothing
matplotlib can do about it.  It's a postscript limitation.  Right now
the only vector output that supports alpha is SVG.  Hopefully we'll
get a PDF backend one day which also supports alpha.

JDH

Re: [Matplotlib-users] Semi transparent boxes around text and Postscript

[Norbert N. <No...@ne...>]

True. Just had to check this again to make sure, but even PS3 does not support 
Alpha transparency in any way. The big improvement there was bitmapped 
masking of images, but the whole concept of true transparency really seems to 
be an extremely new idea.


Am Donnerstag, 2. Dezember 2004 13:26 schrieb John Hunter:
> >>>>> "Carol" == Carol Leger <car...@sr...> writes:
>
>     Carol> The that the polar plot overlayed on a rectangular plot is
>     Carol> working in Postscipt, I am having trouble with the
>     Carol> semi-transparent boxes around the text.
>
> postscript doesn't support the alpha channel and there is nothing
> matplotlib can do about it.  It's a postscript limitation.  Right now
> the only vector output that supports alpha is SVG.  Hopefully we'll
> get a PDF backend one day which also supports alpha.
>
> JDH
>
>
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Re: [Matplotlib-users] Postscript problem

[John H. <jdh...@ac...>]

>>>>> "Carol" == Carol Leger <car...@sr...> writes:

    Carol> I am trying to overlay a polar grid on a previously plotted
    Carol> axis.  The plot looks fine on the screen and in a png file.
    Carol> However, I get an error message when making a postscript
    Carol> file.

Yep, this is a bug.  In backend_ps in the the set_linedashes function
on line 103, replace the line

    if seq: 

with 

    if seq is not None and len(seq):

My guess is you are using numarray, and if memory serves numarray but
not Numeric fails on using an array as a boolean, which is what
backend ps is doing here.

Overlaying a polar plot over a rectangular axes.  Man, what will they
think of next!?  You will send me the screenshot when you're done,
right?

JDH