matplotlib-users

[Matplotlib-users] grayscale text in eps images

[Darren D. <dd...@co...>]

I am displaying some images and overlaying a scalebar. The image on the screen 
displays the requested white text and bar, but they are black in the eps image.

text(1,1,'Hi John!',color=1) ---> black text in eps
text(1,1,'Hi Jochen!',color='w') ---> black text in eps

text(1,1,'I thought this would work...',color=[1,1,1]) ---> black text in eps
text(1,1,'but it didnt, so I tried this...',color='y') ---> yellow text in eps
text(1,1,'and this...',color=[1,1,0]) ---> yellow text in eps

text(1,1,'and finally this.',color=[1,1,.99]) ---> white text in eps

I tried to track this through backend_ps.py, where:
@ line 103:
    def set_color(self, r, g, b, store=1):
        if (r,g,b) != self.color:
            if r==g and r==b:
                self._pswriter.write("%1.3f setgray\n"%r)
                print "%1.3f setgray"%r

>>> 1.000 setgray

becomes this in the eps file: 0.000 setgray

I think there is too much going on behind the scenes for me to follow. This is as far as I could get.

-- 

Darren

Re: [Matplotlib-users] grayscale text in eps images

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

>>>>> "Darren" == Darren Dale <dd...@co...> writes:

    Darren> I am displaying some images and overlaying a scalebar. The
    Darren> image on the screen displays the requested white text and
    Darren> bar, but they are black in the eps image.

Hi Darren,

I'm having trouble replicating the problem.  Make sure you have an
up-to-date matplotlib.  For example, in CVS, I get the expected
behavior in agg and ps with

  from pylab import *
  subplot(111, axisbg='red')
  text(0.5, 3.5,'this is black', color=0)  
  text(0.5, 2.5,'this is black', color='k')
  text(0.5, 1.5,'this is white', color=1)  
  text(0.5, 0.5,'this is white', color='w')
  axis([0,2,0,4])
  savefig('test.ps')
  show()

If you are still having troubles, please submit a complete test
script, and the output of --verbose-helpful when you run it.

Is it possible you have a pre 0.72 CVS?  There were a couple of bugs I
introduced into PS CVS before the last release, but I think I cleaned
them up.

Hope this helps,
JDH

Re: [Matplotlib-users] grayscale text in eps images

[Darren D. <dd...@co...>]

Wow, I was going crazy trying to reproduce this. Your script works fine. Try 
this one:

from pylab import *

a=rand(100,100)
ax=axes()
ax.imshow(a)
ax.xaxis.set_visible(False)
ax.yaxis.set_visible(False)
ax.text(10,10,'white',color='w')
ax.text(10,20,'black',color='k')
savefig('temp.ps')


Both the x *and* y axes have to be set_visible(False) to reproduce the 
behavior.

Darren


On Sunday 20 February 2005 07:47 pm, John Hunter wrote:
> >>>>> "Darren" == Darren Dale <dd...@co...> writes:
>
>     Darren> I am displaying some images and overlaying a scalebar. The
>     Darren> image on the screen displays the requested white text and
>     Darren> bar, but they are black in the eps image.
>
> Hi Darren,
>
> I'm having trouble replicating the problem.  Make sure you have an
> up-to-date matplotlib.  For example, in CVS, I get the expected
> behavior in agg and ps with
>
>   from pylab import *
>   subplot(111, axisbg='red')
>   text(0.5, 3.5,'this is black', color=0)
>   text(0.5, 2.5,'this is black', color='k')
>   text(0.5, 1.5,'this is white', color=1)
>   text(0.5, 0.5,'this is white', color='w')
>   axis([0,2,0,4])
>   savefig('test.ps')
>   show()
>
> If you are still having troubles, please submit a complete test
> script, and the output of --verbose-helpful when you run it.
>
> Is it possible you have a pre 0.72 CVS?  There were a couple of bugs I
> introduced into PS CVS before the last release, but I think I cleaned
> them up.
>
> Hope this helps,
> JDH
>
>
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-- 

Darren

Re: [Matplotlib-users] grayscale text in eps images

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

>>>>> "Darren" == Darren Dale <dd...@co...> writes:

    Darren> Wow, I was going crazy trying to reproduce this. Your
    Darren> script works fine. Try this one:

    ....

    Darren> Both the x *and* y axes have to be set_visible(False) to
    Darren> reproduce the behavior.

OK, that helps.  Thanks.

The problem can be fixed in backend_ps RendererPS.set_color, change
the line

            self.color = (r,g,b)

to 

            if store: self.color = (r,g,b)

Thanks for the report and example.

JDH