in reply to Re: Dumping Tk canvas to postscript
in thread Dumping Tk canvas to postscript

Hey there hmmm sorry but I think I've mislead you a bit. The canvas is a scrolled canvas: 
 $c = $main_window 
    -> Scrolled("Canvas")-> pack();
  $canvas = $c->Subwidget("canvas");

[download]
What you suggested works great for printing out the visible portion but I want to print out the whole canvas (all the objects) hence the bbox.
Any ideas?

Thanks,
toonewbie

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Re: Re: Re: Dumping Tk canvas to postscript
by eserte (Deacon) on Mar 16, 2004 at 12:49 UTC
    I think this bit from the Tk::Canvas documentation:
    Note: by default Postscript is only generated for information that appears in the canvas's window on the screen.
    may be interpreted that only the visible part could be dumped.
[reply]
      hmmm. I have actually generated ps files for the whole scrolled region, did a ps2png conversion and plotted them out just fine. It's when I actually specify the pagewidth or pageheight to be something that I could printout on a printer I get a portion of the diagram clipped.

      Actually the problem seems to be related to moving the objects on the canvas. The ps generated seems to be of the original area where the objects were created. If I move the objects from their start point a portion of the diagram gets clipped. I was starting suspect the bbox but I use it to set my scroll region and it seams to be capturing the bounding area correctly and updates correctly as I move objects around. The width and height values calculated from bbox are correct as well. postscript just does not seem to notice that the top&left edge have changed. The more I move stuff the worse the clipping gets. I tried to compensate by specifying top&left with the -x&-y using the first two values from bbox. This helped to lock the diagram in place but there is still some small amount of clipping occassionally. This I have found out is just a problem with my ps viewer. For some reason it does not recognise the ps as letter size. If I force it to respect letter then all is good.

      So it looks like a combination of issues:
      1. postscript can't seem to track the top&left edge but this can be compensated for with -x&-y settings.
      2. my ps viewer does not recognise the ps file as letter size.

      I've added a program to my scratch pad that lets you experiment with this problem. You can move the middle box all over and print out the canvas. if you comment out the -x,-y parameters in the print sub you will see the clipping issue.

      Thanks to all for your help!
[reply]
        Trying your scratchpad code (with some editing, as whitespace and square brackets got lost) it works as expected I think --- I see squares in the middle, in the upper left and in the lower right corner, without any clipping. I am using ggv as my viewer (which in turn probably uses ghostscript), Tk is 800.025 on a RedHat 8.0 system.
[reply]

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