How do I print a canvas graphic ?

[gerry]

I've written a perl 5.8 client running on W2K that communicates with my perl server module running on each of my 3 Unix Boxes. Each Unix box is running the same C++ application and is set up for load balancing. My client connects via a socket to each box and receives back various statistics on the health of the application for each of the servers.

My perl client then takes the information and creates a canvas to graph the information on. I have been using a screen print utility to capture the graph and print it because I haven't been able to figure out how to print the graphic displayed on the canvas from within the perl module.

The graph I want to print is a typical XY Multi-Line Graph with text information around it. I have 2 arrays where each element in each array represents a minute in time for a 2400 clock - 1440 elements (24*60). Each element in array 1 contains the total number of Transactions processed in that minute of time. The other array is similar, but contains the total number of threads running.

I have looked at CPAN but have been unsuccessful in finding what I need.

Do you know of a way to do this? Is there some utility that I need? Is there a way to save the canvas or graphic in a format that some other graphics program can use?

Your help is greatly appreciated.

a humble perl neophyte

[polettix]

Update: Ok, I misread your question. A look into the links is still worth your time, anyway, for the generation of graphics in well-known image formats.

A look at the Graphics section in CPAN may enlighten you, especially the Chart family. Note that this is only a subset of what you can really do for graphics in Perl (I'm thinking about Image::Magick, which shouldn't be needed in your case).

[gerry]

I checked out CPAN like you suggested and the Chart::Plot and Chart::Plot::Canvas sounds promising. But it's too late to re-write it now.

I was hoping there might be some way to just print the Canvas object that I created.

Thanks for your help.

[zentara]

I don't mess around on windows, but here is how it is done on linux. The code is probably close. There is Win::Photo for Win32 now......see Tk::WinPhoto for ActiveState. And see Tk Screen and Canvas Screenshots

If you want to try the postscript method on win32, here is how you do it.

#!/usr/bin/perl
use Tk;
#to change the background color, edit the ps file 
#  0.000 0.000 0.000 setrgbcolor AdjustColor 
#  fill 

$width = 800;
$height = 500;
my $main = MainWindow->new();
my $canvas = $main->Canvas( -width=>$width, -height=>$height, -backgro
+und=>"black");
$canvas->pack( -expand=>1,-fill=>'both');

&create;

$canvas->update;
$main->update;

$main->Button(
    -text    => "Save",
    -command => [sub {
         $canvas->update;
         my @capture=();
         my ($x0,$y0,$x1,$y1)=$canvas->bbox('all');
         @capture=('-x'=>$x0,'-y'=>$y0,-height=>$y1-$y0,-width=>$x1-$x
+0);
         $canvas -> postscript(-colormode=>'color',
                               -file=>$0.'.ps',
                               -rotate=>0,
                               -width=>800,
                               -height=>500,
                               @capture);

                              }

  ]  )->pack;


MainLoop;

sub create{
$canvas->createOval(100, 100, 600, 600,-fill=>'green')

}

[gerry]

I'll check it out and see if it will accomplish the job. Thanks!

[BrowserUk]

My perl client then takes the information and creates a canvas ...

What type of "canvas"? Is this a Tk::Canvas widget or something else?

[gerry]

Yes, it is a Scrolled Tk::Canvas as in

$c = $mg->Scrolled("Canvas", -scrollbars => 'se', .....)

[BrowserUk]

Then you might consider using the postscript() method to output the canvas to a file and then send that to a postscript printer or use some .ps to .html or similar utility to do the printing.