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Perl/Tk scrolling question...

by jdtoronto (Prior)
on Apr 12, 2007 at 20:15 UTC ( #609737=perlquestion: print w/ replies, xml ) Need Help??
jdtoronto has asked for the wisdom of the Perl Monks concerning the following question:

Esteemed monks,

I have Perl/Tk code which produces a window something like a day-timer week at a view page. Across the top I have the days of the week, down the left hand side time of day in 10 or 15 minute increments. Now comes my problem.

I have scroll bars on both X and Y axes. But when I scroll horizontally I want the days of the week to scroll with the body (the times to remain visble), but when I scroll vertically I want the days of the week to stay visible whilst the times scroll with the body.

The body of the window consists merely of a huge collection of buttons, one for each time slot for each day of the week.

How do I do it?

jdtoronto

Comment on Perl/Tk scrolling question...
Re: Perl/Tk scrolling question...
by jdporter (Canon) on Apr 12, 2007 at 20:40 UTC

    Not that I've tried it — and my experience with Tk leads me to intuit that it won't work out as cleanly as it should — but it sounds to me like you want two scrollables, one inside the other. The outer scrollable would only scroll horizontally. The thing it contains (a Pane, I suppose) would contain a frame at the top, non-scrolling, and a scrollable below that which scrolls vertically.

    A word spoken in Mind will reach its own level, in the objective world, by its own weight
Re: Perl/Tk scrolling question...
by graff (Chancellor) on Apr 13, 2007 at 00:18 UTC
    So if the user scrolls horizontally to the "middle" of the day-of-week range, then scrolls vertically to the "middle" of the time-of-day range, both the day-of-week labels and time-of-week labels need to still be visible, right?

    For that to work, I think you actually need three scrolling windows:

    • a "column headings" window that shows the day-of-week labels (has a height of one line), and only scrolls left-to-right;

    • a "row headings" window that shows the time-of-day labels (has a width of 5 characters: HH:MM), and only scrolls up-and-down;

    • the data grid table of 7 columns by however many rows (each cell is as big as you think necessary), and scrolls in all directions.

    I don't have any specific coding examples handy, but I do remember that there's a way to set up callbacks on the scrollbars for a given scrolling window. The idea is that the scrollbars for the grid window will invoke call backs that will trigger an equivalent amount of scrolling in the x dimension on the column-heading window, as well as an equivalent amount of y-dimension scrolling on the row-heading window.

    Shouldn't be too hard, once you find the right Tk man page (probably Tk::Scrollbar). Good luck with that.

    (update: fixed the link and a spelling error, and wanted to add that you probably want to limit the number of visible scrollbars for all those scrolling windows -- display just one scrollbar for each direction -- and bear in mind that Tk lets the user to a "grab-and-drag" to scroll the grid window.)

Re: Perl/Tk scrolling question...
by zentara (Archbishop) on Apr 13, 2007 at 11:43 UTC
    If I understand your desire correctly, you want linked scrollbars. Here is a canvas example, you can probably make it work on other widgets. I use it in my tvguide program.
    #!/usr/bin/perl use warnings; use strict; use Tk; my $mw = new MainWindow(); $mw->geometry("600x400+200+200"); #for xscroll, must be packed before midframe to be visible my $botframe = $mw->Frame(-bg=>'grey45') ->pack(-fill=>'x',-side=>'bottom'); my $midframe = $mw->Frame(-bg=>'grey45')->pack(); my $midframel = $midframe->Frame(-bg=>'grey45') ->pack(-side=>'left',-expand=>1,-fill=>'y'); my $midframer = $midframe->Frame(-bg=>'grey45') ->pack(-side=>'right'); my $num_channels = 40; my $canvasp; my $canvast = $midframer->Canvas( -bg =>'pale goldenrod', -width=>2400, -height=>25, #need to set scrollregion with a bit extra to ensure #endpoint accuracy. See xscrollit sub -scrollregion=>[-10,0,7450,25], -xscrollincrement => 1, )->pack(-side=>'top'); #for canvasp and yscroll my $midframer1 = $midframer->Frame(-bg=>'grey45') ->pack(-side=>'top'); my $yscroll = $midframer1->Scrollbar( -orient => 'vertical', -command => \&yscrollit, -troughcolor =>'grey45', -activebackground =>'lightseagreen', -background => 'lightseagreen', )->pack(-side=>'right',-fill=>'y'); my $canvasxsd = $botframe->Canvas( #dummy filler -bg =>'grey45', -width=>75, -height=>25, -borderwidth=>0, ) ->pack(-side=>'left'); my $xscroll = $botframe->Scrollbar( -orient => 'horizontal', -command => \&xscrollit , -troughcolor =>'grey45', -activebackground =>'lightseagreen', -background => 'lightseagreen', )->pack(-side=>'right', -fill=>'x',-expand =>1); print "$xscroll\n"; $canvasp = $midframer1->Canvas( -bg =>'lightsteelblue', -width=>2400, -height=> 50 * $num_channels, -scrollregion=>[-10,0,7450,(33 * $num_channels)], -xscrollincrement => 1, -yscrollincrement => 1, -xscrollcommand => [ 'set', $xscroll ], -yscrollcommand => [ 'set', $yscroll ], ) ->pack(-side=>'left');#,-fill=>'both'); my $canvasd = $midframel->Canvas( #top of left frame dummy filler -bg =>'grey45', -width=>75, -height=>25, -borderwidth =>0, )->pack(-side=>'top'); my $canvass = $midframel->Canvas( #left frame canvas -bg =>'lightseagreen', -width=>75, -height=> 50 * $num_channels, -scrollregion=>[0,0,75,(33 * $num_channels)], -yscrollincrement => 1, ) ->pack(-side=>'top'); #fill in some sample data to see scrolling action for( 1 .. 33 * $num_channels){ $canvass->createText(38, 10 + $_ * 33, -text => "C $_" , ); } #set up top frame canvas... a timeline for(0..7200){ if( $_ % 300 == 0){ my $time = $_ / 300; my $padded = ("0" x (2-length( $time ))).$time; $canvast->createLine($_,0,$_,12,-width=> 4,-tags=>['tick'] ); $canvast->createText($_, 20, -text=> "$padded:00",-tags=>['ti +ck'] ); }elsif( $_ % 150 == 0){ my $time = ($_ - 150) / 300; my $padded = ("0" x (2-length( $time ))).$time; $canvast->createLine($_,0,$_,10,-width => 2,-tags=>['tick']); $canvast->createText($_, 20, -text=> "$padded:30",-tags=>['ti +ck'] ); }elsif( $_ % 75 == 0){ $canvast->createLine($_,0,$_,6,-width => 1, -tags=>['tick']); } } #set up main frame canvas for(0..7200){ $canvasp->createText($_ * 20, 5 + $_ * 20, -text=> "Test $_", -tags=>['data'] ); } #--------------------------------------------------------------- MainLoop; ################################################################ ###################################################################### +# sub xscrollit{ my $fraction = $_[1]; $canvast->xviewMoveto($fraction); $canvasp->xviewMoveto($fraction); } ###################################################################### sub yscrollit{ my $fraction = $_[1]; $canvass->yviewMoveto($fraction); $canvasp->yviewMoveto($fraction); } ####################################################################

    I'm not really a human, but I play one on earth. Cogito ergo sum a bum
      zentara

      Thank you once again! It does EXACTLY what I need. I had it about half worked out before I saw your response, but now it is fully worked out.

      Why can't I give you more than one vote?

      jdtoronto

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