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Unbind canvas items and Forget

by Phinix (Acolyte)
on Oct 31, 2012 at 01:46 UTC ( #1001586=perlquestion: print w/ replies, xml ) Need Help??
Phinix has asked for the wisdom of the Perl Monks concerning the following question:

Greetings meisters and monks! I've lurked around this place for many years, each time I've taken on a Perl project. Sadly I was born in America and not Europe where they actually value education, and so am expected to go tens of thousands of dollars into debt to learn anything, leaving me with the internet and late fees at the public library as my only affordable or equitable path to knowledge. Recently I have been attempting a simple application that uses a Canvas to create a background image, then places some additional sized canvases around on top of it as pseudo buttons, bound to mouse events, with image backgrounds over them so that they blend in with the main canvas background. So, first I define the main canvas and background.
my $maincanvas = $mw-> Canvas(-highlightthickness => 0); my $maincanvasi = $mw-> Photo(-file => "$img.jpg"); $maincanvas->createImage(0,0, -image => $maincanvasi, -anchor => 'nw') +;
Then I make the various sub-canvas pseudo buttons (because bind wants a widget and canvas allows a background image):
my $subcanvas1 = $maincanvas-> Canvas(-width => 64, -height => 54, -hi +ghlightthickness => 0); my $subcanvas1i = $maincanvas->Photo(-file => "$button1.jpg"); $subcanvas1-> form(-left => '420', -top => '444'); $subcanvas1-> createImage(0, 0, -image => $subcanvas1i, -anchor => 'nw +');
Further down I bind these sub-canvas buttons to mouse events:
$subcanvas1-> Tk::bind('<Button-1>' => sub { dostuff } );
Later in the script I want to be able to mass-delete and formForget all of these sub-canvas objects. However, when I attempt to do this to an array containing the names of all these psuedo button canvas objects like this:
foreach (@canvasbuttons) { $_->delete('all'); $_->formForget; }
...Perl complains at me saying:
Tk::Error: Window "<yada>" is not managed by the tixForm manager... ... <ButtonRelease-1> (command bound to event)
So, my question is, how can I mass-unbind all these sub-canvas canvas psuedo buttons and unpack them?

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Re: Unbind canvas items and Forget
by Anonymous Monk on Oct 31, 2012 at 02:13 UTC

    So, my question is, how can I mass-unbind all these sub-canvas canvas psuedo buttons and unpack them?

    Try  $obj->destroy , no forgetting, no deleting, just destroy

    or post a short, self-contained, runnable example, and I'll fix it for you

Re: Unbind canvas items and Forget
by zentara (Archbishop) on Oct 31, 2012 at 09:29 UTC
    Can you provide a minimal working example of your code? Packing a subcanvas into another canvas is seldom seen done. Maybe you would have better results using Frames to manage your canvases?

    Here is some code using pack instead of the form manager.

    #!/usr/bin/perl use warnings; use Tk; use strict; my $w=20; my $x=0; my $y=0; my $mw=tkinit; my $f1 = $mw->Frame()->pack(); my $f2 = $mw->Frame()->pack(); my $c1 = $mw->Canvas->pack(-in =>$f1); my $c2 = $mw->Canvas(-bg=>'black')->pack(-in =>$f2); my $b = $mw->Button(-text=>'Switch Frames', -command => sub{ $c1->packForget; $c2->packForget; $c1->pack(-in => $f2); $c2->pack(-in => $f1); })->pack; for (0..9) { my $item=$c1->createRectangle($x,$y,$x+20,$y+20, -fill=>'red', -activefill=>'yellow'); $x+=20; } MainLoop;

    I'm not really a human, but I play one on earth.
    Old Perl Programmer Haiku ................... flash japh

      Thanks for the replies! I put together a quick example. Keep in mind this is a very rough sketch...

      Basically what it does, is set up the frame/canvas structure, then invokes &scan1start; which is a subroutine to build the first fake canvas button, and bind it to right and left mouse (not the reset button, leave that alone for now!)

      Clicking the button runs the next two subroutines to create two more buttons (and also changes the first button's color). I have some commented code as in my working example this changes an image not the background color, but you get the idea.

      Clicking either of these new buttons will change their color, and right-clicking will change it back. Right-clicking the first button hides the two higher buttons, but only if they are "off" (black in this example.)

      You can test all of this and it works fine, until you click the reset button. This button is supposed to basically destroy all the buttons, then run the initial subroutine to re-create the first button and set up it's bindings, basically starting all over. However, as you can see perl complains a ton and the button is never re-created.

      Here's the sample code:

      #!/usr/bin/perl use warnings; use Tk; use strict; my $mw = new MainWindow; $mw-> geometry('640x480'); $mw-> resizable( 0, 0 ); my $numscan1 = 0; my $numscan2 = 0; my $numscan3 = 0; my $leftframe = $mw-> Frame(); $leftframe->form(-left => '%0', -right => '%25', -bottom => '%99', -to +p => '%1'); my $resetb = $leftframe-> Button(-text => 'Reset', -command => \&reset + )->form(-left => '%50', -top => '%50'); my $rightframe = $mw-> Frame(-relief => 'groove', -borderwidth => 1); $rightframe-> form(-left => $leftframe, -right => '%99', -bottom => '% +99', -top => '%1'); my $maincanvas = $rightframe-> Canvas(-background => 'blue', -highligh +tthickness => 0); $maincanvas-> form(-left => '%1', -right => '%99', -bottom => '%99', - +top => '%1'); # I use canvas so I can have a background image beneath my items. # This is how I was doing that, though for this example # I'm just using background color instead: #my $maincanvasi = $mw-> Photo(-file => "background.jpg"); #$maincanvas->createImage(0,0, -image => $maincanvasi, -anchor => 'nw' +); #Here are some fake buttons using sub-canvas: my $scan1 = $maincanvas-> Canvas(-width => 64, -height => 54, -highlig +htthickness => 0); #my $scan1img1 = $maincanvas->Photo(-file => "scan1img1.jpg"); #my $scan1img2 = $maincanvas->Photo(-file => "scan1img2.jpg"); my $scan2 = $maincanvas-> Canvas(-width => 64, -height => 54, -highlig +htthickness => 0); #my $scan2img1 = $maincanvas->Photo(-file => "scan2img1.jpg"); #my $scan2img2 = $maincanvas->Photo(-file => "scan2img2.jpg"); my $scan3 = $maincanvas-> Canvas(-width => 64, -height => 54, -highlig +htthickness => 0); #my $scan3img1 = $maincanvas->Photo(-file => "scan3img1.jpg"); #my $scan3img2 = $maincanvas->Photo(-file => "scan3img2.jpg"); &scan1start; MainLoop; sub reset { my @buttons = ($scan1,$scan2,$scan3); foreach (@buttons) { $_-> destroy; } &scan1start; } sub scan1start { if ($numscan1 == 0) { $scan1-> form(-left => '187', -top => '319'); #$scan1-> createImage(0, 0, -image => $scan1img1, -anchor => ' +nw'); $scan1-> configure(-background => 'black'); $scan1-> Tk::bind('<Button-1>' => sub { #$scan1->delete($scan1img1); $numscan1 = 1; &scan2start; &scan3start; &scan1start; } ); $scan1-> Tk::bind('<Button-3>' => sub { }); } elsif ($numscan1 == 1) { $scan1-> form(-left => '187', -top => '319'); #$scan1-> createImage(0, 0, -image => $scan1img2, -anchor => ' +nw'); $scan1-> configure(-background => 'white'); $scan1-> Tk::bind('<Button-3>' => sub { if (($numscan2 == 0) && ($numscan3 == 0)) { #$scan2->delete($scan2img1); #$scan3->delete($scan3img1); #$scan1->delete($scan1img2); $scan2->formForget; $scan3->formForget; $numscan1 = 0; &scan1start; } } ); $scan1-> Tk::bind('<Button-1>' => sub { }); } } sub scan2start { if ($numscan2 == 0) { $scan2-> form(-left => '102', -top => '211'); #$scan2-> createImage(0, 0, -image => $scan2img1, -anchor => ' +nw'); $scan2-> configure(-background => 'black'); $scan2-> Tk::bind('<Button-1>' => sub { #$scan2->delete($scan2img1); $numscan2 = 1; &scan2start; } ); $scan2-> Tk::bind('<Button-3>' => sub { }); } elsif ($numscan2 == 1) { $scan2-> form(-left => '102', -top => '211'); #$scan2-> createImage(0, 0, -image => $scan2img2, -anchor => ' +nw'); $scan2-> configure(-background => 'white'); $scan2-> Tk::bind('<Button-3>' => sub { #$scan2->delete($scan2img2); $numscan2 = 0; &scan2start; } ); $scan2-> Tk::bind('<Button-1>' => sub { }); } } sub scan3start { if ($numscan3 == 0) { $scan3-> form(-left => '202', -top => '211'); #$scan3-> createImage(0, 0, -image => $scan3img1, -anchor => ' +nw'); $scan3-> configure(-background => 'black'); $scan3-> Tk::bind('<Button-1>' => sub { #$scan3->delete($scan3img1); $numscan3 = 1; &scan3start; } ); $scan3-> Tk::bind('<Button-3>' => sub { }); } elsif ($numscan3 == 1) { $scan3-> form(-left => '202', -top => '211'); #$scan3-> createImage(0, 0, -image => $scan3img2, -anchor => ' +nw'); $scan3-> configure(-background => 'white'); $scan3-> Tk::bind('<Button-3>' => sub { #$scan3->delete($scan3img2); $numscan3 = 0; &scan3start; } ); $scan3-> Tk::bind('<Button-1>' => sub { }); } }
        Hi, your code runs, and the problem is as you describe. However, I think your problem stems from trying to use the Form manager to place multiple canvases on top of another base canvas. I may be wrong, but this is what I was taught. Forming or packing a canvas, on top of another canvas, does not make it an item of the underlying canvas.

        When you try to put another widget into another widget, as opposed to putting them in a container widget, like a frame or window, you need to use the createWindow method of the underlying Canvas. Here is a simple example.

        By the way, what sort of things are you putting in your sub-canvases? Why can't you just use a small image, and bind to it for your mouse actions? Also, buttons can be given background images, with Tk::Compound

        A second example following, shows how to hide createWindow items.

        #!/usr/bin/perl use warnings; use strict; use Tk; use Tk::JPEG; use Image::Magick; my $im = Image::Magick->new; my $image = shift || 'zen16.jpg'; #roughly a 500x500 jpg my ($width, $height, $size, $format) = $im->Ping($image); my $mw = MainWindow->new(); $mw->fontCreate('big', -family=>'courier', -weight=>'bold', -size=>int(-18*18/14)); my $canv = $mw->Canvas( -bg => 'lightsteelblue', -relief => 'sunken', -width => $width, -height => $height)->pack(-expand => 1, -fill => 'both'); my $img = $mw->Photo(-file => $image ); $canv->createImage( 0, 0, -image => $img, -anchor => 'nw' ); my $text = $mw->Scrolled('Text', -bg=>'lightyellow', -scrollbars=>'osoe', ); my $textcontainer = $canv->createWindow( $width/2, $height/2, -window => $text, -width => $width -200, -height => $height-200, -state => 'normal'); my $button = $mw->Button( -bg=>'lightblue', -text=>'Push Me', -command=> sub{ $text->insert('end',time."\n")}, ); my $butcontainer = $canv->createWindow( 125, 25, -window => $button, -width => 125, -height => 25, -state => 'normal'); my $ctext = $canv->createText( 300,20, -font=>'big', -fill=> 'white', -text=>'la di da'); bunchOfBoxes(); $text->focus; MainLoop(); sub bunchOfBoxes { for(0..10){ my $window = $canv->Checkbutton(-text=> $_); $canv->createWindow(450, 20 + ($_ * 20), -window=> $window); } }

        Showing hiding of a createWindow item

        #!/usr/bin/perl use warnings; use strict; use Tk; use Tk::JPEG; use Tk::PNG; #demonstrates need for subwidget method #on Scrolled Canvas, to use lower or raise my $mw = new MainWindow; my $canvas = $mw->Scrolled('Canvas', -bg => 'white', -xscrollincrement => 1, -yscrollincrement => 1, -confine => 1, -scrollbars => 'se', -width => 200, -height => 200, -closeenough =>3, -scrollregion => [ 0, 0, 500, 500 ], )->pack(qw/ -fill both -expand 1 -side top/); my $realcanvas = $canvas->Subwidget('scrolled'); $mw->Button(-text=>"Raise Bunny", -command => sub{ # $canvas->lower( 'bunny' ,'tux' ); # will cause error # need subwidget of the scrolled canvas $realcanvas->raise( 'bunny' ,'background' ); })->pack(); $mw->Button(-text=>"Lower Bunny", -command => sub{ $realcanvas->lower( 'bunny' ,'background' ); })->pack(); my $rect = $canvas->createRectangle(0,0,500, 500, -fill => 'orange', -tags => ['background'], ); my $bunny = $mw->Photo(-data => get_bunny() ); $canvas->createImage( 40, 40, -image => $bunny, -anchor => 'nw', -tags => ['bunny'], ); my $window = $canvas->Checkbutton(-text=> 'Foo'); my $win = $canvas->createWindow(20,20, -window=> $window, ); $canvas->move($win,-1000,-1000); #dx, dy $mw->Button(-text=>"Show Checkbox", -command => sub{ $canvas->move($win, 1000,1000 ); })->pack(); $mw->Button(-text=>"Hide Checkbox", -command => sub{ $canvas->move($win, -1000,-1000 ); })->pack(); # $canvas->lower( 'bunny' ,'background' ); # will cause error # need subwidget $realcanvas->lower( 'bunny' ,'background' ); MainLoop; sub get_bunny{ return 'iVBORw0KGgoAAAANSUhEUgAAAB4AAAAjEAIAAABcJvHFAAAACXBIWXMAAAsSAAALEgHS3 +X78AAAD F0lEQVR42u1YL+yqUBj1vfcLbhY3C44is8BIREYSG9FoNBqNkok2aFhp2BhJDWyadCZN/i +lOGxan jRdOuRsPxl/f+23vJKfX7x6+73znu5dK5RviV9QPDMMwDIPP7/f7/X6XTWU0Go1Go06n0+ +l0PM/z PC91CNu2bduWZVmW5bLpjsfj8XgcBEEQBJPJZDKZZAw0n8/n8zkCGYZhGIYgCIIgFEt3OB +wOh8OA gKZpmqZlDDedTqfTKRnO933f95GVer1er9fz0BVFURRFxCR3QfyMQfv9fr/fDyLgOI7jON +mo419k JUkMBoPBYJCRNBrxdrvdbrco6qvVarVaIWdFpQO/5tIcFBbE4nQ6nU6nJIpHjlGlEklTFE +VRFDIa T32/3+/3+3jqHMdxHBcfB2sK6HFFURRFeb1er9crfksoNUrr0GvUfxGfnA+FmX+QALDItG +LDA6O2 pQyCJFkPqxMDK2p9LodOAhQaLRjfoKRGo2wObl3G8PoDsA0Gb5Q5oonjfSNKTh96AOh+u9 +1ut1uS FuZrONPJ7bJ06tA9TDDsD6QkCnDltEDRkV1Q9AnENyuk8hcyChkkcZKo5uv1er1er3S6cA +PkFXSx MQodPrXFg2zTEsVANhO2JNdEmVo80ub7K/lSDHPyLkNaXrVarVar2W46LMuyLFsKaZ7neZ +4nvwFR NGKeGjYajUajkXz9z+RLn8/n8/ms/ANIQXq5XC6Xy/v9fr/fvw3p9Xq9Xq9VVVVV9fF4PB +6Pokhc r9fr9Vr6s6Lf4dNpbS6/exQA3BHDt/fkPl3wwT85wlcEcrCHZyHO1tmOSl95iGLcQN80Td +M0jTa1 LMuyLF3XdV03TdM0zWaz2Ww2Xdd1XRenDlDHgTbtvj/ykMZpDm/6LpfL5XLBmGi32+12G6 +Th5RAA Pne73W63iwfGYFosFovF4kOZrtVqtVoN16TD4XA4HPAAKDp5yZUkSZIk1GGz2Ww2m91ut9 +vt0Mof lcfxeDwej7PZbDaboRFbrVar1SJfIsLdYZfn8/l8Pue3y1zyiH9VAMFElb5Yp/+PcvAbH/ +25ox5S PYYAAAAASUVORK5CYII='; }

        I'm not really a human, but I play one on earth.
        Old Perl Programmer Haiku ................... flash japh

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