#! /usr/bin/perl -w
#use strict;
use Tk;

my $status = "waiting for action...";
my ($width, $height) = (700, 600);
my ($startX, $startY) = (50, 50);
my ($lStartX, $lStartY) = (10, 10);

my $rectangles = {};
my $i = 0;
my $move = {};
my $psFile = "";

my $mw = MainWindow->new(-title => "Canvas");
$frameMenu = $mw->Frame( -relief => 'sunken', -borderwidth => 2)
    ->pack( -side => 'top', -fill => 'x');
$frameCanvas = $mw->Frame()
    ->pack( -side => 'top', -fill => 'both', -expand => 1);
$frameStatus = $mw->Frame( -relief => 'sunken', -borderwidth => 2)
    ->pack( -side => 'bottom', -fill => 'x');

$frameStatus->Label( -text => 'Status: ', -borderwidth => 1, 
		     -relief => 'raised')
    ->pack( -side => 'left');
$frameStatus->Label( -textvariable => \$status )
    ->pack( -side => 'left');


my $psButton = $frameMenu->Button( -text => "Postscriptdatei erstellen",
				   -command => \&GetPSFilename )
    ->pack( -side => 'right');
$createRoomButton = $frameMenu->Button( -text => "CreateRoom", 
					-command => \&CreateRoom_GetLaenge )
    ->pack( -side => 'left');

$canvas = $frameCanvas->Canvas( -width => $width, -height => $height, 
				-background => 'yellow', -cursor => 'crosshair')
    ->pack ( -side => 'top', -fill => 'both', -expand => 1);

$canvas->Tk::bind("<ButtonPress-1>", [ \&ButtonDown, Ev('x'), Ev('y') ] );
$canvas->Tk::bind("<ButtonRelease-1>", [ \&ButtonUp, Ev('x'), Ev('y') ] );
$canvas->Tk::bind("<Button-2>", [ \&Button2Click, Ev('x'), Ev('y') ] );
$createRoomButton->focus();


MainLoop();
# ------------------------------------------------------------
sub WriteInputField {
    my ($lText, $var, $proc) = @_;
    
    $label = $frameMenu->Label( -text => $lText)
	->pack( -side => 'left');
    $entry = $frameMenu->Entry( -textvariable => \$_[1])
	->pack( -side => 'left');
    $entry->focus();
    $button = $frameMenu->Button( -text => "Save", 
				  -command => $proc )
	->pack( -side => 'left' );
    $entry->bind("<Return>", $proc);
    
    return ($label, $entry, $button);
} # WriteInputField
# ------------------------------------------------------------
sub CreateRoom_GetLaenge {
    $roomLaenge = "";
    $createRoomButton->configure( -state => 'disabled');

    my ($label, $entry, $button)= &WriteInputField
	("Laenge eingeben in cm: ", $roomLaenge, \&CreateRoom_GetBreite);
    
} # CreateRoom_GetLaenge
# ------------------------------------------------------------
sub CreateRoom_GetBreite {
    $roomLaenge =~ /(\d+)/;     $roomLaenge = $1;
    if ($roomLaenge){
	$_->destroy() foreach ($label, $entry, $button);
	my ($label, $entry, $button) = &WriteInputField
	    ("Breite eingeben in cm: ", $roomBreite, \&CreateRoom_DrawRoom);
    } # if
    else {
	print ("Bitte einen numerischen Wert eingeben\n");
	$entry->focus();
    } # else
} # CreateRoom_GetBreite
# ------------------------------------------------------------
sub CreateRoom_DrawRoom {
    $roomLaenge =~ /(\d+)/;     $roomLaenge = $1;
    if ($roomLaenge){
	$_->destroy() foreach ($label, $entry, $button);

	$endX = $startX + $roomBreite;
	$endY = $startY + $roomLaenge;
	
	$canvas->createRectangle($startX, $startY, $endX, $endY, 
				 -fill => 'white');
	for ($startX..$endX){
	    if (($_-$startX) % 50 == 0){
		$canvas->createLine($_, $startY, $_, $endY, -width => 2);
	    }
	    elsif (($_-$startX) % 10 == 0){
		$canvas->createLine($_, $startY, $_, $endY);
	    }
   	}
	for ($startY..$endY){
	    if (($_-$startY) % 50 == 0){
		$canvas->createLine($startX, $_, $endX, $_, -width => 2);
	    }
	    elsif (($_-$startY) % 10 == 0){
		$canvas->createLine($startX, $_, $endX, $_);
	    } # elsif
	}
	$addRectangleButton = $frameMenu->Button
	    ( -text => 'Add Rectangle', -command => \&CreateRect_GetLaenge)
		->pack( -side => 'left');
	$addRectangleButton->focus();
    } # if
    else {
	print ("Bitte einen numerischen Wert eingeben\n");
	$entry->focus();
    } # else
} # CreateRoom_DrawRoom
# ------------------------------------------------------------
sub CreateRect_GetLaenge {
    $addRectangleButton->configure( -state => 'disabled' );

    my ($label, $entry, $button) = &WriteInputField
	("Laenge eingeben in cm: ", $rectLaenge, \&CreateRect_GetBreite);
    
} # GetRectangleLength
# ------------------------------------------------------------
sub CreateRect_GetBreite {
    $rectLaenge =~ /(\d+)/;     $rectLaenge = $1;
    if ($roomLaenge){
	$_->destroy() foreach ($label, $entry, $button);
	
	my ($label, $entry, $button) = &WriteInputField
	    ("Breite eingeben in cm: ", $rectBreite, \&CreateRect_Draw);
    } # if
    else {
	$rectLaenge = "";
	print ("Bitte einen numerischen Wert eingeben\n");
	$entry->focus();
    } # else
} # CreateRect_GetBreite
# ------------------------------------------------------------
sub CreateRect_Draw {
    $rectBreite =~ /(\d+)/;     $rectBreite = $1;
    if ($rectBreite){
	$_->destroy() foreach ($label, $entry, $button);

	$rectangles->{$i}->{laenge} = $rectLaenge;
	$rectangles->{$i}->{breite} = $rectBreite;
	$rectangles->{$i}->{xpos} = $lStartX;
	$rectangles->{$i}->{ypos} = $lStartY;
	$rectangles->{$i}->{rectAngle} = 
	    $canvas->createRectangle($lStartX, $lStartY, 
				     $lStartX + $rectBreite, 
				     $lStartY + $rectLaenge,
				     -fill => 'blue');

	$addRectangleButton->configure( -state => 'normal' );
	$rectLaenge = "";
	$rectBreite = "";
	$i++;
    } # if
    else {
	print ("Bitte einen numerischen Wert eingeben\n");
	$entry->focus();
    }
} # CreateRect_Draw
# ------------------------------------------------------------
sub ButtonDown {
    my ($canv, $x, $y) = @_;
    $move->{x1} = $canv->canvasx($x);    $move->{y1} = $canv->canvasx($y);
    $move->{x2} = "";    $move->{y2} = "";
} # ButtonDown
# ------------------------------------------------------------
sub Button2Click {
    my ($canv, $x, $y) = @_;
    $move->{x1} = $canv->canvasx($x);    $move->{y1} = $canv->canvasx($y);
    
    if ($move->{x1} and $move->{y1}){
	my $i = &GetSelectedItem($move, $rectangles);
	$canvas->delete($rectangles->{$i}->{rectAngle});
	undef $rectangles->{$i};

	print ("Deleted rectangle $i\n");
	$move->{x1} = ""; $move->{y1} = "";
    } # if

} # Button2Click
# ------------------------------------------------------------
sub ButtonUp {
    my ($canv, $x, $y) = @_;

    $move->{x2} = $canv->canvasx($x);    $move->{y2} = $canv->canvasx($y);
#    print ("Movement from $move->{x1}/$move->{y1} to $move->{x2}/$move->{y2}\n");
    &MoveItem($move);
    $move->{x1} = ""; $move->{x2} = ""; $move->{y1} = ""; $move->{y2} = "";
} # ButtonUp
# ------------------------------------------------------------
sub MoveItem {
    my ($form) = shift;

    my $i = &GetSelectedItem($form, $rectangles);
    if (defined($i)){
	my $moveX = $form->{x2} - $form->{x1};
	my $moveY = $form->{y2} - $form->{y1};
#	print ("Moving $i by $moveX/$moveY\n");
	$rectangles->{$i}->{xpos} += $moveY;
	$rectangles->{$i}->{ypos} += $moveX;

	$canvas->move($rectangles->{$i}->{rectAngle}, $moveX, $moveY);
	$i = undef;
    }
} # MoveForm
# ------------------------------------------------------------
sub GetSelectedItem {
    my ($form, $rectangles) = @_;

    foreach my $ra (keys %$rectangles){
	my ($rx1) = $rectangles->{$ra}->{xpos};
	my ($ry1) = $rectangles->{$ra}->{ypos};
	next unless defined $rx1;
	next unless defined $ry1;
	my ($rx2) = $rectangles->{$ra}->{laenge} + $rx1;
	my ($ry2) = $rectangles->{$ra}->{breite} + $ry1;
	
	if (&CoordinatesAreWithinRectangle( $form->{x1}, $form->{y1}, 
					    $rx1, $ry1, $rx2, $ry2 )){
	    return ($ra);
	} # if
    } # foreach 
    
    return (undef);
} # GetSelectedItem
# ------------------------------------------------------------
sub CoordinatesAreWithinRectangle {
    my ($y, $x, $rx1, $ry1, $rx2, $ry2) = @_;
    if ($x >= $rx1 and $x <= $rx2){
	if ($y >= $ry1 and $y <= $ry2){
	    return 1;
	}
    }
    return 0;
} # CoordinatesAreWithinRectangle
# ------------------------------------------------------------
sub GetPSFilename {
    $psButton->configure( -state => 'disabled');
    $label = $frameMenu->Label( -text => "Dateinamen angeben: ")
	->pack( -side => 'left');
    $entry = $frameMenu->Entry( -textvariable => \$psFile )
	->pack( -side => 'left');
    $entry->bind("<Return>", \&MakePSFile );
    $button = $frameMenu->Button( -text => "Save",
				  -command => \&MakePSFile)
	->pack( -side => 'left');

    $entry->focus();

} # GetPSFilename
# ------------------------------------------------------------
sub MakePSFile {
    $_->destroy foreach ($label, $entry, $button);
    
    if (-e $psFile){
	unlink($psFile);
    }
    $canvas->postscript( -file => $psFile );

    $psButton->configure( -state => 'normal');
}