#!/usr/bin/perl -w
# 
# Example 9-2. A grid of red squares collapses in on itself, 
# then expands to its original state.

use strict;
use SWF qw(Movie Shape DisplayItem);

SWF::setScale(1.0);

# Define a grid 

my $grid = 8;
my ($w, $h) = ($grid*100, $grid*100);

# Create a square

my $s = new SWF::Shape();
$s->setLineStyle(1, 255, 0, 0);
$s->movePenTo(0,0);
$s->drawLineTo(0, 50);
$s->drawLineTo(50, 50);
$s->drawLineTo(50, 0);
$s->drawLineTo(0, 0);

# The displayList array holds the DisplayList objects as they are placed onstage

my @displayList = ();
my $m = new SWF::Movie();
$m->setDimension($w, $h);

# Place a grid of squares on the stage and store the reference to each DisplayItem

foreach my $i (0..$grid-1) {
    foreach my $j (0..$grid-1) {
        my $item = $m->add($s);
        $item->moveTo($i*100, $j*100);
        push @displayList, $item;
    }
}

# Now create 30 frames; in each frame, move each square
# 1/30th of the way toward the center of the grid, and rotate
# the square 360/30 degrees. Then repeat the same thing in the
# opposite direction, ending up where we started.

my $frames = 30;
my ($cx, $cy) = ($w/2, $h/2);
foreach my $direction (1, -1) {          # 1 =in, -1 = out
    foreach my $f (1..$frames) {
        foreach my $i (0..$grid-1) {
            foreach my $j (0..$grid-1) {
                $displayList[$i*$grid+$j]->move(
                    $direction*(int($cx-$i*100)/$frames), 
                    $direction*(int($cy-$j*100)/$frames));
                $displayList[$i*$grid+$j]->rotate(360/$frames); 
            }
        }
        $m->nextFrame();
    }
}

# Create the SWF file

$m->save("example9-2.swf");