GUI solution for masak's matchboxes puzzle on Niecza Perl 6

gtk-matchboxes.pl

# gtk-matchboxes.pl - GUI solution for http://irclog.perlgeek.de/perl6/2011-09-23#i_4469618
constant $GTK = "gtk-sharp,Version=2.12.0.0,Culture=neutral,PublicKeyToken=35e10195dab3c99f";
constant $GDK = "gdk-sharp, Version=2.12.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f";
constant $GLIB = "glib-sharp, Version=2.12.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f";
# use 'gacutil -l' to look up similar module details

constant Application    = CLR::("Gtk.Application,$GTK");
constant GdkCairoHelper = CLR::("Gdk.CairoHelper,$GDK");
constant GLibTimeout    = CLR::("GLib.Timeout,$GLIB");
constant GtkDrawingArea = CLR::("Gtk.DrawingArea,$GTK");
constant Window         = CLR::("Gtk.Window,$GTK");

Application.Init;
my $window = Window.new("matchboxes");
my $running = True;
my $gameCount = 0;
constant InitialMatches = 40;
my @matchesA = 0 xx (InitialMatches+1);
my @matchesB = 0 xx (InitialMatches+1);
my $windowSizeX = 600; my $windowSizeY = 500;
$window.Resize($windowSizeX, $windowSizeY);
my $drawingarea = GtkDrawingArea.new;
$drawingarea.add_ExposeEvent(&ExposeEvent);
GLibTimeout.Add( 1000, &TimeoutEvent);
$window.add_DeleteEvent(&DeleteEvent);
$window.Add($drawingarea);
$window.ShowAll;
while $running {  # event loop with custom body
    Application.RunIteration(False);  # handle all Gtk events
    my ($box, $count) = MatchBoxGame(InitialMatches);
    if $box eq 'A' { ++@matchesA[$count] } else { ++@matchesB[$count] }
    ++$gameCount;
}

# Randomly remove matches from box A or B until one of them is empty.
# Return the number of matches in the other box
sub MatchBoxGame($initialMatches)
{
    my $matchesA = my $matchesB = $initialMatches;
    while $matchesA > 0 && $matchesB > 0 {
        if rand < 0.5 { --$matchesA; }
        else          { --$matchesB; }
    }
    return ($matchesA > 0) ?? ('A', $matchesA) !! ('B', $matchesB);
}

sub ExposeEvent($obj, $args) {
    $args;  # suppress 'declared but not used' warnings
    my $cc = GdkCairoHelper.Create($obj.GdkWindow);  # Cairo Context
    # TODO: the following two lines pass parameters by value, need to pass by references to integers
    # my $windowX; my $windowY; my $windowWidth; my $windowHeight; my $windowDepth;
    # $obj.GdkWindow.GetGeometry($windowX, $windowY, $windowWidth, $windowHeight, $windowDepth);
    # Tracked as https://github.com/sorear/niecza/issues/57
    # TODO: remove the following one line cheat that works around the above problem
    my $windowWidth = $windowSizeX; my $windowHeight = $windowSizeY;
    $cc.SetSourceRGB(1, 1, 0.8); $cc.Paint();  # pale yellow background
    DrawGraphs($cc, $windowWidth, $windowHeight);
    $cc.Target.Dispose;
    $cc.dispose-hack;
}

sub DrawGraphs($cc, $windowWidth, $windowHeight)
{
    # Calculate dimensions relative to window size
    my $lineWidth   = (($windowWidth min $windowHeight) * 0.005).Int max 1;
    my $axisTop     = $windowHeight * 0.1;
    my $axisBottom  = $windowHeight * 0.9;
    my $axisALeft   = $windowWidth * 0.1;
    my $axisARight  = $windowWidth * 0.45;
    my $axisBLeft   = $windowWidth * 0.55;
    my $axisBRight  = $windowWidth * 0.9;

    # Draw the histograms
    # NYI [max] @matchesA, @matchesB;
    my $maxMatches = 0;
    for @matchesA -> $m { if $m > $maxMatches { $maxMatches = $m; } }
    for @matchesB -> $m { if $m > $maxMatches { $maxMatches = $m; } }
    my $scaleX = ($axisARight - $axisALeft) / InitialMatches;
    my $scaleY = ($axisBottom - $axisTop) / $maxMatches;
    $cc.SetSourceRGB(1, 0, 0);  # red for box A
    my $i; loop ($i = 1; $i <= InitialMatches; ++$i) {
        my $height = @matchesA[$i] * $scaleY;
        my $x0 = ($axisALeft + $i * $scaleX).Int;
        my $top = $axisBottom - $height;
        $cc.Rectangle($x0,$top,$scaleX-1,$height-1);
        $cc.Fill;
    }
    $cc.SetSourceRGB(0, 1, 0);  # green for box B
    loop ($i = 1; $i <= InitialMatches; ++$i) {
        my $height = @matchesB[$i] * $scaleY;
        my $x0 = ($axisBLeft + $i * $scaleX).Int;
        my $top = $axisBottom - $height;
        $cc.Rectangle($x0,$top,$scaleX-1,$height-1);
        $cc.Fill;
    }
    $cc.Stroke;

    # Draw the horizontal and vertical axes
    $cc.LineWidth = $lineWidth;
    $cc.SetSourceRGB(0, 0, 0);  # Black
    $cc.MoveTo($axisALeft,  $axisTop);
    $cc.LineTo($axisALeft,  $axisBottom);
    $cc.LineTo($axisARight, $axisBottom);
    $cc.MoveTo($axisBLeft,  $axisTop);
    $cc.LineTo($axisBLeft,  $axisBottom);
    $cc.LineTo($axisBRight, $axisBottom);
    $cc.Stroke;
    
    # Label the graphs
    $cc.SetSourceRGB(0, 0, 0);  # Black
    $cc.SetFontSize($windowWidth * 0.1);
    my $textWidth  = $cc.TextExtents('A').Width;
    my $textHeight = $cc.TextExtents('A').Height;
    $cc.MoveTo($axisALeft + $textWidth*3, $axisTop+$textHeight); $cc.ShowText('A');
    $cc.MoveTo($axisBLeft + $textWidth*3, $axisTop+$textHeight); $cc.ShowText('B');
    $cc.SetFontSize($windowWidth * 0.05);
    $textWidth  = $cc.TextExtents('0').Width;
    $textHeight = $cc.TextExtents('0').Height;
    $cc.MoveTo($axisALeft  - $textWidth*0.5, $axisBottom+$textHeight*1.5); $cc.ShowText('0');
    $cc.MoveTo($axisARight - $textWidth,     $axisBottom+$textHeight*1.5); $cc.ShowText('40');
    $cc.MoveTo($axisBLeft  - $textWidth*0.5, $axisBottom+$textHeight*1.5); $cc.ShowText('0');
    $cc.MoveTo($axisBRight - $textWidth,     $axisBottom+$textHeight*1.5); $cc.ShowText('40');
    # Label the Y axis maximum
    $cc.SetFontSize($windowWidth * 0.03);
    $textWidth  = $cc.TextExtents(~ $maxMatches).Width;
    $textHeight = $cc.TextExtents(~ $maxMatches).Height;
    $cc.MoveTo($axisALeft - $textWidth * 1.1, $axisTop+$textHeight*0.5);
    $cc.ShowText(~ $maxMatches);
    $cc.SetFontSize($windowWidth * 0.04);
    # Put a heading above the graphs
    my $heading = "$gameCount Matchbox games";
    $textWidth  = $cc.TextExtents($heading).Width;
    $textHeight = $cc.TextExtents($heading).Height;
    $cc.MoveTo($axisBLeft - $textWidth * 0.5, $axisTop - $textHeight * 0.5);
    $cc.ShowText($heading);
    $cc.Stroke;
}

sub TimeoutEvent  # called once per second
{
    $drawingarea.QueueDrawArea(0,0,$windowSizeX,$windowSizeY);
    return True;  # meaning please continue calling this timeout handler
};

sub DeleteEvent($obj, $args) {
    $obj; $args; # suppress "declared but not used" Potential difficulties
    $running = False;
    Application.Quit;
};