#!/usr/bin/perl -w
#
# PerlQt Example Application: drawdemo
#
# Demonstrates the painter and the printer.
#
use QBrush;
use QColor;
use QFont;
use QPainter;
use QPrinter;
use QPushButton;
use QRadioButton;
use POSIX 'math_h';  # No atan() in Perl.
#
# This function draws a color wheel.
# The coordinate system x=(0..500), y=(0..500) spans the paint device.
#
sub drawColorWheel {
    my $p = shift;
    my $f = new QFont('Times', 18, $Weight{Bold});
    $p->setFont($f);
    $p->setPen($black);
    $p->setWindow(0, 0, 500, 500);
    for(my $i = 0; $i < 36; $i++) {
        my $matrix = new QWMatrix;
        $matrix->translate(250.0, 250.0);
        $matrix->shear(0.0, 0.3);
        $matrix->rotate($i*10);
        $p->setWorldMatrix($matrix);
        $c = new QColor;
        $c->setHsv($i*10, 255, 255);
        $p->setBrush($c);
        $p->drawRect(70, -10, 80, 10);
        $p->drawText(80+70+5, 0, "H=" . $i*10);
    }
}
#
# This function draws a few lines of text using different fonts.
#
{
    my @fonts = ('Helvetica', 'Courier', 'Times');
    my @sizes = (10, 12, 18, 24);
    sub drawFonts {
        my $p = shift;
        my($y) = (0, 0, 0);
        for my $f (@fonts) {
            for my $s (@sizes) {
                my $font = new QFont($f, $s);
                $p->setFont($font);
                my $fm = $p->fontMetrics();
                $y += $fm->ascent();
                $p->drawText(10, $y, "Quartz Glyph Job Vex'd Cwm Finks");
                $y += $fm->descent();
            }
        }
    }
}
#
# This function draws some shapes
#
sub drawShapes {
    my $p = shift;
    my $b1 = new QBrush($blue);
    my $b2 = new QBrush($green, $Brush{Dense6});
    my $b3 = new QBrush($Brush{None});
    my $b4 = new QBrush($Brush{Cross});
    $p->setPen($red);
    $p->setBrush($b1);
    $p->drawRect(10, 10, 200, 100);
    $p->setBrush($b2);
    $p->drawRoundRect(10, 150, 200, 100, 20, 20);
    $p->setBrush($b3);
    $p->drawEllipse(250, 10, 200, 100);
    $p->setBrush($b4);
    $p->drawPie(250, 150, 200, 100, 45*16, 90*16);
}
#
# This function draws a text that follows a (Bezier) curve.
# Notice that this function does not support the general case.
# It should be rewritten to calculate the real dx/dy.
#
sub drawPathText {
    my $p = shift;
    my $a = new QPointArray(4);
    $a->setPoint(0, 100,200);
    $a->setPoint(1, 150,75);
    $a->setPoint(2, 250,75);
    $a->setPoint(3, 300,200);
    $a = $a->quadBezier();
    $p->setPen($lightGray);
    $p->drawPolyline($a);
    $p->setFont(new QFont('Times', 24));
    $p->setPen($black);
    my $text = "PerlQt rocks!";
    my $len = length($text);
    return unless $len;
    my $ipos = 2; # $a->size()/$len;     # ugly hack, fix me
    my $cpos = $ipos;
    for(my $i = 0; $i < $len; $i++) {
        my $p1 = $a->point($cpos-1);
        my $p2 = $a->point($cpos+1);
        my $pt = $a->point($cpos);
        my $dx = $p2->x() - $p1->x();
        my $dy = $p2->y() - $p1->y();
        my $angle = atan($dy/$dx);
        $angle *= 180.0/3.14;
        my $m = new QWMatrix;
        $m->translate($pt->x(), $pt->y());
        $m->rotate($angle);
        $p->setWorldMatrix($m);
        $p->drawText(0, 0, substr($text, $i, 1), 1);
        $cpos += $ipos;
    }
}
package DrawView;
use QButtonGroup;
use QColor;
use QWindow;
use slots 'updateIt(int)', 'printIt()';
@ISA = qw(QWindow);
@ourDrawFunctions = (
    { f => \&main::drawColorWheel, name => 'Draw color wheel' },
    { f => \&main::drawFonts,      name => 'Draw fonts'       },
    { f => \&main::drawShapes,     name => 'Draw shapes'      },
    { f => \&main::drawPathText,   name => 'Draw path text'   }
);
#
# Construct the DrawView with buttons.
#
sub new {
    my $self = shift->SUPER::new;
    $self->setCaption("PerlQt Draw Demo Application");
    $self->setBackgroundColor($white);
    my $printer = new QPrinter;
    # Create a button group to contain all buttons
    my $bgroup = new QButtonGroup($self);
    $bgroup->resize(200, 200);
    $self->connect($bgroup, 'clicked(int)', 'updateIt(int)');
    # Calculate the size for the radio buttons
    my $maxwidth = 80;
    my $i;
    my $n;
    my $fm = $bgroup->fontMetrics();
    for($i = 0; $i < @ourDrawFunctions; $i++) {#$i (0 .. $#ourDrawFunctions) {
        $n = $ourDrawFunctions[$i]{'name'};
        my $w = $fm->width($n);
        $maxwidth = $w > $maxwidth ? $w : $maxwidth;
    }
    $maxwidth += 20;
    for($i = 0; $i < @ourDrawFunctions; $i++) {
        $n = $ourDrawFunctions[$i]{'name'};
        my $rb = new QRadioButton($n, $bgroup)->immortal;
        $rb->setGeometry(10, $i*30+10, $maxwidth, 30);
        $rb->setChecked(1) if $i == 0;
    }
    my $drawindex = 0;
    my $maxindex = $i;
    $maxwidth += 40;
    # Create and setup the print button
    my $print = new QPushButton('Print', $bgroup);
    $print->resize(80, 30);
    $print->move($maxwidth/2 - $print->width()/2, $maxindex*30+20);
    $self->connect($print, 'clicked()', 'printIt()');
    $bgroup->resize($maxwidth, $print->y()+$print->height()+10);
    $self->resize(640, 300);
    @$self{'printer', 'bgroup', 'print', 'drawindex', 'maxindex'} =
        ($printer, $bgroup, $print, $drawindex, $maxindex);
    return $self;
}
#
# Called when a radio button is clicked.
#
sub updateIt {
    my $self = shift;
    my $index = shift;
    if($index < $$self{'maxindex'}) {
        $$self{'drawindex'} = $index;
        $self->update();
    }
}
#
# Calls the drawing function as specified by the radio buttons.
#
sub drawIt {
    my $self = shift;
    my $p = shift;
    my $drawindex = $$self{'drawindex'};
    &{$ourDrawFunctions[$drawindex]{'f'}}($p);
}
#
# Called when the print button is clicked.
#
sub printIt {
    my $self = shift;
    my $printer = $$self{'printer'};
    if($printer->setup($self)) {
        my $paint = new QPainter;
        $paint->begin($printer);
        $self->drawIt($paint);
        $paint->end();
    }
}
sub paintEvent {
    my $self = shift;
    my $paint = new QPainter;
    $paint->begin($self);
    $self->drawIt($paint);
    $paint->end();
}
#
# Called when the widget has been resized.
# Moves the button group to the upper right corner
# of the widget.
#
sub resizeEvent {
    my $self = shift;
    my $bgroup = $$self{'bgroup'};
    $bgroup->move($self->width()-$bgroup->width(), 0);
}
package main;
use Qt;
$draw = new DrawView;
$qApp->setMainWidget($draw);
$draw->show();
exit $qApp->exec();