Re: Simple Graphics::Primitive example?

[hdb]

Based on the example in Graphics::Primitive, I came up with this:

use strict;
use warnings;
use Graphics::Primitive;
use Graphics::Color::RGB;
use Graphics::Primitive::Border;
use Graphics::Primitive::Component;
use Graphics::Primitive::Driver::Cairo;

my $c = Graphics::Primitive::Component->new(
    background_color => Graphics::Color::RGB->new(
        red => 1, green => 0, blue => 0
    ),
    width => 500, height => 350,
    border => new Graphics::Primitive::Border->new( width => 5 )
    );

my $driver = Graphics::Primitive::Driver::Cairo->new(format => 'SVG');

$driver->prepare($c);
$driver->finalize($c);
$driver->draw($c);

$driver->write('test.png');

and then went on to install the missing modules using cpan, specifically Graphics::Primitive and Graphics::Primitive::Driver::Cairo.

As a prerequisite, one has to install the cairo graphics library which I cannot do on my machine. Have you gone through this process?

[kcott]

I realise the "Graphics::Primitive::Component->new(...)" code you posted is a verbatim copy from the Graphics::Primitive POD; however,

    border => new Graphics::Primitive::Border->new( width => 5 )

looks like one "new" too many. From the Graphics::Primitive::Border documentation, that should probably be:

    border => Graphics::Primitive::Border->new( width => 5 )

[hdb]

Thanks for pointing this out. As I got stuck on installing the prerequisites I never quite got to that point.

[djzort]

I am just using the debian provided version of driver::cairo (0.46)

here is the code i am using

#!/usr/bin/perl

use strict;use warnings;

use Graphics::Primitive::Container;
use Graphics::Color::RGB;
use Graphics::Primitive::Font;
use Graphics::Primitive::TextBox;
use Graphics::Primitive::Driver::Cairo;
use Layout::Manager::Compass;

my $black = Graphics::Color::RGB->new(red => 0, green => 0, blue => 0)
+;

my $container = Graphics::Primitive::Container->new( width => 100, hei
+ght => 100);

$container->border->width(1);
$container->border->color($black);
$container->padding(
    Graphics::Primitive::Insets->new(top => 5, bottom => 5, left => 5,
+ right => 5)
);


my $comp = Graphics::Primitive::Component->new;
$comp->background_color($black);
$container->add_component($comp, 'c');

my $lm = Layout::Manager::Compass->new;
$lm->do_layout($container);

my $driver = Graphics::Primitive::Driver::Cairo->new;
$driver->draw($container);
$driver->write('/tmp/foo.png');


__END__

for which i always see this error

dean@laserbeak:/tmp$ perl test.pl 
Use of uninitialized value in subroutine entry at /usr/share/perl5/Gra
+phics/Primitive/Driver/Cairo.pm line 85.
Use of uninitialized value in subroutine entry at /usr/share/perl5/Gra
+phics/Primitive/Driver/Cairo.pm line 85.

Chart::Clicker works fine, so i know that its possible for Graphics::Primitive::Driver::Cairo to output something

[tangent]

Looking at the source of the driver module:

81    my $width = $self->width;
82    my $height = $self->height;
83
84    if(uc($self->format) eq 'PNG') {
85    $surface = Cairo::ImageSurface->create(
86        'argb32', $width, $height
87    );

So it seems that both $width and $height are not defined. I note that the example on the Graphics::Primitive page has:

my $c = Graphics::Primitive::Component->new(
    width => 500, height => 350,
);

Whereas the example on the Graphics::Primitive::Driver::Cairo page has:

my $c = Graphics::Primitive::Container->new(
    width => 500, height => 350,
);

I suggest you try adding the width and height parameters when creating the new Component object (or try just using Component instead of Container) and see if that makes a difference.

[djzort]

that seems to have done the trick, thank ye!