Re: How to use cairo with gtk

["Ye Wenbin" <wenbinye gmail com>]

On Sat, 22 Mar 2008 07:15:06 +0800, muppet <scott asofyet org> wrote:
Thank you very much!
I was told to use cairo_set_source_surface function, that works.
I paste my code here, in case somebody has the same question.

   use Cairo;
   use Gtk2 '-init';
   use Glib qw(TRUE FALSE);

   my ($width, $height) = (300, 200);
   my $window = Gtk2::Window->new('toplevel');
   $window->signal_connect('delete_event' => sub { Gtk2->main_quit; });
   my $surface = create_image();
   my $drawable = Gtk2::DrawingArea->new;
   $drawable->size($width, $height);
   $drawable->signal_connect('expose_event' => \&on_expose_event,  
$surface);
   $window->add($drawable);
   $window->show_all;
   Gtk2->main;

   sub create_image {
       my $surface = Cairo::ImageSurface->create('argb32', $width,  
$height);
       my $cr = Cairo::Context->create($surface);
       $cr->set_source_rgb(0, 0, 0);
       $cr->select_font_face("Sans", 'normal', 'normal');
       $cr->set_font_size(40.0);
       $cr->move_to(10, 50);
       $cr->show_text("Disziplin ist Macht.");
       return $surface;
   }

   sub on_expose_event {
       my ($widget, $event, $surface) = @_;
       my $cr = Gtk2::Gdk::Cairo::Context->create($widget->window);
       $cr->set_source_surface($surface, 0, 0);
       $cr->paint;
       return FALSE;
   }
> The perl API is pretty much the same; $imagesurface->get_data() returns  
> you a scalar holding the image data.  If you ensure that the cairo image  
> surface is created in cairo's RGB24 format, you can use the data  
> directly with Gtk2::Gdk::Pixbuf like this:
>
>
>      my $width = $surface->get_width;
>      my $height = $surface->get_height;
>      my $stride = $surface->get_stride;
>      my $data = $surface->get_data;
>
>      my $pixbuf = Gtk2::Gdk::Pixbuf->new_from_data ($data, 'rgb', FALSE,  
> 8, $wudth, $height, $stride);
>
>      my $image = Gtk2::Image->new_from_pixbuf ($pixbuf);
Also I try this way, but it seems weird, the window is black.
the document of  gdk_pixbuf_new_from_data says "only RGB images with 8
bits per sample are supported", is it the reason?
Any way, thanks again for the help.


--
Best Regards,
Ye Wenbin