use strict;
use warnings;

use SDL v2.3;
use SDL::Video;
use SDL::Event;
use SDL::Events;
use SDL::Surface;

use Cairo;

my $WIDTH  = 400;
my $HEIGHT = 300;

# relevant part starts:
my $screen = SDL::Video::set_video_mode($WIDTH, $HEIGHT, 32, SDL_SWSURFACE);

SDL::Video::lock_surface($screen);

my $surface = Cairo::ImageSurface->create_for_data
(
  $screen->get_pixels_ptr,
  'argb32',
  $screen->w,
  $screen->h,
  $screen->pitch
);

my $cairo = Cairo::Context->create($surface);

$cairo->rectangle(0, 0, 100, 100);
$cairo->set_source_rgb(255, 0, 0);
$cairo->fill;

SDL::Video::unlock_surface($screen);
SDL::Video::update_rect($screen, 0, 0, $WIDTH, $HEIGHT);
# relevant part ends

LOOP: while (1)
{
  my $event = SDL::Event->new();
  
  while (SDL::Events::poll_event($event))
  {
    last LOOP if $event->type == SDL_KEYDOWN
              || $event->type == SDL_QUIT;
  }

  SDL::Events::pump_events();
}

SDL::quit;