#!/usr/bin/perl

use strict;
use warnings;

use SDL;
use SDL::App;
use SDL::Surface;
use SDL::Event;
use SDL::TTFont;

my $count = 1;
my @text;
while (<DATA>){
  chomp;
  push @text, $count++.": $_";
}

my ($sl,$scount, $sinc)= (0,20,1);

my ($tx,$ty,$tw,$th) = (10,20,300,200); # text box dimensions
my $tex_rect = SDL::Rect->new(-x=>$tx,-y=>$ty,-w=>$tw,-h=>$th);

my $TT_FONT = '/usr/share/fonts/truetype/verdana.ttf'; #Set to a valid
+ ttf font on your system

my $app = new SDL::App(
        -title=>'Font test',
        -width=>800,
        -height=>600,
        -depth=>32,
        -flags=>SDL_DOUBLEBUF | SDL_HWSURFACE | SDL_HWACCEL,
);

my $bgcolor = new SDL::Color(-r=>192, -g=>192, -b=>192); 
my $fgcolor = new SDL::Color(-r=>255, -g=>255, -b=>255); 
my $textcolor = new SDL::Color(-r=>0, -g=>0, -b=>100); 
my $font = new SDL::TTFont(-name=>$TT_FONT, -size=>10, -bg=>$textcolor
+, -fg=>$fgcolor);

my $actions = {};
&event_loop();


sub update_screen {
       $app->fill(0, $bgcolor);
       $app->fill($tex_rect, $textcolor);
       
       # Move the box within text back and forth
       if ($sl + $scount >= @text){
        $sinc = -1;
        
       }elsif($sl <= 0){
        $sinc = 1;
       }
       $sl+= $sinc;
       draw_text_box( -surface=>$app,
                      -font=>$font,
                      -x=>$tx,
                      -y=>$ty,
                      -w=>$tw,
                      -h=>$th,
                      -text=>\@text,
                      -startline=>$sl,
                      -linecount=>20, 
                      -linewrap=>1
                    );
       
       $app->sync();
       
}

sub draw_text_box {
      my %args = (
        -surface=> undef, # SDL Surface
        -font =>  undef , # SDL::TTFont
        -x => 0,          # Start X
        -y => 0,          # Start Y
        -w => 100,        # Max Width
        -h => 100,        # Max Height
        -text=> undef,    # Array of text strings
        -startline=>0,    # Start index of text strqings
        -linecount=>100,  # Number of lines to display (line wrap migh
+t effect this if enabled)
        -linewrap => 1,   # Enable/Disable linewrap
        -breakchar=>">",  # Char to display at word wrap or truncation
        @_
      );
      
      return unless defined ($args{-text});
      
      foreach (qw/-x -y -w -h -startline -linecount/){
        die "param $_ = [$args{$_}] not a valid range!" unless $args{$
+_} =~/^\d+$/;
      }
      
      
      
      my ($start,$end, $x,$y) = @args{ qw/-startline -linecount -x -y/
+ };
      my $fontheight = $args{-font}->height("abcDEF019"); # Might not 
+cover max height for all fonts
      
      my $combined_height = $args{-y} + $args{-h} - $fontheight; # Get
+ the total height
      my $wrap_height = defined $args{-breakchar} ?  
                            $args{-font}->width($args{-breakchar}) : 0
+; # break char width if any
      
      for (my $l = $start; $l < $start + $end; $l++){
          my $text = $args{-text}->[$l];

          my $textwidth = $args{-font}->width($text); # Get width of t
+he rendered line
          
          if ($textwidth > 0){ # Skip if nothing to do
            if ( $textwidth <  $args{-w}){ # Fits? Print it.
                $args{-font}->print($args{-surface},$x,$y,$text);
            }else{  # Wrap it.
               
               {
                last unless $text; # Nothing left, done.
                
                my $clen = length($text);    # Get the length of curre
+nt text
                
                my $break_pos = $textwidth - $wrap_height == 0 ?
                                  $clen : int( $clen * ( $args{-w} / (
+$textwidth- $wrap_height)) );
                
                while( 
                  $args{-font}->width(substr($text,0,$break_pos)) 
                  > $args{-w} - $wrap_height and $break_pos 
                )
                {
                  $break_pos --;
                }
                
                if ($clen > $break_pos){ 
                  # Breaks again
                  $args{-font}->print($args{-surface},$x,$y,substr($te
+xt,0,$break_pos,'').$args{-breakchar}) ;
                }else{ 
                  # Done
                  $args{-font}->print($args{-surface},$x,$y,substr($te
+xt,0,$break_pos,'')) ; 
                  last;
                }
                $textwidth = $args{-font}->width($text);
                $y+=$fontheight;          
                # Done if past screen or truncating
                last if $y > $combined_height or ! $args{-linewrap}; 
                redo;
               }
            
            }
            $y+=$fontheight;              
            last if $y > $combined_height;
         }            
      }

}


sub event_loop {
    my $event = new SDL::Event;
  
  MAIN_LOOP:
    while(1) {
        # Update Screen
        update_screen();
    
        while ($event->poll) {
            my $type = $event->type();

            last MAIN_LOOP if ($type == SDL_QUIT);
            last MAIN_LOOP if ($type == SDL_KEYDOWN && $event->key_nam
+e() eq 'escape');

            if ( exists($actions->{$type}) && ref( $actions->{$type} )
+ eq "CODE" ) {
                $actions->{$type}->($event);
            }
        }
        $app->delay(100);
    }
}


__END__
Excerpt from "War of the Worlds" by H.G Wells
A question of graver and universal interest is the possibility of
another attack from the Martians.  I do not think that nearly enough
attention is being given to this aspect of the matter.  At present the
planet Mars is in conjunction, but with every return to opposition I,
for one, anticipate a renewal of their adventure.  In any case, we
should be prepared.  It seems to me that it should be possible to
define the position of the gun from which the shots are discharged, to
keep a sustained watch upon this part of the planet, and to anticipate
the arrival of the next attack.

In that case the cylinder might be destroyed with dynamite or
artillery before it was sufficiently cool for the Martians to emerge,
or they might be butchered by means of guns so soon as the screw
opened.  It seems to me that they have lost a vast advantage in the
failure of their first surprise.  Possibly they see it in the same
light.

Lessing has advanced excellent reasons for supposing that the
Martians have actually succeeded in effecting a landing on the planet
Venus.  Seven months ago now, Venus and Mars were in alignment with
the sun; that is to say, Mars was in opposition from the point of view
of an observer on Venus.  Subsequently a peculiar luminous and sinuous
marking appeared on the unillumined half of the inner planet, and
almost simultaneously a faint dark mark of a similar sinuous character
was detected upon a photograph of the Martian disk.  One needs to see
the drawings of these appearances in order to appreciate fully their
remarkable resemblance in character.

At any rate, whether we expect another invasion or not, our views
of the human future must be greatly modified by these events.  We have
learned now that we cannot regard this planet as being fenced in and a
secure abiding place for Man; we can never anticipate the unseen good
or evil that may come upon us suddenly out of space.  It may be that
in the larger design of the universe this invasion from Mars is not
without its ultimate benefit for men; it has robbed us of that serene
confidence in the future which is the most fruitful source of
decadence, the gifts to human science it has brought are enormous, and
it has done much to promote the conception of the commonweal of
mankind.  It may be that across the immensity of space the Martians
have watched the fate of these pioneers of theirs and learned their
lesson, and that on the planet Venus they have found a securer
settlement.  Be that as it may, for many years yet there will
certainly be no relaxation of the eager scrutiny of the Martian disk,
and those fiery darts of the sky, the shooting stars, will bring with
them as they fall an unavoidable apprehension to all the sons of men.

The broadening of men's views that has resulted can scarcely be
exaggerated.  Before the cylinder fell there was a general persuasion
that through all the deep of space no life existed beyond the petty
surface of our minute sphere.  Now we see further.  If the Martians
can reach Venus, there is no reason to suppose that the thing is
impossible for men, and when the slow cooling of the sun makes this
earth uninhabitable, as at last it must do, it may be that the thread
of life that has begun here will have streamed out and caught our
sister planet within its toils.

Dim and wonderful is the vision I have conjured up in my mind of
life spreading slowly from this little seed bed of the solar system
throughout the inanimate vastness of sidereal space.  But that is a
remote dream.  It may be, on the other hand, that the destruction of
the Martians is only a reprieve.  To them, and not to us, perhaps, is
the future ordained.

I must confess the stress and danger of the time have left an
abiding sense of doubt and insecurity in my mind.  I sit in my study
writing by lamplight, and suddenly I see again the healing valley
below set with writhing flames, and feel the house behind and about me
empty and desolate.  I go out into the Byfleet Road, and vehicles pass
me, a butcher boy in a cart, a cabful of visitors, a workman on a
bicycle, children going to school, and suddenly they become vague and
unreal, and I hurry again with the artilleryman through the hot,
brooding silence.  Of a night I see the black powder darkening the
silent streets, and the contorted bodies shrouded in that layer; they
rise upon me tattered and dog-bitten.  They gibber and grow fiercer,
paler, uglier, mad distortions of humanity at last, and I wake, cold
and wretched, in the darkness of the night.

I go to London and see the busy multitudes in Fleet Street and the
Strand, and it comes across my mind that they are but the ghosts of
the past, haunting the streets that I have seen silent and wretched,
going to and fro, phantasms in a dead city, the mockery of life in a
galvanised body.  And strange, too, it is to stand on Primrose Hill,
as I did but a day before writing this last chapter, to see the great
province of houses, dim and blue through the haze of the smoke and
mist, vanishing at last into the vague lower sky, to see the people
walking to and fro among the flower beds on the hill, to see the
sight-seers about the Martian machine that stands there still, to hear
the tumult of playing children, and to recall the time when I saw it
all bright and clear-cut, hard and silent, under the dawn of that last
great day. . . .

And strangest of all is it to hold my wife's hand again, and to think
that I have counted her, and that she has counted me, among the dead.
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