Viewing file:  fading_text.pl (3.18 KB) -rw-r--r--
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=pod
=head1 NAME
examples/fader.pl - fading text demo
=head1 FEATURES
Demonstrates use of Prima image alpha blending
=cut
use strict;
use warnings;
use Prima qw(Application ImageViewer);
my $w;
my @text;
my $f = @ARGV ? $ARGV[0] : $0;
die "Cannot open $f: $!\n" unless open F, "<", $f;
my $maxlen = 80;
for (<F>) {
chomp;
s/\t/ /g;
if ( $maxlen >= length ) {
push @text, $_;
} else {
push @text, substr( $_, 0, $maxlen, '') while $maxlen < length;
push @text, $_ if length;
}
}
close F;
my ( $canvas, $fader, $texter);
my $yofs = 0;
my $total_fadeout = 0.7;
my $start_from_top_at_yofs;
my ($fh, $fe, $next_yofs, $max_width, $text_height);
sub render_text
{
exit if
defined($text_height) and
$yofs > $texter->height * $total_fadeout / 2 + $text_height;
return if $yofs < ($next_yofs // 0);
unless ( defined $max_width ) {
$texter-> begin_paint_info;
$max_width = 0;
$text_height = 0;
$fh = $texter->font->height;
$fe = $texter->font->externalLeading;
$text_height = @text * ( $fh + $fe );
for ( @text ) {
my $w = $texter->get_text_width($_, 1);
$max_width = $w if $max_width < $w;
}
$texter-> end_paint_info;
}
if ( $max_width < $texter->width ) {
$texter->width($max_width);
}
$texter->begin_paint;
$texter-> clear;
my $th = $texter->height;
my $at_y = $yofs + $th / 2;
for my $text ( @text ) {
$at_y -= $fh + $fe;
next if $at_y > $th * ( 1 + $total_fadeout) / 2 - ( $fh + $fe );
last if $at_y < - ( $fh + $fe );
$texter->text_out( $text, 2, $at_y);
}
$texter-> end_paint;
$next_yofs = $yofs + $th / 2;
}
sub repaint
{
$canvas->clear;
$fader->clear;
render_text;
my ( $dx, $dy ) = (0, 0);
my ( $cw, $ch ) = $fader->size;
my ( $tw, $th ) = $texter->size;
my $xangle = 0.5 * $cw / $ch;
for ( my $i = 0; $i < $th / 2 * $total_fadeout; $i++){
$fader->put_image_indirect( $texter,
$dx, $dy,
0, $i + $next_yofs - $yofs,
$cw - $dx * 2, 1,
$cw, 1,
rop::CopyPut);
$dx += $xangle;
$dy ++;
}
$canvas->put_image(0,0,$fader,rop::Premultiply);
$yofs += $ch / 100;
$w->Image->repaint;
}
sub resize
{
my @size = $w->Image->size;
$canvas = Prima::Image->new(
size => \@size,
type => im::RGB,
backColor => cl::Black,
);
$fader = Prima::Icon->new(
size => \@size,
type => im::RGB,
autoMasking => am::None,
maskType => 8,
backColor => cl::Black,
);
my $fader_alpha = Prima::Image->new(
size => \@size,
type => im::Byte,
);
$fader_alpha->new_gradient(
palette => [cl::White, cl::Black],
poly => [0,0,$total_fadeout/2,0,$total_fadeout,1]
)->bar( 0,0,$fader_alpha-> size);
$fader->mask( $fader_alpha->data );
$texter = Prima::Image->new(
size => [ $size[0], $size[1] * 2 ],
type => im::Byte,
type => im::RGB,
backColor => cl::Black,
color => cl::Yellow,
scaling => ist::None,
);
undef $next_yofs;
repaint;
}
$w = Prima::MainWindow->new(
size => [ 600, 500 ],
text => 'Fading demo',
);
$w-> insert( Widget =>
name => 'Image',
pack => {side => 'top', fill => 'both', pad => 10, expand => 1},
onPaint => sub { shift->put_image(0,0,$canvas) },
onSize => \&resize,
sizeMin => [100,100],
);
resize;
repaint;
$w->insert( Timer =>
timeout => 50,
onTick => \&repaint,
)->start;
run Prima;
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