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#! perl
use strict;
################ Subroutines ################
my $cr;
my $layout;
my $PANGO_SCALE = 1024;
sub showlayout {
my ( $_cr, $_layout, $x, $y ) = @_;
$cr = $_cr;
$layout = $_layout;
$cr->move_to( $x, $y );
$cr->set_source_rgba( 0, 0, 0, 1 );
Pango::Cairo::show_layout( $cr, $layout );
my $dx = ($layout->get_size)[0]/$PANGO_SCALE;
showbb( $x, $y );
return $dx;
}
# Shows the bounding box of the last piece of text that was rendered.
sub showbb {
my ( $x, $y ) = @_;
# Show origin.
_showloc( $x, $y );
# Bounding box, top-left coordinates.
my @e = $layout->get_pixel_extents;
for ( 1, 0 ) {
printf( "%-7s %6.2f %6.2f %6.2f %6.2f\n",
(qw(Ink: Layout:))[$_],
@{%{e[$_]}}{qw( x y width height )} );
}
# NOTE: Some fonts include natural spacing in the bounding box.
# NOTE: Some fonts exclude accents on capitals from the bounding box.
# Show baseline.
$cr->save;
$cr->set_source_rgb(1,0,1);
$cr->set_line_width( 0.25 );
$cr->translate( $x, $y );
my %e = %{$e[1]};
_line( $e{x}, $layout->get_baseline/$PANGO_SCALE, $e{width}, 0 );
# Show BBox.
$cr->rectangle( $e{x}, $e{y}, $e{width}, $e{height} );;
$cr->stroke;
%e = %{$e[0]};
$cr->set_source_rgb(0,1,1);
$cr->rectangle( $e{x}, $e{y}, $e{width}, $e{height} );;
$cr->stroke;
$cr->restore;
}
sub _showloc {
my ( $x, $y, $d ) = @_;
$x ||= 0; $y ||= 0; $d ||= 50;
$cr->save;
$cr->set_source_rgb(0,0,1);
_line( $x-$d, $y, 2*$d, 0 );
_line( $x, $y-$d, 0, 2*$d );
$cr->restore;
}
sub _line {
my ( $x, $y, $w, $h, $lw ) = @_;
$lw ||= 0.5;
$y = $y;
$cr->save;
$cr->move_to( $x, $y );
$cr->rel_line_to( $w, $h );
$cr->set_line_width($lw);
$cr->stroke;
$cr->restore;
}
1;
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