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#!perl -w
use strict;
use Imager;
use Imager::Matrix2d;
use Getopt::Long;
use constant PI => 4 * atan2(1,1);
# this sample requires Freetype 2.x
or die "This sample require Freetype 2.x to be configured in Imager\n";
my $angle = 30;
my $fg = 'white';
my $bg = 'black';
my $size = 20;
my $rotate;
GetOptions('angle|a=f' => \$angle,
'size|s=i' => \$size,
'foreground|fg|f=s' => \$fg,
'background|bg|b=s' => \$bg,
'rotate|r' => \$rotate)
or usage();
# check for sanity
if ($angle < -45 or $angle > 45) {
# while values outside this range are valid, the text would be hard
# to read
die "--angle is limited to the range -45 through +45\n";
elsif ($size < 10) {
die "--size must be 10 or greater\n";
my $fontfile = shift;
my $outfile = shift;
or usage();
my $text = "@ARGV";
my $angle_rads = $angle * (PI / 180);
my $trans;
# this is the only difference between rotation and shearing: the
# transformation matrix
if ($rotate) {
$trans = Imager::Matrix2d->rotate(radians => $angle_rads);
else {
$trans = Imager::Matrix2d->shear(x=>sin($angle_rads)/cos($angle_rads));
# only the Freetype 2.x driver supports transformations for now
my $font = Imager::Font->new(file=>$fontfile, type=>'ft2')
or die "Cannot load font $fontfile: ", Imager->errstr, "\n";
my $bbox = $font->bounding_box(string=>$text, size=>$size);
# these are in font co-ordinates, so y is flipped
my ($left, $miny, $right, $maxy) =
transformed_bounds($bbox, $trans);
# convert to image relative co-ordinates
my ($top, $bottom) = (-$maxy, -$miny);
my ($width, $height) = ($right - $left, $bottom - $top);
my $img = Imager->new(xsize=>$width, ysize=>$height);
# fill with the background
$img->box(filled=>1, color=>$bg);
# and draw our string in the right place
$img->string(text => $text,
color => Imager::Color->new('white'),
x => -$left,
y => -$top,
color => $fg,
font => $font,
size => $size);
or die "Cannot save $outfile: ",$img->errstr,"\n";
sub transformed_bounds {
my ($bbox, $matrix) = @_;
my $bounds;
for my $point ([ $bbox->start_offset, $bbox->ascent ],
[ $bbox->start_offset, $bbox->descent ],
[ $bbox->end_offset, $bbox->ascent ],
[ $bbox->end_offset, $bbox->descent ]) {
$bounds = add_bound($bounds, transform_point(@$point, $matrix));
sub transform_point {
my ($x, $y, $matrix) = @_;
$x * $matrix->[0] + $y * $matrix->[1] + $matrix->[2],
$x * $matrix->[3] + $y * $matrix->[4] + $matrix->[5]
sub add_bound {
my ($bounds, $x, $y) = @_;
$bounds or return [ $x, $y, $x, $y ];
$x < $bounds->[0] and $bounds->[0] = $x;
$y < $bounds->[1] and $bounds->[1] = $y;
$x > $bounds->[2] and $bounds->[2] = $x;
$y > $bounds->[3] and $bounds->[3] = $y;
sub usage {
print <<EOS;
Usage: $0 [options] fontfile outfile text...
--angle <angle> | -a <angle>
Set the slant angle in degrees, limited to -45 to +45. Default 30.
--size <pixels> | -s <angle>
Set the text size in pixels. Must be 10 or greater. Default: 20.
--foreground <color> | --fg <color> | -f <color>
Set the text foreground color. Default: white.
--background <color> | --bg <color> | -b <color>
Set the image background color. Default: black
--rotate | -r
Rotate instead of shearing. Default: shear
# shear
$0 -a 45 fontfiles/ImUgly.ttf output.ppm "something to say"
# rotate at 100 pixel font size, blue foregroune, white background
$0 -rs 100 -b white -f blue fontfiles/ImUgly.ttf output.ppm Imager
exit 1;
=head1 NAME - sample for drawing transformed text
perl [options] fontfile output text
Run without arguments for option details.
This is a sample for drawing transformed text.
It's complicated by the need to create an image to put the text into,
if you have text, a font, and a good idea where it belongs, it's
simple to create the transformation matrix:
use Imager::Matrix2d;
# or call another method for shearing, etc
my $matrix = Imager::Matrix2d->rotate(radians=>$some_angle);
Feed the transformation matrix to the font:
then draw the text as normal:
x => $where_x,
y => $where_y,
font => $font,
size => $size);
But if you do need the bounds, the code above does show you how to do
=item transformed_bounds
Returns a list of bounds:
(minx, miny, maxx, maxy)
These are offsets from the text's starting point in font co-ordinates
- so positive y is I<up>.
Note: this returns the bounds of the transformed bounding box, in most
cases the actual text will not be touching these boundaries.
=head1 AUTHOR
Tony Cook <>
=head1 SEE ALSO
Imager(1), Imager::Cookbook, Imager::Matrix2d
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