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Imager::Tutorial(3)   User Contributed Perl Documentation  Imager::Tutorial(3)

NAME
       Imager::Tutorial	- an introduction to Imager.

DESCRIPTION
   Before you start
       If you have the necessary knowledge, install the	image format libraries
       you want	Imager image file support for, and Imager itself, otherwise
       arrange to have it done.

       You will	also want some sort of image viewer tool, whether an image
       editor like Photoshop or	the GIMP, or a web browser.

   Hello Boxes!	- A Simple Start
       As with any perl	program	it's useful to start with a #! line, and to
       enable strict mode:

	 #!/usr/bin/perl -w
	 # you might to	'use warnings;'	instead	of the -w above
	 use strict;

       These lines will	be omitted in further examples.

       As with any module, you need to load it:

	 use Imager;

       Now create a image to draw on:

	 my $image = Imager->new(xsize => 100, ysize =>	100);

       and draw	a couple of filled rectangles on it:

	 $image->box(xmin => 0,	ymin =>	0, xmax	=> 99, ymax => 99,
		     filled => 1, color	=> 'blue');
	 $image->box(xmin => 20, ymin => 20, xmax => 79, ymax => 79,
		     filled => 1, color	=> 'green');

       Since the first box fills the whole image, it can be simplified to:

	 $image->box(filled => 1, color	=> 'blue');

       and save	it to a	file:

	 $image->write(file=>'tutorial1.ppm')
	     or	die 'Cannot save tutorial1.ppm:	', $image->errstr;

       So our completed	program	is:

	 use Imager;

	 my $image = Imager->new(xsize => 100, ysize =>	100);

	 $image->box(filled => 1, color	=> 'blue');
	 $image->box(xmin => 20, ymin => 20, xmax => 79, ymax => 79,
		     filled => 1, color	=> 'green');

	 $image->write(file=>'tutorial1.ppm')
	     or	die 'Cannot save tutorial1.ppm:	', $image->errstr;

   Adding some text
       The first thing you need	to draw	text is	a font object:

	 # use a different file, depending on the font support you have	in
	 # your	installed Imager.
	 my $font_filename = 'fontfiles/ImUgly.ttf';
	 my $font = Imager::Font->new(file=>$font_filename)
	   or die "Cannot load $font_filename: ", Imager->errstr;

       If you're on Windows, you can supply a face name	instead:

	 my $font = Imager::Font->new(face=>'Arial Bold')
	   or die "Cannot load 'Arial Bold: ", Imager->errstr;

       and draw	the text:

	 my $text = "Hello Boxes!";
	 my $text_size = 12;

	 $font->align(string =>	$text,
		      size => $text_size,
		      color => 'red',
		      x	=> $image->getwidth/2,
		      y	=> $image->getheight/2,
		      halign =>	'center',
		      valign =>	'center',
		      image => $image);

       So inserting this into our existing code	we have:

	 use Imager;

	 my $image = Imager->new(xsize => 100, ysize =>	100);

	 $image->box(xmin => 0,	ymin =>	0, xmax	=> 99, ymax => 99,
		     filled => 1, color	=> 'blue');
	 $image->box(xmin => 20, ymin => 20, xmax => 79, ymax => 79,
		     filled => 1, color	=> 'green');

	 # use a different file, depending on the font support you have	in
	 # your	installed Imager.
	 my $font_filename = 'fontfiles/ImUgly.ttf';
	 my $font = Imager::Font->new(file=>$font_filename)
	   or die "Cannot load $font_filename: ", Imager->errstr;

	 my $text = "Hello Boxes!";
	 my $text_size = 12;

	 $font->align(string =>	$text,
		      size => $text_size,
		      color => 'red',
		      x	=> $image->getwidth/2,
		      y	=> $image->getheight/2,
		      halign =>	'center',
		      valign =>	'center',
		      image => $image);

	 $image->write(file=>'tutorial2.ppm')
	     or	die 'Cannot save tutorial2.ppm:	', $image->errstr;

   Using an existing image as a	base
       To load an image	from a file, first create an empty image object:

	 my $read_image	= Imager->new;

       then call the read method:

	 my $image_source = shift; # from the command-line
	 $read_image->read(file=>$image_source)
	   or die "Cannot load $image_source: ", $image->errstr;

       To keep to our working size, we'll scale	the image:

	 # the scale() method always does a proportional scale,	we don't want
	 # that	here
	 my $scaled_image = $read_image->scaleX(pixels=>100)->scaleY(pixels=>100);

       draw our	inner box on that, and save the	result:

	 $scaled_image->box(xmin => 20,	ymin =>	20, xmax => 79,	ymax =>	79,
		     filled => 1, color	=> 'green');

	 $scaled_image->write(file=>'tutorial3.ppm')
	     or	die 'Cannot save tutorial3.ppm:	', $image->errstr;

       so the complete program is:

	 use Imager;

	 my $read_image	= Imager->new;

	 my $image_source = shift; # from the command-line
	 $read_image->read(file=>$image_source)
	   or die "Cannot load $image_source: ", $image->errstr;

	 # the scale() method always does a proportional scale,	we don't want
	 # that	here
	 my $scaled_image = $read_image->scaleX(pixels=>100)->scaleY(pixels=>100);

	 $scaled_image->box(xmin => 20,	ymin =>	20, xmax => 79,	ymax =>	79,
		     filled => 1, color	=> 'green');

	 $scaled_image->write(file=>'tutorial3.ppm')
	     or	die 'Cannot save tutorial3.ppm:	', $image->errstr;

AUTHOR
       Tony Cook <tonyc@cpan.org>

REVISION
       $Revision$

perl v5.32.1			  2014-01-10		   Imager::Tutorial(3)

NAME | DESCRIPTION | AUTHOR | REVISION

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