NAME

Imager - Perl extension for Generating 24 bit Images

SYNOPSIS

# Thumbnail example

#!/usr/bin/perl -w
use strict;
use Imager;

die "Usage: thumbmake.pl filename\n" if !-f $ARGV[0];
my $file = shift;

my $format;

# see Imager::Files for information on the read() method
my $im = Imager->new(file=>$file)
  or die Imager->errstr();

$file =~ s/\.[^.]*$//;

# Create smaller version
# documented in Imager::Transformations
my $thumb = $img->scale(scalefactor=>.3);

# Autostretch individual channels
$thumb->filter(type=>'autolevels');

# try to save in one of these formats
SAVE:

for $format ( qw( png gif jpeg tiff ppm ) ) {
  # Check if given format is supported
  if ($Imager::formats{$format}) {
    $file.="_low.$format";
    print "Storing image as: $file\n";
    # documented in Imager::Files
    $thumb->write(file=>$file) or
      die $thumb->errstr;
    last SAVE;
  }
}

DESCRIPTION

Imager is a module for creating and altering images. It can read and write various image formats, draw primitive shapes like lines,and polygons, blend multiple images together in various ways, scale, crop, render text and more.

Overview of documentation

Imager - This document - Synopsis, Example, Table of Contents and Overview.
Imager::Tutorial - a brief introduction to Imager.
Imager::Cookbook - how to do various things with Imager.
Imager::ImageTypes - Basics of constructing image objects with new(): Direct type/virtual images, RGB(A)/paletted images, 8/16/double bits/channel, color maps, channel masks, image tags, color quantization. Also discusses basic image information methods.
Imager::Files - IO interaction, reading/writing images, format specific tags.
Imager::Draw - Drawing Primitives, lines, boxes, circles, arcs, flood fill.
Imager::Color - Color specification.
Imager::Fill - Fill pattern specification.
Imager::Font - General font rendering, bounding boxes and font metrics.
Imager::Transformations - Copying, scaling, cropping, flipping, blending, pasting, convert and map.
Imager::Engines - Programmable transformations through transform(), transform2() and matrix_transform().
Imager::Filters - Filters, sharpen, blur, noise, convolve etc. and filter plugins.
Imager::Expr - Expressions for evaluation engine used by transform2().
Imager::Matrix2d - Helper class for affine transformations.
Imager::Fountain - Helper for making gradient profiles.
Imager::API - using Imager's C API
Imager::APIRef - API function reference
Imager::Inline - using Imager's C API from Inline::C
Imager::ExtUtils - tools to get access to Imager's C API.

Basic Overview

An Image object is created with $img = Imager->new(). Examples:

$img=Imager->new();                         # create empty image
$img->read(file=>'lena.png',type=>'png') or # read image from file
   die $img->errstr();                      # give an explanation
                                            # if something failed

or if you want to create an empty image:

$img=Imager->new(xsize=>400,ysize=>300,channels=>4);

This example creates a completely black image of width 400 and height 300 and 4 channels.

ERROR HANDLING

In general a method will return false when it fails, if it does use the errstr() method to find out why:

errstr

Returns the last error message in that context.

If the last error you received was from calling an object method, such as read, call errstr() as an object method to find out why:

my $image = Imager->new;
$image->read(file => 'somefile.gif')
   or die $image->errstr;

If it was a class method then call errstr() as a class method:

my @imgs = Imager->read_multi(file => 'somefile.gif')
  or die Imager->errstr;

Note that in some cases object methods are implemented in terms of class methods so a failing object method may set both.

The Imager->new method is described in detail in Imager::ImageTypes.

METHOD INDEX

Where to find information on methods for Imager class objects.

addcolors() - "addcolors" in Imager::ImageTypes - add colors to a paletted image

addtag() - "addtag" in Imager::ImageTypes - add image tags

align_string() - "align_string" in Imager::Draw - draw text aligned on a point

arc() - "arc" in Imager::Draw - draw a filled arc

bits() - "bits" in Imager::ImageTypes - number of bits per sample for the image

box() - "box" in Imager::Draw - draw a filled or outline box.

circle() - "circle" in Imager::Draw - draw a filled circle

colorcount() - "colorcount" in Imager::Draw - the number of colors in an image's palette (paletted images only)

combines() - "combines" in Imager::Draw - return a list of the different combine type keywords

compose() - "compose" in Imager::Transformations - compose one image over another.

convert() - "Color transformations" in Imager::Transformations - transform the color space

copy() - "copy" in Imager::Transformations - make a duplicate of an image

crop() - "crop" in Imager::Transformations - extract part of an image

def_guess_type() - "def_guess_type" in Imager::Files - default function used to guess the output file format based on the output filename

deltag() - "deltag" in Imager::ImageTypes - delete image tags

difference() - "Image Difference" in Imager::Filters - produce a difference images from two input images.

errstr() - "Basic Overview" - the error from the last failed operation.

filter() - Imager::Filters - image filtering

findcolor() - "findcolor" in Imager::ImageTypes - search the image palette, if it has one

flip() - "flip" in Imager::Transformations - flip an image, vertically, horizontally

flood_fill() - "flood_fill" in Imager::Draw - fill an enclosed or same color area

getchannels() - "getchannels" in Imager::ImageTypes - the number of samples per pixel for an image

getcolorcount() - "getcolorcount" in Imager::ImageTypes - the number of different colors used by an image (works for direct color images)

getcolors() - "getcolors" in Imager::ImageTypes - get colors from the image palette, if it has one

getcolorusage() - "getcolorusage" in Imager::ImageTypes

getcolorusagehash() - "getcolorusagehash" in Imager::ImageTypes

get_file_limits() - "Limiting the sizes of images you read" in Imager::Files

getheight() - "getwidth" in Imager::ImageTypes - height of the image in pixels

getmask() - "getmask" in Imager::ImageTypes - write mask for the image

getpixel() - "getpixel" in Imager::Draw - retrieve one or more pixel colors

getsamples() - "getsamples" in Imager::Draw - retrieve samples from a row or subrow of pixels.

getscanline() - "getscanline" in Imager::Draw - retrieve colors for a row or subrow of pixels.

getwidth() - "getwidth" in Imager::ImageTypes - width of the image in pixels.

img_set() - "img_set" in Imager::ImageTypes - re-use an Imager object for a new image.

init() - "init" in Imager::ImageTypes

is_bilevel() - "is_bilevel" in Imager::ImageTypes - returns whether image write functions should write the image in their bi-level (blank and white, no grey levels) format

line() - "line" in Imager::Draw - draw an interval

load_plugin() - "load_plugin" in Imager::Filters

map() - "Color Mappings" in Imager::Transformations - remap color channel values

masked() - "masked" in Imager::ImageTypes - make a masked image

matrix_transform() - "matrix_transform" in Imager::Engines

maxcolors() - "maxcolors" in Imager::ImageTypes

NC() - "NC" in Imager::Handy

NCF() - "NCF" in Imager::Handy

new() - "new" in Imager::ImageTypes

newcolor() - "newcolor" in Imager::Handy

newcolour() - "newcolour" in Imager::Handy

newfont() - "newfont" in Imager::Handy

NF() - "NF" in Imager::Handy

open() - Imager::Files - an alias for read()

parseiptc() - "parseiptc" in Imager::Files - parse IPTC data from a JPEG image

paste() - "paste" in Imager::Transformations - draw an image onto an image

polygon() - "polygon" in Imager::Draw

polyline() - "polyline" in Imager::Draw

read() - Imager::Files - read a single image from an image file

read_multi() - Imager::Files - read multiple images from an image file

read_types() - "read_types" in Imager::Files - list image types Imager can read.

register_filter() - "register_filter" in Imager::Filters

register_reader() - "register_reader" in Imager::Files

register_writer() - "register_writer" in Imager::Files

rotate() - "rotate" in Imager::Transformations

rubthrough() - "rubthrough" in Imager::Transformations - draw an image onto an image and use the alpha channel

scale() - "scale" in Imager::Transformations

scale_calculate() - "scale_calculate" in Imager::Transformations

scaleX() - "scaleX" in Imager::Transformations

scaleY() - "scaleY" in Imager::Transformations

setcolors() - "setcolors" in Imager::ImageTypes - set palette colors in a paletted image

set_file_limits() - "Limiting the sizes of images you read" in Imager::Files

setmask() - "setmask" in Imager::ImageTypes

setpixel() - "setpixel" in Imager::Draw

setsamples() - "setsamples" in Imager::Draw

setscanline() - "setscanline" in Imager::Draw

settag() - "settag" in Imager::ImageTypes

string() - "string" in Imager::Draw - draw text on an image

tags() - "tags" in Imager::ImageTypes - fetch image tags

to_paletted() - "to_paletted" in Imager::ImageTypes

to_rgb16() - "to_rgb16" in Imager::ImageTypes

to_rgb8() - "to_rgb8" in Imager::ImageTypes

transform() - "transform" in Imager::Engines

transform2() - "transform2" in Imager::Engines

type() - "type" in Imager::ImageTypes - type of image (direct vs paletted)

unload_plugin() - "unload_plugin" in Imager::Filters

virtual() - "virtual" in Imager::ImageTypes - whether the image has it's own data

write() - Imager::Files - write an image to a file

write_multi() - Imager::Files - write multiple image to an image file.

write_types() - "read_types" in Imager::Files - list image types Imager can write.

CONCEPT INDEX

animated GIF - "Writing an animated GIF" in Imager::Files

aspect ratio - "i_xres" in Imager::ImageTypes, "i_yres" in Imager::ImageTypes, "i_aspect_only" in Imager::ImageTypes

blend - alpha blending one image onto another "rubthrough" in Imager::Transformations

blur - "guassian" in Imager::Filters, "conv" in Imager::Filters

boxes, drawing - "box" in Imager::Draw

changes between image - "Image Difference" in Imager::Filters

color - Imager::Color

color names - Imager::Color, Imager::Color::Table

combine modes - "Combine Types" in Imager::Draw

compare images - "Image Difference" in Imager::Filters

contrast - "contrast" in Imager::Filters, "autolevels" in Imager::Filters

convolution - "conv" in Imager::Filters

cropping - "crop" in Imager::Transformations

CUR files - "ICO (Microsoft Windows Icon) and CUR (Microsoft Windows Cursor)" in Imager::Files

diff images - "Image Difference" in Imager::Filters

dpi - "i_xres" in Imager::ImageTypes, "Image spatial resolution" in Imager::Cookbook

drawing boxes - "box" in Imager::Draw

drawing lines - "line" in Imager::Draw

drawing text - "string" in Imager::Draw, "align_string" in Imager::Draw

error message - "ERROR HANDLING"

files, font - Imager::Font

files, image - Imager::Files

filling, types of fill - Imager::Fill

filling, boxes - "box" in Imager::Draw

filling, flood fill - "flood_fill" in Imager::Draw

flood fill - "flood_fill" in Imager::Draw

fonts - Imager::Font

fonts, drawing with - "string" in Imager::Draw, "align_string" in Imager::Draw, Imager::Font::Wrap

fonts, metrics - "bounding_box" in Imager::Font, Imager::Font::BBox

fonts, multiple master - "MULTIPLE MASTER FONTS" in Imager::Font

fountain fill - "Fountain fills" in Imager::Fill, "fountain" in Imager::Filters, Imager::Fountain, "gradgen" in Imager::Filters

GIF files - "GIF" in Imager::Files

GIF files, animated - "Writing an animated GIF" in Imager::File

gradient fill - "Fountain fills" in Imager::Fill, "fountain" in Imager::Filters, Imager::Fountain, "gradgen" in Imager::Filters

grayscale, convert image to - "convert" in Imager::Transformations

guassian blur - "guassian" in Imager::Filters

hatch fills - "Hatched fills" in Imager::Fill

ICO files - "ICO (Microsoft Windows Icon) and CUR (Microsoft Windows Cursor)" in Imager::Files

invert image - "hardinvert" in Imager::Filters

JPEG - "JPEG" in Imager::Files

limiting image sizes - "Limiting the sizes of images you read" in Imager::Files

lines, drawing - "line" in Imager::Draw

matrix - Imager::Matrix2d, "Matrix Transformations" in Imager::Transformations, "transform" in Imager::Font

metadata, image - "Tags" in Imager::ImageTypes

mosaic - "mosaic" in Imager::Filters

noise, filter - "noise" in Imager::Filters

noise, rendered - "turbnoise" in Imager::Filters, "radnoise" in Imager::Filters

paste - "paste" in Imager::Transformations, "rubthrough" in Imager::Transformations

pseudo-color image - "to_paletted" in Imager::ImageTypes, "new" in Imager::ImageTypes

posterize - "postlevels" in Imager::Filters

png files - Imager::Files, "PNG" in Imager::Files

pnm - "PNM (Portable aNy Map)" in Imager::Files

rectangles, drawing - "box" in Imager::Draw

resizing an image - "scale" in Imager::Transformations, "crop" in Imager::Transformations

RGB (SGI) files - "SGI (RGB, BW)" in Imager::Files

saving an image - Imager::Files

scaling - "scale" in Imager::Transformations

SGI files - "SGI (RGB, BW)" in Imager::Files

sharpen - "unsharpmask" in Imager::Filters, "conv" in Imager::Filters

size, image - "getwidth" in Imager::ImageTypes, "getheight" in Imager::ImageTypes

size, text - "bounding_box" in Imager::Font

tags, image metadata - "Tags" in Imager::ImageTypes

text, drawing - "string" in Imager::Draw, "align_string" in Imager::Draw, Imager::Font::Wrap

text, wrapping text in an area - Imager::Font::Wrap

text, measuring - "bounding_box" in Imager::Font, Imager::Font::BBox

tiles, color - "mosaic" in Imager::Filters

unsharp mask - "unsharpmask" in Imager::Filters

watermark - "watermark" in Imager::Filters

writing an image to a file - Imager::Files

THREADS

Imager doesn't support perl threads.

Imager has limited code to prevent double frees if you create images, colors etc, and then create a thread, but has no code to prevent two threads entering Imager's error handling code, and none is likely to be added.

SUPPORT

The best place to get help with Imager is the mailing list.

To subscribe send a message with subscribe in the body to:

imager-devel+request@molar.is

or use the form at:

http://www.molar.is/en/lists/imager-devel/

where you can also find the mailing list archive.

You can report bugs by pointing your browser at:

https://rt.cpan.org/NoAuth/ReportBug.html?Queue=Imager

or by sending an email to:

bug-Imager@rt.cpan.org

Please remember to include the versions of Imager, perl, supporting libraries, and any relevant code. If you have specific images that cause the problems, please include those too.

If you don't want to publish your email address on a mailing list you can use CPAN::Forum:

http://www.cpanforum.com/dist/Imager

You will need to register to post.

CONTRIBUTING TO IMAGER

Feedback

I like feedback.

If you like or dislike Imager, you can add a public review of Imager at CPAN Ratings:

http://cpanratings.perl.org/dist/Imager

This requires a Bitcard Account (http://www.bitcard.org).

You can also send email to the maintainer below.

If you send me a bug report via email, it will be copied to RT.

Patches

I accept patches, preferably against the main branch in subversion. You should include an explanation of the reason for why the patch is needed or useful.

Your patch should include regression tests where possible, otherwise it will be delayed until I get a chance to write them.

AUTHOR

Tony Cook <tony@imager.perl.org> is the current maintainer for Imager.

Arnar M. Hrafnkelsson is the original author of Imager.

Many others have contributed to Imager, please see the README for a complete list.

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