Image::Magick::Iterator(3)

NAME
Image::Magick::Iterator - sequentially read Image::Magick object from a filehandle.

SYNOPSIS
  use strict;
  use Image::Magick::Iterator;

  my $iter = Image::Magick::Iterator->new();

  #assume PPM stream is coming from STDIN;
  $iter->handle(\*STDIN);

  #explicitly set format to PPM, there is no auto-detection built in
  $iter->format('PPM');

  while(my $image = $iter->next){
    print $image->Get('height'),"\n"; #access height attribute of each
                                      #Image::Magick object
  }

DESCRIPTION
Image::Magick::Iterator adds iteration support to Image::Magick. This means that if you have a stream of concatenated images, you can access each image in the stream as an independent Image::Magick object.

Iteration functionality is not present in Image::Magick itself as of version 5.56. Passing a stream of concatenated images would result in essentially a "stack" of images which would all be manipulated in parallel by any Image::Magick calls. Calls to Write() either output an animated series of image (a la animated GIFs), or the first image in the series.

Image::Magick::Iterator is extensible to support many different image filetypes. Currently only PPM support is implemented. See /SYNOPSIS for an example.

SUPPORTED FORMATS
Currently only PPM images can be iterated. It's not difficult to add new image types though, and I'm receptive to new classes for handling more formats. To add another format:

1. Have a look at the source of Image::Magick::Iterator::PPM to get an idea of how to write a new format handling class. It is basically a class with one method, read_image, that when given a filehandle reference reads an image from it and passes back the raw data.

2. add a mapping to "_delegate()" that maps the desired value of "format()" to your image reading class.

FEEDBACK
Email the author.

AUTHOR
Allen Day <allenday@ucla.edu>

COPYRIGHT AND LICENSE
Copyright (C) 2004 by Allen Day, allenday@ucla.edu

This library is released under GPL, the GNU General Public License

APPENDIX
The rest of the documentation details each of the object methods. Internal methods are usually preceded with a '_'. Methods are in alphabetical order for the most part.

  new()

Usage
      my $obj = new Image::Magick::Iterator();

Function
    Builds a new Image::Magick::Iterator object

Returns
    an instance of Image::Magick::Iterator

Arguments
    None

  init()

Usage
      $obj->init(%arg);

Function
    Internal method to initialize a new Image::Magick::Iterator object

Returns
    true on success

Arguments
    Arguments passed to "new()"

  format()

Usage
      $obj->format();        #get existing value

      $obj->format($newval); #set new value

Function
    stores a scalar value of the fileformat to be read from "handle()". currently supported formats are:

      * PPM

Returns
    value of format (a scalar)

Arguments
    (optional) on set, a scalar

  handle()

Usage
      $obj->handle();        #get existing value

      $obj->handle($newval); #set new value

Function
    stores a filehandle reference (eg \*STDIN, or an IO::Handle.

Returns
    value of handle (a scalar)

Arguments
    (optional) on set, a scalar

  next()

Usage
      $obj->next(); #get next Image::Magick from stream

Function
    reads an Image::Magick object from a filehandle.

Returns
    a Image::Magick object, or undef if the filehandle is EOF or contains only a partial image.

Arguments
    none, read-only

  _delegate()

Usage
      $obj->_delegate($format);

Function
    internal method, maps format names to class names

Returns
    class to be delegated to for reading an image of the specified format

Arguments
    name of an image format

POD ERRORS
Hey! The above document had some coding errors, which are explained below:

Around line 39:
    alternative text '/SYNOPSIS' contains non-escaped | or /