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Template Toolkit | Modules | Template::Plugin::Image

Template::Plugin::Image

  Template::Plugin::HTML
Template::Plugin::Iterator  
Plugin access to image sizes

Table of Contents

SYNOPSIS Index  ] [ Modules  ] [ Top  ]

    [% USE Image(filename) %]
    [% Image.width %]
    [% Image.height %]
    [% Image.size.join(', ') %]
    [% Image.attr %]
    [% Image.tag %]

DESCRIPTION Index  ] [ Modules  ] [ Top  ]

This plugin provides an interface to the Image::Info or Image::Size modules for determining the size of image files.

You can specify the plugin name as either 'Image' or 'image'. The plugin object created will then have the same name. The file name of the image should be specified as a positional or named argument.

    [% # all these are valid, take your pick %]
    [% USE Image('foo.gif') %]
    [% USE image('bar.gif') %]
    [% USE Image 'ping.gif' %]
    [% USE image(name='baz.gif') %]
    [% USE Image name='pong.gif' %]

A "root" parameter can be used to specify the location of the image file:

    [% USE Image(root='/path/to/root', name='images/home.png') %]
    # image path: /path/to/root/images/home.png
    # img src: images/home.png

In cases where the image path and image url do not match up, specify the file name directly:

    [% USE Image(file='/path/to/home.png', name='/images/home.png') %]

The "alt" parameter can be used to specify an alternate name for the image, for use in constructing an XHTML element (see the tag() method below).

    [% USE Image('home.png', alt="Home") %]

You can also provide an alternate name for an Image plugin object.

    [% USE img1 = image 'foo.gif' %]
    [% USE img2 = image 'bar.gif' %]

The 'name' method returns the image file name.

    [% img1.name %]     # foo.gif

The 'width' and 'height' methods return the width and height of the image, respectively. The 'size' method returns a reference to a 2 element list containing the width and height.

    [% USE image 'foo.gif' %]
    width: [% image.width %]
    height: [% image.height %]
    size: [% image.size.join(', ') %]

The 'modtime' method returns the ctime of the file in question, suitable for use with date.format:

    [% USE image 'foo.gif' %]
    [% USE date %]
    [% date.format(image.modtime, "%B, %e %Y") %]

The 'attr' method returns the height and width as HTML/XML attributes.

    [% USE image 'foo.gif' %]
    [% image.attr %]

Typical output:

    width="60" height="20"

The 'tag' method returns a complete XHTML tag referencing the image.

    [% USE image 'foo.gif' %]
    [% image.tag %]

Typical output:

    <img src="foo.gif" width="60" height="20" alt="" />

You can provide any additional attributes that should be added to the XHTML tag.

    [% USE image 'foo.gif' %]
    [% image.tag(class="logo" alt="Logo") %]

Typical output:

    <img src="foo.gif" width="60" height="20" alt="Logo" class="logo" />

Note that the 'alt' attribute is mandatory in a strict XHTML 'img' element (even if it's empty) so it is always added even if you don't explicitly provide a value for it. You can do so as an argument to the 'tag' method, as shown in the previous example, or as an argument

    [% USE image('foo.gif', alt='Logo') %]

CATCHING ERRORS Index  ] [ Modules  ] [ Top  ]

If the image file cannot be found then the above methods will throw an 'Image' error. You can enclose calls to these methods in a TRY...CATCH block to catch any potential errors.

    [% TRY;
         image.width;
       CATCH;
         error;      # print error
       END
    %]

USING Image::Info Index  ] [ Modules  ] [ Top  ]

At run time, the plugin tries to load Image::Info in preference to Image::Size. If Image::Info is found, then some additional methods are available, in addition to 'size', 'width', 'height', 'attr', and 'tag'. These additional methods are named after the elements that Image::Info retrieves from the image itself; see Image::Info for more details -- the types of methods available depend on the type of image. These additional methods will always include the following:

  • file_media_type

    This is the MIME type that is appropriate for the given file format. The corresponding value is a string like: "image/png" or "image/jpeg".

  • file_ext

    The is the suggested file name extention for a file of the given file format. The value is a 3 letter, lowercase string like "png", "jpg".

  • color_type

    The value is a short string describing what kind of values the pixels encode. The value can be one of the following:

      Gray
      GrayA
      RGB
      RGBA
      CMYK
      YCbCr
      CIELab

    These names can also be prefixed by "Indexed-" if the image is composed of indexes into a palette. Of these, only "Indexed-RGB" is likely to occur.

    (It is similar to the TIFF field PhotometricInterpretation, but this name was found to be too long, so we used the PNG inpired term instead.)

  • resolution

    The value of this field normally gives the physical size of the image on screen or paper. When the unit specifier is missing then this field denotes the squareness of pixels in the image.

    The syntax of this field is:

       <res> <unit>
       <xres> "/" <yres> <unit>
       <xres> "/" <yres>

    The <res>, <xres> and <yres> fields are numbers. The <unit> is a string like 'dpi', 'dpm' or 'dpcm' (denoting "dots per inch/cm/meter).

  • SamplesPerPixel

    This says how many channels there are in the image. For some image formats this number might be higher than the number implied from the 'color_type'.

  • BitsPerSample

    This says how many bits are used to encode each of samples. The value is a reference to an array containing numbers. The number of elements in the array should be the same as 'SamplesPerPixel'.

  • Comment

    Textual comments found in the file. The value is a reference to an array if there are multiple comments found.

  • Interlace

    If the image is interlaced, then this tell which interlace method is used.

  • Compression

    This tell which compression algorithm is used.

  • Gamma

    A number.

AUTHOR Index  ] [ Modules  ] [ Top  ]

Andy Wardley <abw@wardley.org>

http://wardley.org/

VERSION Index  ] [ Modules  ] [ Top  ]

1.21, distributed as part of the Template Toolkit version 2.19, released on 27 April 2007.

COPYRIGHT Index  ] [ Modules  ] [ Top  ]

  Copyright (C) 1996-2007 Andy Wardley.  All Rights Reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO Index  ] [ Modules  ] [ Top  ]

Template::Plugin


  Template::Plugin::HTML
Template::Plugin::Iterator  
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