GD::Thumbnail - Thumbnail maker for GD
use GD::Thumbnail; my $thumb = GD::Thumbnail->new; my $raw = $thumb->create('test.jpg', 80, 2); my $mime = $thumb->mime; warn sprintf "Dimension: %sx%s\n", $thumb->width, $thumb->height; open IMG, ">thumb.$mime" or die "Error: $!"; binmode IMG; print IMG $raw; close IMG;
use CGI qw(:standard); use GD::Thumbnail; my $thumb = GD::Thumbnail->new; my $raw = $thumb->create('test.jpg', 80, 2); my $mime = $thumb->mime; binmode STDOUT; print header(-type => "image/$mime"); print $raw;
This document describes version
GD::Thumbnail released on
9 September 2012.
This is a thumbnail maker. Thumbnails are smaller versions of the original image/graphic/picture and are used for preview purposes, where bigger images can take a long time to load. They are also used in image galleries to preview a lot of images at a time.
This module also has the capability to add information strips about the original image. Original image's size (in bytes) and resolution & mime type can be added to the thumbnail's upper and lower parts. This feature can be useful for web software (image galleries or forums).
This is a Yet Another type of module. There are several other thumbnail modules on
CPAN, but they simply don't have the features I need, so this module is written to increase the thumbnail generator population on
The module can raise an exception if something goes wrong. So, you may have to use an
eval block to catch them.
All color parameters must be passed as a three element array reference:
$color = [$RED, $GREEN, $BLUE]; $black = [ 0, 0, 0];
Object constructor. Accepts arguments in
key => value format.
my $thumb = GD::Thumbnail->new(%args);
If you want information strips (see "create"), but you don't want to get a longer image, set this to a true value, and the information strips will not affect the image height (but the actual thumbnail image will be smaller).
Alters the information text font. You can set this to
Giant (all are case-insensitive). Default value is
Tiny, which is best for smaller images. If you want to use bigger thumbnails, you can alter the used font via this argument. It may also be useful for adding size & resolution information to existing images. But beware that GD output size may be smaller than the actual image and image quality may also differ.
You'll get a square thumbnail, if this is set to true. If the original image is not a square, the empty parts will be filled with blank (color is the same as
strip_color) instead of stretching the image in
y dimension or clipping it. If, however,
square is set to
crop, you'll get a cropped square thumbnail.
Beware that enabling this option will also auto-enable the
overlay option, since it is needed for a square image.
If set to true, a 1x1 pixel border will be added to the final image.
frame color. Default is black.
Sets the info strip background color. Default is black. You must pass it as a three element array reference containing the red, green, blue values:
$thumb = GD::Thumbnail->new( strip_color => [255, 0, 0] );
Sets the info strip text color. Default is white. You must pass it as a three element array reference containing the red, green, blue values:
$thumb = GD::Thumbnail->new( info_color => [255, 255, 255] );
You can alter the thumbnail mime with this parameter. Can be set to:
If set to true, the resulting dimensions will take the original image dimensions into consideration. Disabled by default.
Creates the thumbnail and returns the raw image data.
create() accepts three arguments:
my $raw = $thumb->create($image , $max, $info); my $raw = $thumb->create('test.jpg', 80, 1 );
Can be a file path, a file handle or raw binary data.
Defines the maximum width of the thumbnail either in pixels or percentage. You'll get a warning, if
info parameter is set and your
max value is to small to fit an info text.
If info parameter is not set, or it has a false value, you'll get a normal thumbnail image:
_____________ | ........... | | ........... | | ...IMAGE... | | ........... | | ........... | |_____________|
If you set it to
1, original image's dimensions and mime will be added below the thumbnail:
_____________ | ........... | | ........... | | ...IMAGE... | | ........... | | ........... | |_____________| | 20x20 JPEG | -------------
If you set it to
2, the byte size of the image will be added to the top of the thumbnail:
_____________ | 25 KB | |-------------| | ........... | | ........... | | ...IMAGE... | | ........... | | ........... | |_____________| | 20x20 JPEG | -------------
As you can see from the examples above, with the default options, thumbnail image dimension is constant when adding information strips (i.e.: strips don't overlay, but attached to upper and lower parts of thumbnail). Each info strip increases thumbnail height by 8 pixels (if the default tiny
Tiny is used).
But see the
square options in "new" to alter this behavior. You may also need to increase
max value if
square is enabled.
Returns the thumbnail mime. Must be called after "create".
Returns the thumbnail width in pixels. Must be called after "create".
Returns the thumbnail height in pixels. Must be called after "create".
You may get a warning, if there is something odd.
GIFformat is not supported by this version (%f) of GD"
You have an old version of GD and your original image is a
GIF image. Also, the code may die after this warning.
max argument to
create is too small to fit information. Either disable
info parameter or increase
You can reverse the strip and info colors and then add a frame to the thumbnail to create a picture frame effect:
my $thumb = GD::Thumbnail->new( strip_color => [255, 255, 255], info_color => [ 0, 0, 0], square => 1, frame => 1, ); my $raw = $thumb->create('test.jpg', 100, 2);
If you have a set of images with the same dimensions, you may use a percentage instead of a constant value:
my $raw = $thumb->create('test.jpg', '10%', 2);
Resulting thumbnail will be 90% smaller (x-y dimensions) than the original image.
Supported image types are limited with GD types, which include
gif and some others. See GD for more information. Usage of any other image type will be resulted with a fatal error.
Burak Gursoy <email@example.com>.
Copyright 2006 - 2012 Burak Gursoy. All rights reserved.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.14.2 or, at your option, any later version of Perl 5 you may have available.