NAME Plack::Middleware::Image::Scale - Resize jpeg and png images on the fly VERSION version 0.005 SYNOPSIS ## example1.psgi builder { enable 'ConditionalGET'; enable 'Image::Scale'; enable 'Static', path => qr{^/images/}; $app; }; A request to /images/foo_40x40.png will use images/foo.(png|jpg|gif) as original, scale it to 40x40 px size and convert to PNG format. ## example2.psgi my $thumber = builder { enable 'ConditionalGET'; enable 'Image::Scale', width => 200, height => 100, flags => { fill => 'ff00ff' }; Plack::App::File->new( root => 'images' ); }; builder { mount '/thumbs' => $thumber; mount '/' => $app; }; A request to /thumbs/foo_x.png will use images/foo.(png|jpg|gif) as original, scale it small enough to fit 200x100 px size, fill extra borders (top/down or left/right, depending on the original image aspect ratio) with cyan background, and convert to PNG format. Also clipping is available, see "CONFIGURATION". ## example3.psgi my %imagesize = Config::General->new('imagesize.conf')->getall; builder { enable 'ConditionalGET'; enable 'Image::Scale', path => sub { s{^(.+)_(.+)\.(jpg|png)$}{$1.$3} || return; ( my %entry = %{$imagesize{$2} || {}} ) || return; return delete @entry{'width','height'}, \%entry; }; enable 'Static', path => qr{^/images/}; $app; }; A request to /images/foo_medium.png will use images/foo.(png|jpg|gif) as original. The size and flags are taken from the configuration file as parsed by Config::General. ## imagesize.conf width 200 height 100 crop width 300 height 100 crop width 50 height 100 fill ff0000 But you might want to use a simple config format, for example: $imagesize = { small => [ 10, 10 ], medium => [ 50, 50 ], big => [ 100, 100, 'crop'] }; # [...] enable 'Image::Scale', path => sub { s{^(.+)_(.+)e.(jpg|png)$}{$1.$3} || return; return @{ $imgsizes->{$2} || [] }; }; DESCRIPTION Scale and convert images to the requested format on the fly. By default the size and other scaling parameters are extracted from the request URI. Scaling is done with Image::Scale. The original image is not modified or even accessed directly by this module. The converted image is not cached, but the request can be validated (If-Modified-Since) against original image without doing the image processing, or even reading the file content from the filesystem. This middleware should be used together a cache proxy, that caches the converted images for all clients, and implements content validation. The response headers (like Last-Modified or ETag) are from the original image, but body is replaced with a PSGI content filter to do the image processing. The original image is fetched from next middleware layer or application with a normal PSGI request. You can use Plack::Middleware::Static, or Catalyst::Plugin::Static::Simple for example. See "CONFIGURATION" for various size/format specifications that can be used in the request URI, and "ATTRIBUTES" for common configuration options that you can give as named parameters to the "enable". ATTRIBUTES match Only matching URIs are processed with this module. The match is done against PATH_INFO. Non-matching requests are delegated to the next middleware layer or application. Must be a RegexpRef, or CodeRef, that may return 3 values (regexp captures or normal return values). The request path is passed to the CodeRef in $_, and can be rewritten during match. This is used to strip off the image parameters from the URI. Rewritten URI is used for fetching the original image. Empty array means no match. First and second captures are the desired width and height of the resulting image. Third capture is an optional flag string. See "CONFIGURATION". orig_ext ArrayRef of possible original image formats. See "fetch_orig". memory_limit Memory limit for the image scaling in bytes, as defined in Image::Scale. jpeg_quality JPEG quality, as defined in Image::Scale. width Use this to set and override image width. height Use this to set and override image height. flags Use this to set and override image processing flags. METHODS fetch_orig Call parameters: PSGI request HashRef $env, Str $basename. Return value: PSGI response ArrayRef $res. The original image is fetched from the next layer or application. All possible extensions defined in "orig_ext" are tried in order, to search for the original image. All other responses except a straight 404 (as returned by Plack::Middleware::Static for example) are considered matches. body_scaler Call parameters: @args. Return value: CodeRef $cb. Create the content filter callback and return a CodeRef to it. The filter will buffer the data and call "image_scale" with parameters @args when EOF is received, and finally return the converted data. image_scale Call parameters: ScalarRef $buffer, String $ct, Int $width, Int $height, HashRef|Str $flags. Return value: $imagedata Read image from $buffer, scale it to $width x $height and return as content-type $ct. Optional $flags to specify image processing options like background fills or cropping. $flags can be a HashRef or CONFIGURATION The default match pattern for URI is "*...**basename*_*width*x*height*-*flags*.*ext*". If URI doesn't match, the request is passed through. Any number of flags can be specified, separated with "-". Flags can be boolean (exists or doesn't exist), or have a numerical value. Flag name and value are separated with a zero-width word to number boundary. For example "z20" specifies flag "z" with value 20. basename Original image is requested from URI *basename*.*orig_ext*, where *orig_ext* is list of filename extensions. See "orig_ext". width Width of the output image. If not defined, it can be anything (to preserve the image aspect ratio). height Height of the output image. If not defined, it can be anything (to preserve the image aspect ratio). flags: fill Image aspect ratio is preserved by scaling the image to fit within the specified size. This means scaling to the smaller or the two possible sizes that preserve aspect ratio. Extra borders of background color are added to fill the requested image size exactly. /images/foo_400x200-fill.png If fill has a value, it specifies the background color to use. Undefined color with png output means transparent background. flags: crop Image aspect ratio is preserved by scaling and cropping from middle of the image. This means scaling to the bigger of the two possible sizes that preserve the aspect ratio, and then cropping to the exact size. flags: z Zoom the specified width or height N percent bigger. For example "z20" to zoom 20%. The zooming applies only to width and/or height defined in the URI, and does not change the crop size. Image is always cropped to the specified pixel width, height or both. /images/foo_40x-crop-z20.png CAVEATS The cropping requires Imager. This is a run-time dependency, and fallback is not to crop the image to the desired size. SEE ALSO Image::Scale Imager Plack::App::ImageMagick AUTHOR Panu Ervamaa COPYRIGHT AND LICENSE This software is copyright (c) 2011 by Panu Ervamaa. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.