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HttpImageFilterModule

Revision as of 18:15, 30 April 2012 by Admin (Talk | contribs)

Contents

Synopsis

Version: 0.7.54+

This module is a filter for transforming JPEG, GIF and PNG images. It is not enabled by default to enable it, provide this option to ./configure when building nginx:

--with-http_image_filter_module 

libgd is required to build and run the module. We recommend using the latest version of libgd.


Example Configuration

location /img/ {
    proxy_pass     http://backend;
    image_filter   resize  150 100;
    error_page     415   = /empty;
}
 
location = /empty {
    empty_gif;
}

Directives

image_filter

ERROR in secure-include.php: could not read the given src URL http://wiki.nginx.org/nginx.org/ngx_http_image_filter_module/image_filter.txt

Specifies the type of transformation to apply to the image, one of the below:

  • test: checking that the response is indeed an image format JPEG, GIF or PNG. Otherwise, an error 415.
  • size: Gives information about the image in JSON format. For example,
{ "img" : { "width": 100, "height": 100, "type": "gif" } }

Or if an error occurs,

{}
  • resize: proportionally reduces the image to a specified size.
  • crop: proportionally reduces the image to a specified size and trims extra edge.

image_filter_buffer

ERROR in secure-include.php: could not read the given src URL http://wiki.nginx.org/nginx.org/ngx_http_image_filter_module/image_filter_buffer.txt

Sets the maximum size for reading the image.

image_filter_jpeg_quality

ERROR in secure-include.php: could not read the given src URL http://wiki.nginx.org/nginx.org/ngx_http_image_filter_module/image_filter_jpeg_quality.txt

Sets the rate of loss of information when processing the images as JPEG. The maximum recommended value is 95.

image_filter_transparency

ERROR in secure-include.php: could not read the given src URL http://wiki.nginx.org/nginx.org/ngx_http_image_filter_module/image_filter_transparency.txt

This directive allows you to disable image transparency in GIF and palette-based PNG to improve image resampling quality.

True color PNG alpha-channels are always preserved despite this setting.

Note: Grayscale PNG's are untested, but should be handled as truecolor PNGs.

References

Original Documentation