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Difference between revisions of "HttpImageFilterModule"

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<span style="color:red">WARNING: this article is obsoleted. Please refer to http://nginx.org/en/docs/ for the latest official documentation.</span>
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= Synopsis =
 
= Synopsis =
  
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== image_filter ==
 
== image_filter ==
<include wikitext nopre src="http://wiki.nginx.org/nginx.org/ngx_http_image_filter_module/image_filter.txt" />
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<include wikitext nopre src="http://wiki.nginx.org/nginx.org/http/ngx_http_image_filter_module/image_filter.txt" />
  
 
Specifies the type of transformation to apply to the image, one of the below:
 
Specifies the type of transformation to apply to the image, one of the below:
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== image_filter_buffer ==
 
== image_filter_buffer ==
<include wikitext nopre src="http://wiki.nginx.org/nginx.org/ngx_http_image_filter_module/image_filter_buffer.txt" />
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<include wikitext nopre src="http://wiki.nginx.org/nginx.org/http/ngx_http_image_filter_module/image_filter_buffer.txt" />
  
 
Sets the maximum size for reading the image.
 
Sets the maximum size for reading the image.
  
 
== image_filter_jpeg_quality ==
 
== image_filter_jpeg_quality ==
<include wikitext nopre src="http://wiki.nginx.org/nginx.org/ngx_http_image_filter_module/image_filter_jpeg_quality.txt" />
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<include wikitext nopre src="http://wiki.nginx.org/nginx.org/http/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'''.
 
Sets the rate of loss of information when processing the images as '''JPEG'''. The maximum recommended value is '''95'''.
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== image_filter_sharpen ==
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<include wikitext nopre src="http://wiki.nginx.org/nginx.org/http/ngx_http_image_filter_module/image_filter_sharpen.txt" />
  
 
== image_filter_transparency ==
 
== image_filter_transparency ==
<include wikitext nopre src="http://wiki.nginx.org/nginx.org/ngx_http_image_filter_module/image_filter_transparency.txt" />
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<include wikitext nopre src="http://wiki.nginx.org/nginx.org/http/ngx_http_image_filter_module/image_filter_transparency.txt" />
  
 
This directive allows you to disable image transparency in GIF and
 
This directive allows you to disable image transparency in GIF and

Revision as of 07:59, 23 August 2013

WARNING: this article is obsoleted. Please refer to http://nginx.org/en/docs/ for the latest official documentation.

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

Syntax: image_filter off
image_filter test
image_filter size
image_filter rotate 90 | 180 | 270
image_filter resize width height
image_filter crop width height
Default: off
Context: location
Reference:image_filter


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

Syntax: image_filter_buffer size
Default: 1M
Context: http
server
location
Reference:image_filter_buffer


Sets the maximum size for reading the image.

image_filter_jpeg_quality

Syntax: image_filter_jpeg_quality quality
Default: 75
Context: http
server
location
Reference:image_filter_jpeg_quality


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

image_filter_sharpen

Syntax: image_filter_sharpen percent
Default: 0
Context: http
server
location
Reference:image_filter_sharpen


image_filter_transparency

Syntax: image_filter_transparency on | off
Default: on
Context: http
server
location
Reference:image_filter_transparency


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