Mastering Nginx

NGINX for the Developer

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Directive Explanation

• size: Emits information about an
  image in JSON format.


• rotate: Rotates an image counter-
  clockwise by either 90, 180, or 270
  degrees.


• resize: Reduces an image
  proportionally by the width and
  height given. One dimension may
  be "-" in order to reduce by only
  the other dimension. If combined
  with rotate, rotation happens
  after reduction. An error will result
  in returning 415 (Unsupported
  Media Type).


• crop: Reduces an image by the size
  of the largest side, as specified by
  the width and height given. Any
  extraneous space along the other
  edges will be cut. One dimension
  may be "-" in order to reduce by only
  the other dimension. If combined
  with rotate, rotation happens
  before reduction. An error will result
  in returning 415 (Unsupported Media
  Type).
  imagefilter
  buffer

The size of the buffer used to process

images. If more memory is needed, the

server will return a 415 error (Unsupported

Media Type).

image_filter_jpeg_

quality

The quality of the resulting JPEG image,

after processing. Not recommended to

exceed 95.

image_filter_

sharpen

Increases the sharpness of a processed

image by this percentage.

image_filter_

transparency

Disables preserving transparency of

transformed GIF and PNG images.

The default on preserves transparency.

Note that the empty_gif directive is not part of the image_filter module, but is
included in a default installation of NGINX.