### HttpImageFilter **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: 这个模块用来分发JPEG，GIF和PNG图片。这个没有默认开启，在编译nginx中通过./configure参数配置 ~~~ --with-http_image_filter_module ~~~ libgd is required to build and run the module. We recommend using the latest version of libgd. 编译和运行这个模块必须安装libgd库。我们推荐使用最新版本的Libgd. ### Example Configuration ~~~ location /img/ { proxy_pass http://backend; image_filter resize 150 100; error_page 415 = /empty; }   location = /empty { empty_gif; } ~~~ ### 指令 ### image_filter **Syntax:***image_filter (test|size|resize width height|crop width height)* **Default:***none* **Context:***location* Specifies the type of transformation to apply to the image, one of the below: 详细的图片后缀类型如下： - test: checking that the response is indeed an image format JPEG, GIF or PNG. Otherwise, an error 415. 测试：测试确定图片文件的后缀格式为JPEG，GIF OR PNG。否则返回415错误 - size: Gives information about the image in JSON format. For example, 尺寸：返回JSON格式的图片信息。例如： ~~~ { "img" : { "width": 100, "height": 100, "type": "gif" } } ~~~ Or if an error occurs, 或者如果发生错误, ~~~ {} ~~~ - resize: proportionally reduces the image to a specified size. 调整大小：缩略图片到特定的尺寸 - crop: proportionally reduces the image to a specified size and trims extra edge. 切割：切割图片到特定的尺寸和特定的分辨率 ### image_filter_buffer **Syntax:***image_filter_buffer size* **Default:***1M* **Context:***http, server, location* Sets the maximum size for reading the image. 设置读取文件的最大的尺寸 ### image_filter_jpeg_quality **Syntax:***image_filter_jpeg_quality [0...100]* **Default:***75* **Context:***http, server, location* Sets the rate of loss of information when processing the images as **JPEG**. The maximum recommended value is **95**. 设置处理JPEG图片的丢失信息率.推荐的最大值为95 ### image_filter_transparency **Syntax:***image_filter_transparency on|off* **Default:***on* **Context:***http, server, location* This directive allows you to disable image transparency in GIF and palette-based PNG to improve image resampling quality. 这个指令容许你关闭GIF图片的透明度和 PNG图片质量 True color PNG alpha-channels are always preserved despite this setting. 真彩色PNG图片保存忽略设定 Note: Grayscale PNG's are untested, but should be handled as truecolor PNGs. 注释：灰度PNG图片未被设置，但应该被作为真彩色PNG图片处理 ### References [Original Documentation](http://sysoev.ru/nginx/docs/http/ngx_http_image_filter_module.html "http://sysoev.ru/nginx/docs/http/ngx_http_image_filter_module.html")