Mercurial > hg > nginx-site
comparison xml/en/docs/http/ngx_http_image_filter_module.xml @ 204:eed54ef19197
English translation of the ngx_http_image_filter_module documentation.
author | Ruslan Ermilov <ru@nginx.com> |
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date | Fri, 25 Nov 2011 09:57:32 +0000 |
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children | f743d1f4683a |
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1 <?xml version="1.0" encoding="utf-8"?> | |
2 | |
3 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> | |
4 | |
5 <module name="Module ngx_http_image_filter_module" | |
6 link="/en/docs/http/ngx_http_image_filter_module.html" | |
7 lang="en"> | |
8 | |
9 <section id="summary"> | |
10 | |
11 <para> | |
12 The <code>ngx_http_image_filter_module</code> module is a filter | |
13 that transforms images in JPEG, GIF, and PNG (0.7.54+) formats. | |
14 </para> | |
15 | |
16 <para> | |
17 This module is not built by default, it should be enabled with the | |
18 <code>--with-http_image_filter_module</code> | |
19 configuration parameter. | |
20 <note> | |
21 This module utilizes the | |
22 <link url="http://libgd.org">libgd</link> library. | |
23 It is recommended to use the latest available version of the library; | |
24 it is version 2.0.35 as of this writing. | |
25 </note> | |
26 </para> | |
27 | |
28 </section> | |
29 | |
30 | |
31 <section id="example" name="Example Configuration"> | |
32 | |
33 <para> | |
34 <example> | |
35 location /img/ { | |
36 proxy_pass http://backend; | |
37 image_filter resize 150 100; | |
38 image_filter rotate 90; | |
39 error_page 415 = /empty; | |
40 } | |
41 | |
42 location = /empty { | |
43 empty_gif; | |
44 } | |
45 </example> | |
46 </para> | |
47 | |
48 </section> | |
49 | |
50 | |
51 <section id="directives" name="Directives"> | |
52 | |
53 <directive name="image_filter"> | |
54 <syntax><parameter>off</parameter></syntax> | |
55 <syntax><parameter>test</parameter></syntax> | |
56 <syntax><parameter>size</parameter></syntax> | |
57 <syntax><parameter>rotate </parameter> | |
58 <value>90</value> | <value>180</value> | <value>270</value> | |
59 </syntax> | |
60 <syntax> | |
61 <parameter>resize </parameter> | |
62 <argument>width height</argument> | |
63 </syntax> | |
64 <syntax> | |
65 <parameter>crop </parameter> | |
66 <argument>width height</argument> | |
67 </syntax> | |
68 <default/> | |
69 <context>location</context> | |
70 | |
71 <para> | |
72 Sets the type of transformation to perform on images: | |
73 <list type="tag"> | |
74 | |
75 <tag-name><parameter>off</parameter></tag-name> | |
76 <tag-desc> | |
77 turns off module processing in a surrounding location. | |
78 </tag-desc> | |
79 | |
80 <tag-name><parameter>test</parameter></tag-name> | |
81 <tag-desc> | |
82 ensures that answers are images in either JPEG, GIF, or PNG format. | |
83 Otherwise, the error | |
84 <http-status code="415" text="Unsupported Media Type"/> | |
85 is returned. | |
86 </tag-desc> | |
87 | |
88 <tag-name><parameter>size</parameter></tag-name> | |
89 <tag-desc> | |
90 outputs information about images in a JSON format, e.g.: | |
91 <example> | |
92 { "img" : { "width": 100, "height": 100, "type": "gif" } } | |
93 </example> | |
94 In case of an error, the following is output: | |
95 <example> | |
96 {} | |
97 </example> | |
98 </tag-desc> | |
99 | |
100 <tag-name><parameter>rotate </parameter> | |
101 <value>90</value>|<value>180</value>|<value>270</value> | |
102 </tag-name> | |
103 <tag-desc> | |
104 rotates images counter-clockwise by the specified number of degrees. | |
105 The argument value can contain variables. | |
106 Can be used either alone, or along with the | |
107 <parameter>resize</parameter> and <parameter>crop</parameter> transformations. | |
108 </tag-desc> | |
109 | |
110 <tag-name><parameter>resize </parameter> | |
111 <argument>width height</argument> | |
112 </tag-name> | |
113 <tag-desc> | |
114 proportionally reduces an image to the specified sizes. | |
115 To reduce by only one dimension, another dimension can be specified as | |
116 “<code>-</code>”. | |
117 In case of an error, the server will return code | |
118 <http-status code="415" text="Unsupported Media Type"/>. | |
119 Values of arguments can contain variables. | |
120 When used along with the <parameter>rotate</parameter> parameter, | |
121 the rotation happens <emphasis>after</emphasis> reduction. | |
122 </tag-desc> | |
123 | |
124 <tag-name><parameter>crop </parameter> | |
125 <argument>width height</argument> | |
126 </tag-name> | |
127 <tag-desc> | |
128 proportionally reduces an image to the size of the largest side | |
129 and crops extraneous edges by another side. | |
130 To reduce by only one dimension, another dimension can be specified as | |
131 “<code>-</code>”. | |
132 In case of an error, the server will return code | |
133 <http-status code="415" text="Unsupported Media Type"/>. | |
134 Values of arguments can contain variables. | |
135 When used along with the <parameter>rotate</parameter> parameter, | |
136 the rotation happens <emphasis>before</emphasis> reduction. | |
137 </tag-desc> | |
138 | |
139 </list> | |
140 </para> | |
141 | |
142 </directive> | |
143 | |
144 | |
145 <directive name="image_filter_buffer"> | |
146 <syntax><value>size</value></syntax> | |
147 <default>1M</default> | |
148 <context>http</context> | |
149 <context>server</context> | |
150 <context>location</context> | |
151 | |
152 <para> | |
153 Sets the maximum size of the buffer used for reading images. | |
154 When a size is exceeded the server will return error | |
155 <http-status code="415" text="Unsupported Media Type"/>. | |
156 </para> | |
157 | |
158 </directive> | |
159 | |
160 | |
161 <directive name="image_filter_jpeg_quality"> | |
162 <syntax><value>1..100</value></syntax> | |
163 <default>75</default> | |
164 <context>http</context> | |
165 <context>server</context> | |
166 <context>location</context> | |
167 | |
168 <para> | |
169 Sets the desired quality of the transformed JPEG images. | |
170 Lesser values usually imply both lower quality and smaller image sizes. | |
171 The maximum recommended value is 95. | |
172 The argument value can contain variables. | |
173 </para> | |
174 | |
175 </directive> | |
176 | |
177 | |
178 <directive name="image_filter_sharpen"> | |
179 <syntax><argument>percent</argument></syntax> | |
180 <default>0</default> | |
181 <context>http</context> | |
182 <context>server</context> | |
183 <context>location</context> | |
184 | |
185 <para> | |
186 Increases sharpness of the final image. | |
187 The sharpness percentage can exceed 100. | |
188 The value of 0 disables sharpening. | |
189 The argument value can contain variables. | |
190 </para> | |
191 | |
192 </directive> | |
193 | |
194 | |
195 <directive name="image_filter_transparency"> | |
196 <syntax><value>on</value>|<value>off</value></syntax> | |
197 <default>on</default> | |
198 <context>http</context> | |
199 <context>server</context> | |
200 <context>location</context> | |
201 | |
202 <para> | |
203 Defines whether transparency should be preserved when transforming | |
204 PNG images with colors specified by a palette, or in GIF images. | |
205 The loss of transparency allows to obtain images of a better quality. | |
206 The alpha channel transparency in PNG is always preserved. | |
207 </para> | |
208 | |
209 </directive> | |
210 | |
211 </section> | |
212 | |
213 </module> |