Mercurial > hg > digilib-old
comparison common/doc/Scaler.html @ 903:7779b37d1d05
refactored into maven modules per servlet type.
can build servlet-api 2.3 and 3.0 via profile now!
author | robcast |
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date | Tue, 26 Apr 2011 20:24:31 +0200 |
parents | servlet/doc/Scaler.html@c9b2938861cf |
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1 <!doctype html public "-//w3c//dtd html 4.0 transitional//en"> | |
2 <html> | |
3 <head> | |
4 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> | |
5 <title>Scaler servlet</title> | |
6 </head> | |
7 <body> | |
8 <h1>Scaler</h1> | |
9 | |
10 <p>A Servlet for scaling images. (Version 1.5.2)</p> | |
11 | |
12 <h2>Web API</h2> | |
13 | |
14 <p>The Scaler servlet takes parameters in the http request format: | |
15 <code>Scaler/request_path/?param1=value1&param2=value2&...</code> | |
16 Unknown parameters will be silently ignored.</p> | |
17 | |
18 <p>Recognised parameters:</p> | |
19 <ul> | |
20 <li><b>request_path</b> path to file or directory.</li> | |
21 | |
22 <li><b>fn</b> path to file or directory below <code>/docuserver/images</code> | |
23 (or other configured image directory). | |
24 This path will be added to the <code>request_path</code> behind the servlet name. | |
25 Either parameter can be empty.</li> | |
26 | |
27 <li><b>pn</b> page number. Index into the (alphabetically sorted) directory | |
28 given by the path. Starts with 1. Ignored if the path points to a file. | |
29 Default: 1.</li> | |
30 | |
31 <li><b>dw</b> destination image width (pixels). If omitted the image is scaled to fit | |
32 dh.</li> | |
33 | |
34 <li><b>dh</b> destination image height (pixels). If omitted the image is scaled to fit | |
35 dw.</li> | |
36 | |
37 <li><b>wx</b> relative x offset of the image area to be sent (0 <= wx <= 1). | |
38 Default: 0.</li> | |
39 | |
40 <li><b>wy</b> relative y offset of the image area to be sent (0 <= wy <= 1). | |
41 Default: 0.</li> | |
42 | |
43 <li><b>ww</b> relative width of the image area to be sent (0 <= ww <= 1). | |
44 Default: 1.</li> | |
45 | |
46 <li><b>wh</b> relative height of the image area to be sent (0 <= wh <= 1). | |
47 Default: 1.</li> | |
48 | |
49 <li><b>ws</b> additional scaling factor. The resulting image will have the size | |
50 <code>[ws*dw,ws*dh]</code>. Default: 1.</li> | |
51 | |
52 <li><b>mo</b> flags for the mode of operation separated by ",". | |
53 <ul> | |
54 <li><b>fit</b>: always scale the image to fit | |
55 <code>[dw,dh]</code> (default).<br> | |
56 | |
57 <b>clip</b>: send the file in its | |
58 original resolution, cropped to fit <code>[dw,dh]</code>. | |
59 <br> | |
60 | |
61 <b>osize</b>: scale to original size based on the image resolution | |
62 (from the image metadata) and display resolution (from parameter | |
63 <code>ddpi</code>). Fails if either resolution is unknown. | |
64 </li> | |
65 | |
66 <li> | |
67 <b>file</b>: send the file as-is (may | |
68 be very large and all sorts of image types!). If configuration | |
69 doesn't allow sending files | |
70 (<code>sendfile-allowed=false</code>) revert to | |
71 <code>clip</code>.<br> | |
72 | |
73 <b>rawfile</b>: send the file as-is with a mime-type of | |
74 <code>application/octet-stream</code> so it can be downloaded with | |
75 the browser. | |
76 </li> | |
77 | |
78 <li><b>errtxt</b>: send error response as HTML.<br> | |
79 <b>errimg</b>: response as image (default).</li> | |
80 | |
81 <li><b>q0</b>-<b>q2</b>: quality of interpolation in scaling | |
82 (<code>q0</code>: worst, default).</li> | |
83 | |
84 <li><b>lores</b>: try to use scaled image (default)<br> | |
85 | |
86 <b>hires</b>: always use unscaled image.<br> | |
87 | |
88 If the image is zoomed (ww, wh < 1) the use of the scaled | |
89 image files depends on the requested resolution.</li> | |
90 | |
91 <li><b>vmir</b>: mirror image vertically.<br> | |
92 | |
93 <b>hmir</b>: mirror image horizontally.</li> | |
94 | |
95 <li><b>jpg</b>: the resulting image is always sent as JPEG | |
96 (otherwise TIFF and PNG images are sent as PNG). | |
97 </li> | |
98 </ul> | |
99 </li> | |
100 | |
101 <li><b>cont</b>: change contrast of the image. Negative value | |
102 reduces contrast, positive value enhances contrast. Pixel value is | |
103 multiplied by 2^cont. Default: 0</li> | |
104 | |
105 <li><b>brgt</b>: change brightness of image. Negative value reduces | |
106 brightness, positive value enhances brightness. The value brgt is | |
107 added to the pixel value. Default: 0</li> | |
108 | |
109 <li><b>rot</b>: rotate image. Rotation angle is given in | |
110 degrees. Default: 0</li> | |
111 | |
112 <li><b>rgbm</b>: modify color by multiplication. The contrast of the | |
113 red green and blue components of the image can be reduced or | |
114 enhanced similar to the <code>cont</code> parameter. The factors for | |
115 red, green and blue are separated by slashes (for example | |
116 0.86/0/-0.5). Default: 0/0/0</li> | |
117 | |
118 <li><b>rgba</b>: modify color by addition. The brightness of the red | |
119 green and blue components of the image can be reduced or enhanced | |
120 similar to the <code>brgt</code> parameter. The factors for red, | |
121 green and blue are separated by slashes (for example | |
122 100/0/25). Default: 0/0/0</li> | |
123 | |
124 <li><b>ddpi</b>: resolution of client display for <code>osize</code> mode. | |
125 Either <code>ddpi</code> or <code>ddpix</code> and <code>ddpiy</code> must | |
126 be set to use <code>osize</code> mode.</li> | |
127 | |
128 <li><b>ddpix</b>: resolution of client display in x direction for | |
129 <code>osize</code> mode.</li> | |
130 | |
131 <li><b>ddpiy</b>: resolution of client display in y direction for | |
132 <code>osize</code> mode.</li> | |
133 | |
134 </ul> | |
135 | |
136 <p>The image to be loaded can be specified by the | |
137 <code>request_path</code> (deprecated) or the <code>fn</code> | |
138 (preferred) parameter and the optional index <code>pn</code></p> | |
139 <ul> | |
140 <li> if <code>fn</code> points to a directory then the file with | |
141 the index <code>pn</code> (in alphabetical order according to | |
142 ASCII) will be loaded</li> | |
143 | |
144 <li>if <code>fn</code> points to a file (with or without | |
145 extension) then this file will be loaded</li> | |
146 </ul> | |
147 | |
148 <p>The image will be scaled equally in horizontal and vertical | |
149 direction such that the resulting image does not exceed the rectangle | |
150 <code>[dw,dh]</code>. If only either height or width is given the | |
151 image is scaled to match only the given parameter. The size of the | |
152 resulting image in the other parameter is determined by the aspect | |
153 ratio of the image. | |
154 </p> | |
155 | |
156 </body> | |
157 </html> |