Mercurial > hg > digilib-old
diff 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 |
|---|---|
| date | Tue, 26 Apr 2011 20:24:31 +0200 |
| parents | servlet/doc/Scaler.html@c9b2938861cf |
| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/common/doc/Scaler.html Tue Apr 26 20:24:31 2011 +0200 @@ -0,0 +1,157 @@ +<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> +<title>Scaler servlet</title> +</head> +<body> +<h1>Scaler</h1> + +<p>A Servlet for scaling images. (Version 1.5.2)</p> + +<h2>Web API</h2> + +<p>The Scaler servlet takes parameters in the http request format: +<code>Scaler/request_path/?param1=value1&param2=value2&...</code> +Unknown parameters will be silently ignored.</p> + +<p>Recognised parameters:</p> +<ul> + <li><b>request_path</b> path to file or directory.</li> + + <li><b>fn</b> path to file or directory below <code>/docuserver/images</code> + (or other configured image directory). + This path will be added to the <code>request_path</code> behind the servlet name. + Either parameter can be empty.</li> + + <li><b>pn</b> page number. Index into the (alphabetically sorted) directory + given by the path. Starts with 1. Ignored if the path points to a file. + Default: 1.</li> + + <li><b>dw</b> destination image width (pixels). If omitted the image is scaled to fit + dh.</li> + + <li><b>dh</b> destination image height (pixels). If omitted the image is scaled to fit + dw.</li> + + <li><b>wx</b> relative x offset of the image area to be sent (0 <= wx <= 1). + Default: 0.</li> + + <li><b>wy</b> relative y offset of the image area to be sent (0 <= wy <= 1). + Default: 0.</li> + + <li><b>ww</b> relative width of the image area to be sent (0 <= ww <= 1). + Default: 1.</li> + + <li><b>wh</b> relative height of the image area to be sent (0 <= wh <= 1). + Default: 1.</li> + + <li><b>ws</b> additional scaling factor. The resulting image will have the size + <code>[ws*dw,ws*dh]</code>. Default: 1.</li> + + <li><b>mo</b> flags for the mode of operation separated by ",". + <ul> + <li><b>fit</b>: always scale the image to fit + <code>[dw,dh]</code> (default).<br> + + <b>clip</b>: send the file in its + original resolution, cropped to fit <code>[dw,dh]</code>. + <br> + + <b>osize</b>: scale to original size based on the image resolution + (from the image metadata) and display resolution (from parameter + <code>ddpi</code>). Fails if either resolution is unknown. + </li> + + <li> + <b>file</b>: send the file as-is (may + be very large and all sorts of image types!). If configuration + doesn't allow sending files + (<code>sendfile-allowed=false</code>) revert to + <code>clip</code>.<br> + + <b>rawfile</b>: send the file as-is with a mime-type of + <code>application/octet-stream</code> so it can be downloaded with + the browser. + </li> + + <li><b>errtxt</b>: send error response as HTML.<br> + <b>errimg</b>: response as image (default).</li> + + <li><b>q0</b>-<b>q2</b>: quality of interpolation in scaling + (<code>q0</code>: worst, default).</li> + + <li><b>lores</b>: try to use scaled image (default)<br> + + <b>hires</b>: always use unscaled image.<br> + + If the image is zoomed (ww, wh < 1) the use of the scaled + image files depends on the requested resolution.</li> + + <li><b>vmir</b>: mirror image vertically.<br> + + <b>hmir</b>: mirror image horizontally.</li> + + <li><b>jpg</b>: the resulting image is always sent as JPEG + (otherwise TIFF and PNG images are sent as PNG). + </li> + </ul> + </li> + + <li><b>cont</b>: change contrast of the image. Negative value + reduces contrast, positive value enhances contrast. Pixel value is + multiplied by 2^cont. Default: 0</li> + + <li><b>brgt</b>: change brightness of image. Negative value reduces + brightness, positive value enhances brightness. The value brgt is + added to the pixel value. Default: 0</li> + + <li><b>rot</b>: rotate image. Rotation angle is given in + degrees. Default: 0</li> + + <li><b>rgbm</b>: modify color by multiplication. The contrast of the + red green and blue components of the image can be reduced or + enhanced similar to the <code>cont</code> parameter. The factors for + red, green and blue are separated by slashes (for example + 0.86/0/-0.5). Default: 0/0/0</li> + + <li><b>rgba</b>: modify color by addition. The brightness of the red + green and blue components of the image can be reduced or enhanced + similar to the <code>brgt</code> parameter. The factors for red, + green and blue are separated by slashes (for example + 100/0/25). Default: 0/0/0</li> + + <li><b>ddpi</b>: resolution of client display for <code>osize</code> mode. + Either <code>ddpi</code> or <code>ddpix</code> and <code>ddpiy</code> must + be set to use <code>osize</code> mode.</li> + + <li><b>ddpix</b>: resolution of client display in x direction for + <code>osize</code> mode.</li> + + <li><b>ddpiy</b>: resolution of client display in y direction for + <code>osize</code> mode.</li> + +</ul> + + <p>The image to be loaded can be specified by the + <code>request_path</code> (deprecated) or the <code>fn</code> + (preferred) parameter and the optional index <code>pn</code></p> + <ul> + <li> if <code>fn</code> points to a directory then the file with + the index <code>pn</code> (in alphabetical order according to + ASCII) will be loaded</li> + + <li>if <code>fn</code> points to a file (with or without + extension) then this file will be loaded</li> + </ul> + + <p>The image will be scaled equally in horizontal and vertical + direction such that the resulting image does not exceed the rectangle + <code>[dw,dh]</code>. If only either height or width is given the + image is scaled to match only the given parameter. The size of the + resulting image in the other parameter is determined by the aspect + ratio of the image. + </p> + +</body> +</html>