Mercurial > hg > digilib-old

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<TITLE>JBuilder Project ScaleServlet2.jpx</TITLE>
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<H1>Scaler</H1>

<p>A Servlet for scaling images.</p>

<p>Scaler takes parameters in the http request format:
<code>Scaler/request_path/?param1=value1&param2=value2&...</code></p>

<p>Recognised parameters:
<ul>
  <li><b>request_path</b> path to file or directory.

  <li><b>fn</b> path to file or directory below <code>/docuserver/images</code>.
    This path will be added to the <code>request_path</code> behind the servlet name.
    Either parameter can be empty.

  <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><b>dw</b> destination image width (pixels).
  <li><b>dh</b> destination image height.

  <li><b>wx</b> relative x offset of the image area to be sent (0 &lt;= wx &lt;= 1).
    Default: 0.
  <li><b>wy</b> relative y offset of the image area to be sent.
    Default: 0.
  <li><b>ww</b> relative width of the image area to be sent.
    Default: 1.
  <li><b>wh</b> relative height of the image area to be sent.
    Default: 1.

  <li><b>ws</b> additional scaling factor. The resulting image will have the size
    <code>[ws*dw,ws*dh]</code>. Default: 1.

  <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>.<br>
        <b>file</b>: send the file as-is (may be very large and all sorts of image types!).<br>
        If none of these flags is set heuristics is used (send unzoomed GIF as-is).

      <li><b>errtxt</b>: send error response as HTML.<br>
        <b>errimg</b>: response as image (default).

      <li><b>q0</b>-<b>q2</b>: quality of interpolation in scaling
        (<code>q0</code>: worst, default).

      <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 &lt; 1) the unscaled image is used in any case.
    </ul>

</ul>
The image will be scaled equally in horizontal and vertical direction such that
the resulting image does not exceed the rectangle <code>[ww,wh]</code>.
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author	cmielack
date	Fri, 06 Mar 2009 11:06:21 +0100
parents	0ff3ede32060
children	4d0e75042673