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New servlet version 1.5b. Mostly cleanup. Global parameters for digilib now in DigilibConfiguration, per request parameters are now all in DigilibRequest. The DocuImage implementation can be selected by the configuration docuimage-class. Pixel-by-pixel view implemented with "mo=clip".
author robcast
date Fri, 24 Jan 2003 22:13:49 +0100
parents 0ff3ede32060
children 4d0e75042673
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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>.
</p>

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