mapObj.zoomRectangle from Java Mapscript.

[José Vilson de Mello de Farias]

Greetings people from Mapserver,

   I've been unsuccessfully trying to make mapObj.zoomRectangle work. My 
goal is to write a simple zoom by rectangle, which lets you to select an 
image area from web browser and submit those coordenates for zoom 
processing inside mapserver. Although I've checked my code more than 
once, the error seems to be related to the way mapserver deals with 
these coordenates. Do you know if there is any problem in 
mapObj.zoomRectangle tool in Java Mapscript?  How could I zoom to a 
specific pixel location using zoomRectangle?

  Suppose I have a map with the following size and extent :

      SIZE 800 450
      EXTENT -180.000000 -90.000000 180.000000 90

   Here is my Java code :

    mapObj mapa = new mapObj("./world.map");
    ...
    rectObj maxExtent = new rectObj(-180, -90, 180, 90,
    mapscript.MS_FALSE);    //map full extent
    rectObj actualExtent = new rectObj(-120, -60, 160, 45,
    mapscript.MS_FALSE); //map actual extent
    rectObj pxArea = new rectObj(170, 200, 270, 400,
    mapscript.MS_FALSE);       //image coordenates for zooming
    mapa.zoomRectangle(pxArea, mapa.getWidth(), mapa.getHeight(),
    actualExtent, maxExtent);

   When I try to execute the zoomRectangle command, the following 
exception is thrown :

    java.lang.UnknownError: mapscript::mapObj::zoomRectangle(): General
    error message. image rectangle miny >= maxy

    	edu.umn.gis.mapscript.mapscriptJNI.mapObj_zoomRectangle(Native Method)
    	edu.umn.gis.mapscript.mapObj.zoomRectangle(mapObj.java:554)
            ...

   By the way, what does the last param of rectObj constructor mean? Is 
imageunits a boolean to indicate whether coordenates are image-relative 
or geographical values? If I try to set it to MS_TRUE I get a different 
exception.

    java.lang.UnknownError: rectObj(): Invalid rectangle. image (pixel/line) units { 'minx': 248.000000 , 'miny': 194.000000 , 'maxx': 387.000000 , 'maxy': 259.000000 }
    	edu.umn.gis.mapscript.mapscriptJNI.new_rectObj(Native Method)
    	edu.umn.gis.mapscript.rectObj.<init>(rectObj.java:69)


Could you please help me to solve this situation?

Best regards,

-- 
*José Vilson de Mello de Farias*
/Analista de Sistemas
//SSE - Segurança Pública/

*DÍGITRO TECNOLOGIA*
*E-mail:* vilson.farias at digitro.com.br 
<mailto:vilson.farias at digitro.com.br%20>
*Messenger: *vilsonfarias at hotmail.com 
<mailto:vilson.farias at digitro.com.br%20>
***Site:* www.digitro.com.br <http://www.digitro.com.br%20> 
<http://www.digitro.com.br%20>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/mapserver-users/attachments/20061206/40969a9d/attachment.htm>