[Mapserver-users] Rendering mapscript style modifications

[Wheaton, William D.]

OK.  I solved the problem with the fatal error:

Fatal error: Object has an invalid _handle_ property in
/var/www/htdocs/els/mapscript_test.phtml on line 43

The problem was with the $layer=draw($map, $image).  According to the
php/mapscript documentation, the draw method for layer objects, just takes
an image object.  So, I tried $layer=draw($image) and then the image
rendered.  

But again, the map reflects what is in the .map file, not what I've changed
in the mapscript code.  The mapscript code is below-- is there something
missing here?  Do I need to specify a symbolname, symbol size etc.?  Again,
the graphic that is produced shows all of the layers in my .map file,
including the one that is modified in mapscript.  But it is ignoring the
modifications I'm making in mapscript for that layer.  Many thanks for your
assistance!

<?PHP

dl('php_mapscript.so');

 $map = ms_newMapObj(mapscript_test.phtml);

      $layer=$map->getlayerbyname('Respondents');
      $class = ms_newClassObj($layer);
	$style = ms_newStyleObj($class);
    	$style->color->setRGB(0, 255, 0);
    	$class->set("status", MS_ON);
	$layer->set("status", MS_ON);

      $image=$map->prepareImage();
      $layer->draw($image);
      $image=$map->draw();

 $image_url=$image->saveWebImage(MS_PNG,1,1,0);

 echo("<img src=\"$image_url\">");
 ?>


-----Original Message-----
From: Wheaton, William D. 
Sent: Wednesday, March 17, 2004 4:44 PM
To: 'Eric Bridger'; Wheaton, William D.
Cc: 'mapserver-users at lists.gis.umn.edu'
Subject: RE: [Mapserver-users] Rendering mapscript style modifications


Eric--

Thanks for the response and suggestion.  Unfortunately, no joy.

I've now tried:

  $image=$map->prepareImage();
  $layer->draw($map, $image);
  $image=$map->draw();

 $image_url=$image->saveWebImage(MS_PNG,1,1,0);

And:

  $image=$map->prepareImage();
  $image=$map->draw();
  $layer->draw($map, $image);

 $image_url=$image->saveWebImage(MS_PNG,1,1,0);

In both cases, I get this error:
Fatal error: Object has an invalid _handle_ property in
/var/www/htdocs/els/mapscript_test.phtml on line 43

The error refers to the $layer->draw($map, $image) line...Is that an error
that helps decipher the problem?  I searched the list and didn't find
anything on that error...Many thanks for helping out!

Bill.


-----Original Message-----
From: Eric Bridger [mailto:eric at gomoos.org] 
Sent: Wednesday, March 17, 2004 4:15 PM
To: Wheaton, William D.
Cc: 'mapserver-users at lists.gis.umn.edu'
Subject: Re: [Mapserver-users] Rendering mapscript style modifications


William,
I remember going thru the same conceptual confusion when I first started
with mapscript.  I use Perl mapscript but the issues are the same. I don't
have the time to check the docs so take the following with a grain of salt.
The fundemental difference is: mapscript methods which take an Image object
and those that don't.

I believe that the call to $map->draw() takes care of "preparing" the GD
image for drawing and then draws all the layers in the map file.

You should switch to using:
$img = $map->prepareImage()
And then using the draw methods which take an $img paramter. E.g.
$layer->draw($map, $img).

It may be, that you could use $img = $map->draw() and then use
$layer->draw($map, $img) afterwards. That might work.

My method requires a lot more work, in the sense of getting all the layers
in the map file and drawing them one by one.

HTH
Eric


On Wed, 2004-03-17 at 15:09, Wheaton, William D. wrote:
> Hello all:
> 
> I'm having a basic conceptual problem understanding the interaction
> between the modification of a layer in php/mapscript and then 
> rendering those modifications...I've searched far and wide in the 
> e-mail archives, but I guess I'm just missing some basic concept here.
> 
> Given a .map file with several layers, then:
> 
> 1) $map = ms_newMapObj(file.map);
> 
> For the layer I want to change, the .map file looks like this: LAYER
>      PROJECTION
>          "proj=latlong"
>          "ellps=clrk66"
>       END
>       CONNECTIONTYPE postgis
>       NAME "Respondents"
>       GROUP "Base Data"
>       CONNECTION "user=xxxx dbname=xxx password=xxxx"
>       DATA "the_geom from resp"
>       STATUS DEFAULT
>       TYPE POINT
>       METADATA
>             LYRNAME "Respondents"
>       END
>   CLASS
>          STYLE
> 		       COLOR 255 0 0
> 		 END
>    END
> END
> 
> 2) Then, through php/mapscript, grab this layer and change its style:
> 
> $layer=$map->getlayerbyname('Respondents');
> 
> 3) Modify the style of this layer:
> 
> $class=ms_newClassObj($layer);
> $style=ms_newStyleObj($class); $style->color->setRGB(0,255,0); 
> $class->set("status", MS_ON); $layer->set("status", MS_ON);
> $image=$map->draw();
> $image_url=$image->saveWebImage(MS_PNG,1,1,0);
> 
> 4) With this, the map gets drawn with the layer symbology as specified
> in the .map file, not with the modifications made above in the 
> mapscript...
> 
> So, I have a basic problem understanding how modifications to a layer
> in a mapscript file get rendered on the map...Is it order?  Am I 
> missing a something?
> 
> Many thanks in advance for any help.  I'm at my wits end!
> 
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