[Mapserver-users] Getting Position of the Label text as MSwill place it

[Lowell Filak]

The following message was sent by "PATTERSON KENNETH ALLEN"
<kapatter at srpnet.com> on Thu, 29 Apr 2004 15:27:12 -0700.

> Yes Lowell your example got me going, thanks. 
> 
> The most unfortunate thing is that I'll have to calculate the size of
> the bounding box.  It sure seems as if the intent is to have member >
labelCacheMemberObj->{poly} provide this information.  "poly" does seem
> to be filled in.  Unless you know otherwise, I'll have to calculate
the > bounding box.  The only way I can think to do this is get the
label > feature min/max size and the "scale data" doing some
calculations. (??)

I expected {poly} to supply the correct {bounds} - what does the output
from your print statements look like (is it completely blank as you
mention below) & if you select just the first label what do you roughly
think the bounds should be - for comparison purposes (if not blank)?

> 
> I can get the upper left pixel point (I think) of the text label >
(pointObj) and I can correlate the label drawn to the layer and class >
(layerindex).  The following code helped me get the values of the >
labelCacheMemberObj object once the MS object has been drawn.

{point} will supply the centroid but that seems to reproduce a function
that already exists but may need tweaked.

> 
> sub ProcessLabelCache {
> 	my $map = shift;
> 	my $label;
> 	
> 	print "In ProcessLableCahe( $map )\n";
> 	while ( $label = $map->nextLabel() ) {
> 	 	print "\t\tlabel Cach: \n";
> 		print "\t\t\tclassindex=$label->{classindex}\n";
> 		print "\t\t\tfeaturesize=$label->{featuresize}\n";
> 		print "\t\t\ttileindex=$label->{tileindex}\n";
> 		print "\t\t\tlabel=$label->{label}\n";	  
> 		print "\t\t\t\tlabel->{sizescaled}=$label->{label}->{sizescaled}\n"; > 
> 		print "\t\t\t\tlabel->{font}=$label->{label}->{font}\n"; 
> 		print "\t\t\t\tlabel->{min/maxsize}=$label->{label}->{minsize}, >
$label->{label}->{maxsize}\n"; 
> 		my $layer = $map->getLayer( $label->{layerindex} );
> 		print "\t\t\tlayerindex=$label->{layerindex}, > name=$layer->{name}\n";
> 		print "\t\t\tnumstyles=$label->{numstyles}\n";		  
> 		print "\t\t\tshapeindex=$label->{shapeindex}\n";		  
> 		print "\t\t\tstatus=$label->{status}\n";
> 		print "\t\t\tstring=$label->{string}\n";
> 		my $shape = $label->{poly};	
> 		print "\t\t\tpoly=$label->{poly}\n";		
> 		print "\t\t\t\tbounds = $shape->{bounds}: $shape->{bounds}->{minx},
> $shape->{bounds}->{maxx} $shape->{bounds}->{miny}, >
$shape->{bounds}->{maxy}\n";
> 		print "\t\t\t\tclassindex = $shape->{classindex}\n";
> 		print "\t\t\t\tindex = $shape->{index}\n";
> 		print "\t\t\t\tline = $shape->{line}\n";
> 		print "\t\t\t\ttext = $shape->{text}\n";
> 		print "\t\t\t\ttype = $shape->{type}\n";
> 		print "\t\t\t\tvalues = $shape->{values}\n";
> 		print "\t\t\tpoint=$label->{point}: $label->{point}->{x}, >
$label->{point}->{y}\n";		
> 		print "\t\t\tstyles=$label->{styles}\n";			
> 	}
> 
> }
> 
> The documentation is close but not quite right.  Is their a preferred
> method for updateing the docs?  

There are a few - the first and fastest is to click on the "X" next to
the labelcachememberobj and then use the bottom frame to edit (add) the
notes in the wiki for the object - thanks. The next is for me to update
the doc ;-)

Lowell

> 
> 	There is no member labelCacheMemberObj->{class}.
> 	Member labelCacheMemberObj->{layeridx} is >
labelCacheMemberObj->{layerindex}
> 
> 3) Not much (if any) of the labelCacheMemberObj member {poly} is
getting > filled in.
> 
> 	labelCacheMemberObj->{poly} is not filed in.
> 
> 
> Thanks,
> 	Ken
> 
> -----Original Message-----
> From: Lowell Filak [mailto:lfilak at medinaco.org]
> Sent: Thursday, April 29, 2004 12:54 PM
> To: PATTERSON KENNETH ALLEN; mapserver-users at lists.gis.umn.edu
> Subject: Re: [Mapserver-users] Getting Position of the Label text as MS
> will place it
> 
> 
> If you incorporate mapscript you can loop through each label in the
> labelcache and pickup the polygon (shapeobj) for each of them.
> The following code is a quick cut from a 3.6 app but I believe it should
> work with 4 & remember to alter the code to use the label
> (labelcachememberobject) polygon instead of the point.
> 
> #
> # Loop through each label in the cache and print string and point x,y.
> while ( $label = $map->nextLabel() ) {
>   if ( $label->{status} ) {
>     my $point = $label->{point};
>     #
>     # Create the imagemap box for the label.
>     $bminx[$spncnt] = $point->{x} - 15;
>     $bminy[$spncnt] = $point->{y} - 10;
>     $bmaxx[$spncnt] = $point->{x} + 15;
>     $bmaxy[$spncnt] = $point->{y} + 10;
>     $ppn[$spncnt] = $label->{shapeidx};
>     $spncnt = $spncnt + 1;
>   }
> }
> 
> HTH
> 
> Lowell
> 
> The following message was sent by "PATTERSON KENNETH ALLEN"
> <kapatter at srpnet.com> on Thu, 29 Apr 2004 11:11:39 -0700.
> 
> > 
> > In our app we create a HTML map used to position popup information
> when the cursor is positions at a specific place on the image.  The user
> can hover the cursor over a point and information will display.  We use
> Perl to program the site.  
> > 
> > It would be very useful for us if we can query the position that MS
> draws the labels at.  Use the following layer definition as the example:
>  How can we get each  bounding box of the text label that is drawn (i.e.
> TEXT "Col_label_nm")?
> > 
> > We are able to get the shape index from the query result set etc.. 
> I'm guessing that since we can't find anything exposed we will need to
> do the same calculations that MS is doing to get the text bounding box.
>  Is this going to get way to tricky?  Should we find another UI
> solution?  Anybody done this before?  Suggestions?
> > 
> > Thanks,
> > 	Ken
> > 
> > 
> > LAYER
> >    NAME "Stuff"
> >    GROUP Geographical
> >    TYPE  POLYGON
> >    STATUS on
> >    template "dummy"
> >    DATA "/.../stuff.shp"
> >    CLASS
> >     	NAME 'aclass'
> >    	OUTLINECOLOR 200 200 200
> > 	TEXT ([Col_label_nm])
> >     	LABEL
> > 	  	TYPE TRUETYPE
> > 	  	FONT helmetBI
> > 	  	antialias off
> > 	  	COLOR 255 0 0  
> > 		MINSIZE 10
> > 		MAXSIZE 14
> > 		POSITION AUTO
> > 		PARTIALS FALSE
> > 	END # Label
> >   END # Class
> > END # Stuff Layer
> > 
> > 
> > 
> > 
> > _______________________________________________
> > Mapserver-users mailing list
> > Mapserver-users at lists.gis.umn.edu
> > http://lists.gis.umn.edu/mailman/listinfo/mapserver-users
> 
>