[Mapserver-users] Re: Clarifications about mapscript 4.2

Wed May 12 16:27:59 EDT 2004

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Hi Sean,

I've been having trouble with styles and colors in Mapscript4.2b2. I've
attached a small perl script and map file which demonstrates the
problem.

Loop thru some points, get the one class and  style defined in the map
file and change various attributes: size, symbol, color.  I have no
problem changing the class symbol or symbol size.  But the color seems
strangely "sticky".  Whichever color is set first using
$style->{color}->setRGB() remains in force.  The color DOES change from
the color defined in the mapfile but then will not change again.

I've also  found that (this is a separate problem)
my $red_color = $mapscript::colorObj(255,0,0);
$style->{color} = $red_color;

does not work as expected.  The color is always black in this case.

Am I missing something?  I will next attempt a completely dynamic
approach, new class, new sytle, etc. and see if that works better.

Thanks,
Eric

On Fri, 2004-05-07 at 13:21, Sean Gillies wrote:
> Hi Eric,
> 
> Was just looking at your Wiki pages and have some clarifications
> for you.
> 
> 1) STYLES: Most users will want to dynamically add new styles to a 
> class by
> this syntax:
> 
>     $class = $layer.getClass(0);
>     $new_style = mapscript::styleObj($class);
> 
> insertStyle() is for more specialized cases where you really want to 
> change
> the ordering of styles or pass a fully-defined style around in your app.
> 
> 2) SYMBOLS: I'd like to recommend that symbols be accessed through
> methods of symbolSetObj class rather than through methods of mapObj.
> For example:
> 
>     $foo_index = $map->{symbolset}->index("foo");
> 
> is, IMO, the better way to go than
> 
>     $foo_index = $map->getSymbolByName("foo");
> 
> The later is a poorly named function because it returns an integer, not 
> a
> symbol, compared to mapObj::getLayerByName which *does* return a layer.
> We're going to leave this in mapscript for backwards compatibility, but
> the future direction is to make mapObj, layerObj, classObj, 
> symbolSetObj,
> etc more container-like with index() methods that return the index of
> a "child" object given the child's name, and that getFoo() methods
> uniformly return instances of Foo, not a mix of instances and indexes.
> 
> 3) You might want to point folks to the development documentation which 
> is
> committed in CVS under mapserver/mapscript/doc/mapscript.txt and to the
> HTML document that I have been generating and keeping online at
> 
>     http://users.frii.com/sgillies/projects/mapscript/
> 
> cheers,
> Sean
> 
> 
> --
> Sean Gillies
> sgillies at frii dot com
> http://users.frii.com/sgillies

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Content-Disposition: attachment; filename=test_color.cgi
Content-Transfer-Encoding: quoted-printable
Content-Type: text/x-perl; name=test_color.cgi; charset=ISO-8859-15

#!/usr/bin/perl
use strict;
# Mapscript 4.2 Beta2
use mapscript42;
use CGI ":cgi";

my $q =3D new CGI;

# A hash of points. hash keys are values used in addFeature() and returned =
by queryByPoint().
my %points =3D (
	1 =3D>	{	'longitude' =3D> -67.0173,
				'latitude'  =3D> 44.8911,
				'size'  =3D> 15,
				},
	2 =3D>	{	'longitude' =3D>  -66.0146,
				'latitude' =3D> 45.2045,
				'size'  =3D> 8,
				},
	3 =3D>	{	'longitude' =3D> -68.3578,
				'latitude' =3D> 43.7148,
				'size'  =3D> 12,
				},
	4 =3D>	{	'longitude' =3D> -66.5528,
				'latitude' =3D> 43.6243,
				'size'  =3D> 18,
				},
	5 =3D>	{	'longitude' =3D> -68.9983,
				'latitude' =3D> 44.0555,
				'size'  =3D> 24,
				},
);

# In tmp/ subdir
my $image_name =3D sprintf("tmp/%0.10d",rand(1000000000)) . ".png";
my $map =3D new mapscript42::mapObj("test_color.map");

my $circle_idx =3D $map->{symbolset}->index("circle");
my $plus_idx =3D $map->{symbolset}->index("plus");

if(!$map){
	warn "New mapObj() error: $mapscript42::ms_error->{message}\n";
}

my $img =3D $map->prepareImage();

if(!$img){
	warn "prepareImage() error: $mapscript42::ms_error->{message}\n";
}

my $layerObj =3D $map->getLayerByName('points');

foreach my $point_id (sort keys %points){
	my $point =3D new mapscript42::pointObj();
	$point->{x} =3D $points{$point_id}{longitude};
	$point->{y} =3D $points{$point_id}{latitude};

	my $class =3D $layerObj->getClass(0);

	unless($class){ warn "No class\n";}

	my $style =3D $class->getStyle(0);
	unless($style){ warn "No style\n";}

	# set class symbol size from database
	$style->{size} =3D $points{$point_id}{size};

	# STYLE COLORS
	if($point_id =3D=3D 1){ # sample test case, the first point
		$style->{symbol} =3D $plus_idx;

		# color objects  can't be assigned at all. symbols are black
		#my $red =3D new mapscript42::colorObj(255,0,0);
		#$style->{color} =3D $red;

		# This first color "sticks", determining all point colors. But {symbol} a=
nd {size} don't
		# outline colors stick also.
		$style->{color}->setRGB( 255,0,0 );
		# $style->{color}->setRGB( 0,255,0 );

	}else{

		$style->{symbol} =3D $circle_idx;

		# This color has no affect after above setRGB()
		# $style->{color}->setRGB( 255,0,0 );
		$style->{color}->setRGB( 0,255,0 );

	}

	#my $color =3D $style->{color};
	#warn "$point_id r:$color->{red} g:$color->{green} b:$color->{blue}\n";

	$class->{label}->{color}->setRGB(0,0,0);

	$point->draw($map, $layerObj, $img, undef, "$point_id");

	#undef $style;
	#undef $class;
}

$map->drawLabelCache($img);

$img->save($image_name);

# Output an HTML form to show image

print $q->header();
print $q->start_html(-title=3D>'MapServer4.2b2 - Dynamic Points', -bgcolor=
=3D>"#ffffff");

print "<form name=3D\"pointmap\" action=3D\"test_color.cgi\" method=3D\"GET=
\">\n";
print "<table border=3D\"1\" cellpadding=3D\"5\" cellspacing=3D\"2\">\n";
print "<tr>\n";
print "<td>\n";
print "<input border=3D\"2\" type=3D\"image\" name=3D\"img\" src=3D\"$image=
_name\">\n";
print "</td>\n";
print "</tr>\n";
print "</table>\n";
print "</form>\n";
print "<p>\n";

print $q->end_html();
exit;

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Content-Disposition: attachment; filename=test_color.map
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain; name=test_color.map; charset=ISO-8859-15

MAP
  NAME "points42"
  STATUS ON
  EXTENT -71.5 39.5 -63.0 46.0
  SIZE 504 385
  IMAGETYPE PNG
  UNITS DD
  PROJECTION
     "proj=3Dlatlong"
  END
  OUTPUTFORMAT
    NAME PNG
    DRIVER "GD/PNG"
    MIMETYPE "image/png"
	# 24bit
    IMAGEMODE RGB
    EXTENSION "png"
  END

SYMBOL
  TYPE ELLIPSE
  NAME "circle"
  POINTS 1 1 END
  FILLED TRUE
END

SYMBOL
  TYPE VECTOR
  NAME "plus"
  POINTS .5 0 .5 1 -99 -99 0 .5 1 .5 END
END=20

LAYER
  NAME "points"
  DEBUG ON
  TYPE POINT
  STATUS ON
  TOLERANCE 10
  TEMPLATE "bogus.html"
  CLASS
    NAME "point"
	STYLE
      SYMBOL "circle"
      SIZE 0=20
	  COLOR 0 255 0
	  OUTLINECOLOR 0 0 0
	END
    LABEL
      COLOR 255 0 0
      TYPE BITMAP
      SIZE MEDIUM
      POSITION AUTO
    END
  END
  PROJECTION
    "proj=3Dlatlong"
  END
END

END

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