Changes between Initial Version and Version 1 of PerlMapScriptExamples35ex17

Timestamp:

Jan 29, 2009, 7:10:34 AM (15 years ago)

Author:

jmckenna

Comment:

--

PerlMapScriptExamples35ex17

@@ +1 @@
+= ref_to_map_ext.pl =
+
+A perl mapscript 3.6.4 sub-routine which converts a reference map mouse click into new map extents for main map. Really just a code snippet. Very little error checking.
+
+Author: Eric Bridger eric@gomoos.org, eric@maine.com
+----
+{{{
+#!perl
+# This is based entirely on the code in mapserver3.6.4 maptemplate.c::setExtent() case FROMREFPT
+# calculate new map extents from mouse click in reference map.
+# assumes CGI Form with:
+# <input type="image" name="ref_map" src="mapserver_reference_map">
+# <input type="hidden" name="imgext" value="MINX MINY MAXX MAXY"
+
+use mapscript;
+use CGI ":cgi";
+my $q = new CGI;
+
+$map = new mapscript::mapObj("mapfile.map");
+
+# This routine sets $map->{extent}{minx}, etc. and returns the new map extent as a string, which can be
+# set in the html form as your current hidden imgext variable.
+
+sub ref_to_map_ext {
+    my ($q, $map) = @_;
+
+    # as default just return current map extent
+    my $mapext = join(' ', $map->{extent}->{minx},$map->{extent}->{miny},$map->{extent}->{maxx},$map->{extent}->{maxy});
+    if(!$q->param('imgext')){
+        return $mapext;
+    }
+    if(!$q->param('ref_map.x')){
+        return $mapext;
+    }
+
+    # get the current map extent from form imgext variable.
+    my @imgext = split(' ', $q->param('imgext'));
+
+    # get mouse click x, y from ref_map image.
+    my $refx = $q->param('ref_map.x');
+    my $refy = $q->param('ref_map.y');
+
+ # reference map vars from  the map file
+    # These never change unless the map file changes.
+    my $ref_width = $map->{reference}{width};
+    my $ref_height = $map->{reference}{height};
+    my $ref_minx = $map->{reference}{extent}{minx};
+    my $ref_maxx = $map->{reference}{extent}{maxx};
+    my $ref_miny = $map->{reference}{extent}{miny};
+    my $ref_maxy = $map->{reference}{extent}{maxy};
+
+    my $map_width = $map->{width};
+    my $map_height = $map->{height};
+
+    my $cellx = ($ref_maxx - $ref_minx) / $ref_width;
+    my $celly = ($ref_maxy - $ref_miny)/ $ref_height;
+    my $map_x = $ref_minx + $cellx*$refx;
+    my $map_y = $ref_maxy - $celly*$refy;
+
+    # set $map to new extent
+    $map->{extent}->{minx} = $map_x - .5*($imgext[2] - $imgext[0]); # calculate new extent
+    $map->{extent}->{miny} = $map_y - .5*($imgext[3] - $imgext[1]);
+    $map->{extent}->{maxx} = $map_x + .5*($imgext[2] - $imgext[0]);
+    $map->{extent}->{maxy} = $map_y + .5*($imgext[3] - $imgext[1]);
+
+    # reset $mapext to new value
+    $mapext = join(' ', $map->{extent}->{minx},$map->{extent}->{miny},$map->{extent}->{maxx},$map->{extent}->{maxy});
+
+    return($mapext);
+}
+}}}
+= Partial map file =
+{{{
+############################################################
+# A patial map file.
+#######################
+MAP
+  STATUS ON
+  EXTENT -71.50 39.5 -63.0 46.0 # MINX MINY MAXX MAXY
+  SIZE 504 385
+  UNITS DD
+  IMAGETYPE PNG
+
+# reference map
+REFERENCE
+  STATUS ON
+  IMAGE "../../data/mapserver/raster/gom/ref_gom30b.png"
+  SIZE 150 115
+  EXTENT -71.5 39.5 -63.0 46.0 # MINX MINY MAXX MAXY
+  COLOR -1 -1 -1
+  OUTLINECOLOR 255 0 0
+END
+}}}
+----
+back to PerlMapScript