--- loncom/homework/imageresponse.pm	2003/11/11 00:39:33	1.42
+++ loncom/homework/imageresponse.pm	2004/01/09 23:22:19	1.43
@@ -1,7 +1,8 @@
+
 # The LearningOnline Network with CAPA
 # image click response style
 #
-# $Id: imageresponse.pm,v 1.42 2003/11/11 00:39:33 albertel Exp $
+# $Id: imageresponse.pm,v 1.43 2004/01/09 23:22:19 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -42,7 +43,9 @@ sub start_imageresponse {
     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
     my $result;
     #when in a radiobutton response use these
-    &Apache::lonxml::register('Apache::imageresponse',('foilgroup','foil','text','image','rectangle','conceptgroup'));
+    &Apache::lonxml::register('Apache::imageresponse',
+			      ('foilgroup','foil','text','image','rectangle',
+			       'polygon','conceptgroup'));
     push (@Apache::lonxml::namespace,'imageresponse');
     my $id = &Apache::response::start_response($parstack,$safeeval);
     if ($target eq 'meta') {
@@ -136,13 +139,22 @@ sub prep_image {
 	my $extrawidth = 2;
 	my @areas = @{ $Apache::response::foilgroup{"$name.area"} };
 	foreach my $area (@areas) {
-	    my ($x1,$y1,$x2,$y2)=
-		($area=~m/rectangle:\(([0-9]+),([0-9]+)\)\-\(([0-9]+),([0-9]+)\)/);
-	    my $i=$x{"cgi.$id.BOXCOUNT"}++;
-	    $x{"cgi.$id.BOX$i"}=join(':',($x1,$y1,$x2,$y2,"FFFFFF",
-					  ($width+$extrawidth)));
-	    $i=$x{"cgi.$id.BOXCOUNT"}++;
-	    $x{"cgi.$id.BOX$i"}=join(':',($x1,$y1,$x2,$y2,"00FF00",$width));
+	    if ($area=~/^rectangle:/) {
+		my ($x1,$y1,$x2,$y2)=
+		    ($area=~m/rectangle:\(([0-9]+),([0-9]+)\)\-\(([0-9]+),([0-9]+)\)/);
+		my $i=$x{"cgi.$id.BOXCOUNT"}++;
+		$x{"cgi.$id.BOX$i"}=join(':',($x1,$y1,$x2,$y2,"FFFFFF",
+					      ($width+$extrawidth)));
+		$i=$x{"cgi.$id.BOXCOUNT"}++;
+		$x{"cgi.$id.BOX$i"}=join(':',($x1,$y1,$x2,$y2,"00FF00",$width));
+	    } elsif ($area=~/^polygon:(.*)/) {
+		my $i=$x{"cgi.$id.POLYCOUNT"}++;
+		$x{"cgi.$id.POLYOPT$i"}=join(':',("FFFFFF",($width+$extrawidth)));
+		$x{"cgi.$id.POLY$i"}=$1;
+		$i=$x{"cgi.$id.POLYCOUNT"}++;
+		$x{"cgi.$id.POLYOPT$i"}=join(':',("00FF00",$width));
+		$x{"cgi.$id.POLY$i"}=$1;
+	    }
 	}
     }
     &Apache::lonnet::appenv(%x);
@@ -211,6 +223,8 @@ sub gradefoils {
 		&Apache::lonxml::debug("Area of type $1");
 		if ($1 eq 'rectangle') {
 		    $grade=&grade_rectangle($area,$x,$y);
+		} elsif ($1 eq 'polygon') {
+		    $grade=&grade_polygon($area,$x,$y);
 		} else {
 		    &Apache::lonxml::error("Unknown area style $area");
 		}
@@ -486,11 +500,7 @@ sub start_rectangle {
 sub grade_rectangle {
     my ($spec,$x,$y) = @_;
     &Apache::lonxml::debug("Spec is $spec");
-    $spec=~m/rectangle:\(([0-9]+),([0-9]+)\)\-\(([0-9]+),([0-9]+)\)/;
-    my $x1=$1;
-    my $y1=$2;
-    my $x2=$3;
-    my $y2=$4;
+    my ($x1,$y1,$x2,$y2)=($spec=~m/rectangle:\(([0-9]+),([0-9]+)\)\-\(([0-9]+),([0-9]+)\)/);
     &Apache::lonxml::debug("Point $x1,$y1,$x2,$y2");
     if ($x1 > $x2) { my $temp=$x1;$x1=$x2;$x2=$temp; }
     if ($y1 > $y2) { my $temp=$y1;$y1=$y2;$y2=$temp; }
@@ -516,6 +526,85 @@ sub end_rectangle {
 	}
     } elsif ($target eq 'edit') {
 	$result=&Apache::edit::end_table();
+    }
+    return $result;
+}
+
+sub start_polygon {
+    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+    my $result='';
+    if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
+	$target eq 'analyze') { 
+	&Apache::lonxml::startredirection; 
+    } elsif ($target eq 'edit') {
+	my $coords=&Apache::lonxml::get_all_text('/polygon',$parser);
+	$result=&Apache::edit::tag_start($target,$token,'Polygon').
+	    &Apache::edit::editline($token->[1],$coords,'Coordinate list',40).
+	    &Apache::edit::entercoordpolygon(undef,'textnode').
+	    &Apache::edit::end_row();
+    } elsif ($target eq "modified") {
+	$result=$token->[4].&Apache::edit::modifiedfield('/polygon',$parser);
+    }
+    return $result;
+}
+
+sub grade_polygon {
+    my ($spec,$x,$y) = @_;
+    &Apache::lonxml::debug("Spec is $spec");
+    $spec=~s/^polygon://;
+    my @polygon;
+    foreach my $coord (split('-',$spec)) {
+	my ($x,$y)=($coord=~m/\(([0-9]+),([0-9]+)\)/);
+	&Apache::lonxml::debug("x $x y $y");
+	push @polygon, {'x'=>$x,'y'=>$y};
+    }
+    #make end point start point
+    push @polygon, $polygon[0];
+    # cribbed from
+    # http://geometryalgorithms.com/Archive/algorithm_0103/algorithm_0103.htm
+    my $crossing = 0;    # the crossing number counter
+
+    # loop through all edges of the polygon
+    for (my $i=0; $i<$#polygon; $i++) {    # edge from V[i] to V[i+1]
+	if ((($polygon[$i]->{'y'} <= $y)
+	     && ($polygon[$i+1]->{'y'} > $y))    # an upward crossing
+	    || 
+	    (($polygon[$i]->{'y'} > $y) 
+	     && ($polygon[$i+1]->{'y'} <= $y))) { # a downward crossing
+	    # compute the actual edge-ray intersect x-coordinate
+            my $vt = ($y - $polygon[$i]->{'y'}) 
+		/ ($polygon[$i+1]->{'y'} - $polygon[$i]->{'y'});
+            if ($x < $polygon[$i]->{'x'} + $vt * 
+		($polygon[$i+1]->{'x'} - $polygon[$i]->{'x'})) { # x<intersect
+                $crossing++;   # a valid crossing of y=P.y right of P.x
+	    }
+	}
+    }
+
+    # 0 if even (out), and 1 if odd (in)
+    if ($crossing%2) {
+	return 'APPROX_ANS';
+    } else {
+	return 'INCORRECT';
+    }
+}
+
+sub end_polygon {
+    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
+    my $result;
+    if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
+	$target eq 'analyze') {
+	my $name = $Apache::imageresponse::curname;
+	my $area = &Apache::lonxml::endredirection;
+	&Apache::lonxml::debug("out is $area for $name");
+	if ( $Apache::imageresponse::conceptgroup
+	     && !&Apache::response::showallfoils()) {
+	    push @{ $Apache::response::conceptgroup{"$name.area"} },"polygon:$area";
+	} else {
+	    push @{ $Apache::response::foilgroup{"$name.area"} },"polygon:$area";
+	}
+    } elsif ($target eq 'edit') {
+	$result=&Apache::edit::end_table();
     }
     return $result;
 }