1:
2: # The LearningOnline Network with CAPA
3: # image click response style
4: #
5: # $Id: imageresponse.pm,v 1.65 2005/04/07 06:56:21 albertel Exp $
6: #
7: # Copyright Michigan State University Board of Trustees
8: #
9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
10: #
11: # LON-CAPA is free software; you can redistribute it and/or modify
12: # it under the terms of the GNU General Public License as published by
13: # the Free Software Foundation; either version 2 of the License, or
14: # (at your option) any later version.
15: #
16: # LON-CAPA is distributed in the hope that it will be useful,
17: # but WITHOUT ANY WARRANTY; without even the implied warranty of
18: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19: # GNU General Public License for more details.
20: #
21: # You should have received a copy of the GNU General Public License
22: # along with LON-CAPA; if not, write to the Free Software
23: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24: #
25: # /home/httpd/html/adm/gpl.txt
26: #
27: # http://www.lon-capa.org/
28: #
29: #FIXME LATER assumes multiple possible submissions but only one is possible
30: #currently
31:
32: package Apache::imageresponse;
33: use strict;
34: use Image::Magick();
35: use Apache::randomlylabel();
36: use Apache::londefdef();
37: use Apache::Constants qw(:common :http);
38: use Apache::lonlocal;
39: use Apache::lonnet;
40:
41: BEGIN {
42: &Apache::lonxml::register('Apache::imageresponse',('imageresponse'));
43: }
44:
45: sub start_imageresponse {
46: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
47: my $result;
48: #when in a radiobutton response use these
49: &Apache::lonxml::register('Apache::imageresponse',
50: ('foilgroup','foil','text','image','rectangle',
51: 'polygon','conceptgroup'));
52: push (@Apache::lonxml::namespace,'imageresponse');
53: my $id = &Apache::response::start_response($parstack,$safeeval);
54: undef(%Apache::response::foilnames);
55: if ($target eq 'meta') {
56: $result=&Apache::response::meta_package_write('imageresponse');
57: } elsif ($target eq 'analyze') {
58: my $part_id="$Apache::inputtags::part.$id";
59: push (@{ $Apache::lonhomework::analyze{"parts"} },$part_id);
60: }
61: return $result;
62: }
63:
64: sub end_imageresponse {
65: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
66: &Apache::response::end_response;
67: pop @Apache::lonxml::namespace;
68: &Apache::lonxml::deregister('Apache::imageresponse',('foilgroup','foil','text','image','rectangle','conceptgroup'));
69: my $result;
70: if ($target eq 'edit') { $result=&Apache::edit::end_table(); }
71: undef(%Apache::response::foilnames);
72: return $result;
73: }
74:
75: %Apache::response::foilgroup=();
76: sub start_foilgroup {
77: %Apache::response::foilgroup=();
78: $Apache::imageresponse::conceptgroup=0;
79: &Apache::response::pushrandomnumber();
80: return '';
81: }
82:
83: sub getfoilcounts {
84: my ($parstack,$safeeval)=@_;
85:
86: my $max = &Apache::lonxml::get_param('max',$parstack,$safeeval,'-2');
87: # +1 since instructors will count from 1
88: my $count = $#{ $Apache::response::foilgroup{'names'} }+1;
89: #if (&Apache::response::showallfoils()) { $max=$count; }
90: return ($count,$max);
91: }
92:
93: sub whichfoils {
94: my ($max)=@_;
95: if (!defined(@{ $Apache::response::foilgroup{'names'} })) { return; }
96: my @names = @{ $Apache::response::foilgroup{'names'} };
97: my @whichopt =();
98: while ((($#whichopt+1) < $max) && ($#names > -1)) {
99: &Apache::lonxml::debug("Have $#whichopt max is $max");
100: my $aopt;
101: # if (&Apache::response::showallfoils()) {
102: # $aopt=0;
103: # } else {
104: $aopt=int(&Math::Random::random_uniform() * ($#names+1));
105: # }
106: &Apache::lonxml::debug("From $#names elms, picking $aopt");
107: $aopt=splice(@names,$aopt,1);
108: &Apache::lonxml::debug("Picked $aopt");
109: push (@whichopt,$aopt);
110: }
111: return @whichopt;
112: }
113:
114: sub prep_image {
115: my ($image,$mode,$name)=@_;
116: my $part=$Apache::inputtags::part;
117: my $respid=$Apache::inputtags::response['-1'];
118: my $id=&Apache::loncommon::get_cgi_id();
119: my (%x,$i);
120: $x{"cgi.$id.BGIMG"}=&Apache::lonnet::escape($image);
121: my ($x,$y)=split(/:/,$Apache::lonhomework::history{"resource.$part.$respid.submission"});
122: #draws 2 xs on the image at the clicked location
123: #one in white and then one in red on top of the one in white
124: if (defined($x) && $x=~/\S/ && defined($y) && $y =~/\S/ && !&Apache::response::show_answer()) {
125: my $length = 6;
126: my $width = 1;
127: my $extrawidth = 2;
128: my $xmin=($x-$length);
129: my $xmax=($x+$length);
130: my $ymin=($y-$length);
131: my $ymax=($y+$length);
132:
133: $x{"cgi.$id.OBJTYPE"}.='LINE:';
134: $i=$x{"cgi.$id.OBJCOUNT"}++;
135: $x{"cgi.$id.OBJ$i"}=join(':',(($xmin),($ymin),($xmax),($ymax),
136: "FFFFFF",($width+$extrawidth)));
137: $x{"cgi.$id.OBJTYPE"}.='LINE:';
138: $i=$x{"cgi.$id.OBJCOUNT"}++;
139: $x{"cgi.$id.OBJ$i"}=join(':',(($xmin),($ymax),($xmax),($ymin),
140: "FFFFFF",($width+$extrawidth)));
141: $x{"cgi.$id.OBJTYPE"}.='LINE:';
142: $i=$x{"cgi.$id.OBJCOUNT"}++;
143: $x{"cgi.$id.OBJ$i"}=join(':',(($xmin),($ymin),($xmax),($ymax),
144: "FF0000",($width)));
145: $x{"cgi.$id.OBJTYPE"}.='LINE:';
146: $i=$x{"cgi.$id.OBJCOUNT"}++;
147: $x{"cgi.$id.OBJ$i"}=join(':',(($xmin),($ymax),($xmax),($ymin),
148: "FF0000",($width)));
149: }
150: if ($mode eq 'answer') {
151: my $width = 1;
152: my $extrawidth = 2;
153: my @areas = @{ $Apache::response::foilgroup{"$name.area"} };
154: foreach my $area (@areas) {
155: if ($area=~/^rectangle:/) {
156: $x{"cgi.$id.OBJTYPE"}.='RECTANGLE:';
157: $i=$x{"cgi.$id.OBJCOUNT"}++;
158: my ($x1,$y1,$x2,$y2)=
159: ($area=~m/rectangle:\(([0-9]+),([0-9]+)\)\-\(([0-9]+),([0-9]+)\)/);
160: $x{"cgi.$id.OBJ$i"}=join(':',($x1,$y1,$x2,$y2,"FFFFFF",
161: ($width+$extrawidth)));
162: $x{"cgi.$id.OBJTYPE"}.='RECTANGLE:';
163: $i=$x{"cgi.$id.OBJCOUNT"}++;
164: $x{"cgi.$id.OBJ$i"}=join(':',($x1,$y1,$x2,$y2,"00FF00",$width));
165: } elsif ($area=~/^polygon:(.*)/) {
166: $x{"cgi.$id.OBJTYPE"}.='POLYGON:';
167: $i=$x{"cgi.$id.OBJCOUNT"}++;
168: $x{"cgi.$id.OBJ$i"}=join(':',("FFFFFF",($width+$extrawidth)));
169: $x{"cgi.$id.OBJEXTRA$i"}=$1;
170: $x{"cgi.$id.OBJTYPE"}.='POLYGON:';
171: $i=$x{"cgi.$id.OBJCOUNT"}++;
172: $x{"cgi.$id.OBJ$i"}=join(':',("00FF00",$width));
173: $x{"cgi.$id.OBJEXTRA$i"}=$1;
174: }
175: }
176: }
177: &Apache::lonnet::appenv(%x);
178: return $id;
179: }
180:
181: sub displayfoils {
182: my ($target,@whichopt) = @_;
183: my $result ='';
184: my $name;
185: my $temp=1;
186: foreach $name (@whichopt) {
187: $result.=$Apache::response::foilgroup{"$name.text"};
188: &Apache::lonxml::debug("Text is $result");
189: if ($target eq 'tex') {$result.="\\vskip 0 mm \n";} else {$result.="<br />\n";}
190: my $image=$Apache::response::foilgroup{"$name.image"};
191: &Apache::lonxml::debug("image is $image");
192: if ( $target eq 'web' && $image !~ /^http:/ ) {
193: $image=&clean_up_image($image);
194: }
195: &Apache::lonxml::debug("image is $image");
196: if ( &Apache::response::show_answer() ) {
197: if ($target eq 'tex') {
198: $result.=$Apache::response::foilgroup{"$name.image"}."\\vskip 0 mm \n";
199: } else {
200: my $token=&prep_image($image,'answer',$name);
201: $result.="<img src=\"/adm/randomlabel.png?token=$token\" /><br />\n";
202: }
203: } else {
204: if ($target eq 'tex') {
205: $result.=$Apache::response::foilgroup{"$name.image"}."\\vskip 0 mm \n";
206: } else {
207: my $id=$Apache::inputtags::response['-1'];
208: my $token=&prep_image($image);
209: my $temp=1;
210: $result.="<input type=\"image\" name=\"HWVAL_$id:$temp\" ".
211: "src=\"/adm/randomlabel.png?token=$token\" /><br />\n";
212: }
213: }
214: $temp++;
215: }
216: return $result;
217: }
218:
219: sub clean_up_image {
220: my ($image)=@_;
221: if ($image =~ /\s*<img\s*/) {
222: ($image) = ($image =~ /src\s*=\s*[\"\']([^\"\']+)[\"\']/i);
223: if ($image !~ /^http:/) {
224: $image=&Apache::lonnet::hreflocation('',$image);
225: }
226: if (!$image) {
227: $image='/home/httpd/html/adm/lonKaputt/lonlogo_broken.gif';
228: }
229: } else {
230: $image=&Apache::lonnet::filelocation($Apache::lonxml::pwd[-1],$image);
231: if (&Apache::lonnet::repcopy($image) ne 'ok') {
232: $image='/home/httpd/html/adm/lonKaputt/lonlogo_broken.gif';
233: }
234: }
235: return $image;
236: }
237:
238: sub gradefoils {
239: my (@whichopt) = @_;
240: my $x;
241: my $y;
242: my $result;
243: my $id=$Apache::inputtags::response['-1'];
244: my $temp=1;
245: foreach my $name (@whichopt) {
246: $x=$env{"form.HWVAL_$id:$temp.x"};
247: $y=$env{"form.HWVAL_$id:$temp.y"};
248: &Apache::lonxml::debug("Got a x of $x and a y of $y for $name");
249: if (defined($x) && defined($y) &&
250: defined(@{ $Apache::response::foilgroup{"$name.area"} })) {
251: my @areas = @{ $Apache::response::foilgroup{"$name.area"} };
252: my $grade="INCORRECT";
253: foreach my $area (@areas) {
254: &Apache::lonxml::debug("Area is $area for $name");
255: $area =~ m/([a-z]*):/;
256: &Apache::lonxml::debug("Area of type $1");
257: if ($1 eq 'rectangle') {
258: $grade=&grade_rectangle($area,$x,$y);
259: } elsif ($1 eq 'polygon') {
260: $grade=&grade_polygon($area,$x,$y);
261: } else {
262: &Apache::lonxml::error("Unknown area style $area");
263: }
264: &Apache::lonxml::debug("Area said $grade");
265: if ($grade eq 'APPROX_ANS') { last; }
266: }
267: &Apache::lonxml::debug("Foil was $grade");
268: if ($grade eq 'INCORRECT') { $result= 'INCORRECT'; }
269: if (($grade eq 'APPROX_ANS') && ($result ne 'APPROX_ANS')) { $result=$grade; }
270: &Apache::lonxml::debug("Question is $result");
271: $temp++;
272: }
273: }
274: my $responsestr="$x:$y";
275: my $part=$Apache::inputtags::part;
276: my %previous=&Apache::response::check_for_previous($responsestr,$part,$id);
277: if ($result
278: && $Apache::lonhomework::type eq 'survey') { $result='SUBMITTED'; }
279: &Apache::response::handle_previous(\%previous,$result);
280: $Apache::lonhomework::results{"resource.$part.$id.submission"}=$responsestr;
281: $Apache::lonhomework::results{"resource.$part.$id.awarddetail"}=$result;
282: return '';
283: }
284:
285: sub end_foilgroup {
286: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
287: my $result='';
288: my @whichopt;
289: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
290: $target eq 'analyze') {
291: my ($count,$max) = &getfoilcounts($parstack,$safeeval);
292: if ($count>$max) { $count=$max }
293: &Apache::lonxml::debug("Count is $count from $max");
294: @whichopt = &whichfoils($max);
295: if ($target eq 'web' || $target eq 'tex') {
296: $result=&displayfoils($target,@whichopt);
297: } elsif ($target eq 'grade') {
298: if ( defined $env{'form.submitted'}) { &gradefoils(@whichopt); }
299: } elsif ( $target eq 'analyze') {
300: &Apache::response::analyze_store_foilgroup(\@whichopt,
301: ['text','image','area']);
302: }
303: } elsif ($target eq 'edit') {
304: $result=&Apache::edit::end_table();
305: }
306: &Apache::response::poprandomnumber();
307: return $result;
308: }
309:
310: sub start_conceptgroup {
311: $Apache::imageresponse::conceptgroup=1;
312: %Apache::response::conceptgroup=();
313: return '';
314: }
315:
316: sub end_conceptgroup {
317: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
318: $Apache::imageresponse::conceptgroup=0;
319: my $result;
320: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
321: $target eq 'analyze') {
322: &Apache::response::pick_foil_for_concept($target,
323: ['area','text','image'],
324: \%Apache::hint::image,
325: $parstack,$safeeval);
326: } elsif ($target eq 'edit') {
327: $result=&Apache::edit::end_table();
328: }
329: return $result;
330: }
331:
332: sub insert_foil {
333: return '
334: <foil>
335: <image></image>
336: <text></text>
337: <rectangle></rectangle>
338: </foil>
339: ';
340: }
341:
342: $Apache::imageresponse::curname='';
343: sub start_foil {
344: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
345: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
346: $target eq 'analyze') {
347: my $name = &Apache::lonxml::get_param('name',$parstack,$safeeval);
348: if (!$name) {
349: &Apache::lonxml::error("Foils without names exist. This can cause problems to malfunction.");
350: $name=$Apache::lonxml::curdepth;
351: }
352: if (defined($Apache::response::foilnames{$name})) {
353: &Apache::lonxml::error(&mt("Foil name <b><tt>[_1]</tt></b> appears more than once. Foil names need to be unique.",$name));
354: }
355: $Apache::response::foilnames{$name}++;
356: if ( $Apache::imageresponse::conceptgroup
357: #&& !&Apache::response::showallfoils()
358: ) {
359: push(@{ $Apache::response::conceptgroup{'names'} }, $name);
360: } else {
361: push(@{ $Apache::response::foilgroup{'names'} }, $name);
362: }
363: $Apache::imageresponse::curname=$name;
364: }
365: return '';
366: }
367:
368: sub end_foil {
369: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
370: my $result;
371: if ($target eq 'edit') {
372: $result=&Apache::edit::end_table();
373: }
374: return $result;
375: }
376:
377: sub start_text {
378: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
379: my $result='';
380: if ($target eq 'web' || $target eq 'tex' || $target eq 'analyze') {
381: &Apache::lonxml::startredirection;
382: } elsif ($target eq 'edit') {
383: my $descr=&Apache::lonxml::get_all_text('/text',$parser);
384: $result=&Apache::edit::tag_start($target,$token,'Task Description').
385: &Apache::edit::editfield($token->[1],$descr,'Text',60,2).
386: &Apache::edit::end_row();
387: } elsif ($target eq "modified") {
388: $result=$token->[4].&Apache::edit::modifiedfield('/text',$parser);
389: }
390: return $result;
391: }
392:
393: sub end_text {
394: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
395: my $result;
396: if ($target eq 'web' || $target eq 'tex' || $target eq 'analyze') {
397: my $name = $Apache::imageresponse::curname;
398: if ( $Apache::imageresponse::conceptgroup
399: #&& !&Apache::response::showallfoils()
400: ) {
401: $Apache::response::conceptgroup{"$name.text"} = &Apache::lonxml::endredirection;
402: } else {
403: $Apache::response::foilgroup{"$name.text"} = &Apache::lonxml::endredirection;
404: }
405: } elsif ($target eq 'edit') {
406: $result=&Apache::edit::end_table();
407: }
408: return $result;
409: }
410:
411: sub start_image {
412: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
413: my $result='';
414: if ($target eq 'web' || $target eq 'tex' || $target eq 'analyze') {
415: &Apache::lonxml::startredirection;
416: } elsif ($target eq 'edit') {
417: my $bgimg=&Apache::lonxml::get_all_text('/image',$parser);
418: $Apache::edit::bgimgsrc=$bgimg;
419: $Apache::edit::bgimgsrcdepth=$Apache::lonxml::curdepth;
420:
421: $result=&Apache::edit::tag_start($target,$token,'Clickable Image').
422: &Apache::edit::editline($token->[1],$bgimg,'Image Source File',40);
423: $result.=&Apache::edit::browse(undef,'textnode').' ';
424: $result.=&Apache::edit::search(undef,'textnode').
425: &Apache::edit::end_row();
426: } elsif ($target eq "modified") {
427: $result=$token->[4].&Apache::edit::modifiedfield('/image',$parser);
428: }
429: return $result;
430: }
431:
432: sub end_image {
433: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
434: my $result;
435: my $name = $Apache::imageresponse::curname;
436: if ($target eq 'web') {
437: my $image = &Apache::lonxml::endredirection();
438: &Apache::lonxml::debug("original image is $image");
439: if ( $Apache::imageresponse::conceptgroup
440: #&& !&Apache::response::showallfoils()
441: ) {
442: $Apache::response::conceptgroup{"$name.image"} = $image;
443: } else {
444: $Apache::response::foilgroup{"$name.image"} = $image;
445: }
446: } elsif ($target eq 'analyze') {
447: my $image = &Apache::lonxml::endredirection();
448: if ( $Apache::imageresponse::conceptgroup
449: #&& !&Apache::response::showallfoils()
450: ) {
451: $Apache::response::conceptgroup{"$name.image"} = $image;
452: } else {
453: $Apache::response::foilgroup{"$name.image"} = $image;
454: }
455: } elsif ($target eq 'edit') {
456: $result=&Apache::edit::end_table();
457: } elsif ($target eq 'tex') {
458: my $src = &Apache::lonxml::endredirection();
459: my ($path,$file) = &Apache::londefdef::get_eps_image($src);
460: my ($height_param,$width_param)=
461: &Apache::londefdef::image_size($src,0.3,$parstack,$safeeval);
462: $Apache::response::foilgroup{"$name.image"} ='\vskip 0 mm \noindent\graphicspath{{'.$path.'}}\includegraphics[width='.$width_param.' mm]{'.$file.'} ';
463: }
464: return $result;
465: }
466:
467: sub start_rectangle {
468: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
469: my $result='';
470: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
471: $target eq 'analyze') {
472: &Apache::lonxml::startredirection;
473: } elsif ($target eq 'edit') {
474: my $coords=&Apache::lonxml::get_all_text('/rectangle',$parser);
475: $result=&Apache::edit::tag_start($target,$token,'Rectangle').
476: &Apache::edit::editline($token->[1],$coords,'Coordinate Pairs',40).
477: &Apache::edit::entercoord(undef,'textnode',undef,undef,'box').
478: &Apache::edit::end_row();
479: } elsif ($target eq "modified") {
480: &Apache::edit::deletecoorddata();
481: $result=$token->[4].&Apache::edit::modifiedfield('/rectangle',$parser);
482: }
483: return $result;
484: }
485:
486: sub grade_rectangle {
487: my ($spec,$x,$y) = @_;
488: &Apache::lonxml::debug("Spec is $spec");
489: my ($x1,$y1,$x2,$y2)=($spec=~m/rectangle:\(([0-9]+),([0-9]+)\)\-\(([0-9]+),([0-9]+)\)/);
490: &Apache::lonxml::debug("Point $x1,$y1,$x2,$y2");
491: if ($x1 > $x2) { my $temp=$x1;$x1=$x2;$x2=$temp; }
492: if ($y1 > $y2) { my $temp=$y1;$y1=$y2;$y2=$temp; }
493: if (($x >= $x1) && ($x <= $x2) && ($y >= $y1) && ($y <= $y2)) {
494: return 'APPROX_ANS';
495: }
496: return 'INCORRECT';
497: }
498:
499: sub end_rectangle {
500: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
501: my $result;
502: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
503: $target eq 'analyze') {
504: my $name = $Apache::imageresponse::curname;
505: my $area = &Apache::lonxml::endredirection;
506: $area=~s/\s//g;
507: &Apache::lonxml::debug("out is $area for $name");
508: if ( $Apache::imageresponse::conceptgroup
509: #&& !&Apache::response::showallfoils()
510: ) {
511: push @{ $Apache::response::conceptgroup{"$name.area"} },"rectangle:$area";
512: } else {
513: push @{ $Apache::response::foilgroup{"$name.area"} },"rectangle:$area";
514: }
515: } elsif ($target eq 'edit') {
516: $result=&Apache::edit::end_table();
517: }
518: return $result;
519: }
520:
521: sub start_polygon {
522: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
523: my $result='';
524: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
525: $target eq 'analyze') {
526: &Apache::lonxml::startredirection;
527: } elsif ($target eq 'edit') {
528: my $coords=&Apache::lonxml::get_all_text('/polygon',$parser);
529: $result=&Apache::edit::tag_start($target,$token,'Polygon').
530: &Apache::edit::editline($token->[1],$coords,'Coordinate list',40).
531: &Apache::edit::entercoord(undef,'textnode',undef,undef,'polygon').
532: &Apache::edit::end_row();
533: } elsif ($target eq "modified") {
534: $result=$token->[4].&Apache::edit::modifiedfield('/polygon',$parser);
535: }
536: return $result;
537: }
538:
539: sub grade_polygon {
540: my ($spec,$x,$y) = @_;
541: &Apache::lonxml::debug("Spec is $spec");
542: $spec=~s/^polygon://;
543: my @polygon;
544: foreach my $coord (split('-',$spec)) {
545: my ($x,$y)=($coord=~m/\(([0-9]+),([0-9]+)\)/);
546: &Apache::lonxml::debug("x $x y $y");
547: push @polygon, {'x'=>$x,'y'=>$y};
548: }
549: #make end point start point
550: push @polygon, $polygon[0];
551: # cribbed from
552: # http://geometryalgorithms.com/Archive/algorithm_0103/algorithm_0103.htm
553: my $crossing = 0; # the crossing number counter
554:
555: # loop through all edges of the polygon
556: for (my $i=0; $i<$#polygon; $i++) { # edge from V[i] to V[i+1]
557: if ((($polygon[$i]->{'y'} <= $y)
558: && ($polygon[$i+1]->{'y'} > $y)) # an upward crossing
559: ||
560: (($polygon[$i]->{'y'} > $y)
561: && ($polygon[$i+1]->{'y'} <= $y))) { # a downward crossing
562: # compute the actual edge-ray intersect x-coordinate
563: my $vt = ($y - $polygon[$i]->{'y'})
564: / ($polygon[$i+1]->{'y'} - $polygon[$i]->{'y'});
565: if ($x < $polygon[$i]->{'x'} + $vt *
566: ($polygon[$i+1]->{'x'} - $polygon[$i]->{'x'})) { # x<intersect
567: $crossing++; # a valid crossing of y=P.y right of P.x
568: }
569: }
570: }
571:
572: # 0 if even (out), and 1 if odd (in)
573: if ($crossing%2) {
574: return 'APPROX_ANS';
575: } else {
576: return 'INCORRECT';
577: }
578: }
579:
580: sub end_polygon {
581: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
582: my $result;
583: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
584: $target eq 'analyze') {
585: my $name = $Apache::imageresponse::curname;
586: my $area = &Apache::lonxml::endredirection;
587: $area=~s/\s*//g;
588: &Apache::lonxml::debug("out is $area for $name");
589: if ( $Apache::imageresponse::conceptgroup
590: #&& !&Apache::response::showallfoils()
591: ) {
592: push @{ $Apache::response::conceptgroup{"$name.area"} },"polygon:$area";
593: } else {
594: push @{ $Apache::response::foilgroup{"$name.area"} },"polygon:$area";
595: }
596: } elsif ($target eq 'edit') {
597: $result=&Apache::edit::end_table();
598: }
599: return $result;
600: }
601: 1;
602: __END__
603:
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