1:
2: # The LearningOnline Network with CAPA
3: # image click response style
4: #
5: # $Id: imageresponse.pm,v 1.46 2004/01/28 20:00:26 sakharuk 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:
39: BEGIN {
40: &Apache::lonxml::register('Apache::imageresponse',('imageresponse'));
41: }
42:
43: sub start_imageresponse {
44: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
45: my $result;
46: #when in a radiobutton response use these
47: &Apache::lonxml::register('Apache::imageresponse',
48: ('foilgroup','foil','text','image','rectangle',
49: 'polygon','conceptgroup'));
50: push (@Apache::lonxml::namespace,'imageresponse');
51: my $id = &Apache::response::start_response($parstack,$safeeval);
52: if ($target eq 'meta') {
53: $result=&Apache::response::meta_package_write('imageresponse');
54: } elsif ($target eq 'analyze') {
55: my $part_id="$Apache::inputtags::part.$id";
56: push (@{ $Apache::lonhomework::analyze{"parts"} },$part_id);
57: }
58: return $result;
59: }
60:
61: sub end_imageresponse {
62: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
63: &Apache::response::end_response;
64: pop @Apache::lonxml::namespace;
65: &Apache::lonxml::deregister('Apache::imageresponse',('foilgroup','foil','text','image','rectangle','conceptgroup'));
66: my $result;
67: if ($target eq 'edit') { $result=&Apache::edit::end_table(); }
68: return $result;
69: }
70:
71: %Apache::response::foilgroup=();
72: sub start_foilgroup {
73: %Apache::response::foilgroup=();
74: $Apache::imageresponse::conceptgroup=0;
75: &Apache::response::setrandomnumber();
76: return '';
77: }
78:
79: sub getfoilcounts {
80: my ($parstack,$safeeval)=@_;
81:
82: my $max = &Apache::lonxml::get_param('max',$parstack,$safeeval,'-2');
83: # +1 since instructors will count from 1
84: my $count = $#{ $Apache::response::foilgroup{'names'} }+1;
85: if (&Apache::response::showallfoils()) { $max=$count; }
86: return ($count,$max);
87: }
88:
89: sub whichfoils {
90: my ($max)=@_;
91: if (!defined(@{ $Apache::response::foilgroup{'names'} })) { return; }
92: my @names = @{ $Apache::response::foilgroup{'names'} };
93: my @whichopt =();
94: while ((($#whichopt+1) < $max) && ($#names > -1)) {
95: &Apache::lonxml::debug("Have $#whichopt max is $max");
96: my $aopt;
97: if (&Apache::response::showallfoils()) {
98: $aopt=0;
99: } else {
100: $aopt=int(&Math::Random::random_uniform() * ($#names+1));
101: }
102: &Apache::lonxml::debug("From $#names elms, picking $aopt");
103: $aopt=splice(@names,$aopt,1);
104: &Apache::lonxml::debug("Picked $aopt");
105: push (@whichopt,$aopt);
106: }
107: return @whichopt;
108: }
109:
110: sub prep_image {
111: my ($image,$mode,$name)=@_;
112: my $part=$Apache::inputtags::part;
113: my $respid=$Apache::inputtags::response['-1'];
114: my $id=&Apache::loncommon::get_cgi_id();
115: my %x;
116: $x{"cgi.$id.BGIMG"}=$image;
117: my ($x,$y)=split(/:/,$Apache::lonhomework::history{"resource.$part.$respid.submission"});
118: #draws 2 xs on the image at the clicked location
119: #one in white and then one in red on top of the one in white
120: if (defined($x) && defined($y)) {
121: $x{"cgi.$id.LINECOUNT"}=4;
122: my $length = 6;
123: my $width = 1;
124: my $extrawidth = 2;
125: $x{"cgi.$id.LINE0"}=
126: join(':',(($x-$length),($y-$length),($x+$length),($y+$length),
127: "FFFFFF",($width+$extrawidth)));
128: $x{"cgi.$id.LINE1"}=
129: join(':',(($x-$length),($y+$length),($x+$length),($y-$length),
130: "FFFFFF",($width+$extrawidth)));
131: $x{"cgi.$id.LINE2"}=
132: join(':',(($x-$length),($y-$length),($x+$length),($y+$length),
133: "FF0000",($width)));
134: $x{"cgi.$id.LINE3"}=
135: join(':',(($x-$length),($y+$length),($x+$length),($y-$length),
136: "FF0000",($width)));
137: }
138: if ($mode eq 'answer') {
139: my $width = 1;
140: my $extrawidth = 2;
141: my @areas = @{ $Apache::response::foilgroup{"$name.area"} };
142: foreach my $area (@areas) {
143: if ($area=~/^rectangle:/) {
144: my ($x1,$y1,$x2,$y2)=
145: ($area=~m/rectangle:\(([0-9]+),([0-9]+)\)\-\(([0-9]+),([0-9]+)\)/);
146: my $i=$x{"cgi.$id.BOXCOUNT"}++;
147: $x{"cgi.$id.BOX$i"}=join(':',($x1,$y1,$x2,$y2,"FFFFFF",
148: ($width+$extrawidth)));
149: $i=$x{"cgi.$id.BOXCOUNT"}++;
150: $x{"cgi.$id.BOX$i"}=join(':',($x1,$y1,$x2,$y2,"00FF00",$width));
151: } elsif ($area=~/^polygon:(.*)/) {
152: my $i=$x{"cgi.$id.POLYCOUNT"}++;
153: $x{"cgi.$id.POLYOPT$i"}=join(':',("FFFFFF",($width+$extrawidth)));
154: $x{"cgi.$id.POLY$i"}=$1;
155: $i=$x{"cgi.$id.POLYCOUNT"}++;
156: $x{"cgi.$id.POLYOPT$i"}=join(':',("00FF00",$width));
157: $x{"cgi.$id.POLY$i"}=$1;
158: }
159: }
160: }
161: &Apache::lonnet::appenv(%x);
162: return $id;
163: }
164:
165: sub displayfoils {
166: my ($target,@whichopt) = @_;
167: my $result ='';
168: my $name;
169: my $temp=1;
170: foreach $name (@whichopt) {
171: $result.=$Apache::response::foilgroup{"$name.text"};
172: &Apache::lonxml::debug("Text is $result");
173: if ($target eq 'tex') {$result.="\\vskip 0 mm \n";} else {$result.="<br />\n";}
174: my $image=$Apache::response::foilgroup{"$name.image"};
175: &Apache::lonxml::debug("image is $image");
176: if ( $target eq 'web' && $image !~ /^http:/ ) {
177: $image=&Apache::lonnet::filelocation($Apache::lonxml::pwd[-1],$image);
178: if (&Apache::lonnet::repcopy($image) ne OK) {
179: $image='/home/httpd/html/adm/lonKaputt/lonlogo_broken.gif';
180: }
181: }
182: &Apache::lonxml::debug("image is $image");
183: if ( &Apache::response::show_answer() ) {
184: if ($target eq 'tex') {
185: $result.=$Apache::response::foilgroup{"$name.image"}."\\vskip 0 mm \n";
186: } else {
187: my $token=&prep_image($image,'answer',$name);
188: $result.="<img src=\"/adm/randomlabel.png?token=$token\" /><br />\n";
189: }
190: } else {
191: if ($target eq 'tex') {
192: $result.=$Apache::response::foilgroup{"$name.image"}."\\vskip 0 mm \n";
193: } else {
194: my $id=$Apache::inputtags::response['-1'];
195: my $token=&prep_image($image);
196: my $temp=1;
197: $result.="<input type=\"image\" name=\"HWVAL_$id:$temp\" ".
198: "src=\"/adm/randomlabel.png?token=$token\" /><br />\n";
199: }
200: }
201: $temp++;
202: }
203: return $result;
204: }
205:
206: sub gradefoils {
207: my (@whichopt) = @_;
208: my $x;
209: my $y;
210: my $result;
211: my $id=$Apache::inputtags::response['-1'];
212: my $temp=1;
213: foreach my $name (@whichopt) {
214: $x=$ENV{"form.HWVAL_$id:$temp.x"};
215: $y=$ENV{"form.HWVAL_$id:$temp.y"};
216: &Apache::lonxml::debug("Got a x of $x and a y of $y for $name");
217: if (defined($x) && defined($y) &&
218: defined(@{ $Apache::response::foilgroup{"$name.area"} })) {
219: my @areas = @{ $Apache::response::foilgroup{"$name.area"} };
220: my $grade="INCORRECT";
221: foreach my $area (@areas) {
222: &Apache::lonxml::debug("Area is $area for $name");
223: $area =~ m/([a-z]*):/;
224: &Apache::lonxml::debug("Area of type $1");
225: if ($1 eq 'rectangle') {
226: $grade=&grade_rectangle($area,$x,$y);
227: } elsif ($1 eq 'polygon') {
228: $grade=&grade_polygon($area,$x,$y);
229: } else {
230: &Apache::lonxml::error("Unknown area style $area");
231: }
232: &Apache::lonxml::debug("Area said $grade");
233: if ($grade eq 'APPROX_ANS') { last; }
234: }
235: &Apache::lonxml::debug("Foil was $grade");
236: if ($grade eq 'INCORRECT') { $result= 'INCORRECT'; }
237: if (($grade eq 'APPROX_ANS') && ($result ne 'APPROX_ANS')) { $result=$grade; }
238: &Apache::lonxml::debug("Question is $result");
239: $temp++;
240: }
241: }
242: $Apache::lonhomework::results{"resource.$Apache::inputtags::part.$id.submission"}="$x:$y";
243: $Apache::lonhomework::results{"resource.$Apache::inputtags::part.$id.awarddetail"}=$result;
244: return '';
245: }
246:
247: sub end_foilgroup {
248: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
249: my $result='';
250: my @whichopt;
251: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
252: $target eq 'analyze') {
253: my ($count,$max) = &getfoilcounts($parstack,$safeeval);
254: if ($count>$max) { $count=$max }
255: &Apache::lonxml::debug("Count is $count from $max");
256: @whichopt = &whichfoils($max);
257: if ($target eq 'web' || $target eq 'tex') {
258: $result=&displayfoils($target,@whichopt);
259: } elsif ($target eq 'grade') {
260: if ( defined $ENV{'form.submitted'}) { &gradefoils(@whichopt); }
261: } elsif ( $target eq 'analyze') {
262: &Apache::response::analyze_store_foilgroup(\@whichopt,
263: ['text','image','area']);
264: }
265: } elsif ($target eq 'edit') {
266: $result=&Apache::edit::end_table();
267: }
268: return $result;
269: }
270:
271: sub start_conceptgroup {
272: $Apache::imageresponse::conceptgroup=1;
273: %Apache::response::conceptgroup=();
274: return '';
275: }
276:
277: sub end_conceptgroup {
278: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
279: $Apache::imageresponse::conceptgroup=0;
280: my $result;
281: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
282: $target eq 'analyze') {
283: &Apache::response::pick_foil_for_concept($target,
284: ['area','text','image'],
285: \%Apache::hint::image,
286: $parstack,$safeeval);
287: } elsif ($target eq 'edit') {
288: $result=&Apache::edit::end_table();
289: }
290: return $result;
291: }
292:
293: sub insert_foil {
294: return '
295: <foil>
296: <image></image>
297: <text></text>
298: <rectangle></rectangle>
299: </foil>
300: ';
301: }
302:
303: $Apache::imageresponse::curname='';
304: sub start_foil {
305: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
306: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
307: $target eq 'analyze') {
308: my $name = &Apache::lonxml::get_param('name',$parstack,$safeeval);
309: if ($name eq '') { $name=$Apache::lonxml::curdepth; }
310: if ( $Apache::imageresponse::conceptgroup
311: && !&Apache::response::showallfoils()) {
312: push(@{ $Apache::response::conceptgroup{'names'} }, $name);
313: } else {
314: push(@{ $Apache::response::foilgroup{'names'} }, $name);
315: }
316: $Apache::imageresponse::curname=$name;
317: }
318: return '';
319: }
320:
321: sub end_foil {
322: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
323: my $result;
324: if ($target eq 'edit') {
325: $result=&Apache::edit::end_table();
326: }
327: return $result;
328: }
329:
330: sub start_text {
331: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
332: my $result='';
333: if ($target eq 'web' || $target eq 'tex' || $target eq 'analyze') {
334: &Apache::lonxml::startredirection;
335: } elsif ($target eq 'edit') {
336: my $descr=&Apache::lonxml::get_all_text('/text',$parser);
337: $result=&Apache::edit::tag_start($target,$token,'Task Description').
338: &Apache::edit::editfield($token->[1],$descr,'Text',60,2).
339: &Apache::edit::end_row();
340: } elsif ($target eq "modified") {
341: $result=$token->[4].&Apache::edit::modifiedfield('/text',$parser);
342: }
343: return $result;
344: }
345:
346: sub end_text {
347: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
348: my $result;
349: if ($target eq 'web' || $target eq 'tex' || $target eq 'analyze') {
350: my $name = $Apache::imageresponse::curname;
351: if ( $Apache::imageresponse::conceptgroup
352: && !&Apache::response::showallfoils() ) {
353: $Apache::response::conceptgroup{"$name.text"} = &Apache::lonxml::endredirection;
354: } else {
355: $Apache::response::foilgroup{"$name.text"} = &Apache::lonxml::endredirection;
356: }
357: } elsif ($target eq 'edit') {
358: $result=&Apache::edit::end_table();
359: }
360: return $result;
361: }
362:
363: sub start_image {
364: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
365: my $result='';
366: if ($target eq 'web' || $target eq 'tex' || $target eq 'analyze') {
367: &Apache::lonxml::startredirection;
368: } elsif ($target eq 'edit') {
369: my $bgimg=&Apache::lonxml::get_all_text('/image',$parser);
370: $Apache::edit::bgimgsrc=$bgimg;
371: $Apache::edit::bgimgsrcdepth=$Apache::lonxml::curdepth;
372:
373: $result=&Apache::edit::tag_start($target,$token,'Clickable Image').
374: &Apache::edit::editline($token->[1],$bgimg,'Image Source File',40);
375: $result.=&Apache::edit::browse(undef,'textnode').' ';
376: $result.=&Apache::edit::search(undef,'textnode').
377: &Apache::edit::end_row();
378: } elsif ($target eq "modified") {
379: $result=$token->[4].&Apache::edit::modifiedfield('/image',$parser);
380: }
381: return $result;
382: }
383:
384: sub end_image {
385: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
386: my $result;
387: my $name = $Apache::imageresponse::curname;
388: if ($target eq 'web') {
389: my $image = &Apache::lonxml::endredirection;
390: &Apache::lonxml::debug("original image is $image");
391: if ( $Apache::imageresponse::conceptgroup
392: && !&Apache::response::showallfoils()) {
393: $Apache::response::conceptgroup{"$name.image"} = $image;
394: } else {
395: $Apache::response::foilgroup{"$name.image"} = $image;
396: }
397: } elsif ($target eq 'analyze') {
398: my $image = &Apache::lonxml::endredirection;
399: if ( $Apache::imageresponse::conceptgroup
400: && !&Apache::response::showallfoils()) {
401: $Apache::response::conceptgroup{"$name.image"} = $image;
402: } else {
403: $Apache::response::foilgroup{"$name.image"} = $image;
404: }
405: } elsif ($target eq 'edit') {
406: $result=&Apache::edit::end_table();
407: } elsif ($target eq 'tex') {
408: my $src = &Apache::lonxml::endredirection;
409: $src=&Apache::lonnet::filelocation($Apache::lonxml::pwd[-1],$src);
410: my $width_param = '';
411: my $height_param = '';
412: my $scaling = .3;
413: my $image = Image::Magick->new;
414: my $current_figure = $image->Read($src);
415: $width_param = $image->Get('width') * $scaling;;
416: $height_param = $image->Get('height') * $scaling;;
417: undef $image;
418: my $epssrc = $src;
419: $epssrc =~ s/(\.gif|\.jpg)$/\.eps/i;
420: if (not -e $epssrc) {
421: my $localfile = $epssrc;
422: $localfile =~ s/.*(\/res)/$1/;
423: my $file;
424: my $path;
425: if ($localfile =~ m!(.*)/([^/]*)$!) {
426: $file = $2;
427: $path = $1.'/';
428: }
429: my $signal_eps = 0;
430: my @content_directory = &Apache::lonnet::dirlist($path);
431: for (my $iy=0;$iy<=$#content_directory;$iy++) {
432: my @tempo_array = split(/&/,$content_directory[$iy]);
433: $content_directory[$iy] = $tempo_array[0];
434: if ($file eq $tempo_array[0]) {
435: $signal_eps = 1;
436: last;
437: }
438: }
439: if ($signal_eps) {
440: my $eps_file = &Apache::lonnet::getfile($localfile);
441: } else {
442: $localfile = $src;
443: $localfile =~ s/.*(\/res)/$1/;
444: my $as = &Apache::lonnet::getfile($src);
445: }
446: }
447: my $file;
448: my $path;
449: if ($src =~ m!(.*)/([^/]*)$!) {
450: $file = $2;
451: $path = $1.'/';
452: }
453: my $newsrc = $src;
454: $newsrc =~ s/(\.gif|\.jpg|\.jpeg)$/\.eps/i;
455: $file=~s/(\.gif|\.jpg|\.jpeg)$/\.eps/i;
456: #do we have any specified size of the picture?
457: my $TeXwidth = &Apache::lonxml::get_param('TeXwidth',$parstack,$safeeval);
458: my $TeXheight = &Apache::lonxml::get_param('TeXheight',$parstack,$safeeval);
459: my $width = &Apache::lonxml::get_param('width',$parstack,$safeeval);
460: if ($TeXwidth ne '') {
461: $width_param = $TeXwidth;
462: } elsif ($TeXheight ne '') {
463: $width_param = $TeXheight/$height_param*$width_param;
464: } elsif ($width ne '') {
465: $width_param = $width*$scaling;
466: }
467: #where can we find the picture?
468: if (-e $newsrc) {
469: if ($path) {
470: $Apache::response::foilgroup{"$name.image"} ='\vskip 0 mm \noindent\graphicspath{{'.$path.'}}\includegraphics[width='.$width_param.' mm]{'.$file.'} ';
471: }
472: } else {
473: #care about eps dynamical generation
474: $Apache::response::foilgroup{"$name.image"}='\vskip 0 mm '.&Apache::londefdef::eps_generation($src,$file,$width_param);
475: }
476: }
477: return $result;
478: }
479:
480: sub start_rectangle {
481: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
482: my $result='';
483: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
484: $target eq 'analyze') {
485: &Apache::lonxml::startredirection;
486: } elsif ($target eq 'edit') {
487: my $coords=&Apache::lonxml::get_all_text('/rectangle',$parser);
488: $result=&Apache::edit::tag_start($target,$token,'Rectangle').
489: &Apache::edit::editline($token->[1],$coords,'Coordinate Pairs',40).
490: &Apache::edit::entercoord(undef,'textnode',undef,undef,'box').
491: &Apache::edit::end_row();
492: } elsif ($target eq "modified") {
493: &Apache::edit::deletecoorddata();
494: $result=$token->[4].&Apache::edit::modifiedfield('/rectangle',$parser);
495: }
496: return $result;
497: }
498:
499: sub grade_rectangle {
500: my ($spec,$x,$y) = @_;
501: &Apache::lonxml::debug("Spec is $spec");
502: my ($x1,$y1,$x2,$y2)=($spec=~m/rectangle:\(([0-9]+),([0-9]+)\)\-\(([0-9]+),([0-9]+)\)/);
503: &Apache::lonxml::debug("Point $x1,$y1,$x2,$y2");
504: if ($x1 > $x2) { my $temp=$x1;$x1=$x2;$x2=$temp; }
505: if ($y1 > $y2) { my $temp=$y1;$y1=$y2;$y2=$temp; }
506: if (($x >= $x1) && ($x <= $x2) && ($y >= $y1) && ($y <= $y2)) {
507: return 'APPROX_ANS';
508: }
509: return 'INCORRECT';
510: }
511:
512: sub end_rectangle {
513: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
514: my $result;
515: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
516: $target eq 'analyze') {
517: my $name = $Apache::imageresponse::curname;
518: my $area = &Apache::lonxml::endredirection;
519: &Apache::lonxml::debug("out is $area for $name");
520: if ( $Apache::imageresponse::conceptgroup
521: && !&Apache::response::showallfoils()) {
522: push @{ $Apache::response::conceptgroup{"$name.area"} },"rectangle:$area";
523: } else {
524: push @{ $Apache::response::foilgroup{"$name.area"} },"rectangle:$area";
525: }
526: } elsif ($target eq 'edit') {
527: $result=&Apache::edit::end_table();
528: }
529: return $result;
530: }
531:
532: sub start_polygon {
533: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
534: my $result='';
535: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
536: $target eq 'analyze') {
537: &Apache::lonxml::startredirection;
538: } elsif ($target eq 'edit') {
539: my $coords=&Apache::lonxml::get_all_text('/polygon',$parser);
540: $result=&Apache::edit::tag_start($target,$token,'Polygon').
541: &Apache::edit::editline($token->[1],$coords,'Coordinate list',40).
542: &Apache::edit::entercoord(undef,'textnode',undef,undef,'polygon').
543: &Apache::edit::end_row();
544: } elsif ($target eq "modified") {
545: $result=$token->[4].&Apache::edit::modifiedfield('/polygon',$parser);
546: }
547: return $result;
548: }
549:
550: sub grade_polygon {
551: my ($spec,$x,$y) = @_;
552: &Apache::lonxml::debug("Spec is $spec");
553: $spec=~s/^polygon://;
554: my @polygon;
555: foreach my $coord (split('-',$spec)) {
556: my ($x,$y)=($coord=~m/\(([0-9]+),([0-9]+)\)/);
557: &Apache::lonxml::debug("x $x y $y");
558: push @polygon, {'x'=>$x,'y'=>$y};
559: }
560: #make end point start point
561: push @polygon, $polygon[0];
562: # cribbed from
563: # http://geometryalgorithms.com/Archive/algorithm_0103/algorithm_0103.htm
564: my $crossing = 0; # the crossing number counter
565:
566: # loop through all edges of the polygon
567: for (my $i=0; $i<$#polygon; $i++) { # edge from V[i] to V[i+1]
568: if ((($polygon[$i]->{'y'} <= $y)
569: && ($polygon[$i+1]->{'y'} > $y)) # an upward crossing
570: ||
571: (($polygon[$i]->{'y'} > $y)
572: && ($polygon[$i+1]->{'y'} <= $y))) { # a downward crossing
573: # compute the actual edge-ray intersect x-coordinate
574: my $vt = ($y - $polygon[$i]->{'y'})
575: / ($polygon[$i+1]->{'y'} - $polygon[$i]->{'y'});
576: if ($x < $polygon[$i]->{'x'} + $vt *
577: ($polygon[$i+1]->{'x'} - $polygon[$i]->{'x'})) { # x<intersect
578: $crossing++; # a valid crossing of y=P.y right of P.x
579: }
580: }
581: }
582:
583: # 0 if even (out), and 1 if odd (in)
584: if ($crossing%2) {
585: return 'APPROX_ANS';
586: } else {
587: return 'INCORRECT';
588: }
589: }
590:
591: sub end_polygon {
592: my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
593: my $result;
594: if ($target eq 'web' || $target eq 'grade' || $target eq 'tex' ||
595: $target eq 'analyze') {
596: my $name = $Apache::imageresponse::curname;
597: my $area = &Apache::lonxml::endredirection;
598: &Apache::lonxml::debug("out is $area for $name");
599: if ( $Apache::imageresponse::conceptgroup
600: && !&Apache::response::showallfoils()) {
601: push @{ $Apache::response::conceptgroup{"$name.area"} },"polygon:$area";
602: } else {
603: push @{ $Apache::response::foilgroup{"$name.area"} },"polygon:$area";
604: }
605: } elsif ($target eq 'edit') {
606: $result=&Apache::edit::end_table();
607: }
608: return $result;
609: }
610: 1;
611: __END__
612:
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