shape ops work in progress

git-svn-id: http://skia.googlecode.com/svn/trunk@6223 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/Intersection/as.htm b/experimental/Intersection/as.htm
index a6d2be9..43dceb4 100644
--- a/experimental/Intersection/as.htm
+++ b/experimental/Intersection/as.htm
@@ -92,11 +92,89 @@
 debugShowActiveSpans id=21 (343.709442,175.778046 328.570923,175.778046 326.837006,195.984955) t=0 (343.709442,175.778046) other=20 otherT=1 otherIndex=3 windSum=? windValue=1
 </div>
 
+<div id="quad59">
+debugShowQuadIntersection wtTs[0]=0 (369.863983,145.645813 382.380371,121.254936 406.236359,121.254936) (369.863983,145.645813) wnTs[0]=1 (406.236359,121.254936 409.445679,121.254936 412.975952,121.789818) (412.975952,121.789818)
+debugShowQuadLineIntersection wtTs[0]=1 (369.863983,145.645813 382.380371,121.254936 406.236359,121.254936) (406.236359,121.254936) wnTs[0]=0 (412.975952,121.789818 369.863983,145.645813) (412.975952,121.789818)
+debugShowQuadLineIntersection wtTs[0]=0 (406.236359,121.254936 409.445679,121.254936 412.975952,121.789818) (406.236359,121.254936) wnTs[0]=1 (412.975952,121.789818 369.863983,145.645813) (369.863983,145.645813)
+debugShowQuadIntersection no intersect (369.863983,145.645813 382.380371,121.254936 406.236359,121.254936) (369.970581,137.94342 383.98465,121.254936 406.235992,121.254936)
+debugShowQuadIntersection no intersect (369.863983,145.645813 382.380371,121.254936 406.236359,121.254936) (406.235992,121.254936 425.705902,121.254936 439.71994,137.087616)
+debugShowQuadLineIntersection wtTs[0]=0.934062756 (369.863983,145.645813 382.380371,121.254936 406.236359,121.254936) (403.139679,121.360977) wnTs[0]=0.17423 (439.71994,137.087616 369.970581,137.94342) (427.567535,137.236725)
+debugShowQuadIntersection wtTs[0]=9.61225644e-05 (406.236359,121.254936 409.445679,121.254936 412.975952,121.789818) (406.236969,121.254936) wnTs[0]=0.000495996 (406.235992,121.254936 425.705902,121.254936 439.71994,137.087616) (406.25531,121.254944)
+debugShowQuadLineIntersection no intersect (369.970581,137.94342 383.98465,121.254936 406.235992,121.254936) (412.975952,121.789818 369.863983,145.645813)
+debugShowQuadLineIntersection no intersect (406.235992,121.254936 425.705902,121.254936 439.71994,137.087616) (412.975952,121.789818 369.863983,145.645813)
+debugShowQuadIntersection wtTs[0]=0 (369.970581,137.94342 383.98465,121.254936 406.235992,121.254936) (369.970581,137.94342) wnTs[0]=1 (406.235992,121.254936 425.705902,121.254936 439.71994,137.087616) (439.71994,137.087616)
+debugShowQuadLineIntersection wtTs[0]=1 (369.970581,137.94342 383.98465,121.254936 406.235992,121.254936) (406.235992,121.254936) wnTs[0]=0 (439.71994,137.087616 369.970581,137.94342) (439.71994,137.087616)
+debugShowQuadLineIntersection wtTs[0]=0 (406.235992,121.254936 425.705902,121.254936 439.71994,137.087616) (406.235992,121.254936) wnTs[0]=1 (439.71994,137.087616 369.970581,137.94342) (369.970581,137.94342)
+</div>
+
+<div id="quad59b">
+debugShowActiveSpans id=1 (369.863983,145.645813 382.380371,121.254936 406.236359,121.254936) t=0 (369.863983,145.645813) other=3 otherT=1 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=1 (369.863983,145.645813 382.380371,121.254936 406.236359,121.254936) t=0.174229721 (374.569672,137.886993) other=6 otherT=0.934062756 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=2 (406.236359,121.254936 409.445679,121.254936 412.975952,121.789818) t=0 (406.236359,121.254936) other=1 otherT=1 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=2 (406.236359,121.254936 409.445679,121.254936 412.975952,121.789818) t=0.000495995847 (406.239532,121.254936) other=5 otherT=9.61225644e-05 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=3 (412.975952,121.789818 369.863983,145.645813) t=0 (412.975952,121.789818) other=2 otherT=1 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=3 (412.975952,121.789818 369.863983,145.645813) t=0.669864243 (384.096771,137.770096) other=6 otherT=0.797471908 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=4 (369.970581,137.94342 383.98465,121.254936 406.235992,121.254936) t=0 (369.970581,137.94342) other=6 otherT=1 otherIndex=3 windSum=? windValue=1
+debugShowActiveSpans id=5 (406.235992,121.254936 425.705902,121.254936 439.71994,137.087616) t=0 (406.235992,121.254936) other=4 otherT=1 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=5 (406.235992,121.254936 425.705902,121.254936 439.71994,137.087616) t=9.61225644e-05 (406.239746,121.254936) other=2 otherT=0.000495995847 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=6 (439.71994,137.087616 369.970581,137.94342) t=0 (439.71994,137.087616) other=5 otherT=1 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=6 (439.71994,137.087616 369.970581,137.94342) t=0.797471908 (384.096771,137.770096) other=3 otherT=0.669864243 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=6 (439.71994,137.087616 369.970581,137.94342) t=0.934062756 (374.569672,137.886993) other=1 otherT=0.174229721 otherIndex=1 windSum=? windValue=1
+</div>
+
+<div id="quad60">
+debugShowActiveSpans id=1 (360.416077,166.795715 370.126831,147.872162 388.635406,147.872162) t=0 (360.416077,166.795715) other=2 otherT=1 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=2 (388.635406,147.872162 360.416077,166.795715) t=0 (388.635406,147.872162) other=1 otherT=1 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=2 (388.635406,147.872162 360.416077,166.795715) t=0.00925761141 (388.374176,148.047348) other=4 otherT=0.883679938 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=3 (353.2948,194.351074 353.2948,173.767563 364.167572,160.819855) t=0 (353.2948,194.351074) other=5 otherT=1 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=4 (364.167572,160.819855 375.040314,147.872162 392.303894,147.872162) t=0 (364.167572,160.819855) other=3 otherT=1 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=4 (364.167572,160.819855 375.040314,147.872162 392.303894,147.872162) t=0.883679938 (388.374176,148.047348) other=2 otherT=0.00925761141 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=5 (392.303894,147.872162 353.2948,194.351074) t=0 (392.303894,147.872162) other=4 otherT=1 otherIndex=2 windSum=? windValue=1
+</div>
+
+<div id="quad61">
+debugShowActiveSpans id=1 (348.781738,123.864815 369.848602,123.864815) t=0 (348.781738,123.864815) other=4 otherT=1 otherIndex=4 windSum=? windValue=1
+debugShowActiveSpans id=2 (369.848602,123.864815 369.848602,145.680267) t=0 (369.848602,123.864815) other=1 otherT=1 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=3 (369.848602,145.680267 382.360413,121.298294 406.207703,121.298294) t=0 (369.848602,145.680267) other=2 otherT=1 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=3 (369.848602,145.680267 382.360413,121.298294 406.207703,121.298294) t=0.258355433 (377.070221,134.709274) other=6 otherT=0.8038997 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=3 (369.848602,145.680267 382.360413,121.298294 406.207703,121.298294) t=0.914354357 (402.206024,121.477142) other=4 otherT=0.0696842495 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=3 (369.848602,145.680267 382.360413,121.298294 406.207703,121.298294) t=0.999082394 (406.16394,121.298317) other=5 otherT=0.998890674 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=4 (406.207703,121.298294 348.781738,123.864815) t=1.0265934e-07 (406.207703,121.298294) other=5 otherT=0.999874327 otherIndex=3 windSum=? windValue=1
+debugShowActiveSpans id=4 (406.207703,121.298294 348.781738,123.864815) t=0.0696842495 (402.206024,121.477142) other=3 otherT=0.914354357 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=4 (406.207703,121.298294 348.781738,123.864815) t=0.0881931013 (401.143127,121.524643) other=5 otherT=0.883517581 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=5 (369.961151,137.980698 383.970093,121.298294 406.213287,121.298294) t=0 (369.961151,137.980698) other=6 otherT=1 otherIndex=2 windSum=? windValue=1
+debugShowActiveSpans id=5 (369.961151,137.980698 383.970093,121.298294 406.213287,121.298294) t=0.883517581 (401.143127,121.524643) other=4 otherT=0.0881931013 otherIndex=3 windSum=? windValue=1
+debugShowActiveSpans id=5 (369.961151,137.980698 383.970093,121.298294 406.213287,121.298294) t=0.998890674 (406.16394,121.298317) other=3 otherT=0.999082394 otherIndex=3 windSum=? windValue=1
+debugShowActiveSpans id=5 (369.961151,137.980698 383.970093,121.298294 406.213287,121.298294) t=0.999874327 (406.207703,121.298294) other=4 otherT=1.0265934e-07 otherIndex=1 windSum=? windValue=1
+debugShowActiveSpans id=6 (406.213287,121.298294 369.961151,137.980698) t=0 (406.213287,121.298294) other=5 otherT=1 otherIndex=4 windSum=? windValue=1
+debugShowActiveSpans id=6 (406.213287,121.298294 369.961151,137.980698) t=0.8038997 (377.070221,134.709274) other=3 otherT=0.258355433 otherIndex=1 windSum=? windValue=1
+</div>
+
+<div id="quad61b">
+debugShowQuadLineIntersection wtTs[0]=0.914354357 (369.848602,145.680267 382.360413,121.298294 406.207703,121.298294) (402.206024,121.477142) wtTs[1]=1 (406.207703,121.298294) wnTs[0]=0.0696842 (406.207703,121.298294 348.781738,123.864815) (402.206024,121.477142) wnTs[1]=0 (406.207703,121.298294)
+debugShowQuadIntersection wtTs[0]=0.999082394 (369.848602,145.680267 382.360413,121.298294 406.207703,121.298294) (406.16394,121.298317) wnTs[0]=0.998891 (369.961151,137.980698 383.970093,121.298294 406.213287,121.298294) (406.16394,121.298317)
+debugShowQuadLineIntersection wtTs[0]=0.258355433 (369.848602,145.680267 382.360413,121.298294 406.207703,121.298294) (377.070221,134.709274) wnTs[0]=0.8039 (406.213287,121.298294 369.961151,137.980698) (377.070221,134.709274)
+debugShowQuadLineIntersection wtTs[0]=0.883517581 (369.961151,137.980698 383.970093,121.298294 406.213287,121.298294) (401.143127,121.524643) wtTs[1]=0.999874327 (406.207703,121.298294) wnTs[0]=0.0881931 (406.207703,121.298294 348.781738,123.864815) (401.143127,121.524643) wnTs[1]=1.0265934e-07 (406.207703,121.298294)
+debugShowQuadLineIntersection wtTs[0]=0 (369.961151,137.980698 383.970093,121.298294 406.213287,121.298294) (369.961151,137.980698) wtTs[1]=1 (406.213287,121.298294) wnTs[0]=1 (406.213287,121.298294 369.961151,137.980698) (369.961151,137.980698) wnTs[1]=0 (406.213287,121.298294)
+</div>
+
+<div id="quad61c">
+debugShowActiveSpans id=3 (369.848602,145.680267 382.360413,121.298294 406.207703,121.298294) t=0.914354357 (402.206024,121.477142) other=4 otherT=0.0696842495 otherIndex=2 windSum=-1 windValue=1
+debugShowActiveSpans id=4 (406.207703,121.298294 348.781738,123.864815) t=1.0265934e-07 (406.207703,121.298294) other=5 otherT=0.999874327 otherIndex=3 windSum=-1 windValue=1
+debugShowActiveSpans id=5 (369.961151,137.980698 383.970093,121.298294 406.213287,121.298294) t=0.998890674 (406.16394,121.298317) other=3 otherT=0.999082394 otherIndex=3 windSum=-1 windValue=1
+</div>
+
 </div>
 
 <script type="text/javascript">
 
 var testDivs = [
+    quad61,
+    quad61b,
+    quad61c,
+    quad60,
+    quad59b,
+    quad59,
     quad58b,
     quad58a,
     quad57c,
@@ -119,7 +197,7 @@
 var srcLeft, srcTop;
 var srcWidth, srcHeight;
 var screenWidth, screenHeight;
-var drawnPts;
+var drawnPts, drawnLines, drawnQuads, deferredLines, deferredQuads;
 
 var ptLabels = true;
 var digit_mode = false;
@@ -155,7 +233,14 @@
 var SPAN_Q_SUM = 14;
 var SPAN_Q_VAL = 15;
 
-var Q_LENGTH = 18;
+var ACTIVE_LINE_SPAN = 1;
+var ACTIVE_QUAD_SPAN = 2;
+var INTERSECT_QUAD_LINE = 3;
+var INTERSECT_QUAD_LINE_2 = 4;
+var INTERSECT_QUAD_LINE_NO = 5;
+var INTERSECT_QUAD = 6;
+var INTERSECT_QUAD_2 = 7;
+var INTERSECT_QUAD_NO = 8;
 
 function strs_to_nums(strs) {
     var result = [];
@@ -171,9 +256,18 @@
     return result;
 }
 
+function construct_regexp(pattern) {
+    var escape = pattern.replace(/[-/\\^$*+?.()|[\]{}]/g, '\\$&');
+    escape = escape.replace(/PT_VAL/g, "(\\d+\\.?\\d*),(\\d+\\.?\\d*)");
+    escape = escape.replace(/T_VAL/g, "(\\d+\\.?\\d*e?-?\\d*)");
+    escape = escape.replace(/IDX/g, "(\\d+)");
+    escape = escape.replace(/OPT/g, "(\\?|-?\\d+)");
+    return new RegExp(escape, 'i');
+}
+
 function parse_debugShowActiveSpans(test, title) {
-    var re_quad = / id=(\d+) \((\d+\.?\d*),(\d+\.?\d*) (\d+\.?\d*),(\d+\.?\d*) (\d+\.?\d*),(\d+\.?\d*)\) t=(\d+\.?\d*) \((\d+\.?\d*),(\d+\.?\d*)\) other=(\d+) otherT=(\d+\.?\d*) otherIndex=(\d+) windSum=(\?|-?\d+) windValue=(\d+)/;
-    var re_line = / id=(\d+) \((\d+\.?\d*),(\d+\.?\d*) (\d+\.?\d*),(\d+\.?\d*)\) t=(\d+\.?\d*) \((\d+\.?\d*),(\d+\.?\d*)\) other=(\d+) otherT=(\d+\.?\d*) otherIndex=(\d+) windSum=(\?|-?\d+) windValue=(\d+)/;
+    var re_quad = construct_regexp(" id=IDX (PT_VAL PT_VAL PT_VAL) t=T_VAL (PT_VAL) other=IDX otherT=T_VAL otherIndex=IDX windSum=OPT windValue=IDX");
+    var re_line = construct_regexp(" id=IDX (PT_VAL PT_VAL) t=T_VAL (PT_VAL) other=IDX otherT=T_VAL otherIndex=IDX windSum=OPT windValue=IDX");
     
     var strs = test.split("debugShowActiveSpans");
     if (strs.length == 1)
@@ -187,10 +281,12 @@
         if (re_line.test(str)) {
             var lineStrs = re_line.exec(str);
             var line = strs_to_nums(lineStrs);
+            spans.push(ACTIVE_LINE_SPAN);
             spans.push(line);
         } else if (re_quad.test(str)) {
             var quadStrs = re_quad.exec(str);
             var quad = strs_to_nums(quadStrs);
+            spans.push(ACTIVE_QUAD_SPAN);
             spans.push(quad);
         }
     }
@@ -200,6 +296,45 @@
     }
 }
 
+function filter_str_by(id, str, regex, array) {
+    if (regex.test(str)) {
+        var strs = regex.exec(str);
+        var result = strs_to_nums(strs);
+        array.push(id);
+        array.push(result);
+    }
+}
+
+function parse_intersections(test, title) {
+    var re_quad_line = construct_regexp(" wtTs[0]=T_VAL (PT_VAL PT_VAL PT_VAL) (PT_VAL) wnTs[0]=T_VAL (PT_VAL PT_VAL) (PT_VAL)");
+    var re_quad_line_2 = construct_regexp(" wtTs[0]=T_VAL (PT_VAL PT_VAL PT_VAL) (PT_VAL) wtTs[1]=T_VAL (PT_VAL) wnTs[0]=T_VAL (PT_VAL PT_VAL) (PT_VAL) wnTs[1]=T_VAL (PT_VAL)");
+    var re_quad_line_no_intersect = construct_regexp(" no intersect (PT_VAL PT_VAL PT_VAL) (PT_VAL PT_VAL)");
+    var re_quad = construct_regexp(" wtTs[0]=T_VAL (PT_VAL PT_VAL PT_VAL) (PT_VAL) wnTs[0]=T_VAL (PT_VAL PT_VAL PT_VAL) (PT_VAL)");
+    var re_quad_2 = construct_regexp(" wtTs[0]=T_VAL (PT_VAL PT_VAL PT_VAL) (PT_VAL) wtTs[1]=T_VAL wnTs[0]=T_VAL (PT_VAL PT_VAL PT_VAL) (PT_VAL) wnTs[1]=T_VAL");
+    var re_quad_no_intersect = construct_regexp(" no intersect (PT_VAL PT_VAL PT_VAL) (PT_VAL PT_VAL PT_VAL)");
+    
+    var strs = test.split(/debugShow[A-Za-z]+Intersection/);
+    if (strs.length == 1)
+        return;
+    var spans = [];
+    for (var s in strs) {
+        var str = strs[s];
+        if (str == "\n") {
+            continue;
+        }
+        filter_str_by(INTERSECT_QUAD_LINE, str, re_quad_line, spans);
+        filter_str_by(INTERSECT_QUAD_LINE_2, str, re_quad_line_2, spans);
+        filter_str_by(INTERSECT_QUAD_LINE_NO, str, re_quad_line_no_intersect, spans);
+        filter_str_by(INTERSECT_QUAD, str, re_quad, spans);
+        filter_str_by(INTERSECT_QUAD_2, str, re_quad_2, spans);
+        filter_str_by(INTERSECT_QUAD_NO, str, re_quad_no_intersect, spans);
+    }
+    if (spans.length >= 1) {
+        tests.push(spans);
+        testTitles.push(title);
+    }
+}
+
 function init(test) {
     var canvas = document.getElementById('canvas');
     if (!canvas.getContext) return;
@@ -210,15 +345,55 @@
     var xmax = -Infinity;
     ymin = Infinity;
     var ymax = -Infinity;
-    for (var scans in test) {
+    var scanType = -1;
+    for (var scansStr in test) {
+        var scans = parseInt(scansStr);
         var scan = test[scans];
-        var last = scan.length >= Q_LENGTH ? SPAN_X3 : SPAN_X2;
-        for (var idx = SPAN_X1; idx <= last; idx += 2) {
-            xmin = Math.min(xmin, scan[idx]);
-            xmax = Math.max(xmax, scan[idx]);
-            ymin = Math.min(ymin, scan[idx + 1]);
-            ymax = Math.max(ymax, scan[idx + 1]);
+        if (scanType == -1) {
+            scanType = scan;
+            continue;
         }
+        if (scanType == ACTIVE_LINE_SPAN || scanType == ACTIVE_QUAD_SPAN) {
+            var last = scanType == ACTIVE_QUAD_SPAN ? SPAN_X3 : SPAN_X2;
+            for (var idx = SPAN_X1; idx <= last; idx += 2) {
+                xmin = Math.min(xmin, scan[idx]);
+                xmax = Math.max(xmax, scan[idx]);
+                ymin = Math.min(ymin, scan[idx + 1]);
+                ymax = Math.max(ymax, scan[idx + 1]);
+            }
+        } else {
+            var start = 1;
+            if (scanType != INTERSECT_QUAD_LINE_NO && scanType != INTERSECT_QUAD_NO) {
+                start = 2;
+            }
+            for (var idx = start; idx < start + 6; idx += 2) {
+                xmin = Math.min(xmin, scan[idx]);
+                xmax = Math.max(xmax, scan[idx]);
+                ymin = Math.min(ymin, scan[idx + 1]);
+                ymax = Math.max(ymax, scan[idx + 1]);
+            }
+            start = start + 6;
+            if (scanType == INTERSECT_QUAD_LINE || scanType == INTERSECT_QUAD) {
+                start += 3;
+            }
+            if (scanType == INTERSECT_QUAD_LINE_2) {
+                start += 6;
+            }
+            if (scanType == INTERSECT_QUAD_2) {
+                start += 4;
+            }
+            var end = start + 4;
+            if (scanType == INTERSECT_QUAD || scanType == INTERSECT_QUAD_2 || scanType == INTERSECT_QUAD_NO) {
+                end += 2;
+            }
+            for (var idx = start; idx < end; idx += 2) {
+                xmin = Math.min(xmin, scan[idx]);
+                xmax = Math.max(xmax, scan[idx]);
+                ymin = Math.min(ymin, scan[idx + 1]);
+                ymax = Math.max(ymax, scan[idx + 1]);
+            }
+        }
+        scanType = -1;
     }
     srcWidth = xmax - xmin;
     srcHeight = ymax - ymin;
@@ -250,85 +425,219 @@
     ctx.fillText(label, _px + 5, _py);
 }
 
+function drawLine(x1, y1, x2, y2, selected) {
+    for (var pts = 0; pts < drawnLines.length; pts += 4) {
+        if (x1 == drawnLines[pts] && y1 == drawnLines[pts + 1]) {
+            return;
+        }
+        if (x2 == drawnLines[pts + 2] && x2 == drawnLines[pts + 3]) {
+            return;
+        }
+    }
+    if (selected) {
+        drawnLines.push(x1);
+        drawnLines.push(y1);
+        drawnLines.push(x2);
+        drawnLines.push(y2);
+        ctx.beginPath();
+        ctx.moveTo((x1 - srcLeft) * scale,
+                (y1 - srcTop) * scale);
+        ctx.lineTo((x2 - srcLeft) * scale,
+                (y2 - srcTop) * scale);
+        ctx.stroke();
+        return;
+    }
+    deferredLines.push(x1);
+    deferredLines.push(y1);
+    deferredLines.push(x2);
+    deferredLines.push(y2);
+}
+
+function drawQuad(x1, y1, x2, y2, x3, y3, selected) {
+    for (var pts = 0; pts < drawnQuads.length; pts += 6) {
+        if (x1 == drawnQuads[pts] && y1 == drawnQuads[pts + 1]) {
+            return;
+        }
+        if (x2 == drawnQuads[pts + 2] && x2 == drawnQuads[pts + 3]) {
+            return;
+        }
+        if (x2 == drawnQuads[pts + 4] && x2 == drawnQuads[pts + 5]) {
+            return;
+        }
+    }
+    if (selected) {
+        drawnQuads.push(x1);
+        drawnQuads.push(y1);
+        drawnQuads.push(x2);
+        drawnQuads.push(y2);
+        drawnQuads.push(x3);
+        drawnQuads.push(y3);
+        ctx.beginPath();
+        ctx.moveTo((x1 - srcLeft) * scale,
+                (y1 - srcTop) * scale);
+        ctx.quadraticCurveTo((x2 - srcLeft) * scale,
+                (y2 - srcTop) * scale,
+                (x3 - srcLeft) * scale,
+                (y3 - srcTop) * scale);
+        ctx.stroke();
+        return;
+    }
+    deferredQuads.push(x1);
+    deferredQuads.push(y1);
+    deferredQuads.push(x2);
+    deferredQuads.push(y2);
+    deferredQuads.push(x3);
+    deferredQuads.push(y3);
+}
+
+function drawDeferred() {
+    for (var pts = 0; pts < deferredQuads.length; pts += 6) {
+        drawQuad(deferredQuads[pts], deferredQuads[pts + 1],
+                deferredQuads[pts + 2], deferredQuads[pts + 3],
+                deferredQuads[pts + 4], deferredQuads[pts + 5], true);
+    }
+    for (var pts = 0; pts < deferredLines.length; pts += 4) {
+        drawLine(deferredLines[pts], deferredLines[pts + 1],
+                deferredLines[pts + 2], deferredLines[pts + 3], true);
+    }
+}
+
 function draw(test, title) {
     ctx.fillStyle = "rgba(0,0,0, 0.1)";
     ctx.font = "normal 50px Arial";
     ctx.fillText(title, 50, 50);
     ctx.font = "normal 10px Arial";
     ctx.lineWidth = "1.001"; "0.999";
-    var id = -1;
+    var curId = -1;
     var firstIdx;
     var lastIdx;
     var index_tst = -1;
     drawnPts = [];
+    drawnLines = [];
+    drawnQuads = [];
+    deferredLines = [];
+    deferredQuads = [];
+    var scanType = -1;
+    var partIndex = 0;
     for (var scansStr in test) {
         var scans = parseInt(scansStr);
         var scan = test[scans];
-        var isQuad = scan.length >= Q_LENGTH;
-        if (id != scan[SPAN_ID]) {
-            id = scan[SPAN_ID];
-            firstIdx = lastIdx = scans;
-            ++index_tst;
-            var nextIdx = lastIdx + 1;
-            while (nextIdx < test.length && test[nextIdx][SPAN_ID] == id) {
-                lastIdx = nextIdx++;
-            }
-        }
-        var seq = sequence % test.length;
-        var selected = sequence >= 0 ? seq == scans
-                : (index_bits & (1 << index_tst)) != 0 && scans == firstIdx;
-        var skippable = (sequence >= 0 && seq >= firstIdx && seq <= lastIdx)
-                || scans != firstIdx;
-        if (skippable && !selected) {
+        if (scanType == -1) {
+            scanType = scan;
             continue;
         }
-        ctx.strokeStyle = selected ? "red" : "rgba(0,0,0, 0.2)";
-        ctx.beginPath();
-        ctx.moveTo((scan[SPAN_X1] - srcLeft)* scale,
-                (scan[SPAN_Y1] - srcTop) * scale);
-        if (isQuad) {
-            ctx.quadraticCurveTo((scan[SPAN_X2] - srcLeft) * scale,
-                    (scan[SPAN_Y2] - srcTop) * scale,
-                    (scan[SPAN_X3] - srcLeft) * scale,
-                    (scan[SPAN_Y3] - srcTop) * scale);
-        } else {
-            ctx.lineTo((scan[SPAN_X2] - srcLeft)* scale,
-                    (scan[SPAN_Y2] - srcTop) * scale);
+        partIndex++;
+        var hasId = scanType == ACTIVE_LINE_SPAN || scanType == ACTIVE_QUAD_SPAN ? SPAN_ID : -1;
+        if (hasId >= 0 && curId != scan[hasId]) {
+            curId = hasId;
+            firstIdx = lastIdx = partIndex;
+            index_tst++;
+            var nextIdx = lastIdx + 1;
+            while (nextIdx * 2 < test.length && test[nextIdx * 2][hasId] == curId) {
+                lastIdx = nextIdx++;
+            }
+        } else if (hasId < 0) {
+            firstIdx = lastIdx = partIndex;
+            index_tst++;
         }
-        ctx.stroke();
+        var seq = sequence % (test.length / 2);
+        var selected = sequence >= 0 ? seq == partIndex
+                : (index_bits & (1 << index_tst)) != 0 && partIndex == firstIdx;
+        var skippable = (sequence >= 0 && seq >= firstIdx && seq <= lastIdx)
+                || partIndex != firstIdx;
+        if (skippable && !selected) {
+            scanType = -1;
+            continue;
+        }
+        var types = [scanType == ACTIVE_LINE_SPAN ? 0 : 1];
+        var pts = [];
+        if (scanType == ACTIVE_LINE_SPAN || scanType == ACTIVE_QUAD_SPAN) {
+            pts.push(SPAN_X1);
+        } else {
+            pts.push(scanType != INTERSECT_QUAD_NO && scanType != INTERSECT_QUAD_LINE_NO ? 2 : 1);
+            types.push(scanType == INTERSECT_QUAD_NO || scanType == INTERSECT_QUAD || scanType == INTERSECT_QUAD_2 ? 1 : 0);
+            pts.push(scanType == INTERSECT_QUAD_LINE || scanType == INTERSECT_QUAD ? 11
+                    : scanType == INTERSECT_QUAD_LINE_2 ? 14 : scanType == INTERSECT_QUAD_2 ? 12 : 7);
+        }
+        ctx.strokeStyle = "red";
+        for (var typeIndex = 0; typeIndex < types.length; ++typeIndex) {
+            var type = types[typeIndex];
+            var index = pts[typeIndex];
+            if (type == 1) {
+                drawQuad(scan[index + 0], scan[index + 1], scan[index + 2], scan[index + 3],
+                        scan[index + 4], scan[index + 5], selected);
+            } else {
+                drawLine(scan[index + 0], scan[index + 1], scan[index + 2], scan[index + 3],
+                        selected);
+            }
+        }
         if (debug_xy && selected) {
             var debugText = "";
-            for (var idx = SPAN_X1; idx <= (isQuad ? SPAN_X3 : SPAN_X2); idx += 2) {
-                var screenX = (scan[idx] - srcLeft) * scale;
-                var screenY = (scan[idx + 1] - srcTop) * scale;
-                debugText += screenX.toFixed(decimal_places) + ", ";
-                debugText += screenY.toFixed(decimal_places) + " ";
+            for (var typeIndex = 0; typeIndex < types.length; ++typeIndex) {
+                var type = types[typeIndex];
+                var index = pts[typeIndex];
+                for (var idx = pts[typeIndex]; idx < (type == 1 ? pts[typeIndex] + 6 : pts[typeIndex] + 4); idx += 2) {
+                    var screenX = (scan[idx] - srcLeft) * scale;
+                    var screenY = (scan[idx + 1] - srcTop) * scale;
+                    debugText += screenX.toFixed(decimal_places) + ", ";
+                    debugText += screenY.toFixed(decimal_places) + " ";
+                }
             }
             ctx.fillStyle="blue";
-            ctx.fillText(debugText, 50, scans * 50 + 100);
+            ctx.fillText(debugText, 50, partIndex * 50 + 100);
         }
         if (ptLabels && selected) {
             ctx.fillStyle="blue";
-            drawPoint(scan[SPAN_X1], scan[SPAN_Y1]);
-            drawPoint(scan[SPAN_X2], scan[SPAN_Y2]);
-            if (scan.length >= Q_LENGTH) {
-                drawPoint(scan[SPAN_X3], scan[SPAN_Y3]);
+            for (var typeIndex = 0; typeIndex < types.length; ++typeIndex) {
+                var type = types[typeIndex];
+                var index = pts[typeIndex];
+                for (var idx = pts[typeIndex]; idx < (type == 1 ? pts[typeIndex] + 6 : pts[typeIndex] + 4); idx += 2) {
+                    drawPoint(scan[idx], scan[idx + 1]);
+                }
             }
         }
+        var infoText = "";
         if (info_mode && selected) {
-            var infoText = "id=" + scan[SPAN_ID];
+            infoText += hasId >= 0 ? "id=" + scan[hasId] : partIndex;
+        }
+        if (intersect_mode && selected) {
+            if (scanType == ACTIVE_QUAD_SPAN) {
+                infoText += " t=" + scan[SPAN_Q_T];
+            } else if (scanType == ACTIVE_LINE_SPAN) {
+                infoText += " t=" + scan[SPAN_L_T];
+            } else if (scanType == INTERSECT_QUAD_LINE ||scanType == INTERSECT_QUAD) {
+                infoText += " t0[0]=" + scan[1] + " t1[0]=" + scan[10];
+            } else if (scanType == INTERSECT_QUAD_LINE_2 || scanType == INTERSECT_QUAD_2) {
+                infoText += " t0[0]=" + scan[1] + " t0[1]=" + scan[10] + " t1[0]=" + scan[13];
+                if (scanType == INTERSECT_QUAD_LINE_2) {
+                    infoText += " t1[1]=" + scan[18];
+                } else {
+                    infoText += " t0[1]=" + scan[20];
+                }
+            }
+        }
+        if (infoText.length > 0) {
             ctx.fillStyle="green";
-            ctx.fillText(infoText, 10, scans * 50 + 100);
+            ctx.fillText(infoText, 10, (hasId >= 0 && sequence >= 0
+                    ? hasId : partIndex) * 30 + 50);
         }
         if (intersect_mode && selected) {
             ctx.fillStyle="rgba(50,100,200, 1.0)";
-            if (isQuad) {
+            if (scanType == ACTIVE_QUAD_SPAN) {
                 drawPoint(scan[SPAN_Q_TX], scan[SPAN_Q_TY]);
-            } else {
+            } else if (scanType == ACTIVE_LINE_SPAN) {
                 drawPoint(scan[SPAN_L_TX], scan[SPAN_L_TY]);
+            } else if (scanType != INTERSECT_QUAD_NO && scanType != INTERSECT_QUAD_LINE_NO) {
+                drawPoint(scan[8], scan[9]);
+                if (scanType == INTERSECT_QUAD_LINE_2 || scanType == INTERSECT_QUAD_2) {
+                    drawPoint(scan[11], scan[12]);
+                }
             }
         }
+        ctx.strokeStyle = "rgba(0,0,0, 0.2)";
+        scanType = -1;
     }
+    drawDeferred();
 }
 
 function drawTop() {
@@ -403,7 +712,14 @@
         break;
     case 's':
         sequence++;
-        drawTop();
+        redraw();
+        break;
+    case 'S':
+        sequence--;
+        if (sequence < 0) {
+            sequence = 0;
+        }
+        redraw();
         break;
     case 't':
         intersect_mode ^= true;
@@ -468,6 +784,7 @@
         var title = testDivs[i].id.toString();
         var str = testDivs[i].firstChild.data;
         parse_debugShowActiveSpans(str, title);
+        parse_intersections(str, title);
     }
     drawTop();
     window.addEventListener('keypress', doKeyPress, true);