def traceStroke(stroke):
"""Take in a true stroke with timing data, bitmap it and
then trace the data for it"""
#logger.debug("Stripping Timing Information from Stroke")
#logger.debug("Stroke in, %s points" % len(stroke.Points))
strokeLen = GeomUtils.strokeLength(stroke)
sNorm = GeomUtils.strokeNormalizeSpacing(stroke, int(len(stroke.Points) * 1.5)) #Normalize to ten pixel spacing
graph = {}
#Graph structure looks like
# { <point (x, y)> : {'kids' : <set of Points>, 'thickness' : <number>} }
#Find self intersections
intersections = {}
for i in range(len(sNorm.Points) - 1):
seg1 = (sNorm.Points[i], sNorm.Points[i+1])
for j in range(i+1, len(sNorm.Points) - 1 ):
seg2 = (sNorm.Points[j], sNorm.Points[j+1])
cross = GeomUtils.getLinesIntersection( seg1, seg2)
#Create a new node at the intersection
if cross != None \
and cross != seg1[0] \
and cross != seg2[0]:
crossPt = (cross.X, cross.Y)
intDict = intersections.setdefault(crossPt, {'kids' : set(), 'thickness' : 1})
for pt in seg1 + seg2: #Add the segment endpoints as kids
coords = (int(pt.X), int(pt.Y))
if coords != crossPt:
intDict['kids'].add(coords)
prevPt = None
#for i in range(1, len(sNorm.Points)):
for pt in sNorm.Points:
curPt = (int(pt.X), int(pt.Y))
if prevPt != None:
#prevPt = (pt.X, pt.Y)
graph[curPt] = {'kids' : set([prevPt]), 'thickness':1}
graph[prevPt]['kids'].add(curPt)
else:
graph[curPt] = {'kids' : set(), 'thickness' :1 }
prevPt = curPt
for pt, ptDict in intersections.items():
for k in graph.get(pt, {'kids' : []})['kids']:
ptDict['kids'].add(k)
graph[k]['kids'].add(pt)
for k in ptDict['kids']:
graph[k]['kids'].add(pt)
graph[pt] = ptDict
strokeList = ImageStrokeConverter.graphToStrokes(graph)
if len(strokeList) > 1:
#logger.debug("Stroke tracing split into multiple strokes")
strokeList.sort(key=(lambda s: -len(s.points)))
retPts = []
if len(strokeList) > 0:
for pt in strokeList[0].points:
#logger.debug("Adding point %s" % (str(pt)))
retPts.append(Point(pt[0], pt[1]))
#logger.debug("Stroke out, %s points" % len(retPts))
retStroke = Stroke(retPts)
#saver = StrokeStorage.StrokeStorage()
#saver.saveStrokes([stroke, retStroke])
return retStroke
