def _isSingleStrokeArrow(stroke):
"Input: Single stroke for evaluation. Returns a tuple of points (tip, tail) if the stroke is an arrow, (None, None) otherwise"
logger.debug("stroke len %d", stroke.length() )
if len(stroke.Points) < 10:
return (None, None)# too small to be arrow
norm_len = len(stroke.Points)
points = GeomUtils.strokeNormalizeSpacing( stroke, numpoints=norm_len).Points
points.reverse() # start from end
# find the first 90 degree turn in the stroke
orilist = GeomUtils.strokeLineSegOrientations( Stroke(points) )
logger.debug("stroke ori %s", str(orilist) )
prev = None
i = 0
for i,ori in enumerate(orilist):
if prev is None:
prev = ori
continue
if GeomUtils.angleDiff(ori,prev)>90: break # found the first turn at index i
first_corner = i
# now we know the scale of the arrow head if there is one
# if the first corner is more than 1/4 of the way from the end of the stroke
if first_corner > norm_len/5:
return (None, None) # scale is wrong for an arrowhead
tail = stroke.Points[0] # first of the original points
tip = points[i] # reverse point
# create a list of the monoticity of all substrokes from the first corner to some dist after
m_list = [ GeomUtils.strokeMonotonicity(Stroke(points[first_corner:x])) for x in range(first_corner+2,first_corner*3) ]
if len(m_list) == 0:
return (None, None)
m_min = min(m_list)
logger.debug("stroke mon (%f)", m_min )
if m_min>0.65:
return (None, None)# too monotonic after the first corner, need to double back
return (tip, tail)
def _isSingleStrokeArrow(stroke):
"Input: Single stroke for evaluation. Returns a tuple of points (tip, tail) if the stroke is an arrow, (None, None) otherwise"
if len(stroke.Points) < 10:
logger.debug("Not a single-stroke arrow: stroke too short")
return (None, None)# too small to be arrow
"""
#Starting code for line curvature classification
#points = GeomUtils.strokeNormalizeSpacing( stroke, numpoints=50).Points
for gran in range(1, 10):
norm_len = max(len(stroke.Points) / gran, 5)
points = GeomUtils.strokeNormalizeSpacing( stroke, numpoints=norm_len).Points
points.reverse() # start from end
# find the first 90 degree turn in the stroke
curvatures = GeomUtils.strokeGetPointsCurvature( Stroke(points) )
gran = 0.1
for idx, ori in enumerate(curvatures):
print "%s:\t|" % (idx),
quantity = ori
while quantity > 0:
quantity -= gran
print "X",
print "\t\t%s" % (ori)
print "_______________________________"
print "Max:%s, Avg%s" % (max(curvatures), sum(curvatures)/float(len(curvatures)))
print "_______________________________"
#/EndCurvature classification
"""
norm_len = max(len(stroke.Points) / 10, 15)
points = GeomUtils.strokeNormalizeSpacing( stroke, numpoints=norm_len).Points
orilist = GeomUtils.strokeLineSegOrientations( Stroke(points) )
#logger.debug("stroke ori %s", str(orilist) )
prev = None
i = 0
for i,ori in enumerate(orilist):
if prev is None:
prev = ori
continue
if GeomUtils.angleDiff(ori,prev)>90: break # found the first turn at index i
first_corner = i
# now we know the scale of the arrow head if there is one
# if the first corner is more than 1/4 of the way from the end of the stroke
if first_corner > norm_len/5:
logger.debug("Not a ss arrow: First right angle too far from endpoint")
return (None, None) # scale is wrong for an arrowhead
tail = stroke.Points[0] # first of the original points
tip = points[i] # reverse point
# create a list of the monoticity of all substrokes from the first corner to some dist after
m_list = [ GeomUtils.strokeMonotonicity(Stroke(points[first_corner:x])) for x in range(first_corner+2,first_corner*3) ]
if len(m_list) == 0:
logger.debug("Not a ss arrow: Stroke monotonicity list zero length")
return (None, None)
m_min = min(m_list)
#logger.debug("stroke mon (%f)", m_min )
if m_min>0.65:
logger.debug("Not a ss arrow: Stroke too monotonic")
return (None, None)# too monotonic after the first corner, need to double back
logger.debug("Single Stroke Arrow found!")
return (tip, tail)
