def _BresTriBase(p0,p1,p2,dss_rerun=False, iscan_iline=None):
'''Do grunt work common to both Bresenham Triangle functions'''
borderPts = GetTriangleBorderPoints(p0,p1,p2)
if iscan_iline is not None:
iscan, iline = iscan_iline
return iscan, iline, borderPts
# Get the steepest dimension relative to every other dimension:
dSS = GetDirectionsOfSteepestSlope(p0,p1,p2)
dSS_notNone = [i for i in dSS if i!=None]
if len(dSS_notNone) == 0:
# Degenerate slope matrix (all 0's); points are collinear
return borderPts
iscan = getMostCommonVal(dSS_notNone)
if dss_rerun:
all_but = [i for i in range(len(p0)) if i != iscan]
p0a,p1a,p2a = fL([p0,p1,p2])[:, all_but]
dSS2 = GetDirectionsOfSteepestSlope(p0a,p1a,p2a)
dSS2_notNone = [i for i in dSS2 if i!=None]
iline = getMostCommonVal(dSS2_notNone)
if iline >= iscan:
iline += 1
else:
iline = dSS[iscan]
assert iline!=None, "iline is <flat>, that can't be right!"
return iscan, iline, borderPts
def GetDirectionsOfSteepestSlope_BorderCheckingVersion(borderPts):
'''Taking each dimension as the potential scanning dimension,
find the other dimension that has the largest slope.
Needs the list of points of the triangle's boundary.
Returns a list of integers (one for each dimension).
'''
ndim = len(borderPts[0])
def minMaxDiff(l):
return max(l)-min(l)
maxSlopeDim = []
for i in range(ndim): # loop over all dimensions as the assumed scan dimension (i)
# Bin the points into hyper-planes with the same value on the i-axis
binnedPts = {}
for p in borderPts:
binnedPts.setdefault(p[i],[]).append(p)
# Traversing along the i-axis, find the other dimension(s) with the greatest slope
# Collect the results in dimsOfGreatestExtent, a flat list of integers
dimsOfGreatestExtent = []
for pts in binnedPts.values(): # loop through the points in each bin (hyperplane)
deltas = [ minMaxDiff([ p[j] for p in pts ]) # get the maximum delta in each dimension
for j in range(ndim) ]
maxExtent = max(deltas)
dimsOfGreatestExtent += [ j for j in range(ndim) if deltas[j]==maxExtent ]
# Get the dimension that most often has the steepest slope
maxSlopeDim.append(getMostCommonVal(dimsOfGreatestExtent))
return maxSlopeDim
