Select PS Eraser points properly for over_exclude (cf #2689) #4191
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@skef By the way: I have written an own PS-import function in python for FontForge in https://github.com/linusromer/mf2outline/blob/master/mf2outline.py which is far from complete. However, it works quite well with EPS from MetaPost. It uses the python package # own postscript interpreter for a postscript file "eps"
# into the glyph "glyph"
def import_ps(eps,glyph):
from booleanOperations import BooleanOperationManager
from booleanOperations.booleanGlyph import BooleanGlyph
with open(eps, "r") as epsfile:
# read through the lines and write them continously as contours
# in a fontforge char
# this is specialized for Metapost Output and useless for
# general postscript
#
# some variable declarations
rawglyph = [] # will be filled with raw contours
is_white = False # any other color than white will be interpreted as black
linewidth = 1 # just default
stack = [] # ps stack (coordinate of points, pen dimensions etc.)
ctm = [1.0,0.0,0.0,1.0,0.0,0.0] # current transformation matrix
dash = 0
linecap = "round"
linejoin = "round"
miterlimit = 10
contour = []
stroke_follows_fill = False
gsave_contour = [] # (list) bezier path that is saved by gsave
gsave_ctm = [1.0,0.0,0.0,1.0,0.0,0.0] # current transformation matrix that is saved by gsave
gsave_is_white = False # "color" saved by gsave
#
# okay, let's start:
for line in epsfile:
if line[0] != "%" and len(line)>0: # ignore comments
if "gsave fill grestore stroke" in line: # this happens just so often, so we treat it as special case
stroke_follows_fill = True # pay attention...
words = line.split()
for word in words: # go through the words
# showpage will have no effect
if isolate_number(word) != None:
stack.append(isolate_number(word))
elif word == "newpath":
contour = [] # (list) bezier path
elif (word == "moveto") or (word == "lineto"):
contour.append([(stack[-2],stack[-1])])
stack = stack[:-2]
elif word == "curveto":
contour.append([
(stack[-6],stack[-5]),
(stack[-4],stack[-3]),
(stack[-2],stack[-1])
])
stack = stack[:-6]
elif word == "closepath":
if (len(contour) > 1) and \
(contour[0][0][0] != contour[-1][-1][0]) or \
(contour[0][0][1] != contour[-1][-1][1]):
contour.append([(contour[0][0][0],contour[0][0][1])])
elif word == "setrgbcolor":
if stack[-1] == 1 and \
stack[-2] == 1 and \
stack[-3] == 1:
is_white = True
else:
is_white = False
stack = stack[:-3]
elif word == "setlinewidth":
linewidth = stack.pop()
elif word == "setdash":
dash = stack.pop()
elif word == "setlinecap":
linecapcode = stack.pop()
if linecapcode == 0:
linecap = "butt"
elif linecapcode == 2:
linecap = "square"
else:
linecap = "round"
elif word == "setlinejoin":
linejoincode = stack.pop()
if linejoincode == 0:
linejoin = "miter"
elif linejoincode == 2:
linejoin = "bevel"
else:
linejoin = "round"
elif word == "setmiterlimit":
miterlimit = stack.pop()
elif word == "scale":
sy=stack.pop()
sx=stack.pop()
ctm=[ctm[0]*sx,ctm[1]*sy,ctm[2]*sx,ctm[3]*sy,ctm[4]*sx,ctm[5]*sy]
elif word == "concat":
f=stack.pop()
e=stack.pop()
d=stack.pop()
c=stack.pop()
b=stack.pop()
a=stack.pop()
ctm=[a*ctm[0]+c*ctm[1],b*ctm[0]+d*ctm[1],\
a*ctm[2]+c*ctm[3],b*ctm[2]+d*ctm[3],\
a*ctm[4]+c*ctm[5]+e,b*ctm[4]+d*ctm[5]+f]
elif word == "dtransform":
dy=stack.pop()
dx=stack.pop()
stack.extend(homogeneous(ctm[:4],dx,dy))
elif word == "idtransform":
dy=stack.pop()
dx=stack.pop()
stack.extend(homogeneous(invertmatrix(ctm[:4]),dx,dy))
elif word == "transform":
y=stack.pop()
x=stack.pop()
stack.extend(homogeneous(ctm,x,y))
elif word == "itransform":
y=stack.pop()
x=stack.pop()
stack.extend(homogeneous(invertmatrix(ctm),x,y))
elif word == "exch":
last = stack.pop()
secondlast = stack.pop()
stack.extend([last,secondlast])
#elif word == "truncate":
# truncate is problematic, as it produces
# results that are not exact
# I do not know, why this is in METAPOST
# stack[len(stack)-1]=int(stack[len(stack)-1])
elif word == "pop":
stack.pop()
elif word == "fill" and not stroke_follows_fill:
if is_white:
if windingnumber(contour) > 0:
contour = bezierreverse(contour) # make counterclockwise
rawglyph = rawDifference(rawglyph,[contour])
else:
if windingnumber(contour) < 0:
contour = bezierreverse(contour) # make clockwise
rawglyph.append(contour) #rawglyph = romerUnion(rawglyph,[contour])
elif word == "stroke":
# We have to determine the angle and the
# axis of the ellipse that is the product of
# a circle with radius=linewidth with the
# ctm (current transformation matrix.
# One would have to consider also shearing,
# but METAPOST makes the ctm (for pens)
# always as a product of rotation matrix and
# a diagonal (non-uniform scaling) matrix.
# Hence, we make a quick an dirty computation
if ctm[0] == ctm[1]:
alpha = .25*math.pi
else:
alpha = math.atan(ctm[1]/ctm[0])
pen_x = abs(linewidth*ctm[0]/math.cos(alpha))
pen_y = abs(linewidth*ctm[3]/math.cos(alpha))
if stroke_follows_fill:
tempcontour = bezierouteroutline(contour,pen_x,pen_y,alpha)
stroke_follows_fill = False
else:
tempcontour = bezieroutline(contour,pen_x,pen_y,alpha)
if is_white:
if windingnumber(tempcontour) > 0:
tempcontour = bezierreverse(tempcontour) # make counterclockwise
rawglyph = rawDifference(rawglyph,[tempcontour])
else:
if windingnumber(tempcontour) < 0:
tempcontour = bezierreverse(tempcontour) # make clockwise
rawglyph.append(tempcontour) #rawglyph = romerUnion(rawglyph,[tempcontour])
elif word == "gsave":
gsave_contour = list(contour) # clone contour
gsave_ctm = ctm
gsave_is_white = is_white
elif word == "grestore":
contour = list(gsave_contour)
ctm = gsave_ctm
is_white = gsave_is_white
# now fill the raw glyph into a fontforge glyph:
#rawglyphrounded = roundRawGlyph(rawglyph,10)
for c in rawglyph:
glyph.foreground += rawPathToFontforgeContour(c)
if not args.raw:
glyph.removeOverlap() |
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The missing corner rounding should be fixed by #4183, which is waiting on review. FontForge's exclude function does appear to act strangely with nested contours. From a very quick look based on your examples it appears that
These aren't difficult changes so I'll give it a shot and update the draft PR, probably sometime this evening. Problem 2 seems like a bug separate from PS input, though, so once I confirm the fix is possible I'll ask about potentially changing the main algorithm. |
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(I merged #4183 and rebased to fix the join problem.) @linusromer I worked around the immediate problems by running Remove Overlap on both SplineSets separately before running Exclude. The three examples now work as shown in your illustration. I realize that incrementally debugging FontForge's implementation may not be of much interest but unless and until I can track down a proper reference on this subject you're my main resource. Still, feel free to bow out now or whenever. |
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@skef Yes, the three old EPS work now (and the rounded corners, too). However, the following still won't work: |
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@skef, what remains on this one? |
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I think this one might remain a draft for a while. The current version represents progress but it's not done and I'm not sure its a priority. |
Closes #2689