def draw_networkx_nodes(G,
pos,
nodelist=None,
node_size=300,
node_color='r',
node_shape='o',
alpha=1.0,
cmap=None,
vmin=None,
vmax=None,
ax=None,
**kwds):
"""Draw nodes of graph G
This draws only the nodes of the graph G.
pos is a dictionary keyed by vertex with a two-tuple
of x-y positions as the value.
See networkx.layout for functions that compute node positions.
nodelist is an optional list of nodes in G to be drawn.
If provided only the nodes in nodelist will be drawn.
see draw_networkx for the list of other optional parameters.
"""
from matplotlib.pylab import gca, hold, draw_if_interactive
if ax is None:
ax = gca()
if nodelist is None:
nodelist = G.nodes()
x = asarray([pos[v][0] for v in nodelist])
y = asarray([pos[v][1] for v in nodelist])
node_collection = ax.scatter(x,
y,
s=node_size,
c=node_color,
marker=node_shape,
cmap=cmap,
vmin=vmin,
vmax=vmax,
alpha=alpha)
node_collection.set_zorder(2)
return node_collection
def draw_markers(self, gc, path, rgbFace, x, y, trans):
self.check_gc(gc, rgbFace)
fillp = rgbFace is not None
marker = self.file.markerObject(path, fillp, self.gc._linewidth)
x, y = trans.numerix_x_y(asarray(x), asarray(y))
x, y = self.dpi_factor * x, self.dpi_factor * y
nan_at = isnan(x) | isnan(y)
self.file.output(Op.gsave)
ox, oy = 0, 0
for i in range(len(x)):
if nan_at[i]: continue
dx, dy, ox, oy = x[i] - ox, y[i] - oy, x[i], y[i]
self.file.output(1, 0, 0, 1, dx, dy, Op.concat_matrix, marker,
Op.use_xobject)
self.file.output(Op.grestore)
def set_dashes(self, offset, dashes):
self._dashes = offset, dashes
if dashes == None:
self.ctx.set_dash([], 0) # switch dashes off
else:
self.ctx.set_dash(self.renderer.points_to_pixels(asarray(dashes)),
offset)
def points_to_pixels(self, points):
"""
convert point measures to pixes using dpi and the pixels per
inch of the display
"""
return asarray(points) * (PIXELS_PER_INCH / 72.0 * self.dpi.get() /
72.0)
def set_dashes(self, offset, dashes):
self._dashes = offset, dashes
if dashes == None:
self.ctx.set_dash([], 0) # switch dashes off
else:
dashes_pixels = self.renderer.points_to_pixels(asarray(dashes))
self.ctx.set_dash(dashes_pixels, offset)
def to_rgba(self, x, alpha=1.0):
# assume normalized rgb, rgba
x = asarray(x)
if len(x.shape) > 2:
return x
x = self.norm(x)
return self.cmap(x, alpha)
def __call__(self, value):
vmin = self.vmin
vmax = self.vmax
if type(value) in [IntType, FloatType]:
vtype = 'scalar'
val = array([value])
else:
vtype = 'array'
val = nx.asarray(value)
# if both vmin is None and vmax is None, we'll automatically
# norm the data to vmin/vmax of the actual data, so the
# clipping step won't be needed.
if vmin is None and vmax is None:
needs_clipping = False
else:
needs_clipping = True
if vmin is None or vmax is None:
rval = nx.ravel(val)
#do this if sentinels (values to ignore in data)
if self.ignore:
sortValues = nx.sort(rval)
if vmin is None:
# find the lowest non-sentinel value
for thisVal in sortValues:
if thisVal not in self.ignore:
vmin = thisVal #vmin is the lowest non-sentinel value
break
else:
vmin = 0.
if vmax is None:
for thisVal in sortValues[::-1]:
if thisVal not in self.ignore:
vmax = thisVal #vmax is the greatest non-sentinel value
break
else:
vmax = 0.
else:
if vmin is None: vmin = min(rval)
if vmax is None: vmax = max(rval)
if vmin > vmax:
raise ValueError("minvalue must be less than or equal to maxvalue")
elif vmin == vmax:
return 0. * value
else:
if needs_clipping:
val = nx.clip(val, vmin, vmax)
result = (1.0 / (vmax - vmin)) * (val - vmin)
# replace sentinels with original (non-normalized) values
for thisIgnore in self.ignore:
result = nx.where(val == thisIgnore, thisIgnore, result)
if vtype == 'scalar':
result = result[0]
return result
def __call__(self, value):
vmin = self.vmin
vmax = self.vmax
if type(value) in [IntType, FloatType]:
vtype = 'scalar'
val = array([value])
else:
vtype = 'array'
val = nx.asarray(value)
# if both vmin is None and vmax is None, we'll automatically
# norm the data to vmin/vmax of the actual data, so the
# clipping step won't be needed.
if vmin is None and vmax is None:
needs_clipping = False
else:
needs_clipping = True
if vmin is None or vmax is None:
rval = nx.ravel(val)
#do this if sentinels (values to ignore in data)
if self.ignore:
sortValues=nx.sort(rval)
if vmin is None:
# find the lowest non-sentinel value
for thisVal in sortValues:
if thisVal not in self.ignore:
vmin=thisVal #vmin is the lowest non-sentinel value
break
else:
vmin=0.
if vmax is None:
for thisVal in sortValues[::-1]:
if thisVal not in self.ignore:
vmax=thisVal #vmax is the greatest non-sentinel value
break
else:
vmax=0.
else:
if vmin is None: vmin = min(rval)
if vmax is None: vmax = max(rval)
if vmin > vmax:
raise ValueError("minvalue must be less than or equal to maxvalue")
elif vmin==vmax:
return 0.*value
else:
if needs_clipping:
val = nx.clip(val,vmin, vmax)
result = (1.0/(vmax-vmin))*(val-vmin)
# replace sentinels with original (non-normalized) values
for thisIgnore in self.ignore:
result = nx.where(val==thisIgnore,thisIgnore,result)
if vtype == 'scalar':
result = result[0]
return result
def draw_markers(self, gc, path, rgbFace, x, y, trans): self.check_gc(gc, rgbFace) fillp = rgbFace is not None marker = self.file.markerObject(path, fillp, self.gc._linewidth) x, y = trans.numerix_x_y(asarray(x), asarray(y)) x, y = self.dpi_factor * x, self.dpi_factor * y nan_at = isnan(x) | isnan(y) self.file.output(Op.gsave) ox, oy = 0, 0 for i in range(len(x)): if nan_at[i]: continue dx, dy, ox, oy = x[i]-ox, y[i]-oy, x[i], y[i] self.file.output(1, 0, 0, 1, dx, dy, Op.concat_matrix, marker, Op.use_xobject) self.file.output(Op.grestore)
def to_rgba(self, x, alpha=1.0):
# assume normalized rgb, rgba
#print '0', type(x), x.shape
x = asarray(x)
#print '1', type(x), x.shape
if len(x.shape)>2: return x
x = self.norm(x)
x = self.cmap(x, alpha)
return x
def to_rgba(self, x, alpha=1.0):
# assume normalized rgb, rgba
#print '0', type(x), x.shape
x = asarray(x)
#print '1', type(x), x.shape
if len(x.shape) > 2: return x
x = self.norm(x)
x = self.cmap(x, alpha)
return x
def set_dashes(self, dash_offset, dash_list):
GraphicsContextBase.set_dashes(self, dash_offset, dash_list)
if dash_list == None:
self.gdkGC.line_style = gdk.LINE_SOLID
else:
pixels = self.renderer.points_to_pixels(asarray(dash_list))
dl = [max(1, int(round(val))) for val in pixels]
self.gdkGC.set_dashes(dash_offset, dl)
self.gdkGC.line_style = gdk.LINE_ON_OFF_DASH
def set_dashes(self, dash_offset, dash_list):
GraphicsContextBase.set_dashes(self, dash_offset, dash_list)
if dash_list == None:
self.gdkGC.line_style = gdk.LINE_SOLID
else:
pixels = self.renderer.points_to_pixels(asarray(dash_list))
dl = [max(1, int(round(val))) for val in pixels]
self.gdkGC.set_dashes(dash_offset, dl)
self.gdkGC.line_style = gdk.LINE_ON_OFF_DASH
def dash_path(self, gc, path):
"""
Add dashes to the path and return it if dashes are set
"""
offset, dashes = gc.get_dashes()
if dashes is not None:
dashes = tuple(self.points_to_pixels(asarray(dashes)))
return path.dash(offset, dashes)
else:
return path
def dash_path(self, gc, path):
"""
Add dashes to the path and return it if dashes are set
"""
offset, dashes = gc.get_dashes()
if dashes is not None:
dashes = tuple(self.points_to_pixels(asarray(dashes)))
return path.dash(offset, dashes)
else:
return path
def get_colours(n):
""" Return n pastel colours. """
base = asarray([[1, 0, 0], [0, 1, 0], [0, 0, 1]])
if n <= 3:
return base[0:n]
# how many new colours to we need to insert between
# red and green and between green and blue?
needed = (((n - 3) + 1) / 2, (n - 3) / 2)
colours = []
for start in (0, 1):
for x in linspace(0, 1, needed[start] + 2):
colours.append((base[start] * (1.0 - x)) + (base[start + 1] * x))
return [pastel(c) for c in colours[0:n]]
def get_colours(n):
""" Return n pastel colours. """
base = asarray([[1,0,0], [0,1,0], [0,0,1]])
if n <= 3:
return base[0:n]
# how many new colours to we need to insert between
# red and green and between green and blue?
needed = (((n - 3) + 1) / 2, (n - 3) / 2)
colours = []
for start in (0, 1):
for x in linspace(0, 1, needed[start]+2):
colours.append((base[start] * (1.0 - x)) +
(base[start+1] * x))
return [pastel(c) for c in colours[0:n]]
def draw_networkx_nodes(G,
pos,
nodelist=None,
node_size=300,
node_color='r',
node_shape='o',
alpha=1.0,
cmap=None,
vmin=None,
vmax=None,
ax=None,
linewidths=None,
**kwds):
"""Draw nodes of graph G
This draws only the nodes of the graph G.
pos is a dictionary keyed by vertex with a two-tuple
of x-y positions as the value.
See networkx.layout for functions that compute node positions.
nodelist is an optional list of nodes in G to be drawn.
If provided only the nodes in nodelist will be drawn.
see draw_networkx for the list of other optional parameters.
"""
if ax is None:
ax = matplotlib.pylab.gca()
if nodelist is None:
nodelist = G.nodes()
if not nodelist or len(nodelist) == 0: # empty nodelist, no drawing
return None
try:
xy = asarray([pos[v] for v in nodelist])
except KeyError, e:
raise networkx.NetworkXError('Node %s has no position.' % e)
def draw_networkx_nodes(G, pos,
nodelist=None,
node_size=300,
node_color='r',
node_shape='o',
alpha=1.0,
cmap=None,
vmin=None,
vmax=None,
ax=None,
linewidths=None,
**kwds):
"""Draw nodes of graph G
This draws only the nodes of the graph G.
pos is a dictionary keyed by vertex with a two-tuple
of x-y positions as the value.
See networkx_v099.layout for functions that compute node positions.
nodelist is an optional list of nodes in G to be drawn.
If provided only the nodes in nodelist will be drawn.
see draw_networkx_v099 for the list of other optional parameters.
"""
if ax is None:
ax=matplotlib.pylab.gca()
if nodelist is None:
nodelist=G.nodes()
if not nodelist or len(nodelist)==0: # empty nodelist, no drawing
return None
try:
xy=asarray([pos[v] for v in nodelist])
except KeyError,e:
raise networkx_v099.NetworkXError('Node %s has no position.'%e)
def pastel(colour, weight=2.4):
""" Convert colour into a nice pastel shade"""
rgb = asarray(colorConverter.to_rgb(colour))
# scale colour
maxc = max(rgb)
if maxc < 1.0 and maxc > 0:
# scale colour
scale = 1.0 / maxc
rgb = rgb * scale
# now decrease saturation
total = asum(rgb)
slack = 0
for x in rgb:
slack += 1.0 - x
# want to increase weight from total to weight
# pick x s.t. slack * x == weight - total
# x = (weight - total) / slack
x = (weight - total) / slack
rgb = [c + (x * (1.0 - c)) for c in rgb]
return rgb
def pastel(colour, weight=2.4):
""" Convert colour into a nice pastel shade"""
rgb = asarray(colorConverter.to_rgb(colour))
# scale colour
maxc = max(rgb)
if maxc < 1.0 and maxc > 0:
# scale colour
scale = 1.0 / maxc
rgb = rgb * scale
# now decrease saturation
total = sum(rgb)
slack = 0
for x in rgb:
slack += 1.0 - x
# want to increase weight from total to weight
# pick x s.t. slack * x == weight - total
# x = (weight - total) / slack
x = (weight - total) / slack
rgb = [c + (x * (1.0-c)) for c in rgb]
return rgb
def points_to_pixels(self, points):
"""
convert point measures to pixes using dpi and the pixels per
inch of the display
"""
return asarray(points)*(PIXELS_PER_INCH/72.0*self.dpi.get()/72.0)
def closeto(x,y):
return abs(asarray(x)-asarray(y))<1e-10
def draw_networkx_edges(G,
pos,
edgelist=None,
width=1.0,
edge_color='k',
style='solid',
alpha=1.0,
ax=None,
**kwds):
"""Draw the edges of the graph G
This draws only the edges of the graph G.
pos is a dictionary keyed by vertex with a two-tuple
of x-y positions as the value.
See networkx.layout for functions that compute node positions.
edgelist is an optional list of the edges in G to be drawn.
If provided, only the edges in edgelist will be drawn.
See draw_networkx for the list of other optional parameters.
"""
from matplotlib.pylab import gca, hold, draw_if_interactive
if ax is None:
ax = gca()
if edgelist is None:
edgelist = G.edges()
if not edgelist: # no edges!
return None
# set edge positions
head = []
tail = []
for e in edgelist:
# edge e can be a 2-tuple (Graph) or a 3-tuple (Xgraph)
u = e[0]
v = e[1]
head.append(pos[u])
tail.append(pos[v])
edge_pos = asarray(zip(head, tail))
if not cb.iterable(width):
lw = (width, )
else:
lw = width
# edge colors specified with floats won't work here
# since LineCollection doesn't use ScalarMappable.
# You can use an array of RGBA or text labels
if not cb.is_string_like(edge_color) \
and cb.iterable(edge_color) \
and len(edge_color)==len(edge_pos):
edge_colors = None
else:
edge_colors = (colorConverter.to_rgba(edge_color, alpha), )
if G.is_directed():
edge_collection = LineCollection(
edge_pos,
colors=edge_colors,
linewidths=lw,
antialiaseds=(1, ),
linestyle=style,
transOffset=ax.transData,
)
edge_collection.set_alpha(alpha)
else:
arrows = []
for src, dst in edge_pos:
x1, y1 = src
x2, y2 = dst
dx = x2 - x1 # x offset
dy = y2 - y1 # y offset
arrows.append(Arrow(x1, y1, dx, dy, width=lw).get_verts())
edge_collection = PolyCollection(
arrows,
facecolors=edge_colors,
antialiaseds=(1, ),
transOffset=ax.transData,
)
# update view
xx = [x for (x, y) in head + tail]
yy = [y for (x, y) in head + tail]
minx = amin(xx)
maxx = amax(xx)
miny = amin(yy)
maxy = amax(yy)
w = maxx - minx
h = maxy - miny
padx, pady = 0.05 * w, 0.05 * h
corners = (minx - padx, miny - pady), (maxx + padx, maxy + pady)
ax.update_datalim(corners)
ax.autoscale_view()
edge_collection.set_zorder(1) # edges go behind nodes
ax.add_collection(edge_collection)
return edge_collection
def draw_networkx_edges(G, pos,
edgelist=None,
width=1.0,
edge_color='k',
style='solid',
alpha=1.0,
edge_cmap=None,
edge_vmin=None,
edge_vmax=None,
ax=None,
arrows=True,
node_size=300, # Added by qrancik
**kwds):
"""Draw the edges of the graph G
This draws only the edges of the graph G.
pos is a dictionary keyed by vertex with a two-tuple
of x-y positions as the value.
See networkx.layout for functions that compute node positions.
edgelist is an optional list of the edges in G to be drawn.
If provided, only the edges in edgelist will be drawn.
edgecolor can be a list of matplotlib color letters such as 'k' or
'b' that lists the color of each edge; the list must be ordered in
the same way as the edge list. Alternatively, this list can contain
numbers and those number are mapped to a color scale using the color
map edge_cmap.
For directed graphs, "arrows" (actually just thicker stubs) are drawn
at the head end. Arrows can be turned off with keyword arrows=False.
See draw_networkx for the list of other optional parameters.
"""
if ax is None:
ax=matplotlib.pylab.gca()
if edgelist is None:
edgelist=G.edges()
if not edgelist or len(edgelist)==0: # no edges!
return None
# set edge positions
edge_pos=asarray([(pos[e[0]],pos[e[1]]) for e in edgelist])
if not cb.iterable(width):
lw = (width,)
else:
lw = width
if not cb.is_string_like(edge_color) \
and cb.iterable(edge_color) \
and len(edge_color)==len(edge_pos):
if matplotlib.numerix.alltrue([cb.is_string_like(c)
for c in edge_color]):
# (should check ALL elements)
# list of color letters such as ['k','r','k',...]
edge_colors = tuple([colorConverter.to_rgba(c,alpha)
for c in edge_color])
elif matplotlib.numerix.alltrue([not cb.is_string_like(c)
for c in edge_color]):
# numbers (which are going to be mapped with a colormap)
edge_colors = None
else:
raise ValueError('edge_color must consist of either color names or numbers')
else:
if len(edge_color)==1:
edge_colors = ( colorConverter.to_rgba(edge_color, alpha), )
else:
raise ValueError('edge_color must be a single color or list of exactly m colors where m is the number or edges')
# edge_collection = LineCollection(edge_pos, # Deleted by qrancik
edge_collection = ArrowedLineCollection(edge_pos, # Added by qrancik
colors = edge_colors,
linewidths = lw,
antialiaseds = (1,),
linestyle = style,
transOffset = ax.transData,
)
edge_collection.set_alpha(alpha)
# Added by Satyam
arrow_collection=None
if G.is_directed() and arrows:
edge_collection.add_arrows(math.sqrt(node_size)/1.5) # Found emprically to work well. Maybe more systematic approach needed?
arrow_colors = ( colorConverter.to_rgba('k', alpha), )
arrow_collection = LineCollection(edge_pos, # Added by qrancik
colors = arrow_colors,
linewidths = lw,
antialiaseds = (1,),
linestyle = style,
transOffset = ax.transData,
)
# need 0.87.7 or greater for edge colormaps
mpl_version=matplotlib.__version__
if mpl_version.endswith('svn'):
mpl_version=matplotlib.__version__[0:-3]
if mpl_version.endswith('pre'):
mpl_version=matplotlib.__version__[0:-3]
if map(int,mpl_version.split('.'))>=[0,87,7]:
if edge_colors is None:
if edge_cmap is not None: assert(isinstance(edge_cmap, Colormap))
edge_collection.set_array(asarray(edge_color))
edge_collection.set_cmap(edge_cmap)
if edge_vmin is not None or edge_vmax is not None:
edge_collection.set_clim(edge_vmin, edge_vmax)
else:
edge_collection.autoscale()
matplotlib.pylab.sci(edge_collection)
# update view
minx = amin(ravel(edge_pos[:,:,0]))
maxx = amax(ravel(edge_pos[:,:,0]))
miny = amin(ravel(edge_pos[:,:,1]))
maxy = amax(ravel(edge_pos[:,:,1]))
w = maxx-minx
h = maxy-miny
padx, pady = 0.05*w, 0.05*h
corners = (minx-padx, miny-pady), (maxx+padx, maxy+pady)
ax.update_datalim( corners)
ax.autoscale_view()
edge_collection.set_zorder(1) # edges go behind nodes
ax.add_collection(edge_collection)
if arrow_collection:
arrow_collection.set_zorder(1) # edges go behind nodes
ax.add_collection(arrow_collection)
return edge_collection
def __array__(self, t=None, context=None):
if t is not None:
return nx.asarray(self.value).astype(t)
else:
return nx.asarray(self.value, 'O')
def __array__(self, t = None, context = None):
if t is not None:
return nx.asarray(self.value).astype(t)
else:
return nx.asarray(self.value, 'O')
def closeto(x, y):
return abs(asarray(x) - asarray(y)) < 1e-10
def to_rgba(self, x, alpha=1.0):
# assume normalized rgb, rgba
x = asarray(x)
if len(x.shape)>2: return x
x = self.norm(x)
return self.cmap(x, alpha)
def autocorr(x, lag=1):
"""Returns the autocorrelation x."""
x = nx.asarray(x)
mu = nx.mlab.mean(x)
sigma = nx.mlab.std(x)
return nx.dot(x[:-lag]-mu, x[lag:]-mu)/(sigma**2.)/(len(x) - lag)
def autocorr(x, lag=1):
"""Returns the autocorrelation x."""
x = nx.asarray(x)
mu = nx.mlab.mean(x)
sigma = nx.mlab.std(x)
return nx.dot(x[:-lag]-mu, x[lag:]-mu)/(sigma**2.)/(len(x) - lag)
def draw_networkx_edges(G, pos,
edgelist=None,
width=1.0,
edge_color='k',
style='solid',
alpha=1.0,
edge_cmap=None,
edge_vmin=None,
edge_vmax=None,
ax=None,
arrows=True,
**kwds):
"""Draw the edges of the graph G
This draws only the edges of the graph G.
pos is a dictionary keyed by vertex with a two-tuple
of x-y positions as the value.
See networkx_v099.layout for functions that compute node positions.
edgelist is an optional list of the edges in G to be drawn.
If provided, only the edges in edgelist will be drawn.
edgecolor can be a list of matplotlib color letters such as 'k' or
'b' that lists the color of each edge; the list must be ordered in
the same way as the edge list. Alternatively, this list can contain
numbers and those number are mapped to a color scale using the color
map edge_cmap.
For directed graphs, "arrows" (actually just thicker stubs) are drawn
at the head end. Arrows can be turned off with keyword arrows=False.
See draw_networkx_v099 for the list of other optional parameters.
"""
if ax is None:
ax=matplotlib.pylab.gca()
if edgelist is None:
edgelist=G.edges()
if not edgelist or len(edgelist)==0: # no edges!
return None
# set edge positions
edge_pos=asarray([(pos[e[0]],pos[e[1]]) for e in edgelist])
if not cb.iterable(width):
lw = (width,)
else:
lw = width
if not cb.is_string_like(edge_color) \
and cb.iterable(edge_color) \
and len(edge_color)==len(edge_pos):
if matplotlib.numerix.alltrue([cb.is_string_like(c)
for c in edge_color]):
# (should check ALL elements)
# list of color letters such as ['k','r','k',...]
edge_colors = tuple([colorConverter.to_rgba(c,alpha)
for c in edge_color])
elif matplotlib.numerix.alltrue([not cb.is_string_like(c)
for c in edge_color]):
# numbers (which are going to be mapped with a colormap)
edge_colors = None
else:
raise ValueError('edge_color must consist of either color names or numbers')
else:
if len(edge_color)==1:
edge_colors = ( colorConverter.to_rgba(edge_color, alpha), )
else:
raise ValueError('edge_color must be a single color or list of exactly m colors where m is the number or edges')
edge_collection = LineCollection(edge_pos,
colors = edge_colors,
linewidths = lw,
antialiaseds = (1,),
linestyle = style,
transOffset = ax.transData,
)
edge_collection.set_alpha(alpha)
# need 0.87.7 or greater for edge colormaps
mpl_version=matplotlib.__version__
if mpl_version.endswith('svn'):
mpl_version=matplotlib.__version__[0:-3]
if mpl_version.endswith('pre'):
mpl_version=matplotlib.__version__[0:-3]
if map(int,mpl_version.split('.'))>=[0,87,7]:
if edge_colors is None:
if edge_cmap is not None: assert(isinstance(edge_cmap, Colormap))
edge_collection.set_array(asarray(edge_color))
edge_collection.set_cmap(edge_cmap)
if edge_vmin is not None or edge_vmax is not None:
edge_collection.set_clim(edge_vmin, edge_vmax)
else:
edge_collection.autoscale()
matplotlib.pylab.sci(edge_collection)
# else:
# sys.stderr.write(\
# """matplotlib version >= 0.87.7 required for colormapped edges.
# (version %s detected)."""%matplotlib.__version__)
# raise UserWarning(\
# """matplotlib version >= 0.87.7 required for colormapped edges.
# (version %s detected)."""%matplotlib.__version__)
arrow_collection=None
if G.directed and arrows:
# a directed graph hack
# draw thick line segments at head end of edge
# waiting for someone else to implement arrows that will work
arrow_colors = ( colorConverter.to_rgba('k', alpha), )
a_pos=[]
p=1.0-0.25 # make head segment 25 percent of edge length
for src,dst in edge_pos:
x1,y1=src
x2,y2=dst
dx=x2-x1 # x offset
dy=y2-y1 # y offset
d=sqrt(float(dx**2+dy**2)) # length of edge
if d==0: # source and target at same position
continue
if dx==0: # vertical edge
xa=x2
ya=dy*p+y1
if dy==0: # horizontal edge
ya=y2
xa=dx*p+x1
else:
theta=arctan2(dy,dx)
xa=p*d*cos(theta)+x1
ya=p*d*sin(theta)+y1
a_pos.append(((xa,ya),(x2,y2)))
arrow_collection = LineCollection(a_pos,
colors = arrow_colors,
linewidths = [4*ww for ww in lw],
antialiaseds = (1,),
transOffset = ax.transData,
)
# update view
minx = amin(ravel(edge_pos[:,:,0]))
maxx = amax(ravel(edge_pos[:,:,0]))
miny = amin(ravel(edge_pos[:,:,1]))
maxy = amax(ravel(edge_pos[:,:,1]))
w = maxx-minx
h = maxy-miny
padx, pady = 0.05*w, 0.05*h
corners = (minx-padx, miny-pady), (maxx+padx, maxy+pady)
ax.update_datalim( corners)
ax.autoscale_view()
edge_collection.set_zorder(1) # edges go behind nodes
ax.add_collection(edge_collection)
if arrow_collection:
arrow_collection.set_zorder(1) # edges go behind nodes
ax.add_collection(arrow_collection)
return edge_collection
