"""A couple of classes for decorating diagram elements."""
import math
import pyx
from pyfeyn2.render.pyx import config
from pyfeyn2.render.pyx.diagrams import FeynDiagram
from pyfeyn2.render.pyx.utils import Visible
###########################################################################################
## Added by George S. Williams to allow PyFeyn to work with PyX versions 0.12.x and 0.11.x
## Also see changes in class Arrow and class ParallelArrow
[docs]def getarrowpath(
arrowtopath, selfpos, var1, selfsize, var2, selfconstriction, constrictionlen
):
arrowpath = pyx.deco._arrowhead(
arrowtopath, selfpos, var1, selfsize, var2, selfconstriction, constrictionlen
)
return arrowpath
###########################################################################################
## Arrow decorator class
[docs]class Arrow(pyx.deco.deco, pyx.attr.attr):
"""Arrow for Feynman diagram lines"""
def __init__(self, pos=0.5, size=6 * pyx.unit.v_pt, angle=45, constriction=0.8):
"""Constructor."""
self.pos = pos
self.size = size
self.angle = angle
self.constriction = constriction
[docs] def decorate(self, dp):
"""Attach arrow to a path (usually a line)."""
dp.ensurenormpath()
constrictionlen = (
self.size * self.constriction * math.cos(self.angle * math.pi / 360.0)
)
arrowtopos = self.pos * dp.path.arclen() + 0.5 * self.size
arrowtopath = dp.path.split(arrowtopos)[0]
arrowpath = getarrowpath(
arrowtopath,
self.pos * dp.path.arclen(),
1,
self.size,
45,
self.constriction,
constrictionlen,
)
dp.ornaments.fill(arrowpath)
return dp
[docs]class FreeArrow(Visible):
"""Arrow not attached to any line in a diagram."""
def __init__(
self,
length=0.5 * pyx.unit.v_cm,
size=6 * pyx.unit.v_pt,
angle=45,
constriction=0.8,
pos=None,
x=None,
y=None,
direction=0,
):
"""Constructor."""
self.x, self.y = 0, 0
if x is not None:
self.x = x
if y is not None:
self.y = y
if pos is not None:
self.x, self.y = pos.getXY()
self.direction = direction
self.length = length
self.size = size
self.angle = angle
self.constriction = constriction
## Add this to the current diagram automatically
FeynDiagram.currentDiagram.add(self)
[docs] def draw(self, canvas):
"""Draw this arrow on the supplied canvas."""
endx, endy = self.x - self.length * math.sin(
self.direction * math.pi / 180.0
), self.y - self.length * math.cos(self.direction * math.pi / 180.0)
linepath = pyx.deco.decoratedpath(
pyx.path.path(pyx.path.moveto(endx, endy), pyx.path.lineto(self.x, self.y))
)
styles = [
pyx.deco.earrow(
size=self.size, angle=self.angle, constriction=self.constriction
)
]
canvas.stroke(linepath.path, styles)
[docs]class ParallelArrow(Visible):
"""Arrow running parallel to a line, for momenta, helicities etc."""
def __init__(
self,
line,
pos=0.5,
displace=0.3,
length=0.5 * pyx.unit.v_cm,
size=6 * pyx.unit.v_pt,
angle=45,
constriction=0.8,
sense=+1,
curved=False,
stems=1,
stemsep=0.03,
):
"""Constructor."""
self.line = line
self.pos = pos
self.displace = pyx.unit.length(displace)
self.length = length
self.size = size
self.angle = angle
self.constriction = constriction
self.sense = sense
self.curved = curved
self.stems = stems
self.stemsep = stemsep
[docs] def draw(self, canvas):
"""Draw this arrow on the supplied canvas."""
p = self.line.getPath()
posparam = p.begin() + self.pos * p.arclen()
x, y = self.line.fracpoint(self.pos).getXY()
arrx, arry = self.line.fracpoint(
self.pos + self.length / 2.0 / p.arclen()
).getXY()
endx, endy = self.line.fracpoint(
self.pos - self.length / 2.0 / p.arclen()
).getXY()
## Calculate the displacement from the line
displacement = self.displace
intrinsicwidth = pyx.unit.length(0.1)
if hasattr(self.line, "arcradius"):
intrinsicwidth = self.line.arcradius
if displacement > 0:
displacement += intrinsicwidth
else:
displacement -= intrinsicwidth
if config.getOptions().DEBUG:
print("Displacement = ", displacement)
## Position the arrow on the right hand side of lines
tangent = p.tangent(posparam, displacement)
normal = tangent.transformed(pyx.trafo.rotate(90, x, y))
nx, ny = normal.atend()
nxcm, nycm = pyx.unit.tocm(nx - x), pyx.unit.tocm(ny - y)
vx, vy = p.atbegin()
vxcm, vycm = pyx.unit.tocm(x - vx), pyx.unit.tocm(y - vy)
## If the arrow is on the left, flip it by 180 degrees
if (vxcm * nycm - vycm * nxcm) > 0:
normal = normal.transformed(pyx.trafo.rotate(180, x, y))
nx, ny = normal.atend()
if displacement < 0:
normal = normal.transformed(pyx.trafo.rotate(180, x, y))
nx, ny = normal.atend()
if config.getOptions().VDEBUG:
FeynDiagram.currentDiagram.currentCanvas.stroke(normal)
## Displace the arrow by this normal vector
endx, endy = endx + (nx - x), endy + (ny - y)
arrx, arry = arrx + (nx - x), arry + (ny - y)
if self.sense < 0.0:
arrx, arry, endx, endy = endx, endy, arrx, arry
if not self.curved:
linepath = pyx.path.path(
pyx.path.moveto(endx, endy), pyx.path.lineto(arrx, arry)
)
styles = [
pyx.deco.earrow(
size=self.size, angle=self.angle, constriction=self.constriction
)
]
dist = self.stemsep
n = self.stems
if n > 1: # helicity style arrow
arrowtopath = linepath.split(0.8 * linepath.arclen())[0]
constrictionlen = (
self.size
* self.constriction
* math.cos(self.angle * math.pi / 360.0)
)
arrowpath = getarrowpath(
arrowtopath,
linepath.arclen(),
1,
self.size,
45,
self.constriction,
constrictionlen,
)
canvas.fill(arrowpath)
path = pyx.deformer.parallel(-(n + 1) / 2.0 * dist).deform(arrowtopath)
defo = pyx.deformer.parallel(dist)
for m in range(n):
path = defo.deform(path)
canvas.stroke(path, [])
else: # ordinary (momentum) arrow
canvas.stroke(linepath, styles)
else: # curved arrow (always momentum-style)
curvepiece = self.line.getPath().split(
[
(self.pos * p.arclen() - self.length / 2.0),
(self.pos * p.arclen() + self.length / 2.0),
]
)
arrpiece = curvepiece[1]
if self.sense < 0:
arrpiece = arrpiece.reversed()
linepath = pyx.deco.decoratedpath(
pyx.deformer.parallel(displacement).deform(arrpiece)
)
styles = [
pyx.deco.earrow(
size=self.size, angle=self.angle, constriction=self.constriction
)
]
canvas.stroke(linepath.path, styles)
## Label
[docs]class Label(Visible):
"""General label, unattached to any diagram elements"""
def __init__(self, text, pos=None, x=None, y=None, size=pyx.text.size.normalsize):
"""Constructor."""
self.x, self.y = 0, 0
if x is not None:
self.x = x
if y is not None:
self.y = y
self.size = size
self.text = text
self.textattrs = []
self.pos = pos
## Add this to the current diagram automatically
FeynDiagram.currentDiagram.add(self)
[docs] def draw(self, canvas):
"""Draw this label on the supplied canvas."""
textattrs = pyx.attr.mergeattrs(
[pyx.text.halign.center, pyx.text.vshift.mathaxis, self.size]
+ self.textattrs
)
t = pyx.text.latexrunner().text(self.x, self.y, self.text, textattrs)
canvas.insert(t)
## PointLabel
[docs]class PointLabel(Label):
"""Label attached to points on the diagram"""
def __init__(
self, point, text, displace=0.3, angle=0, size=pyx.text.size.normalsize
):
"""Constructor."""
self.size = size
self.displace = pyx.unit.length(displace)
self.angle = angle
self.text = text
self.point = point
self.textattrs = []
[docs] def getPoint(self):
"""Get the point associated with this label."""
return self.point
[docs] def setPoint(self, point):
"""Set the point associated with this label."""
self.point = point
return self
[docs] def draw(self, canvas):
"""Draw this label on the supplied canvas."""
if config.getOptions().VDEBUG:
canvas.fill(
pyx.path.circle(self.point.getX(), self.point.getY(), 0.05),
[pyx.color.rgb.green],
)
x = self.point.getX() + self.displace * math.cos(math.radians(self.angle))
y = self.point.getY() + self.displace * math.sin(math.radians(self.angle))
textattrs = pyx.attr.mergeattrs(
[pyx.text.halign.center, pyx.text.vshift.mathaxis, self.size]
+ self.textattrs
)
t = pyx.text.latexrunner().text(x, y, self.text, textattrs)
canvas.insert(t)
## LineLabel
[docs]class LineLabel(Label):
"""Label for Feynman diagram lines"""
def __init__(
self, line, text, pos=0.5, displace=0.3, angle=0, size=pyx.text.size.normalsize
):
"""Constructor."""
self.pos = pos
self.size = size
self.displace = pyx.unit.length(displace)
self.angle = angle
self.text = text
self.line = line
self.textattrs = []
[docs] def getLine(self):
"""Get the associated line."""
return self.line
[docs] def setLine(self, line):
"""Set the associated line."""
self.line = line
return self
[docs] def draw(self, canvas):
"""Draw this label on the supplied canvas."""
p = self.line.getPath()
# x, y = self.line.fracPoint(self.pos).getXY()
posparam = p.begin() + self.pos * p.arclen()
x, y = p.at(posparam)
## Calculate the displacement from the line
displacement = self.displace
intrinsicwidth = pyx.unit.length(0.1)
if hasattr(self.line, "arcradius"):
intrinsicwidth = self.line.arcradius
if displacement > 0:
displacement += intrinsicwidth
else:
displacement -= intrinsicwidth
if config.getOptions().DEBUG:
print("Displacement = ", displacement)
## Position the label on the right hand side of lines
tangent = p.tangent(posparam, displacement)
normal = tangent.transformed(pyx.trafo.rotate(90, x, y))
nx, ny = normal.atend()
nxcm, nycm = pyx.unit.tocm(nx - x), pyx.unit.tocm(ny - y)
vx, vy = p.atbegin()
vxcm, vycm = pyx.unit.tocm(x - vx), pyx.unit.tocm(y - vy)
## If the label is on the left, flip it by 180 degrees
if (vxcm * nycm - vycm * nxcm) > 0:
normal = normal.transformed(pyx.trafo.rotate(180, x, y))
nx, ny = normal.atend()
if displacement < 0:
normal = normal.transformed(pyx.trafo.rotate(180, x, y))
nx, ny = normal.atend()
if config.getOptions().VDEBUG:
FeynDiagram.currentDiagram.currentCanvas.stroke(normal)
## Displace the label by this normal vector
x, y = nx, ny
textattrs = pyx.attr.mergeattrs(
[pyx.text.halign.center, pyx.text.vshift.mathaxis, self.size]
+ self.textattrs
)
t = pyx.text.latexrunner().text(x, y, self.text, textattrs)
# t.linealign(self.displace,
# math.cos(self.angle * math.pi/180),
# math.sin(self.angle * math.pi/180))
canvas.insert(t)