def get_segment_points(self, rad):
"""
Calculates coordinates for segment vertices at a specified radius.
"""
# Note that the nominal radius of the bend is calculated to the
# center of the segment at its mid-point, not at its end. If this
# were not so, the midpoint of the bend ends would not align with the
# nominal radius, as the bend is always ended with half segments.
# Since we are calculating coordinates for the segment vertices
# at the ends, and not for the mid-points, we cannot use the
# nominal radius to do this. Instead, we use the 'erad' variable
# which calculates the radius we need to use for the segment
# vertices that will cause the segment mid-points to align
# with the nominal radius.
# Contrast this with calculating the segment intrados and
# extrados lengths, in the class initializer, where we do
# use the nominal radius, but calculate a tangent. This
# is not available here due to the ptoc() function needing
# a radius to the end points, rather than to the mid point.
pts = []
s_ang = self.segment_angle
b_arc = self.bend_arc
erad = rad / cos(s_ang / 2)
pts.append(ptoc(0, rad))
for ang in [n + 0.5 for n in range(self.num_segments)]:
pts.append(ptoc(s_ang * ang, erad))
pts.append(ptoc(b_arc, rad))
return pts
def draw_curved_bend(self, ctx, comp, fill=False,
edges=False, outline=False):
"""
Draws a smoothly curved (not segmented) bend component.
Arguments:
ctx -- a Pycairo context
comp -- type of component, "co", "ci", "lo" or "li"
outline -- draws an outline around the entire component if True.
"""
b_arc = self.bend_arc
rads = self.radii
ctx.save()
if fill or outline:
ctx.move_to(*ptoc(0, rads["inner"][comp]).t())
ctx.line_to(*ptoc(0, rads["outer"][comp]).t())
ctx.arc_negative(0, 0, rads["outer"][comp], 0, pi * 2 - b_arc)
ctx.line_to(*ptoc(b_arc, rads["inner"][comp]).t())
ctx.arc(0, 0, rads["inner"][comp], pi * 2 - b_arc, 0)
ctx.close_path()
if fill:
if comp == "co" and self.hatching:
ctx.set_source(self.chatch)
else:
ctx.set_source_rgb(*self.colors["comp"][comp])
if outline:
ctx.fill_preserve()
else:
ctx.fill()
if outline:
ctx.set_source_rgb(*self.drawing_line_color)
ctx.stroke()
if edges:
ctx.set_source_rgb(*self.drawing_line_color)
for i in ["outer", "inner"]:
ctx.arc(0, 0, rads[i][comp], pi * 2 - b_arc, 0)
ctx.stroke()
ctx.restore()
def draw_rad_dims(self, ctx):
"""
Draw the radius dimensions of the bend.
Arguments:
ctx -- a Pycairo context
"""
# The angle at which the radius dimension lines are drawn
# depends on the bend angle for pipe bends, but is always
# vertical for pipe straights. Since this will be called
# from a subclass, check whether we have a pipe bend by
# verifying whether the "bend_arc" instance attribute is set.
if hasattr(self, "bend_arc"):
b_arc = self.bend_arc # pylint: disable=E1101
else:
b_arc = 0
pts = {}
ctx.save()
for scale, comp in zip(range(4, 0, -1), ["co", "ci", "lo", "li"]):
# pylint: disable=E1101
dll = self.dim_line_length * scale
for i in ["out", "in"]:
point = self.pc_pts[i][comp][-1 if i == "out" else 0]
pts[i] = ptoc(b_arc + pi / 2, dll, point)
ctx.move_to(*point.t())
ctx.line_to(*pts[i].t())
# pylint: enable=E1101
ctx.stroke()
draw_dim_line(ctx, pts["out"], pts["in"],
self.diameters[comp], self.scale, 0)
ctx.restore()
def draw_arc_dims(self, ctx):
"""
Draws dimensions for a bend arc and radius.
ctx -- a Pycairo context
"""
b_arc = self.bend_arc
s_ang = self.segment_angle
rad = self.radii["inner"]["fo"] * 0.95
ctx.save()
# Draw angle lines to origin
ctx.move_to(*ptoc(b_arc, rad).t())
ctx.line_to(0, 0)
ctx.line_to(rad, 0)
ctx.stroke()
# Draw angle arc and dimension label
rad /= 3
ctx.arc(0, 0, rad, pi * 2 - b_arc, 0)
ctx.stroke()
draw_arrowhead(ctx, b_arc + pi / 2, ptoc(b_arc, rad), self.scale)
draw_arrowhead(ctx, pi * 3 / 2, ptoc(0, rad), self.scale)
draw_dim_label(ctx, ptoc(b_arc / 2, rad),
self.bend_arc_d, self.scale, 0, "d")
# Draw nominal radius dimension line and label
rad *= 2
if self.num_segments % 2:
angle = b_arc / 2 + s_ang / 2
else:
angle = b_arc / 2
pt1 = ptoc(angle, rad)
pt2 = ptoc(angle, self.radii["nom"])
ctx.move_to(*pt1.t())
ctx.line_to(*pt2.t())
ctx.stroke()
draw_arrowhead(ctx, angle, pt2, self.scale)
draw_dim_label(ctx, pt1, self.radii["nom"], self.scale, 0, "r")
ctx.restore()
def draw_seg_dims(self, ctx):
"""
Draw segment extrados and intrados dimensions.
Arguments:
ctx -- a Pycairo context
"""
segs = self.num_segments
s_ang = self.segment_angle
cld = self.p_rad["co"] - self.p_rad["lo"]
dpt = self.dos_dim_dp
ddll = self.dos_dim_line_length
idx = [0, 0]
pts = [0, 0]
ctx.save()
if segs >= 3:
# Draw extrados dimensions
idx[0] = segs // 2 + (segs % 2)
idx[1] = idx[0] + 1
for comp, dim in zip(["co", "lo"],
[self.segdims[k].value for k in ["cex", "lex"]]):
if comp == "co" and self.casing_type == "onepiece":
continue
for line in range(2):
stp = self.pc_pts["out"][comp][idx[line]]
lnl = ddll * 1.7 if comp == "co" else cld + ddll * 0.7
pts[line] = ptoc(s_ang * idx[0], lnl, stp)
ctx.move_to(*stp.t())
ctx.line_to(*pts[line].t())
ctx.stroke()
draw_dim_line(ctx, pts[1], pts[0], dim, self.scale, dpt)
# Draw intrados dimensions
idx[0] += 1 - (segs % 2)
idx[1] = idx[0] + 1
for comp, dim in zip(["co", "lo"],
[self.segdims[k].value for k in ["cin", "lin"]]):
if comp == "co" and self.casing_type == "onepiece":
continue
for line in range(2):
if self.casing_type == "onepiece":
mult = 0.7
else:
mult = 1.7
stp = self.pc_pts["in"][comp][idx[line]]
lnl = ddll * 0.7 if comp == "co" else cld + ddll * mult
pts[line] = ptoc(s_ang * (idx[0] - 2 + segs % 2) +
pi, lnl, stp)
ctx.move_to(*stp.t())
ctx.line_to(*pts[line].t())
ctx.stroke()
draw_dim_line(ctx, pts[1], pts[0], dim, self.scale, dpt)
ctx.restore()
def draw_profile(self, ctx, dash_style):
"""
Draws the flange arcs, including bolt holes.
Arguments:
ctx -- a Pycairo context
dash_style -- style of dashes to use to the bolt
hole diameter
"""
rfr = self.raised_face_diameter / 2.0
hrd = self.hole_diameter / 2.0
frd = self.flange_diameter / 2.0
bcr = self.bolt_circle_diameter / 2.0
bhr = self.bolt_hole_diameter / 2.0
nbs = self.num_bolts / 2
hls = Flange.bolt_hole_line_size
ctx.save()
# Draw flange arcs
ctx.move_to(hrd, 0)
ctx.line_to(frd, 0)
ctx.arc(0, 0, frd, 0, pi)
ctx.line_to(-hrd, 0)
ctx.arc_negative(0, 0, hrd, pi, 0)
ctx.close_path()
ctx.set_source_rgb(*Flange.colors["arc"])
ctx.fill_preserve()
ctx.set_source_rgb(*Flange.colors["line"])
ctx.stroke()
ctx.arc(0, 0, rfr, 0, pi)
ctx.stroke()
# Draw bolt holes
for i in range(nbs):
ang = -pi / (nbs * 2) * (1 + i * 2)
bhc = ptoc(ang, bcr)
ctx.arc(bhc.x, bhc.y, bhr, 0, pi * 2)
ctx.set_source_rgb(1, 1, 1)
ctx.fill_preserve()
ctx.set_source_rgb(*Flange.colors["line"])
ctx.move_to(*ptoc(ang, bcr - bhr * hls).t())
ctx.line_to(*ptoc(ang, bcr + bhr * hls).t())
ctx.stroke()
# Draw bolt hole circle arc
if dash_style:
ctx.set_dash(dash_style)
ctx.arc(0, 0, bcr, 0, pi)
ctx.stroke()
# Extend center line arc to flange hole diameter
ctx.move_to(0, 0)
ctx.line_to(0, 0 + hrd)
ctx.stroke()
ctx.restore()
