# Copyright (C) 2019 chrysn <chrysn@fsfe.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from math import cos, pi, sin, sqrt
from boxes import *
def offset_radius_in_square(squareside, angle, outset):
"""From the centre of a square, rotate by an angle relative to the
vertical, move away from the center (down if angle = 0), and then in a
right angle until the border of the square. Return the length of that last
segment.
Note that for consistency with other boxes.py methods, angle is given in
degree.
>>> # Without rotation, it's always half the square length
>>> offset_radius_in_square(20, 0, 0)
10.0
>>> offset_radius_in_square(20, 0, 5)
10.0
>>> # Without offset, it's half square length divided by cos(angle) -- at
>>> # least before it hits the next wall
>>> offset_radius_in_square(20, 15, 0) # doctest:+ELLIPSIS
10.35276...
>>> offset_radius_in_square(20, 45, 0) # doctest:+ELLIPSIS
14.1421...
>>> # Positive angles make the segment initially shorter...
>>> offset_radius_in_square(20, 5, 10) < 10
True
>>> # ... while negative angles make it longer.
>>> offset_radius_in_square(20, -5, 10) > 10
True
"""
if angle <= -90:
return offset_radius_in_square(squareside, angle + 180, outset)
if angle > 90:
return offset_radius_in_square(squareside, angle - 180, outset)
angle = angle / 180 * pi
step_right = outset * sin(angle)
step_down = outset * cos(angle)
try:
len_right = (squareside / 2 - step_right) / cos(angle)
except ZeroDivisionError:
return squareside / 2
if angle == 0:
return len_right
if angle > 0:
len_up = (squareside / 2 + step_down) / sin(angle)
return min(len_up, len_right)
else: # angle < 0
len_down = - (squareside / 2 - step_down) / sin(angle)
return min(len_down, len_right)
[docs]
class DiscRack(Boxes):
"""A rack for storing disk-shaped objects vertically next to each other"""
ui_group = "Shelf"
def __init__(self) -> None:
Boxes.__init__(self)
self.buildArgParser(sx="20*10")
self.argparser.add_argument(
"--disc_diameter", action="store", type=float, default=150.0,
help="Disc diameter in mm")
self.argparser.add_argument(
"--disc_thickness", action="store", type=float, default=5.0,
help="Thickness of the discs in mm")
self.argparser.add_argument(
"--lower_factor", action="store", type=float, default=0.75,
help="Position of the lower rack grids along the radius")
self.argparser.add_argument(
"--rear_factor", action="store", type=float, default=0.75,
help="Position of the rear rack grids along the radius")
self.argparser.add_argument(
"--disc_outset", action="store", type=float, default=3.0,
help="Additional space kept between the disks and the outbox of the rack")
# These can be parameterized, but the default value of pulling them up
# to the box front is good enough for so many cases it'd only clutter
# the user interface.
#
# The parameters can be resurfaced when there is something like rare or
# advanced settings.
'''
self.argparser.add_argument(
"--lower_outset", action="store", type=float, default=0.0,
help="Space in front of the disk slits (0: automatic)")
self.argparser.add_argument(
"--rear_outset", action="store", type=float, default=0.0,
help="Space above the disk slits (0: automatic)")
'''
self.argparser.add_argument(
"--angle", action="store", type=float, default=18,
help="Backwards slant of the rack")
self.addSettingsArgs(edges.FingerJointSettings)
def parseArgs(self, *args, **kwargs):
Boxes.parseArgs(self, *args, **kwargs)
self.lower_outset = self.rear_outset = 0
self.calculate()
def calculate(self):
self.outer = self.disc_diameter + 2 * self.disc_outset
r = self.disc_diameter / 2
# distance between radius line and front (or rear) end of the slit
self.lower_halfslit = r * sqrt(1 - self.lower_factor**2)
self.rear_halfslit = r * sqrt(1 - self.rear_factor**2)
if True: # self.lower_outset == 0: # when lower_outset parameter is re-enabled
toplim = offset_radius_in_square(self.outer, self.angle, r * self.lower_factor)
# With typical positive angles, the lower surface of board will be limiting
bottomlim = offset_radius_in_square(self.outer, self.angle, r * self.lower_factor + self.thickness)
self.lower_outset = min(toplim, bottomlim) - self.lower_halfslit
if True: # self.rear_outset == 0: # when rear_outset parameter is re-enabled
# With typical positive angles, the upper surface of board will be limiting
toplim = offset_radius_in_square(self.outer, -self.angle, r * self.rear_factor)
bottomlim = offset_radius_in_square(self.outer, -self.angle, r * self.rear_factor + self.thickness)
self.rear_outset = min(toplim, bottomlim) - self.rear_halfslit
# front outset, space to radius, space to rear part, plus nothing as fingers extend out
self.lower_size = self.lower_outset + \
self.lower_halfslit + \
r * self.rear_factor
self.rear_size = r * self.lower_factor + \
self.rear_halfslit + \
self.rear_outset
self.warn_on_demand()
def warn_on_demand(self):
warnings = []
# Are the discs supported on the outer ends?
def word_thickness(length):
if length > 0:
return f"very thin ({length:.2g} mm at a thickness of {self.thickness:.2g} mm)"
if length < 0:
return "absent"
if self.rear_outset < self.thickness:
warnings.append("Rear upper constraint is %s. Consider increasing the disc outset parameter, or move the angle away from 45°." % word_thickness(self.rear_outset))
if self.lower_outset < self.thickness:
warnings.append("Lower front constraint is %s. Consider increasing the disc outset parameter, or move the angle away from 45°." % word_thickness(self.lower_outset))
# Are the discs supported where the grids meet?
r = self.disc_diameter / 2
inner_lowerdistance = r * self.rear_factor - self.lower_halfslit
inner_reardistance = r * self.lower_factor - self.rear_halfslit
if inner_lowerdistance < 0 or inner_reardistance < 0:
warnings.append("Corner is inside the disc radios, discs would not be supported. Consider increasing the factor parameters.")
# Won't the type-H edge on the rear side make the whole contraption
# wiggle?
max_slitlengthplush = offset_radius_in_square(
self.outer, self.angle, r * self.rear_factor + self.thickness)
slitlengthplush = self.rear_halfslit + self.thickness * ( 1 +
self.edgesettings['FingerJoint']['edge_width'])
if slitlengthplush > max_slitlengthplush:
warnings.append("Joint would protrude from lower box edge. Consider increasing the the disc outset parameter, or move the angle away from 45°.")
# Can the discs be removed at all?
# Does not need explicit checking, for Thales' theorem tells us that at
# the point where there is barely support in the corner, three contact
# points on the circle form just a semicircle and the discs can be
# inserted/removed. When we keep the other contact points and move the
# slits away from the corner, the disc gets smaller and thus will fit
# through the opening that is as wide as the diameter of the largest
# possible circle.
# Act on warnings
if warnings:
self.argparser.error("\n".join(warnings))
def sidewall_holes(self):
r = self.disc_diameter / 2
self.moveTo(self.outer/2, self.outer/2, -self.angle)
# can now move down to paint horizontal lower part, or right to paint
# vertical rear part
with self.saved_context():
self.moveTo(
r * self.rear_factor,
-r * self.lower_factor - self.thickness/2,
90)
self.fingerHolesAt(0, 0, self.lower_size)
with self.saved_context():
self.moveTo(
r * self.rear_factor + self.thickness/2,
-r * self.lower_factor,
0)
self.fingerHolesAt(0, 0, self.rear_size)
if self.debug:
self.circle(0, 0, self.disc_diameter / 2)
def _draw_slits(self, inset, halfslit):
total_x = 0
for x in self.sx:
center_x = total_x + x / 2
total_x += x
self.rectangularHole(inset, center_x, 2 * halfslit, self.disc_thickness)
if self.debug:
self.ctx.rectangle(inset - halfslit, center_x - x/2, 2 * halfslit, x)
def lower_holes(self):
r = self.disc_diameter / 2
inset = self.lower_outset + self.lower_halfslit
self._draw_slits(inset, self.lower_halfslit)
def rear_holes(self):
r = self.disc_diameter / 2
inset = r * self.lower_factor
self._draw_slits(inset, self.rear_halfslit)
def render(self):
o = self.outer
self.lower_factor = min(self.lower_factor, 0.99)
self.rear_factor = min(self.rear_factor, 0.99)
self.rectangularWall(o, o, "eeee", move="right", callback=[self.sidewall_holes])
self.rectangularWall(o, o, "eeee", move="right mirror", callback=[self.sidewall_holes])
self.rectangularWall(self.lower_size, sum(self.sx), "fffe", move="right", callback=[self.lower_holes])
self.rectangularWall(self.rear_size, sum(self.sx), "fefh", move="right", callback=[self.rear_holes])
