def _get_polygon_rays(self, vertices, clip_rect):
"""Return rays that emanate from convex vertices to the outside
clipping rectangle.
"""
rays = []
for A, B, C in vertices:
# Calculate the interior angle bisector segment
# using the angle bisector theorem:
# https://en.wikipedia.org/wiki/Angle_bisector_theorem
AC = geom.Line(A, C)
d1 = B.distance(C)
d2 = B.distance(A)
mu = d2 / (d1 + d2)
D = AC.point_at(mu)
bisector = geom.Line(D, B)
# find the intersection with the clip rectangle
dx = bisector.p2.x - bisector.p1.x
dy = bisector.p2.y - bisector.p1.y
# if dx is zero the line is vertical
if geom.float_eq(dx, 0.0):
y = clip_rect.ymax if dy > 0 else clip_rect.ymin
x = bisector.p1.x
else:
# if slope is zero the line is horizontal
m = dy / dx
b = (m * -bisector.p1.x) + bisector.p1.y
if dx > 0:
if geom.float_eq(m, 0.0):
y = b
x = clip_rect.xmax
else:
y = clip_rect.xmax * m + b
if m > 0:
y = min(clip_rect.ymax, y)
else:
y = max(clip_rect.ymin, y)
x = (y - b) / m
else:
if geom.float_eq(m, 0.0):
y = b
x = self.clip_rect.xmin
else:
y = self.clip_rect.xmin * m + b
if m < 0:
y = min(clip_rect.ymax, y)
else:
y = max(clip_rect.ymin, y)
x = (y - b) / m
clip_pt = geom.P(x, y)
rays.append(geom.Line(bisector.p2, clip_pt))
return rays
def _cutpath_process_corners(self, cutpath):
if len(cutpath) <= 1:
return [cutpath,]
cutpath_list = []
new_cutpath = paths.Path(name=getattr(cutpath, 'name'))
firstline = cutpath[0]
line1 = firstline
for line2 in cutpath[1:]:
# TODO: also process curves using tangent lines
if isinstance(line1, geom.Line) and isinstance(line2, geom.Line):
corner_angle = line1.p2.angle2(line1.p1, line2.p2)
new_segments = ()
if self.allow_corner_reversals and abs(corner_angle) <= self.min_corner_angle:
new_segments = self._corner_reversal(line1, line2, corner_angle)
elif abs(corner_angle) > self.min_corner_angle and not geom.float_eq(abs(corner_angle), math.pi):
new_segments = self._corner_turn(line1, line2, corner_angle)
if new_segments:
new_cutpath.extend(new_segments[:-1])
line2 = new_segments[-1]
else:
new_cutpath.append(line1)
if not geom.float_eq(abs(corner_angle), math.pi):
# Split this path if the corner can't be processed
cutpath_list.append(new_cutpath)
new_cutpath = paths.Path()
else:
new_cutpath.append(line1)
line1 = line2
new_cutpath.append(line2)
# process last segment of polygon
if self.close_polygons and new_cutpath.is_closed() \
and isinstance(new_cutpath[-1], geom.Line) \
and isinstance(firstline, geom.Line):
# and geom.float_eq(new_cutpath[0].p1, new_cutpath[-1].p2):
line1 = new_cutpath[-1]
line2 = firstline
corner_angle = line1.p2.angle2(line1.p1, line2.p2)
new_segments = ()
if self.allow_corner_reversals and abs(corner_angle) <= self.min_corner_angle:
new_segments = self._corner_reversal(line1, line2, corner_angle)
elif abs(corner_angle) > self.min_corner_angle and not geom.float_eq(abs(corner_angle), math.pi):
new_segments = self._corner_turn(line1, line2, corner_angle)
if new_segments:
new_cutpath[0] = new_segments[-1]
del new_cutpath[-1]
new_cutpath.extend(new_segments[0:-1])
if len(new_cutpath) > 0:
cutpath_list.append(new_cutpath)
return cutpath_list
def _calc_rotation3(self, new_angle):
""""""
if geom.float_eq(self.current_angle, new_angle):
return 0.0
prev_angle = math.fmod(self.current_angle, 2*math.pi)
new_angle = math.fmod(new_angle, 2*math.pi)
rotation_angle = new_angle - prev_angle
# logger.debug('rotation: %d, %d, %d' % (math.degrees(self.current_angle), math.degrees(new_angle), math.degrees(rotation_angle)))
return rotation_angle
def _cutpath_process_pathends(self, cutpath):
# Brush landing
segment = cutpath[0]
if not isinstance(segment, geom.Line) and not isinstance(segment, geom.Arc):
logging.debug('segment type=%s' % segment.__name__)
assert(isinstance(segment, geom.Line) or isinstance(segment, geom.Arc))
d = max(self.brush_trail_down, 0.01)
if segment.length() > d:
seg1, seg2 = segment.subdivide(d / segment.length())
cutpath[0] = seg1
cutpath.insert(1, seg2)
cutpath[0].inline_z = self.brush_depth
# Brush liftoff
segment = cutpath[-1]
assert(isinstance(segment, geom.Line) or isinstance(segment, geom.Arc))
brush_direction = getattr(segment, 'inline_end_angle', segment.end_tangent_angle())
# Default overshoot distance works fine for 90d angles
overshoot_dist = self.brush_trail_down#self.tool_width/2
# Closed path?
if geom.float_eq(segment.p2, cutpath[0].p1):
# tangent to reverse brush direction
t1 = geom.P.from_polar(1.0, brush_direction + math.pi)
corner_angle = abs(cutpath[0].p1.angle2(cutpath[0].p1 + t1, cutpath[0].p2))
if not geom.float_eq(corner_angle, math.pi):
# overshoot_dist = self.brush_trail_down
# else:
# Calculate overshoot based on corner angle
d = (math.pi - (corner_angle % math.pi)) / math.pi
overshoot_dist *= d
logger.debug('overshoot dist: %.4f, %.4f, %.4f' % (math.degrees(corner_angle), d, overshoot_dist))
# logger.debug('brush_direction= %.4f [%.4f]' % (math.degrees(brush_direction), math.degrees(segment.end_tangent_angle())))
delta = geom.P(math.cos(brush_direction), math.sin(brush_direction))
overshoot_endp = segment.p2 + (delta * overshoot_dist)
overshoot_line = geom.Line(segment.p2, overshoot_endp)
liftoff_dist = self.brush_trail_down
liftoff_endp = overshoot_endp + (delta * liftoff_dist)
liftoff_line = geom.Line(overshoot_endp, liftoff_endp)
liftoff_line.inline_z = 0.0
cutpath.append(overshoot_line)
cutpath.append(liftoff_line)
return cutpath
def _calc_rotation2(self, new_angle):
""":new_angle: -PI <= new_angle <= PI"""
if geom.float_eq(self.current_angle, new_angle):
return 0.0
prev_angle = self._normalize_angle(self.current_angle)
new_angle = self._normalize_angle(new_angle)
rotation_angle = new_angle - prev_angle
if rotation_angle < -math.pi:
rotation_angle += 2*math.pi
elif rotation_angle > math.pi:
rotation_angle -= 2*math.pi
# logger.debug('rotation: %d, %d, %d' % (math.degrees(self.current_angle), math.degrees(new_angle), math.degrees(rotation_angle)))
return rotation_angle
def split_path_g1(path):
"""Split the path at path vertices that connect
non-tangential segments.
Args:
path: The path to split.
Returns:
A list of one or more paths.
"""
path_list = []
new_path = []
seg1 = path[0]
for seg2 in path[1:]:
new_path.append(seg1)
if (not geom.float_eq(seg1.end_tangent_angle(),
seg2.start_tangent_angle())
or hasattr(seg1, 'ignore_g1') or hasattr(seg2, 'ignore_g1')):
path_list.append(new_path)
new_path = []
seg1 = seg2
new_path.append(seg1)
path_list.append(new_path)
return path_list
def split_path_g1(path):
"""Split the path at path vertices that connect
non-tangential segments.
Args:
path: The path to split.
Returns:
A list of one or more paths.
"""
path_list = []
new_path = []
seg1 = path[0]
for seg2 in path[1:]:
new_path.append(seg1)
if (not geom.float_eq(seg1.end_tangent_angle(),
seg2.start_tangent_angle()) or
hasattr(seg1, 'ignore_g1') or hasattr(seg2, 'ignore_g1')):
path_list.append(new_path)
new_path = []
seg1 = seg2
new_path.append(seg1)
path_list.append(new_path)
return path_list
def parse_path_geom(path_data, ellipse_to_bezier=False):
"""
Parse SVG path data and convert to geometry objects.
Args:
path_data: The `d` attribute value of an SVG path element.
ellipse_to_bezier: Convert elliptical arcs to bezier curves
if True. Default is False.
Returns:
A list of zero or more subpaths.
A subpath being a list of zero or more Line, Arc, EllipticalArc,
or CubicBezier objects.
"""
subpath = []
subpath_list = []
p1 = (0.0, 0.0)
for cmd, params in svg.parse_path(path_data):
p2 = (params[-2], params[-1])
if cmd == 'M':
# Start of path or sub-path
if subpath:
subpath_list.append(subpath)
subpath = []
elif cmd == 'L':
subpath.append(geom.Line(p1, p2))
elif cmd == 'A':
rx = params[0]
ry = params[1]
phi = params[2]
large_arc = params[3]
sweep_flag = params[4]
elliptical_arc = geom.ellipse.EllipticalArc.from_endpoints(
p1, p2, rx, ry, large_arc, sweep_flag, phi)
if elliptical_arc is None:
# Parameters must be degenerate...
# Try just making a line
logger = logging.getLogger(__name__)
logger.debug('Degenerate arc...')
subpath.append(geom.Line(p1, p2))
elif geom.float_eq(rx, ry):
# If it's a circular arc then create one using
# the previously computed ellipse parameters.
segment = geom.Arc(p1, p2, rx, elliptical_arc.sweep_angle,
elliptical_arc.center)
subpath.append(segment)
elif ellipse_to_bezier:
# Convert the elliptical arc to cubic Beziers
subpath.extend(bezier.bezier_ellipse(elliptical_arc))
else:
subpath.append(elliptical_arc)
elif cmd == 'C':
c1 = (params[0], params[1])
c2 = (params[2], params[3])
subpath.append(bezier.CubicBezier(p1, c1, c2, p2))
elif cmd == 'Q':
c1 = (params[0], params[1])
subpath.append(bezier.CubicBezier.from_quadratic(p1, c1, p2))
p1 = p2
if subpath:
subpath_list.append(subpath)
return subpath_list
def offset_path(path, offset, min_arc_dist, g1_tolerance=None):
"""Recalculate path to compensate for a trailing tangential offset.
This will shift all of the segments by `offset` amount. Arcs will
be recalculated to correct for the shift offset.
Args:
path: The path to recalculate.
offset: The amount of tangential tool trail.
min_arc_dist: The minimum distance between two connected
segment end points that can be bridged with an arc.
A line will be used if the distance is less than this.
g1_tolerance: The angle tolerance to determine if two segments
are g1 continuous.
Returns:
A new path
Raises:
:class:`cam.toolpath.ToolpathException`: if the path contains segment
types other than Line or Arc.
"""
if geom.float_eq(offset, 0.0):
return path
offset_path = []
prev_seg = None
prev_offset_seg = None
for seg in path:
if seg.p1 == seg.p2:
# Skip zero length segments
continue
if isinstance(seg, geom.Line):
# Line segments are easy - just shift them forward by offset
offset_seg = seg.shift(offset)
elif isinstance(seg, geom.Arc):
offset_seg = offset_arc(seg, offset)
else:
raise toolpath.ToolpathException('Unrecognized path segment type.')
# Fix discontinuities caused by offsetting non-G1 segments
if prev_seg is not None:
if prev_offset_seg.p2 != offset_seg.p1:
seg_distance = prev_offset_seg.p2.distance(offset_seg.p1)
# If the distance between the two segments is less than the
# minimum arc distance or if the segments are G1 continuous
# then just insert a connecting line.
if (seg_distance < min_arc_dist or geom.segments_are_g1(
prev_offset_seg, offset_seg, g1_tolerance)):
connect_seg = geom.Line(prev_offset_seg.p2, offset_seg.p1)
else:
# Insert an arc in tool path to rotate the tool to the next
# starting tangent when the segments are not G1 continuous.
# TODO: avoid creating tiny segments by extending
# offset segment.
p1 = prev_offset_seg.p2
p2 = offset_seg.p1
angle = prev_seg.p2.angle2(p1, p2)
# TODO: This should be a straight line if the arc is tiny
connect_seg = geom.Arc(p1, p2, offset, angle, prev_seg.p2)
# if connect_seg.length() < 0.01:
# logger.debug('tiny arc! length= %f, radius=%f, angle=%f', connect_seg.length(), connect_seg.radius, connect_seg.angle)
connect_seg.inline_start_angle = prev_seg.end_tangent_angle()
connect_seg.inline_end_angle = seg.start_tangent_angle()
offset_path.append(connect_seg)
prev_offset_seg = connect_seg
elif (geom.segments_are_g1(prev_seg, seg, g1_tolerance)
and not hasattr(prev_seg, 'ignore_g1')
and not hasattr(seg, 'ignore_g1')):
# Add hint for smoothing pass
prev_offset_seg.g1 = True
prev_seg = seg
prev_offset_seg = offset_seg
offset_path.append(offset_seg)
# Compensate for starting angle
start_angle = (offset_path[0].p1 - path[0].p1).angle()
offset_path[0].inline_start_angle = start_angle
return offset_path
def _generate_segment_gcode(self, segment, depth):
"""Generate G code for Line and Arc path segments."""
# If enabled and the tool has traveled a specified interval distance
# then allow a subclass to generate some G code at this point.
if self.feed_interval > 0.0 \
and self.feed_interval_travel >= self.feed_interval:
self.generate_feed_interval_gcode(self.current_angle, depth)
self.preview_plotter.draw_interval_marker(self.last_point, depth)
self.feed_interval_travel = 0.0
seglen = segment.length()
if seglen < geom.EPSILON:
# This avoids an accumulated error if there are a string of very
# tiny segments (where each segment length < EPSILON).
self._tinyseg_accumulation += seglen
if seglen > geom.EPSILON or self._tinyseg_accumulation > geom.EPSILON:
self.feed_distance += seglen + self._tinyseg_accumulation
self.feed_interval_travel += seglen + self._tinyseg_accumulation
self._tinyseg_accumulation = 0.0
previous_angle = self.current_angle
# Amount needed to rotate to new start tangent
rotation = self._calc_rotation2(segment.start_tangent_angle())
inline_rotation = self._calc_rotation2(getattr(segment, 'inline_end_angle', self.current_angle))
# logger.debug('length= %f, prev-angle= %f, angle= %f' % (seglen, previous_angle, self.current_angle))
# Extract any rendering hints attached to the segment
depth = getattr(segment, 'inline_z', depth)
inline_delta_a = getattr(segment, 'inline_delta_a', 0.0)
inline_flip_tool = getattr(segment, 'inline_flip_tool', False)
inline_ignore_angle = getattr(segment, 'inline_ignore_angle', False)
if not inline_flip_tool and not inline_ignore_angle:
self.current_angle += rotation
if not geom.float_eq(previous_angle, self.current_angle):
# self.gc.feed_rotate(self.current_angle)
self.gc.feed(a=self.current_angle)
self.preview_plotter.draw_feed_rotate(self.last_point,
previous_angle,
self.current_angle,
depth)
previous_angle = self.current_angle
end_angle = self.current_angle + inline_rotation + inline_delta_a
if isinstance(segment, geom.Line):
self.gc.feed(segment.p2.x, segment.p2.y, a=end_angle, z=depth)
self.preview_plotter.draw_feed_line(self.last_point,
segment.p2, previous_angle,
end_angle, depth)
elif isinstance(segment, geom.Arc):
arcv = segment.center - segment.p1
if geom.float_eq(inline_rotation, 0.0):
end_angle += segment.angle
self.gc.feed_arc(segment.is_clockwise(),
segment.p2.x, segment.p2.y,
arcv.x, arcv.y, a=end_angle, z=depth)
self.preview_plotter.draw_feed_arc(segment, previous_angle,
end_angle, depth)
self.current_angle = end_angle
if not geom.float_eq(inline_delta_a, 0.0):
self.preview_plotter.draw_angle_marker(segment.p2, end_angle,
depth)
if inline_flip_tool:
self.current_angle += rotation
self.gc.axis_offset['A'] -= rotation
self.last_point = segment.p2
def parse_path_geom(path_data, ellipse_to_bezier=False):
"""
Parse SVG path data and convert to geometry objects.
Args:
path_data: The `d` attribute value of an SVG path element.
ellipse_to_bezier: Convert elliptical arcs to bezier curves
if True. Default is False.
Returns:
A list of zero or more subpaths.
A subpath being a list of zero or more Line, Arc, EllipticalArc,
or CubicBezier objects.
"""
subpath = []
subpath_list = []
p1 = (0.0, 0.0)
for cmd, params in svg.parse_path(path_data):
p2 = (params[-2], params[-1])
if cmd == 'M':
# Start of path or sub-path
if subpath:
subpath_list.append(subpath)
subpath = []
elif cmd == 'L':
subpath.append(geom.Line(p1, p2))
elif cmd == 'A':
rx = params[0]
ry = params[1]
phi = params[2]
large_arc = params[3]
sweep_flag = params[4]
elliptical_arc = geom.ellipse.EllipticalArc.from_endpoints(
p1, p2, rx, ry, large_arc, sweep_flag, phi)
if elliptical_arc is None:
# Parameters must be degenerate...
# Try just making a line
logger = logging.getLogger(__name__)
logger.debug('Degenerate arc...')
subpath.append(geom.Line(p1, p2))
elif geom.float_eq(rx, ry):
# If it's a circular arc then create one using
# the previously computed ellipse parameters.
segment = geom.Arc(p1, p2, rx, elliptical_arc.sweep_angle,
elliptical_arc.center)
subpath.append(segment)
elif ellipse_to_bezier:
# Convert the elliptical arc to cubic Beziers
subpath.extend(bezier.bezier_ellipse(elliptical_arc))
else:
subpath.append(elliptical_arc)
elif cmd == 'C':
c1 = (params[0], params[1])
c2 = (params[2], params[3])
subpath.append(bezier.CubicBezier(p1, c1, c2, p2))
elif cmd == 'Q':
c1 = (params[0], params[1])
subpath.append(bezier.CubicBezier.from_quadratic(p1, c1, p2))
p1 = p2
if subpath:
subpath_list.append(subpath)
return subpath_list
