"""
Demo for var_bar, bar and var_bar_pts
var_bar can use b_arc (default) or p_arc (poly approximation internally based on arc_pts now)
var_bar_pts uses arc_pts
"""
mode = 0
def setup():
size(400, 400)
def draw():
background(200)
fill(0)
text('click to toggle p_arc polygonal aprox. and var_bar_pts', 20, 20)
text(('var_bar with b_arc', 'var_bar with p_arc', 'var_bar_pts')[mode], 20, 380)
fill(0, 0, 200, 100)
strokeWeight(1)
line(50, 50, 350, 250)
if mode == 0:
var_bar(50, 165, 350, 315, 40, 0) # by default arc_func=b_arc
bar(50, 55, 350, 255, thickness=60, shorter=mouseX)
var_bar(50, 255, 50 + mouseX * 0.6, 255 + mouseX * 0.25, 20, 40)
elif mode == 1:
var_bar(50, 165, 350, 315, 40, 0, arc_func=p_arc, num_points=6)
bar(50, 55, 350, 255, thickness=60, shorter=mouseX,
arc_func=p_arc, num_points=3)
var_bar(50, 255, 50 + mouseX * 0.6, 255 + mouseX * 0.25, 20, 40,
arc_func=p_arc, num_points=8)
else:
pts1 = var_bar_pts(50, 165, 350, 315, 40, 0, num_points=6)
pts2 = var_bar_pts(50, 55, 350, 255, 30, 30, shorter=mouseX, num_points=3)
pts3 = var_bar_pts(50, 255, 50 + mouseX * 0.6, 255 + mouseX * 0.25, 20, 40,
num_points=8)
strokeWeight(5)
for px, py in pts1 + pts2 + pts3:
point(px, py)
def mousePressed(e=None):
global mode
mode = (mode + 1) % 3
DEBUG, TEXT_HEIGHT = False, 12 # For debug
def b_arc(cx, cy, w, h, start_angle, end_angle, mode=0):
# Based on ideas from Richard DeVeneza via code by Golan Levin:
# http://www.flong.com/blog/2009/bezier-approximation-of-a-circular-arc-in-processing/
theta = end_angle - start_angle
if mode != 1 or abs(theta) < HALF_PI:
x0 = cos(theta / 2.0)
y0 = sin(theta / 2.0)
x3 = x0
y3 = 0 - y0
x1 = (4.0 - x0) / 3.0
y1 = ((1.0 - x0) * (3.0 - x0)) / (3.0 * y0) if y0 != 0 else 0
x2 = x1
y2 = 0 - y1
bezAng = start_angle + theta / 2.0
cBezAng = cos(bezAng)
sBezAng = sin(bezAng)
rx0 = cBezAng * x0 - sBezAng * y0
ry0 = sBezAng * x0 + cBezAng * y0
rx1 = cBezAng * x1 - sBezAng * y1
ry1 = sBezAng * x1 + cBezAng * y1
rx2 = cBezAng * x2 - sBezAng * y2
ry2 = sBezAng * x2 + cBezAng * y2
rx3 = cBezAng * x3 - sBezAng * y3
ry3 = sBezAng * x3 + cBezAng * y3
# Compute scaled and translated Bezier coordinates.
rx, ry = w / 2.0, h / 2.0
px0 = cx + rx * rx0
py0 = cy + ry * ry0
px1 = cx + rx * rx1
py1 = cy + ry * ry1
px2 = cx + rx * rx2
py2 = cy + ry * ry2
px3 = cx + rx * rx3
py3 = cy + ry * ry3
if DEBUG:
ellipse(px3, py3, 3, 3)
ellipse(px0, py0, 5, 5)
if mode == 0: # 'normal' arc (not 'middle' nor 'naked')
beginShape()
if mode != 1: # if not 'middle'
vertex(px3, py3)
if abs(theta) < HALF_PI:
bezierVertex(px2, py2, px1, py1, px0, py0)
else:
b_arc(cx, cy, w, h, start_angle, end_angle - theta / 2.0, mode=1)
b_arc(cx, cy, w, h, start_angle + theta / 2.0, end_angle, mode=1)
if mode == 0: # end of a 'normal' arc
endShape()
def p_arc(cx, cy, w, h, start_angle, end_angle, mode=0,
num_points=24, vertex_func=None):
vertex_func = vertex_func or vertex
if mode == 0:
beginShape()
vertex_pts = arc_pts(cx, cy, w, h, start_angle, end_angle, num_points)
for vx, vy in vertex_pts:
vertex_func(vx, vy)
if mode == 0:
endShape()
def bar(x1, y1, x2, y2, thickness, **kwargs):
var_bar(x1, y1, x2, y2, thickness / 2, **kwargs)
def var_bar(p1x, p1y, p2x, p2y, r1, r2=None, **kwargs):
r2 = r2 if r2 is not None else r1
draw_internal_circle = kwargs.pop('internal', True)
arc_func = kwargs.pop('arc_func', b_arc)
shorter = kwargs.pop('shorter', 0)
assert not (shorter and r1 != r2),\
"Can't draw shorter var_bar with different radii"
d = dist(p1x, p1y, p2x, p2y)
ri = r1 - r2
if d > abs(ri):
clipped_ri_over_d = min(1, max(-1, ri / d))
beta = asin(clipped_ri_over_d) + HALF_PI
push()
translate(p1x, p1y)
angle = atan2(p1x - p2x, p2y - p1y)
rotate(angle + HALF_PI)
beginShape()
offset = shorter / 2.0 if shorter < d else d / 2.0
arc_func(offset, 0, r1 * 2, r1 * 2,
-beta - PI, beta - PI, mode=2, **kwargs)
arc_func(d - offset, 0, r2 * 2, r2 * 2,
beta - PI, PI - beta, mode=2, **kwargs)
endShape(CLOSE)
pop()
else: # draw a circle with the bigger radius if distance is too small
r = max(r1, r2)
x, y = (p1x, p1y) if r1 > r2 else (p2x, p2y)
arc_func(x, y, r * 2, r * 2, 0, TWO_PI, **kwargs)
if draw_internal_circle:
r = min(r1, r2)
x, y = (p1x, p1y) if r1 < r2 else (p2x, p2y)
arc_func(x, y, r * 2, r * 2, 0, TWO_PI, **kwargs)
def arc_pts(cx, cy, w, h, start_angle, end_angle, num_points=24):
"""
Returns points approximating an arc using the same
signature as the original Processing arc().
"""
sweep_angle = end_angle - start_angle
if abs(sweep_angle) < 0.0001:
vx = cx + cos(start_angle) * w / 2.0
vy = cy + sin(start_angle) * h / 2.0
return [(vx, vy)]
pts_list = []
step_angle = float(sweep_angle) / num_points
va = start_angle
side = 1 if sweep_angle > 0 else -1
while va * side < end_angle * side or abs(va - end_angle) < 0.0001:
vx = cx + cos(va) * w / 2.0
vy = cy + sin(va) * h / 2.0
pts_list.append((vx, vy))
va += step_angle
return pts_list
def var_bar_pts(p1x, p1y, p2x, p2y, r1, r2=None, **kwargs):
r2 = r2 if r2 is not None else r1
shorter = kwargs.pop('shorter', 0)
assert not (shorter and r1 != r2),\
"Can't draw shorter var_bar with different radii"
d = dist(p1x, p1y, p2x, p2y)
ri = r1 - r2
result = []
if d > abs(ri):
clipped_ri_over_d = min(1, max(-1, ri / d))
beta = asin(clipped_ri_over_d) + HALF_PI
angle = atan2(p1x - p2x, p2y - p1y) + HALF_PI
offset = shorter / 2.0 if shorter < d else d / 2.0
result.extend(arc_pts(offset, 0, r1 * 2, r1 * 2,
-beta - PI, beta - PI, **kwargs))
result.extend(arc_pts(d - offset, 0, r2 * 2, r2 * 2,
beta - PI, PI - beta, **kwargs))
return rotate_offset_points(result, angle, p1x, p1y)
else:
r = max(r1, r2)
x, y = (p1x, p1y) if r1 > r2 else (p2x, p2y)
return arc_pts(x, y, r * 2, r * 2, 0, TWO_PI, **kwargs)
def rotate_offset_points(pts, angle, offx, offy, y0=0, x0=0):
return [(((xp - x0) * cos(angle) - (yp - y0) * sin(angle)) + x0 + offx,
((yp - y0) * cos(angle) + (xp - x0) * sin(angle)) + y0 + offy)
for xp, yp in pts]