kirby urner schrieb
For those of you looking for a way cool use of Python's ReportLab, I
so far have permission to release this one example "PDF flipbook"
showing how geometry concepts might be communicated using this simple
animation technique:
http://www.4dsolutions.net/presentations/pdf_animation_by_ron_resch.pdf
Very impressive and instructive! Is there a description somewhere, how
'flipbooks' like these
can be produced?
With me this way of communicating geometry concepts worked rather well,
as you can see in the
attachment.
Regards,
Gregor
I've been sharing this as a teaser with Software Association of Oregon
as well, knowing Ron has a lot more where that came from (I'm suppose
to download a half-gig PDF next time in Pauling House for a bored er
board meeting).
Kirby
# uses turtle module from Python 2.6
# hint from Kirby, 15. 5. 09
# http://www.4dsolutions.net/presentations/pdf_animation_by_ron_resch.pdf
from turtle import Turtle, Screen, Vec2D, mainloop
import math
A = 50. # adjust this to your needs
SHS = A / 20
SF = 1.0
DSF = 1.0038582416
e = Vec2D(3**.5/2, 0.5)
def dsin(angle):
return math.sin(angle*math.pi/180)
def lines(l):
for i in range(6):
d.fd(l)
d.bk(l)
d.left(60)
class TriTurtle(Turtle):
def __init__(self, c, r, tritype):
Turtle.__init__(self, shape="triangle")
self.c = c
self.r = r
self.speed(0)
self.pencolor(0,0,0)
if tritype == 1:
self.basecolor = (1.0, 0.80392, 0.0)
self.f = -1
self.left(30)
else:
self.basecolor = (0.43137, 0.43137, 1.0)
self.f = 1
self.left(90)
self.fillcolor(self.basecolor)
self.pu()
self.goto(c*A, r*A*3**.5/3)
self.shapesize(SHS, SHS, 1)
self.D = self.distance(0,0)
self.e = (1/self.D)*self.pos()
def setturn(self, phi):
self.goto(SF*self.D*dsin(90-phi)*self.e)
self.settiltangle(phi*self.f)
self.shapesize(SHS*SF)
if abs(self.c) + abs(self.r) > 2:
self.fillcolor([x + (1-x)*phi/360 for x in self.basecolor])
bc = phi/360.
self.pencolor(bc, bc, bc)
s = Screen()
s.reset()
s.tracer(0)
d = Turtle(visible=False)
lines(500)
triangles = []
for c in range(-5,6,2):
triangles.append(TriTurtle(c, 1, 1))
triangles.append(TriTurtle(c, -1, 2))
for c in range(-4,5,2):
triangles.append(TriTurtle(c, 2, 2))
triangles.append(TriTurtle(c, -2, 1))
triangles.append(TriTurtle(c, -4, 2))
triangles.append(TriTurtle(c, 4, 1))
for c in range(-3,4,2):
triangles.append(TriTurtle(c, 5, 2))
triangles.append(TriTurtle(c, -5, 1))
triangles.append(TriTurtle(c, -7, 2))
triangles.append(TriTurtle(c, 7, 1))
for c in range(-2,3,2):
triangles.append(TriTurtle(c, 8, 2))
triangles.append(TriTurtle(c, -8, 1))
s.tracer(1)
for phi in range(1,361):
SF = SF*DSF
s.tracer(0)
for t in triangles:
t.setturn(phi)
s.tracer(1)
mainloop()
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