File:Spinning-disk.svg

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Original file(SVG file, nominally 220 × 146 pixels, file size: 3 KB)

Captions

Captions

Add a one-line explanation of what this file represents

Summary[edit]

Description
English: Illustration of a solid spinning disk
Date
Source Own work
Author Geek3
Other versions Ehrenfest-paradox-disk.svg

Source Code[edit]

The image is created by the following source-code. Requirements:

python source code:

#!/usr/bin/python
# -*- coding: utf8 -*-

try:
    import svgwrite as svg
except ImportError:
    print 'You need to install svgwrite: http://pypi.python.org/pypi/svgwrite/'
    exit(1)

from math import *

size = 220, 146
rx, ry = size[0] / 2 - 3, 50
v = float(ry) / float(rx)
l = 40
lw = 2

# document
doc = svg.Drawing('spinning-disk.svg', size=size)
doc['stroke-width'] = lw
doc['fill'] = 'white'
doc['stroke'] = 'black'
doc['stroke-linejoin'] = 'miter'

# background
doc.add(doc.rect(id='background', insert=(0, 0), size=size, stroke='none'))

# disk
grad = doc.defs.add(doc.linearGradient(id='grad', start=('0%',0), end=('100%',0), gradientUnits='objectBoundingBox'))
grad.add_stop_color(offset=0, color='#f7f7f7')
grad.add_stop_color(offset=0.5, color='#dddddd')
grad.add_stop_color(offset=1, color='#999999')
disk = doc.add(doc.g(id='disk', transform='translate(' + str(size[0]/2) + ',' + str(ry+3) + ')'))
path = 'M ' + str(-rx) + ',0 V ' + str(l)
path += ' A ' + str(rx) + ',' + str(ry) + ' 0 1 0 ' + str(rx) + ',' + str(l)
path += ' V 0 Z'
disk.add(doc.path(d=path, fill='url(#grad)', stroke_linejoin='bevel'))
disk.add(doc.ellipse(center=(0, 0), r=(rx, ry), fill='#d8d8d8'))
disk.add(doc.ellipse(center=(0, 0), r=(2, 2.0*v), fill='black'))
radius_angle = radians(-40.0)
csr = cos(radius_angle), sin(radius_angle)
disk.add(doc.line(start=(0,0), end=(rx*csr[0], ry*csr[1]),
    stroke_width=lw*sqrt(csr[0]**2 + (v*csr[1])**2)))
# round arrow
ar, aw, ah, ab, al, a0, a1 = 0.7*rx, 7, 2, 1, 3, radians(160), radians(100)
apath = 'M ' + str(ar*cos(a0)) + ',' + str(ar*sin(a0))
apath += ' A %f,%f 0 0 0 %f,%f' % (ar, ar, ar*cos(a1), ar*sin(a1))
arrowhead = doc.defs.add(doc.marker(id='arrowhead', orient='auto', overflow='visible'))
arrowhead.add(doc.path(fill='black', stroke='none',
    d='M 0.0,0.0 L %f,%f L %f,0 L %f,%f L 0,0 z'%(-ab, -ah, al, -ab, ah)))
arrow = doc.path(d=apath, fill='none', stroke_width=aw, transform='scale(1,' + str(v) + ')')
arrow['marker-end'] = arrowhead.get_funciri()
disk.add(arrow)

# text
doc.add(doc.path(id='omega', stroke='none', fill='black',
transform='translate(70,70) scale(0.03,-0.03)',
d='M 13 0 m 251 82 c 9 -63 43 -93 94 -93 c 59 0 113 38 153 93 c 75 104 94 \
255 94 289 c 0 71 -37 71 -43 71 c -25 0 -50 -26 -50 -48 c 0 -13 6 -19 15 -27 \
c 32 -33 35 -65 35 -87 c 0 -85 -85 -219 -190 -219 c -9 0 -37 0 -55 23 c -12 \
16 -20 35 -20 55 c 0 3 0 5 6 16 c 19 45 33 100 33 113 c 0 12 -7 23 -21 23 c \
-11 0 -20 -9 -28 -25 c -2 -5 -14 -49 -21 -101 c -2 -18 -2 -20 -9 -27 c -44 \
-61 -90 -77 -124 -77 c -66 0 -88 55 -88 114 c 0 75 37 158 84 225 c 10 14 10 \
16 10 19 c 0 8 -6 12 -12 12 c -16 0 -62 -88 -76 -120 c -37 -89 -38 -171 -38 \
-180 c 0 -80 30 -142 106 -142 c 65 0 113 46 145 93 z'))
doc.add(doc.path(id='r', stroke='none', fill='black',
transform='translate(152,60) scale(0.03,-0.03)',
d='M 29 0 m 59 59 c -3 -15 -9 -38 -9 -43 c 0 -18 14 -27 29 -27 c 12 0 30 8 \
37 28 c 2 4 36 140 40 158 c 8 33 26 103 32 130 c 4 13 32 60 56 82 c 8 7 37 33 \
80 33 c 26 0 41 -12 42 -12 c -30 -5 -52 -29 -52 -55 c 0 -16 11 -35 38 -35 c \
27 0 55 23 55 59 c 0 35 -32 65 -83 65 c -65 0 -109 -49 -128 -77 c -8 45 -44 \
77 -91 77 c -46 0 -65 -39 -74 -57 c -18 -34 -31 -94 -31 -97 c 0 -10 10 -10 12 \
-10 c 10 0 11 1 17 23 c 17 71 37 119 73 119 c 17 0 31 -8 31 -46 c 0 -21 -3 \
-32 -16 -84 z'))

doc.save()

Licensing[edit]

I, the copyright holder of this work, hereby publish it under the following licenses:
GNU head Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.
w:en:Creative Commons
attribution
This file is licensed under the Creative Commons Attribution 3.0 Unported license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
You may select the license of your choice.

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current00:26, 21 January 2013Thumbnail for version as of 00:26, 21 January 2013220 × 146 (3 KB)Geek3 (talk | contribs){{Information |Description ={{en|1=Illustration of a solid spinning disk}} |Source =own |Author =Geek3 |Date =21.01.2013 |Permission = |other_versions =Ehrenfest-paradox-disk.svg }}

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