Ficheiro:Harmonic partials on strings.svg
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Tamaño desta vista previa en PNG do ficheiro en formato SVG: 620 × 590 píxeles. Outras resolucións: 252 × 240 píxeles | 504 × 480 píxeles | 807 × 768 píxeles | 1.076 × 1.024 píxeles | 2.152 × 2.048 píxeles.
Ficheiro orixinal (ficheiro SVG; resolución de 620 × 590 píxeles; tamaño do ficheiro: 10 kB)
Resumo
| Descrición |
English: Illustration of harmonic overtones on the wave set up along a string when it is held steady in certain places, as when a guitar string is plucked while lightly held exactly half way along its length. |
| Data | |
| Orixe |
Obra própria, baseada em: Overtone.jpg:  |
| Autoría | Qef / Houtlijm |
| Outras versións |
|
| SVG desenvolvimento |  Este insígnia SVG emprega texto encapsulado que pode ser traducido de xeito doado cun editor de texto. |
Source code
Created by a specially written program in the Lua programming language. To recreate the image just run the program, and it will write the SVG into a file. There are various parameters that can be adjusted at the start of the code. The sine-wave approximation using Bezier curves is derived from Bezier curve sinewave approximation (PDF) by Jim Fitzsimmons.
local MARGIN = 10
local AMPLITUDE, WAVE_WIDTH = 30, 600
local GAP_BETWEEN_WAVES = 25
local NUM_WAVES = 7
local FONT_SIZE, FONT_FUDGE = 20, 5
local WAVE_STYLE = ' stroke="#000" stroke-width="1.5" fill="none"'
local img_wd = 2 * MARGIN + WAVE_WIDTH
local img_ht = 2 * MARGIN + NUM_WAVES * AMPLITUDE * 2 +
(NUM_WAVES - 1) * GAP_BETWEEN_WAVES
local PI = math.asin(1) * 2
local XD = PI / 12
local SQRT2 = math.sqrt(2)
local Y1 = (2 * SQRT2) / 7 - 1 / 7
local Y2 = (4 * SQRT2) / 7 - 2 / 7
local Y3 = SQRT2 / 2
local Y4 = (3 * SQRT2) / 7 + 2 / 7
function sine_wave_path (x, y, width, amp, num_half_waves)
local xmul = width / (num_half_waves * PI)
local xd = XD * xmul
local path = 'M' .. coords(x, y)
for _ = 1, num_half_waves do
path = path .. ' C' .. coords(x + xd, y + amp * Y1)
.. ' ' .. coords(x + 2*xd, y + amp * Y2)
.. ' ' .. coords(x + 3*xd, y + amp * Y3)
.. ' C' .. coords(x + 4*xd, y + amp * Y4)
.. ' ' .. coords(x + 5*xd, y + amp)
.. ' ' .. coords(x + 6*xd, y + amp)
.. ' C' .. coords(x + 7*xd, y + amp)
.. ' ' .. coords(x + 8*xd, y + amp * Y4)
.. ' ' .. coords(x + 9*xd, y + amp * Y3)
.. ' C' .. coords(x + 10*xd, y + amp * Y2)
.. ' ' .. coords(x + 11*xd, y + amp * Y1)
.. ' ' .. coords(x + 12*xd, y)
x = x + width / num_half_waves
amp = amp * -1 -- flip over vertically every half wave
end
return path
end
function coords (x, y)
return string.format('%g,%g', x, y)
end
local fh = assert(io.open("Harmonic_partials_on_strings.svg", "wb"))
fh:write('<?xml version="1.0" encoding="UTF-8"?>\n' ..
'<svg version="1.0" width="', img_wd, '" height="', img_ht,
'" xmlns="http://www.w3.org/2000/svg">\n')
local y_origin = MARGIN + AMPLITUDE
local wave_labels, pick_circles = '', ''
for n = 1, NUM_WAVES do
local amp = AMPLITUDE - (n - 1) * AMPLITUDE * 0.1
fh:write(' <path', WAVE_STYLE, ' d="',
sine_wave_path(MARGIN, y_origin, WAVE_WIDTH, amp, n), ' ',
sine_wave_path(MARGIN, y_origin, WAVE_WIDTH, -amp, n),
'"/>\n')
if n > 1 then
local pick_x = MARGIN + WAVE_WIDTH / n
local pick_r = AMPLITUDE * 0.2
pick_circles = pick_circles .. ' <circle cx="' .. pick_x ..
'" cy="' .. y_origin + pick_r ..
'" r="' .. pick_r .. '"/>\n'
wave_labels = wave_labels .. ' <text x="' .. pick_x ..
'" y="' .. y_origin - FONT_SIZE + 2 * FONT_FUDGE ..
'">1/' .. n .. '</text>\n'
end
y_origin = y_origin + 2 * AMPLITUDE + GAP_BETWEEN_WAVES
end
fh:write(' <g stroke="#000" fill="#bbb">\n', pick_circles, ' </g>\n',
' <g font-family="Bitstream Vera Sans" font-size="', FONT_SIZE, 'px"',
' text-anchor="middle">\n',
' <text x="', MARGIN + FONT_FUDGE,
'" y="', MARGIN + AMPLITUDE - FONT_SIZE + 2 * FONT_FUDGE,
'">0</text>\n',
' <text x="', MARGIN + WAVE_WIDTH - FONT_FUDGE,
'" y="', MARGIN + AMPLITUDE - FONT_SIZE + 2 * FONT_FUDGE,
'">1</text>\n',
wave_labels,
' </g>\n',
'</svg>\n')
Licenza
|
O autor desta obra, Qef, liberouna e agora pertence ao dominio público. Isto é válido en todo o mundo. Nalgúns países, isto pode non ser legalmente posible; entón: |
Historial do ficheiro
Prema nunha data/hora para ver o ficheiro tal e como estaba nese momento.
| Data/Hora | Miniatura | Dimensións | Usuario | Comentario | |
|---|---|---|---|---|---|
| actual | 8 de xullo de 2008 ás 15:46 | | 620 × 590 (10 kB) | wikimediacommons>Qef | {{Information |Description={{en|1=Illustration of harmonic overtones on the wave set up along a string when it is held steady in certain places, as when a guitar string is plucked while lightly held exactly half way along its length. }} |Source=Own work |
Uso do ficheiro
A seguinte páxina usa este ficheiro:
