Fil:Archimedean spiral.png - Wikipedia

# Fil:Archimedean spiral.png

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Archimedean_spiral.png‎ (10KB, MIME-type: `image/png`)

| Dette er ei fil frå Wikimedia Commons. Sjå filomtalen der for meir informasjon.

Følgjande er henta frå filomtalen åt denne fila på Wikimedia Commons:

A vector version of this image ("SVG") is available !
And should be used in place of this raster image when superior.

  * [[:Image:Archimedean spiral.png]] [[:Image:Archimedean spiral.svg]]

For more information about vector graphics, read about Commons transition to SVG.
There is also information about MediaWiki's support of SVG images.

eo: La bildo estas kopiita de wikipedia:en. La originala priskribo estas:

## [edit] Summary

Three 360° turnings of one arm of an Archimedean spiral (higher-resolution picture). Produced with the following PostScript code:

    %!
    .75 setgray
    2 setlinewidth
    280 640 moveto 0 -540 rlineto stroke
    16 396 moveto 580 0 rlineto stroke
    1 0 0 setrgbcolor
    %%%%%%%%%%%%%%%%
    % PostScript program to display an Archimedean spiral by approximating
    % it with Bezier curves.  Can display a double spiral (two spirals
    % rotated by 180 degrees with respect to each other).
    %%%  Parameters:
    /sepwid 100 def  % width separating successive turnings of spiral
                     % (half this if double spiral is selected)
    /incrm 11.25 def % insert a curve point after this number of degrees
    /sweeps 3 def    % number of 360 degree turnings to show
    /centerx 280 def % horizontal coordinate of center of spiral
    /centery 396 def % vertical coordinate of center of spiral
    /double 0 def    % change to 1 to display double spiral
    /linew 3 def     % increase number for thicker line
    %%%  Procedures:
    /pi 3.1415926535898 def/radians 57.295779513082 def
    /sepwid sepwid pi div 2 div def
    gsave centerx centery translate linew setlinewidth
    /aspiral{/prevbezy 0 def 0 0 moveto
        0 incrm sweeps 360 mul{7{dup}repeat
            phase add cos/costh exch def
            phase add sin/sinth exch def
            costh mul radians div/thcosth exch def
            sinth mul radians div/thsinth exch def
            thcosth sepwid mul/x exch def
            thsinth sepwid mul/y exch def
            /slope sinth thcosth add costh thsinth sub div def
            sinth 0 gt sinth 0 eq costh -1 eq and or{/flag -1 def}{/flag 1
                def}ifelse
            /A exch def A 49.29348 lt A 180 gt A 196.273450852 lt and A 360
                gt A 368.8301 lt and A 540 gt A 545.9907 lt and A 720 gt A
                724.5217 lt and A 900 gt A 903.6281968 lt and or or or or
                or{/flag flag neg def}if
            incrm sub 3{dup}repeat phase add cos sepwid mul mul radians div
                /prevx exch def phase add sin sepwid mul mul radians div
                /prevy exch def
            incrm add 3{dup}repeat phase add cos sepwid mul mul radians div
                /nextx exch def phase add sin sepwid mul mul radians div
                /nexty exch def
            /prevdist x prevx sub dup mul y prevy sub dup mul add sqrt pi
                div def
            /nextdist x nextx sub dup mul y nexty sub dup mul add sqrt pi
                div def
            /normaliz slope slope mul 1 add sqrt def
            0 eq{/prevbezx phase cos nextdist mul def}{prevbezx prevbezy
            x 1 flag mul normaliz div prevdist mul sub y slope flag mul
                normaliz div prevdist mul sub
            x y curveto
            /prevbezx x 1 flag mul normaliz div nextdist mul add def
            /prevbezy y slope flag mul normaliz div nextdist mul add def}ifelse}
        for stroke}def
    /phase 0 def aspiral
    %%% If different sweeps parameter for second spiral, define here:
    %%%%%%%%%%%%%%%%
    double 0 ne{/phase 180 def aspiral}if grestore
    showpage
    %%EOF

## [edit] Licensing

| This image has been released into the public domain by its author, AnonMoos. This applies worldwide. In some countries this may not be legally possible; if so: AnonMoos grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

## [edit] Edit history on en.wikipedia

date/time | username | edit summary
--- | --- | ---
22:42, 20 November 2005 | en:User:AnonMoos | (update description to reflect new version of image)
23:05, 16 November 2005 | en:User:AnonMoos | (add category)
12:59, 23 October 2005 | en:User:AnonMoos | (tweaking)
02:16, 23 October 2005 | en:User:AnonMoos | →Summary
01:40, 23 October 2005 | en:User:AnonMoos |
01:38, 23 October 2005 | en:User:AnonMoos | (tags)
01:20, 23 October 2005 | en:User:AnonMoos | (One arm of an Archimedean spiral (higher-resolution picture). Produced with the following PostScript code: .75 setgray 2 setlinewidth 280 640 moveto 0 -540 rlineto stroke 16 396 moveto 580 0 rlineto stroke 1 0 0 setrgbcolor 1 setlinecap %%%%%)

## [edit] Upload history on en.wikipedia

Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version.

Click on date to download the file or see the image uploaded on that date.

- (del) (cur) 22:38, 20 November 2005 . . en:User:AnonMoos AnonMoos ( en:User_talk:AnonMoos Talk) . . 656x600 (9955 bytes) (larger slightly-corrected version)
- (del) (rev) 01:20, 23 October 2005 . . en:User:AnonMoos AnonMoos ( en:User_talk:AnonMoos Talk) . . 600x550 (9150 bytes) (One arm of an Archimedean spiral (higher-resolution picture). Produced with the following PostScript code: <nowiki> %! .75 setgray 2 setlinewidth 280 640 moveto 0 -540 rlineto stroke 16 396 moveto 580 0 rlineto stroke 1 0 0 setrgbcolor 1 setlinecap %%%%%)

## Fillenkjer

Dei følgjande sidene har lenkjer til denne fila:

- Arkimedisk spiral

Henta frå «http://nn.wikipedia.org../../../a/r/c/Fil%7EArchimedean_spiral.png_c14e.html»

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