{"id":2554,"date":"2016-12-08T06:13:29","date_gmt":"2016-12-07T21:13:29","guid":{"rendered":"http:\/\/stuffy.dip.jp\/wordpress\/?p=2554"},"modified":"2017-10-09T08:38:37","modified_gmt":"2017-10-08T23:38:37","slug":"coordinate-transformation","status":"publish","type":"post","link":"https:\/\/www.stuffy.site\/wordpress\/?p=2554","title":{"rendered":"JavaScript\u306e\u5ea7\u6a19\u5909\u63db\u306e\u4f8b"},"content":{"rendered":"

\u4eca\u56de\u306fJavaScript\u306e\u5ea7\u6a19\u5909\u63db\u3092\u4f7f\u3063\u3066\u6b63\u4e94\u89d2\u5f62\u3092Canvas\u306b\u63cf\u753b\u3057\u3066\u307f\u307e\u3057\u305f\u3002<\/p>\n

\u534a\u5f84 r \u306e\u5186\u306b\u5185\u63a5\u3059\u308b\u6b63\u4e94\u89d2\u5f62\u306e\u5186\u306e\u4e2d\u5fc3\u304b\u3089\u5404\u8fba\u306b\u4e0b\u3057\u305f\u5782\u7dda\u306e\u9577\u3055 [pmath]ay={{1+sqrt{5}}\/{4}}r\u00a0[\/pmath] , \u5186\u306e\u4e2d\u5fc3\u3092\u539f\u70b9\u3068\u3057\u3066\u5404\u8fba\u306e\u4e00\u8fba\u306e\u9577\u3055[pmath]a=2ax={{sqrt{10-2sqrt{5}}}\/{2}}r[\/pmath]\u00a0\u304c\u65e2\u77e5\u3068\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n

https:\/\/stuffy.mydns.jp\/~gusachan\/javascript\/pentagon.html<\/a><\/p>\n

var c=document.getElementById(\"graph\");\r\nvar ctx=c.getContext(\"2d\");\r\nvar dgr =\u00a0 Math.PI\/180;\r\nfunction pentagon() {\r\n\u00a0 var r = 160, ax, ay, bx, by;\r\n\u00a0 ax = -(Math.sqrt(10 - 2*Math.sqrt(5)))*r\/4;\r\n\u00a0 ay = (1 + Math.sqrt(5))*r\/4;\r\n\u00a0 bx = -ax;\r\n\u00a0 by = ay;\r\n\u00a0 ctx.beginPath();\r\n\u00a0 ctx.save();\r\n\u00a0 ctx.translate(200 + ax, 200 + ay);\r\n\u00a0 ctx.moveTo(0,0);\r\n\u00a0 leg();\r\n\u00a0 ctx.rotate(-72*dgr);\r\n\u00a0 leg();\r\n\u00a0 ctx.rotate(-72*dgr);\r\n\u00a0 leg();\r\n\u00a0 ctx.rotate(-72*dgr);\r\n\u00a0 leg();\r\n\u00a0 ctx.rotate(-72*dgr);\r\n\u00a0 leg();\r\n\u00a0 ctx.closePath();\r\n\u00a0 ctx.restore();\r\n\u00a0 function leg() {\r\n\u00a0\u00a0\u00a0 ctx.save();\r\n\u00a0\u00a0\u00a0 ctx.lineTo(2*bx,0);\r\n\u00a0\u00a0\u00a0 ctx.restore();\r\n\u00a0\u00a0\u00a0 ctx.translate(2*bx,0);\r\n\u00a0 }\r\n}\r\npentagon();\r\nctx.stroke();\r\nbeginPath();\r\nctx.arc(200,200,160,0,360*dgr,false);\r\nctx.stroke();\r\n<\/span><\/pre>\n
\u5186\u306e\u4e2d\u5fc3\u3092\u539f\u70b9\u3068\u3057\u3066\u4e94\u89d2\u5f62\u306e\u5de6\u4e0b\u9685\u306e\u89d2\u306e\u5ea7\u6a19(ax, ay) =(-(Math.sqrt(10 – 2*Math.sqrt(5)))*r\/4, -(1 + Math.sqrt(5))*r\/4) \u3092Canvas\u306e\u5ea7\u6a19\u306e\uff08\u5de6\u4e0a\u9685\u3092(0,0)\u3068\u3059\u308b\uff09\u539f\u70b9\u304b\u3089translate(200 + ax, 200 + ay)) \u3057\u3066\u59cb\u70b9\u3068\u3057\u3001leg() \u95a2\u6570\u3092\u547c\u3073\u51fa\u3057\u3066\u5e95\u8fba\u3092\u4e00\u56de\u63cf\u753b\u3057\u305f\u306e\u3061\u3001restore()\u3067\u5ea7\u6a19\u7cfb\u5909\u63db\u3092\u5143\u306b\u623b\u3057translate(2*bx, 0)\u3067\u30ec\u30b0\u306e\u7d42\u70b9\u3092(0,0) \u306b\u306a\u308b\u3088\u3046\u306b\u79fb\u52d5\u3057\u3066rotate(-72*dgr)\u306772\u00b0\u53cd\u6642\u8a08\u56de\u308a\u306b\u56de\u8ee2 \u3001\u6b21\u306e\u5e95\u8fba\u306e\u518d\u63cf\u753b\uff5e\u30924\u56de\u7e70\u308a\u8fd4\u3057\u3066stroke()\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n
\u30c6\u30ad\u30b9\u30c8\u3067\u306f\u30d5\u30e9\u30af\u30bf\u30eb\u96ea\u7247\u3092\u518d\u5e30\u30ec\u30d9\u30eb4\u3067\u63cf\u753b\u3057\u3066\u3044\u307e\u3057\u305f\u3002<\/p>\n
\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
\u4eca\u56de\u306fJavaScript\u306e\u5ea7\u6a19\u5909\u63db\u3092\u4f7f\u3063\u3066\u6b63\u4e94\u89d2\u5f62\u3092Canvas\u306b\u63cf\u753b\u3057\u3066\u307f\u307e\u3057\u305f\u3002 \u534a\u5f84 r \u306e\u5186\u306b\u5185\u63a5\u3059\u308b\u6b63\u4e94\u89d2\u5f62\u306e\u5186\u306e\u4e2d\u5fc3\u304b\u3089\u5404\u8fba\u306b\u4e0b\u3057\u305f\u5782\u7dda\u306e\u9577\u3055 [pmath]ay={{1+sqrt{5}}\/{4}}r\u00a0[\/ … \u7d9a\u304d\u3092\u8aad\u3080 JavaScript\u306e\u5ea7\u6a19\u5909\u63db\u306e\u4f8b<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[87,5],"tags":[],"class_list":["post-2554","post","type-post","status-publish","format-standard","hentry","category-javascript","category-software"],"_links":{"self":[{"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2554","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2554"}],"version-history":[{"count":12,"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2554\/revisions"}],"predecessor-version":[{"id":4631,"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2554\/revisions\/4631"}],"wp:attachment":[{"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2554"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2554"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.stuffy.site\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2554"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}