Canvas | zip358.com

Canvasで円がぐるぐる回る。

2019.03.09

<!DOCTYPE html>
<html>
    <head>
    </head>
<body>
    <canvas id="ctx" ></canvas>
    <script>
            "use strict";
            let x = 0,y = 0;
            let xs = 300,ys = 300;
            let xc = 1,yc = 1;
            let ctx = document.querySelector("#ctx");
            let canvas;
            ctx.width = window.screen.width;
            ctx.height = window.screen.height;
            if(ctx.getContext)
            {
               canvas = ctx.getContext("2d");
               setInterval(draw,77);
            }
            function draw(){
               canvas.beginPath();
               canvas.fillStyle = "#3399ff";
               canvas.arc(x,y,35,0,Math.PI*2,true);
               canvas.globalCompositeOperation = "xor";
               canvas.fill();
                x =((Math.sin (xc) * xs)) + 500;
                y =(Math.cos(yc) * ys) + 500;
                console.log(x + ":" + ctx.width);
                console.log(y + ":" + ctx.height);
                if(x < 0 || x > ctx.width)
                {
                   xs*=-1;
                }
                if(y < 0 || y > ctx.height)
                {
                    ys*=-1;
                }
                if(x<0)
                {
                    x=0;
                }
                if(y<0)
                {
                    y=0;
                }
                if(x > ctx.width)
                {
                    x=ctx.width;
                }
                if( y > ctx.height)
                {
                    y=ctx.height;
                }
                xc+=1
                if(xc>360)
                {
                    xc=0;
                }
                yc+=1
                if(yc>360)
                {
                    yc=0;
                }
            }
        </script>
</body>
</html>

Canvasでぐるぐる円を廻す。
ガラクタコードが少しあります、最初違うコードを書いていたので
これを可変していろいろお試しください。
https://zip358.com/tool/demo5/js/index-3.html

著者名 @taoka_toshiaki

※この記事は著者が30代前半に書いたものです．

Profile
高知県在住の@taoka_toshiakiです、記事を読んで頂きありがとうございます.
数十年前から息を吸うように日々記事を書いてます．たまに休んだりする日もありますがほぼ毎日投稿を心掛けています😅．
SNSも使っています、フォロー、いいね、シェア宜しくお願い致します🙇.
SNS::@taoka_toshiaki

OFUSEで応援を送る

投稿日時 2019年03月09 05:30日

タグ

0, １, 300, body, Canvas, ctx, DOCTYPE, document, gt, head, Height, html, ID, let, lt, querySelector, screen, script, strict, use, Width, win, window, xc, xs, yc, YS, 円,

There is a library file called “Three.js”.
Overwhelming lettering processing can be done on “canvas”.
I initially thought that it would be running on “node.js”.That was a mistake.
Using “Three.js” enables advanced lettering processing. For example, if you use “game development”, “alternative to Flash” etc, a new world will open out.
The other day my colleague was pleased to tell me the library file “Three.js”.I think this is a libraryfile worth studying.
https://threejs.org/
https://github.com/mrdoob/three.js/
https://liginc.co.jp/web/html-css/html/91988
https://liginc.co.jp/315939

著者名 @taoka_toshiaki

※この記事は著者が30代前半に書いたものです．

OFUSEで応援を送る

投稿日時 2018年01月06 05:00日

タグ

a new world will open out, alternative to Flash, Canvas, enables advanced lettering processing, For example, game development, I initially thought that it would be, I think this is a libraryfile worth, if you use, JavaScript 3Dライブラリ, node.js, Overwhelming lettering processing can be done on, That was a mistake, The other day my colleague was pleased, There is a library file called, Three.js, Three.js is great, WebGL,

Canvasで円がぐるぐる回る。

Three.js is great!!