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    CanvasRenderingContext2D.beginPath()

    この記事はまだボランティアによって 日本語 に翻訳されていません。ぜひ MDN に参加して翻訳を手伝ってください！

    The CanvasRenderingContext2D.beginPath() method of the Canvas 2D API starts a new path by emptying the list of sub-paths. Call this method when you want to create a new path.

    Syntax

    void ctx.beginPath();

    Examples

    Using the beginPath method

    This is just a simple code snippet which uses the beginPath method.

    HTML

    <canvas id="canvas"></canvas>

    JavaScript

    var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");

// First path
ctx.beginPath();
ctx.strokeStyle = 'blue';
ctx.moveTo(20,20);
ctx.lineTo(200,20);
ctx.stroke();

// Second path
ctx.beginPath();
ctx.strokeStyle = 'green';
ctx.moveTo(20,20);
ctx.lineTo(120,120);
ctx.stroke();

    Edit the code below and see your changes update live in the canvas:

    Playable code
    <canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas>
<div class="playable-buttons">
  <input id="edit" type="button" value="Edit" />
  <input id="reset" type="button" value="Reset" />
</div>
<textarea id="code" class="playable-code" style="height:200px">
// First path
ctx.beginPath();
ctx.strokeStyle = 'blue';
ctx.moveTo(20,20);
ctx.lineTo(200,20);
ctx.stroke();

// Second path
ctx.beginPath();
ctx.strokeStyle = 'green';
ctx.moveTo(20,20);
ctx.lineTo(120, 120);
ctx.stroke();</textarea>

    var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var textarea = document.getElementById("code");
var reset = document.getElementById("reset");
var edit = document.getElementById("edit");
var code = textarea.value;

function drawCanvas() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  eval(textarea.value);
}

reset.addEventListener("click", function() {
  textarea.value = code;
  drawCanvas();
});

edit.addEventListener("click", function() {
  textarea.focus();
})

textarea.addEventListener("input", drawCanvas);
window.addEventListener("load", drawCanvas);

    Specifications

    Specification Status Comment
    WHATWG HTML Living Standard
    The definition of 'CanvasRenderingContext2D.beginPath' in that specification.    		 Living Standard  

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
    Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
    Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
    Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

    See also

    ドキュメントのタグと貢献者

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     このページの貢献者: fscholz
     最終更新者: fscholz,