--- title: Path2D.addPath() slug: Web/API/Path2D/addPath translation_of: Web/API/Path2D/addPath ---
{{APIRef("Canvas API")}}

Path2D.addPath() 是 Canvas 2D API 根据指定路径变量添加路径的方法。

语法

void path.addPath(path [, transform]);

参数

path
需要添加的 {{domxref("Path2D")}} 路径。
transform {{optional_inline}}
{{domxref("SVGMatrix")}} 作为新增路径的变换矩阵。

示例

使用 addPath 方法

这是一段使用 addPath 方法的简单的代码片段。

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

// Create a new path with a rect
var p1 = new Path2D();
p1.rect(0,0,100,100);

// Create another path with a rect
var p2 = new Path2D();
p2.rect(0,0,100,100);

// Create transformation matrix that moves vertically 300 points to the right
var m = document.createElementNS("http://www.w3.org/2000/svg", "svg").createSVGMatrix();
m.a = 1; m.b = 0;
m.c = 0; m.d = 1;
m.e = 300; m.f = 0;

// add the second path to the first path
p1.addPath(p2, m);

// Finally, fill the first path onto the canvas
ctx.fill(p1);

修改下面的代码并在线查看 canvas 的变化 (查看浏览器兼容性列表，确定你目前的浏览器是否支持这个方法)：

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:220px;">
var p1 = new Path2D();
p1.rect(0,0,100,100);

var p2 = new Path2D();
p2.rect(0,0,100,100);

var m = document.createElementNS("http://www.w3.org/2000/svg", "svg").createSVGMatrix();
m.a = 1; m.b = 0;
m.c = 0; m.d = 1;
m.e = 300; m.f = 0;

p1.addPath(p2, m);
ctx.fill(p1);</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);

{{ EmbedLiveSample('Playable_code', 700, 500) }}

规范描述

Specification Status Comment
{{SpecName('HTML WHATWG', "scripting.html#dom-path2d-addpath", "Path2D.addPath()")}} {{Spec2('HTML WHATWG')}} Initial defintion.

浏览器兼容性

{{CompatibilityTable}}

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support {{CompatNo}} {{CompatGeckoDesktop(34)}} {{CompatNo}} {{CompatVersionUnknown}} {{CompatVersionUnknown}}
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support {{CompatVersionUnknown}} {{CompatVersionUnknown}} {{CompatGeckoMobile(34)}} {{CompatNo}} {{CompatVersionUnknown}} {{CompatNo}}

参见