CanvasRenderingContext2D.isPointInPath()是 Canvas 2D API 用于判断在当前路径中是否包含检测点的方法。
boolean ctx.isPointInPath(x, y); boolean ctx.isPointInPath(x, y, fillRule); boolean ctx.isPointInPath(path, x, y); boolean ctx.isPointInPath(path, x, y, fillRule);
fillRulepathisPointInPath 方法这是一段简单的代码片段，使用 isPointInPath 方法检查某点是否在当前的路径内。
<canvas id="canvas"></canvas>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.rect(10, 10, 100, 100);
ctx.stroke();
console.log(ctx.isPointInPath(10, 10)); // true
修改下面的代码， 在线查看 canvas的变化并在你的 控制台 中观察日志信息：
<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"> ctx.rect(10, 10, 100, 100); ctx.stroke(); console.log(ctx.isPointInPath(10, 10)); // true</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, 360) }}
| Specification | Status | Comment |
|---|---|---|
| {{SpecName('HTML WHATWG', "scripting.html#dom-context-2d-ispointinpath", "CanvasRenderingContext2D.isPointInPath")}} | {{Spec2('HTML WHATWG')}} |