CanvasRenderingContext2D.resetTransform() 是 Canvas 2D API 使用单位矩阵重新设置当前变形的方法。
void ctx.resetTransform();
resetTransform 方法这是一段使用 resetTransform 方法的简单的代码片段。
<canvas id="canvas"></canvas>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.rotate(45 * Math.PI / 180);
ctx.fillRect(70,0,100,30);
// reset current transformation matrix to the identity matrix
ctx.resetTransform();
修改下面的代码并在线查看 canvas 的变化：
<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.rotate(45 * Math.PI / 180); ctx.fillRect(70,0,100,30); ctx.resetTransform();</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) }}
你可以使用 {{domxref("CanvasRenderingContext2D.setTransform()")}} 方法重新设置当前变形为单位矩阵，如下：
ctx.setTransform(1, 0, 0, 1, 0, 0);
| Specification | Status | Comment |
|---|---|---|
| {{SpecName('HTML WHATWG', "scripting.html#dom-context-2d-resettransform", "CanvasRenderingContext2D.resetTransform")}} | {{Spec2('HTML WHATWG')}} |