如何在Flash中常见的JavaScript HTML 5 Canvas图像"页面翻转"？

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

function flipCanvas(ctx, type, center) {
  ctx.translate(center, center);
  if (type === "horizontal") {
    ctx.scale(-1, 1);
  } else if (type === "vertical") {
    ctx.scale(1, -1);
  }
  ctx.translate(-center, -center);
}

// 水平翻转
flipCanvas(ctx, "horizontal", canvas.width / 2);

// 垂直翻转
flipCanvas(ctx, "vertical", canvas.height / 2);

var image = new Image();
image.src = "your-image-url";
image.onload = function () {
  ctx.drawImage(image, 0, 0, canvas.width, canvas.height);
};