[旋轉圖片] Rotate Image #bookmarklet

bml_roate_img.js

javascript: (function() {
  window.addEventListener("click", function(event) {
		if(event.target.tagName == 'IMG') {
			event.preventDefault();
			var image = event.target;
			var canvas = document.createElement('canvas');
			canvas.id = 'myCanvas' + new Date().getTime();
			var ctx = canvas.getContext('2d');
			var width = image.width,
				height = image.height,
				x = 0,
				y = 0;
			var degree = prompt('Rotate Angle ?\n[90,180,270]', '90');
			switch(degree) {
			case '90':
				width = image.height;
				height = image.width;
				y = image.height * (-1);
				break;
			case '180':
				x = image.width * (-1);
				y = image.height * (-1);
				break;
			case '270':
				width = image.height;
				height = image.width;
				x = image.width * (-1);
				break;
			}
			canvas.setAttribute('width', width);
			canvas.setAttribute('height', height);
			ctx.rotate(degree * Math.PI / 180);
			ctx.drawImage(image, x, y);
			image.parentElement.insertBefore(canvas, image);
			image.style.display = "none";
		}
	}, false);
})()