Steps to Reproduce

run the attachment progressmeter-animation-not-catching-up.zul
click one button at a time (reload the browser between clicks)

Current Result

a high update rate of the progressbar value leads to animations not catching up with the actual value

Expected Result

stay closer to the actual value

Root Cause

1) the _fixImgWidth function of the progressmeter widget call jq.animate with the default option "queue:true" which makes each animation wait for the previous to finish, causing an increasing delay with higher update rates
-> set queue to false

2) the default easing starts at a slow speed -> restarting the animation at a high rate will remain in the slow bit of the animation most of the time
*-> consider: easing:'linear' to be closer to the current value
*
3) the animation speed is 'slow' so each animation takes at 600ms
-> consider default or fast update speed to be closer to the actual value

simplify the code by using percentage width, there's no need to convert from % to pixels
*-> just use % directly * (positive side effect, resizing is no longer necessary)

Workaround

override the _fixImgWidth function

	zk.afterLoad('zul.wgt', function() {
		var xProgressmeter = {};
		zk.override(zul.wgt.Progressmeter.prototype, xProgressmeter, {
			_fixImgWidth : function() {
				var n = this.$n(),
				    img = this.$n('img');
				if (img) {
					if (zk(n).isRealVisible()) {
						var $img = jq(img);
						$img.animate({
							width: this._value + '%' /*use percent-value directly*/
						}, {
							duration: $img.zk.getAnimationSpeed('slow'), /*slow = questionable? consider using default*/
							queue: false, /*disable queueing*/
							easing: "linear" 
						});
					}
				}
			}
		});//zk.override
	});//zk.afterLoad