How to stop mouse flicker?

[TroyMcClure]

Hi,
I have a bit of javascript code causes the mouse to flicker. How can I prevent this?

The code takes about 1/2 second to run, but in that time, the flicker is noticeable and jarring.
Thanks for any help,
--T

 

[checkai]

a 1/2 second is "jarring"?

 

[trollacious]

Post the code.

Lee

 

[TroyMcClure]

Yes...it's not the time so much--if it flickered *once* and took 5 only milliseconds, that's noticeable--the user looks away because something happened. In this case, it's flickering for a full 1/2 second--and it's jarring.
--T

 

[TroyMcClure]

Here is the code. It's freeware, from youngpup.com, it's code for a slideout menu:
(the slideouts work fine, but as I said, when the user clicks the link to slide the menu, the mouse flickers as the slide happens) (IE 6.0.28)

/*****************************************************
 * ypSlideOutMenu
 * 3/04/2001
 * 
 * a nice little script to create exclusive, slide-out
 * menus for ns4, ns6, mozilla, opera, ie4, ie5 on 
 * mac and win32. I've got no linux or unix to test on but 
 * it should(?) work... 
 *
 * --youngpup--
 *****************************************************/

ypSlideOutMenu.Registry = []
ypSlideOutMenu.aniLen = 250
ypSlideOutMenu.hideDelay = 1000
ypSlideOutMenu.minCPUResolution = 10

// constructor
function ypSlideOutMenu(id, dir, left, top, width, height)
{
	this.ie  = document.all ? 1 : 0
	this.ns4 = document.layers ? 1 : 0
	this.dom = document.getElementById ? 1 : 0

	if (this.ie || this.ns4 || this.dom) {
		this.id			 = id
		this.dir		 = dir
		this.orientation = dir == "left" || dir == "right" ? "h" : "v"
		this.dirType	 = dir == "right" || dir == "down" ? "-" : "+"
		this.dim		 = this.orientation == "h" ? width : height
		this.hideTimer	 = false
		this.aniTimer	 = false
		this.open		 = false
		this.over		 = false
		this.startTime	 = 0

		// global reference to this object
		this.gRef = "ypSlideOutMenu_"+id
		eval(this.gRef+"=this")

		// add this menu object to an internal list of all menus
		ypSlideOutMenu.Registry[id] = this

		var d = document
		d.write('<style type="text/css">')
		d.write('#' + this.id + 'Container { visibility:hidden; ')
		d.write('left:' + left + 'px; ')
		d.write('top:' + top + 'px; ')
		d.write('overflow:hidden; }')
		d.write('#' + this.id + 'Container, #' + this.id + 'Content { position:absolute; ')
		d.write('width:' + width + 'px; ')
		d.write('height:' + height + 'px; ')
		d.write('clip:rect(0 ' + width + ' ' + height + ' 0); ')
		d.write('}')
		d.write('</style>')

		this.load()
	}
}

ypSlideOutMenu.prototype.load = function() {
	var d = document
	var lyrId1 = this.id + "Container"
	var lyrId2 = this.id + "Content"
	var obj1 = this.dom ? d.getElementById(lyrId1) : this.ie ? d.all[lyrId1] : d.layers[lyrId1]
	if (obj1) var obj2 = this.ns4 ? obj1.layers[lyrId2] : this.ie ? d.all[lyrId2] : d.getElementById(lyrId2)
	var temp

	if (!obj1 || !obj2) window.setTimeout(this.gRef + ".load()", 100)
	else {
		this.container	= obj1
		this.menu		= obj2
		this.style		= this.ns4 ? this.menu : this.menu.style
		this.homePos	= eval("0" + this.dirType + this.dim)
		this.outPos		= 0
		this.accelConst	= (this.outPos - this.homePos) / ypSlideOutMenu.aniLen / ypSlideOutMenu.aniLen 

		// set event handlers.
		if (this.ns4) this.menu.captureEvents(Event.MOUSEOVER | Event.MOUSEOUT);
		this.menu.onmouseover = new Function("ypSlideOutMenu.showMenu('" + this.id + "')")
		this.menu.onmouseout = new Function("ypSlideOutMenu.hideMenu('" + this.id + "')")

		//set initial state
		this.endSlide()
	}
}
	
ypSlideOutMenu.showMenu = function(id)
{
	var reg = ypSlideOutMenu.Registry
	var obj = ypSlideOutMenu.Registry[id]
	
	if (obj.container) {
		obj.over = true

		// close other menus.
		for (menu in reg) if (id != menu) ypSlideOutMenu.hide(menu)

		// if this menu is scheduled to close, cancel it.
		if (obj.hideTimer) { reg[id].hideTimer = window.clearTimeout(reg[id].hideTimer) }

		// if this menu is closed, open it.
		if (!obj.open && !obj.aniTimer) reg[id].startSlide(true)
	}
}

ypSlideOutMenu.hideMenu = function(id)
{
	// schedules the menu to close after <hideDelay> ms, which
	// gives the user time to cancel the action if they accidentally moused out
	var obj = ypSlideOutMenu.Registry[id]
	if (obj.container) {
		if (obj.hideTimer) window.clearTimeout(obj.hideTimer)
		obj.hideTimer = window.setTimeout("ypSlideOutMenu.hide('" + id + "')", ypSlideOutMenu.hideDelay);
	}
}

ypSlideOutMenu.hideAll = function()
{
        var reg = ypSlideOutMenu.Registry
        for (menu in reg) {
                ypSlideOutMenu.hide(menu);
                if (menu.hideTimer) window.clearTimeout(menu.hideTimer);
        }
}

ypSlideOutMenu.hide = function(id)
{
	var obj = ypSlideOutMenu.Registry[id]
	obj.over = false

	if (obj.hideTimer) window.clearTimeout(obj.hideTimer)
	
	// flag that this scheduled event has occured.
	obj.hideTimer = 0

	// if this menu is open, close it.
	if (obj.open && !obj.aniTimer) obj.startSlide(false)
}

ypSlideOutMenu.prototype.startSlide = function(open) {
	this[open ? "onactivate" : "ondeactivate"]()
	this.open = open
	if (open) this.setVisibility(true)
	this.startTime = (new Date()).getTime()	
	this.aniTimer = window.setInterval(this.gRef + ".slide()", ypSlideOutMenu.minCPUResolution)
}

ypSlideOutMenu.prototype.slide = function() {
	var elapsed = (new Date()).getTime() - this.startTime
	if (elapsed > ypSlideOutMenu.aniLen) this.endSlide()
	else {
		var d = Math.round(Math.pow(ypSlideOutMenu.aniLen-elapsed, 2) * this.accelConst)
		if (this.open && this.dirType == "-")		d = -d
		else if (this.open && this.dirType == "+")	d = -d
		else if (!this.open && this.dirType == "-")	d = -this.dim + d
		else										d = this.dim + d

		this.moveTo(d)
	}
}

ypSlideOutMenu.prototype.endSlide = function() {
	this.aniTimer = window.clearTimeout(this.aniTimer)
	this.moveTo(this.open ? this.outPos : this.homePos)
	if (!this.open) this.setVisibility(false)
	if ((this.open && !this.over) || (!this.open && this.over)) {
		this.startSlide(this.over)
	}
}

ypSlideOutMenu.prototype.setVisibility = function(bShow) { 
	var s = this.ns4 ? this.container : this.container.style
	s.visibility = bShow ? "visible" : "hidden"
}
ypSlideOutMenu.prototype.moveTo = function(p) { 
	this.style[this.orientation == "h" ? "left" : "top"] = this.ns4 ? p : p + "px"
}
ypSlideOutMenu.prototype.getPos = function(c) {
	return parseInt(this.style[c])
}

// events
ypSlideOutMenu.prototype.onactivate		= function() { }
ypSlideOutMenu.prototype.ondeactivate	= function() { }

--T

 

[TroyMcClure]

...I forgot to mention...and it's probably the cause--I've got a jpeg as the background for the menu's Div.

I'm sure this is it...since this script repaints the div several times to cause the 'slide' effect, the jpg is probably(?) being schleped over the wire each time.

but I guess it begs the question: Is there any way that I can instruct--either java, ie/netscape, or whatever--to not re-fetch the friggin picture each time since the image file is definitely not going to change in those few seconds?
--T