/*

tip_centerwindow.js  v. 1.2



The latest version is available at

http://www.walterzorn.com

or http://www.devira.com

or http://www.walterzorn.de



Initial author: Walter Zorn

Last modified: 23.6.2007



Extension for the tooltip library wz_tooltip.js.

Centers a sticky tooltip in the window's visible clientarea,

optionally even if the window is being scrolled or resized.

*/



// Here we define new global configuration variable(s) (as members of the

// predefined "config." class).

// From each of these config variables, wz_tooltip.js will automatically derive

// a command which can be passed to Tip() or TagToTip() in order to customize

// tooltips individually. These command names are just the config variable

// name(s) translated to uppercase,

// e.g. from config. CenterWindow a command CENTERWINDOW will automatically be

// created.



//===================  GLOBAL TOOPTIP CONFIGURATION  =========================//

config. CenterWindow = false	// true or false - set to true if you want this to be the default behaviour

config. CenterAlways = false	// true or false - recenter if window is resized or scrolled

//=======  END OF TOOLTIP CONFIG, DO NOT CHANGE ANYTHING BELOW  ==============//





// Create a new tt_Extension object (make sure that the name of that object,

// here ctrwnd, is unique amongst the extensions available for

// wz_tooltips.js):

var ctrwnd = new tt_Extension();



// Implement extension eventhandlers on which our extension should react

ctrwnd.OnLoadConfig = function()

{

	if(tt_aV[CENTERWINDOW])

	{

		// Permit CENTERWINDOW only if the tooltip is sticky

		if(tt_aV[STICKY])

		{

			if(tt_aV[CENTERALWAYS])

			{

				// IE doesn't support style.position "fixed"

				if(tt_ie)

					tt_AddEvtFnc(window, "scroll", Ctrwnd_DoCenter);

				else

					tt_aElt[0].style.position = "fixed";

				tt_AddEvtFnc(window, "resize", Ctrwnd_DoCenter);

			}

			return true;

		}

		tt_aV[CENTERWINDOW] = false;

	}

	return false;

};

// We react on the first OnMouseMove event to center the tip on that occasion

ctrwnd.OnMoveBefore = Ctrwnd_DoCenter;

ctrwnd.OnKill = function()

{

	if(tt_aV[CENTERWINDOW] && tt_aV[CENTERALWAYS])

	{

		tt_RemEvtFnc(window, "resize", Ctrwnd_DoCenter);

		if(tt_ie)

			tt_RemEvtFnc(window, "scroll", Ctrwnd_DoCenter);

		else

			tt_aElt[0].style.position = "absolute";

	}

	return false;

};

// Helper function

function Ctrwnd_DoCenter()

{

	if(tt_aV[CENTERWINDOW])

	{

		var x, y, dx, dy;



		// Here we use some functions and variables (tt_w, tt_h) which the

		// extension API of wz_tooltip.js provides for us

		if(tt_ie || !tt_aV[CENTERALWAYS])

		{

			dx = tt_GetScrollX();

			dy = tt_GetScrollY();

		}

		else

		{

			dx = 0;

			dy = 0;

		}

		// Position the tip, offset from the center by OFFSETX and OFFSETY

		x = (tt_GetClientW() - tt_w) / 2 + dx + tt_aV[OFFSETX];

		y = (tt_GetClientH() - tt_h) / 2 + dy + tt_aV[OFFSETY];

		tt_SetTipPos(x, y);

		return true;

	}

	return false;

}