/******************************************************************************
* scroller.js *
* *
* Copyright 1999 by Mike Hall. *
* Visit http://www.dynamicdrive.com *
* Last update: December 1, 1999. *
* *
* Allows you to create scrolling displays on a page. Multiple scrollers can *
* be defined, each with it's own parameters and list of items. Item text can *
* include basic HTML tags, including links and images. *
* Note: requires dhtmllib.js. *
******************************************************************************/
//*****************************************************************************
// Scroller constructor.
//*****************************************************************************
function Scroller(x, y, width, height, border, padding) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
this.border = border;
this.padding = padding;
this.items = new Array();
this.created = false;
// Set default colors.
this.fgColor = "#000000";
this.bgColor = "#ffffff";
this.bdColor = "#000000";
// Set default font.
this.fontFace = "Arial,Helvetica";
this.fontSize = "2";
// Set default scroll timing values.
this.speed = 50;
this.pauseTime = 2000;
// Define methods.
this.setColors = scrollerSetColors;
this.setFont = scrollerSetFont;
this.setSpeed = scrollerSetSpeed;
this.setPause = scrollersetPause;
this.addItem = scrollerAddItem;
this.create = scrollerCreate;
this.show = scrollerShow;
this.hide = scrollerHide;
this.moveTo = scrollerMoveTo;
this.moveBy = scrollerMoveBy;
this.getzIndex = scrollerGetzIndex;
this.setzIndex = scrollerSetzIndex;
this.stop = scrollerStop;
this.start = scrollerStart;
}
//*****************************************************************************
// Scroller methods.
//*****************************************************************************
function scrollerSetColors(fgcolor, bgcolor, bdcolor) {
if (this.created) {
alert("Scroller Error: Scroller has already been created.");
return;
}
this.fgColor = fgcolor;
this.bgColor = bgcolor;
this.bdColor = bdcolor;
}
function scrollerSetFont(face, size) {
if (this.created) {
alert("Scroller Error: Scroller has already been created.");
return;
}
this.fontFace = face;
this.fontSize = size;
}
function scrollerSetSpeed(pps) {
if (this.created) {
alert("Scroller Error: Scroller has already been created.");
return;
}
this.speed = pps;
}
function scrollersetPause(ms) {
if (this.created) {
alert("Scroller Error: Scroller has already been created.");
return;
}
this.pauseTime = ms;
}
function scrollerAddItem(str) {
if (this.created) {
alert("Scroller Error: Scroller has already been created.");
return;
}
this.items[this.items.length] = str;
}
function scrollerCreate() {
var start, end;
var str;
var i, j;
var x, y;
if (!isMinNS4 && !isMinIE4)
return;
// On first scroller, start interval timer.
if (scrollerList.length == 0)
setInterval('scrollerGo()', scrollerInterval);
// Create the scroller only once.
if (this.created) {
alert("Scroller Error: Scroller has already been created.");
return;
}
this.created = true;
// Copy first item to the end of the list, this lets us scroll from the last
// defined item to the first without jumping.
this.items[this.items.length] = this.items[0];
// Set up HTML code for item text.
start = '
'
+ '
'
+ '';
end = '
';
// Build the layers.
if (isMinNS4) {
this.baseLayer = new Layer(this.width);
this.scrollLayer = new Layer(this.width, this.baseLayer);
this.scrollLayer.visibility = "inherit";
this.itemLayers = new Array();
for (i = 0; i < this.items.length; i++) {
this.itemLayers[i] = new Layer(this.width, this.scrollLayer);
this.itemLayers[i].document.open();
this.itemLayers[i].document.writeln(start + this.items[i] + end);
this.itemLayers[i].document.close();
this.itemLayers[i].visibility = "inherit";
}
// Set background colors.
setBgColor(this.baseLayer, this.bdColor);
setBgColor(this.scrollLayer, this.bgColor);
}
if (isMinIE4) {
i = scrollerList.length;
str = '
\n';
// Insert HTML code at end of page. For IE4, need to scroll window to
// end of page, insert and scroll back to correct bug.
if (!isMinIE5) {
x = getPageScrollX();
y = getPageScrollY();
window.scrollTo(getPageWidth(), getPageHeight());
}
document.body.insertAdjacentHTML("beforeEnd", str);
if (!isMinIE5)
window.scrollTo(x, y);
// Get handles to each layer.
this.baseLayer = getLayer("scroller" + i + "_baseLayer");
this.scrollLayer = getLayer("scroller" + i + "_scrollLayer");
this.itemLayers = new Array();
for (j = 0; j < this.items.length; j++)
this.itemLayers[j] = getLayer("scroller" + i + "_itemLayers" + j);
}
// Position and clip base and scroll layers.
moveLayerTo(this.baseLayer, this.x, this.y);
clipLayer(this.baseLayer, 0, 0, this.width, this.height);
moveLayerTo(this.scrollLayer, this.border, this.border);
clipLayer(this.scrollLayer, 0, 0,
this.width - 2 * this.border, this.height - 2 * this.border);
// Position and clip each item layer.
x = 0;
y = 0;
for (i = 0; i < this.items.length; i++) {
moveLayerTo(this.itemLayers[i], x, y);
clipLayer(this.itemLayers[i], 0, 0, this.width, this.height);
y += this.height;
}
// Set up scrolling parameters.
this.stopped = false;
this.currentY = 0;
this.stepY = this.speed / (1000 / scrollerInterval);
this.stepY = Math.min(this.height, this.stepY);
this.nextY = this.height;
this.maxY = this.height * (this.items.length - 1);
this.paused = true;
this.counter = 0;
// Add to global list.
scrollerList[scrollerList.length] = this;
// Display it.
showLayer(this.baseLayer);
}
function scrollerShow() {
if (this.created)
showLayer(this.baseLayer);
}
function scrollerHide() {
if (this.created)
hideLayer(this.baseLayer);
}
function scrollerMoveTo(x, y) {
if (this.created)
moveLayerTo(this.baseLayer, x, y);
}
function scrollerMoveBy(dx, dy) {
if (this.created)
moveLayerBy(this.baseLayer, dx, dy);
}
function scrollerGetzIndex() {
if (this.created)
return(getzIndex(this.baseLayer));
else
return(0);
}
function scrollerSetzIndex(z) {
if (this.created)
setzIndex(this.baseLayer, z);
}
function scrollerStart() {
this.stopped = false;
}
function scrollerStop() {
this.stopped = true;
}
//*****************************************************************************
// Code for scrolling.
//*****************************************************************************
// An array is used to hold a pointer to each scroller that is defined. The
// scrollerGo() function runs at regular intervals and updates each scroller
// in this list.
var scrollerList = new Array();
var scrollerInterval = 20;
function scrollerGo() {
var i;
// Update each scroller object in the list.
for (i = 0; i < scrollerList.length; i++) {
// If stopped, skip.
if (scrollerList[i].stopped);
// If paused, update counter.
else if (scrollerList[i].paused) {
scrollerList[i].counter += scrollerInterval;
if (scrollerList[i].counter > scrollerList[i].pauseTime)
scrollerList[i].paused = false;
}
// Scroll it.
else {
scrollerList[i].currentY += scrollerList[i].stepY;
// Pause it if the next item has scrolled into view.
if (scrollerList[i].currentY >= scrollerList[i].nextY) {
scrollerList[i].paused = true;
scrollerList[i].counter = 0;
scrollerList[i].currentY = scrollerList[i].nextY;
scrollerList[i].nextY += scrollerList[i].height;
}
// When we reach the end, start over.
if (scrollerList[i].currentY >= scrollerList[i].maxY) {
scrollerList[i].currentY -= scrollerList[i].maxY;
scrollerList[i].nextY = scrollerList[i].height;
}
scrollLayerTo(scrollerList[i].scrollLayer,
0, Math.round(scrollerList[i].currentY),
false);
}
}
}
//*****************************************************************************
// Code to handle a window resize.
//*****************************************************************************
// These variables are used to determine if a resize event is a true one.
// Necessary due to a bug in older NS4 releases.
var origWidth;
var origHeight;
// Fix for resize bug.
if (isMinNS4) {
origWidth = window.innerWidth;
origHeight = window.innerHeight;
}
window.onresize = scrollerReload;
function scrollerReload() {
// Reload page in case of a browser resize. First make sure it's a true
// resize.
if (isMinNS4 && origWidth == window.innerWidth && origHeight == window.innerHeight)
return;
window.location.href = window.location.href;
}