// wind.loop.v01.js
// v1 2007-05-11 mtd - Butchered IDR.loop.v06.js for the WATL Wind Forecast loops
// Usage:
// (1) Call 'launch()' once (e.g. from BODY onload="..") to start this code.
// (2) Assumes that these Image dependent variables have already been defined:
// If there are some images, loop them.
// else when no images are available, exit now.
// Assume that the enclosing html will provide a message.
// remember when this page started (so we can kill the loops later).
start_time = new Date();
start_seconds = start_time.getTime() / 1000;
loop_limit_seconds = 300+60;
var doc; // Holds a pointer to MS or NN document (see launch).
// Now the general Looping code.
//============================================================
// >> jsImagePlayer 1.0 <<
// for Netscape3.0+, September 1996
// by (c)BASTaRT 1996
// Praha, Czech Republic, Europe
// feel free to copy and use as long as the credits are given
// by having this header in the code
// contact: xholecko@sgi.felk.cvut.cz
// http://sgi.felk.cvut.cz/~xholecko
// modified by D. Watson and A. Earnhart (CIRA/CSU), 7/30/97
// and Greg Thompson (NCAR/RAP) Dec. 11 1997
//============================================================
// step 1: define the images
// This is done in wind.js using Dynamic XMLHttpObject requests.
// step 2: define variables used to control images
var image_href = "";
var first_image = 0;
var last_image;
//=== global variables ====
theImages = new Array(); //holds the images
imageNum = new Array(); //keeps track of which images to omit from loop
normal_delay = 300;
delay = normal_delay; //delay between frames in 1/100 seconds
delay_step = 50;
delay_max = 4000;
delay_min = 50;
dwell_multipler = 3;
dwell_step = 1;
end_dwell_multipler = dwell_multipler;
start_dwell_multipler = dwell_multipler - 1;
current_image = first_image; //number of the current image
timeID = null;
looping = 0; // 0-stopped, 1-playing
play_mode = 0; // 0-normal, 1-loop, 2-sweep
size_valid = 0;
//===> Load and initialize everything once page is downloaded
// (called from 'onLoad' in )
function launch() {
var i;
last_image = nImages-1;
doc = document;
theImages = new Array(); //holds the images
imageNum = new Array(); //keeps track of which images to omit from loop
if(nImages==0) {
doc.animation.src = "" // Scrub the 'Please wait' image.
return;
}
// If there is only 1 image, show it, but dont start the loop.
if(nImages==1) {
current_image = 0;
theImages[current_image] = new Image();
theImages[current_image].src = image_href + theImageNames[current_image];
imageNum[current_image] = true; // pretend it is ready.
display_current_image();
return;
}
// construct filenames for all images in the loop
for (i = first_image; i <= last_image; i++) {
current_image = i;
theImages[current_image] = new Image();
theImages[current_image].src = image_href + theImageNames[current_image];
imageNum[current_image] = false; // image is not ready yet.
}
current_image = theStep;
imageNum[current_image] = true; // pretend it is ready.
// this needs to be done to set the right mode when the page is manually reloaded
change_mode (1);
document.getElementById('h-value').value = theStep+1;
display_current_image();
}
// Load the first next two images and previous two images from theStep
function launch_EC() {
var i;
last_image = nImages-1;
doc = document;
theImages = new Array(); //holds the images
imageNum = new Array(); //keeps track of which images to omit from loop
if(nImages==0) {
doc.animation.src = "" // Scrub the 'Please wait' image.
return;
}
// construct filenames and preload the next two images
for (i = theStep; i <= (theStep+2); i++) {
if(i > last_image) break;
current_image = i;
theImages[current_image] = new Image();
theImages[current_image].src = image_href + theImageNames[current_image];
imageNum[current_image] = false; // image is not ready yet.
}
// construct filenames and preload the previous two images
for (i = theStep; i >= (theStep-2); i--) {
if(i < first_image) break;
current_image = i;
theImages[current_image] = new Image();
theImages[current_image].src = image_href + theImageNames[current_image];
imageNum[current_image] = false; // image is not ready yet.
}
current_image = theStep;
imageNum[current_image] = true; // pretend it is ready.
display_current_image_EC();
}
function loop_time_OK ()
{
// This whole web page should auto-refresh itself every nnn seconds
// e.g. every 300 seconds (5 minutes).
// If we see that the loops have been running for more than nnn seconds,
// then assume that the browser has been iconised, which prevents html
// refreshes, but does not stop the loop. The loop maybe uselessly
// trying to fetch out of date images and generating a lot of 404's
// swamping the web server.
// So we stop the loop ourselves, and stop useless web traffic.
// When the browser is un-iconised, the page-refresh kicks in an restarts it.
// Usage:
// if (loop_time_OK ()) { continue looping }
// else { stop(); }
/*
now_time = new Date();
now_seconds = now_time.getTime() / 1000;
elaspsed_seconds = now_seconds - start_seconds;
if (elaspsed_seconds < loop_limit_seconds) { return 1;}
else { return 0;}
*/
return true;
}
//==> Display the 'current_image'.
function display_current_image() {
//display image onto screen
document.animation.src = theImages[current_image].src;
if(theImages.length>1) {
document.getElementById('h-value').value = current_image+1;
if(current_image <= 0) {
document.getElementById('earlier_img_div').innerHTML = "![\"Previous](\"/watl/images/symbols/earlier-0.gif\" "\\"Previous")
";
} else {
document.getElementById('earlier_img_div').innerHTML = "![\"Previous](\"/watl/images/symbols/earlier.gif\" "\\"Previous")
";
}
if(current_image >= theImages.length-1) {
document.getElementById('later_img_div').innerHTML = "![\"No](\"/watl/images/symbols/later-0.gif\" "\\"No")
";
} else {
document.getElementById('later_img_div').innerHTML = "![\"Next](\"/watl/images/symbols/later.gif\" "\\"Next")
";
}
document.forms.control_form.time.selectedIndex = current_image;
}
s.setValue(current_image+1);
}
//==> Display the 'current_image' for the EC model.
function display_current_image_EC() {
//display image onto screen
document.animation.src = theImages[current_image].src;
if(theImages.length>1) {
if(current_image <= 0) {
document.getElementById('earlier_img_div').innerHTML = "
";
} else {
document.getElementById('earlier_img_div').innerHTML = "
";
}
if(current_image >= theImages.length-1) {
document.getElementById('later_img_div').innerHTML = "
";
} else {
document.getElementById('later_img_div').innerHTML = "
";
}
document.forms.control_form.time.selectedIndex = current_image;
}
}
//==> Display the 'current_image' from the slider.
function display_current_image_from_slider(position) {
current_image = position;
//display image onto screen
if((position >= 0) && (position < nImages)) {
document.animation.src = theImages[position].src;
if(theImages.length>1) {
document.getElementById('h-value').value = position+1;
//alert(document.earlier_img.src + " ... " + document.later_img.src);
if(position <= 0) {
document.getElementById('earlier_img_div').innerHTML = "
";
} else {
document.getElementById('earlier_img_div').innerHTML = "
";
}
if(position >= theImages.length-1) {
document.getElementById('later_img_div').innerHTML = "
";
} else {
document.getElementById('later_img_div').innerHTML = "
";
}
document.forms.control_form.time.selectedIndex = position;
}
}
}
//===> Stop the animation
function stop() {
//== cancel animation (timeID holds the expression which calls the fwd or bkwd function) ==
if(looping == 1) {
clearTimeout (timeID);
}
looping = 0;
return;
}
//===> Display animation in fwd direction in either loop or sweep mode
function animate_fwd() {
if(nImages<=1) return;
current_image++; //increment image number
//== check if current image has exceeded loop bound ==
if(current_image > last_image) {
if(play_mode == 1) { //fwd loop mode - skip to first image
current_image = first_image;
}
if(play_mode == 2) { //sweep mode - change directions (go bkwd)
current_image = last_image;
animate_rev();
return;
}
}
//== check to ensure that current image has not been deselected from the loop ==
//== if it has, then find the next image that hasn't been ==
while(imageNum[current_image] == false) {
if(theImages[current_image].complete) {
imageNum[current_image] = true;
break;
}
current_image++;
if(current_image > last_image) {
if(play_mode == 1)
current_image = first_image;
if(play_mode == 2) {
current_image = last_image;
animate_rev();
return;
}
}
}
display_current_image();
delay_time = delay;
if(current_image == first_image) delay_time = start_dwell_multipler*delay;
if(current_image == last_image) delay_time = end_dwell_multipler*delay;
//== call "animate_fwd()" again after a set time (delay_time) has elapsed ==
// (Maybe stop the loops if we are iconised).
// if (loop_time_OK()) { timeID = setTimeout("animate_fwd()", delay_time); }
if(looping == 1) { timeID = setTimeout("animate_fwd()", delay_time); }
else { stop(); }
}
//===> Increment to next image
function incrementImage()
{
var number;
if(nImages<=1) return;
stop();
current_image++;
number = current_image;
//== if image is last in loop, increment to first image ==
if(number > last_image) number = first_image;
//== check to ensure that image has not been deselected from loop ==
while(imageNum[number] == false) {
if(theImages[number].complete) {
imageNum[number] = true;
break;
}
number++;
if(number > last_image) number = first_image;
}
current_image = number;
display_current_image();
}
// **********************************************************************************************
// We need a separate function for the EC images since they do not have the loop function
function incrementImageEC()
{
var number;
if(nImages<=1) return;
current_image++;
number = current_image;
if(((current_image+2) <= last_image) && (imageNum[current_image+2] == null)) {
theImages[current_image+2] = new Image();
theImages[current_image+2].src = image_href + theImageNames[current_image+2];
imageNum[current_image+2] = false; // image is not ready yet.
}
//== check to ensure that image is loaded
while(imageNum[number] == false) {
if(theImages[number].complete) {
imageNum[number] = true;
break;
}
}
display_current_image_EC();
}
//===> Decrement to next image
function decrementImage()
{
var number;
if(nImages<=1) return;
stop();
current_image--;
number = current_image;
//== if image is first in loop, decrement to last image ==
if(number < first_image) number = last_image;
//== check to ensure that image has not been deselected from loop ==
while(imageNum[number] == false) {
if(theImages[number].complete) {
imageNum[number] = true;
break;
}
number--;
if(number < first_image) number = last_image;
}
current_image = number;
display_current_image();
}
function decrementImageEC()
{
var number;
if(nImages<=1) return;
current_image--;
number = current_image;
if(((current_image-2) >= first_image) && (imageNum[current_image-2] == null)) {
theImages[current_image-2] = new Image();
theImages[current_image-2].src = image_href + theImageNames[current_image-2];
imageNum[current_image-2] = false; // image is not ready yet.
}
//== check to ensure that image is loaded
while(imageNum[number] == false) {
if(theImages[number].complete) {
imageNum[number] = true;
break;
}
}
display_current_image_EC();
}
//===> Changes playing speed by adding to or substracting from the delay between frames
function change_speed(dv)
{
delay+=dv;
//== check to ensure max and min delay constraints have not been crossed ==
if(delay > delay_max) delay = delay_max;
if(delay < delay_min) delay = delay_min;
}
//===> "Play forward"
function fwd()
{
stop();
slider_interrupt = 0;
looping = 1;
play_mode = 1;
animate_fwd();
}
//===> Change play mode (normal, loop, swing)
function change_mode(mode)
{
play_mode = mode;
}
//==> Empty function - used to deal with image buttons rather than HTML buttons
function func()
{
}