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javascript function to stop show

I modified some code I found to display a slide show and have it working exactly as I want. I have run into a problem where I cannot stop the show and clear the canvas. Here is the code to run the slideshow:

// JavaScript Document
  
var imagePaths = [
  "_sites/BBB_homepage.png",
  "_sites/CabezonKidsDental_homepage.png",
  "_sites/djer_homepage.png",
  "_sites/enchanted_homepage.png",
  "_sites/JoeSSausage_homepage.png",
  "_sites/MMCS_homepage.png",
  "_sites/mySRB.png",
  "_sites/PHCP_homepage.png",
  "_sites/smilesforkidsnm_homepage.png",
  "_sites/t2consulting_homepage.png",
  "_sites/Upward_homepage.png",
  "_sites/Webb_based_homepage.png"
];
var showCanvas = null;
var showCanvasCtx = null;
var img = document.createElement("img");
var currentImage = 0;
var revealTimer;
var stopShow = 0;
  
function slideShow() {
  if (!stopShow){
    showCanvas = document.getElementById('Canvas1');
    showCanvasCtx = showCanvas.getContext('2d');

    //clear canvas
    showCanvasCtx.clearRect(0,0,showCanvasCtx.canvas.width,showCanvasCtx.canvas.height);
  
    img.setAttribute('width','500');
    img.setAttribute('height','400');
    switchImage();
    
    //start the animation
    setInterval(switchImage,3000);
  }
}

function switchImage() {
  img.setAttribute('src',imagePaths[currentImage++]);
  if (currentImage >= imagePaths.length)
      currentImage = 0;
    
  showCanvasCtx.globalAlpha = 0.1;
  revealTimer = setInterval(revealImage,100);
}
  
function revealImage() {
  showCanvasCtx.save();
  showCanvasCtx.drawImage(img,100,0,500,400);
  showCanvasCtx.globalAlpha += 0.1;
  if (showCanvasCtx.globalAlpha >= 1.0) clearInterval(revealTimer);
  showCanvasCtx.restore();
}

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Here is the function that I wrote thinking that it would stop the slideshow:

function stopSlideShow() {
  //alert('stop show');
  clearInterval(revealTimer);
  stopShow=1;
}

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ASKER CERTIFIED SOLUTION

leakim971

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prostang

ASKER

When I launch the slideShow function, there is no fading. All images are now stacked and the alpha is set for the entire canvas to .1. It does stop the show and allows me to clear.

SOLUTION