onclick图标弹出图像

Question

这是我第一次问一些问题。 我是脚本和任何语言的初学者，所以我需要一些帮助。 我正在使用mr.progz的脚本来图像缩放和平移，我想如何添加png图标，但现在最近几天我有问题我怎么能当我点击该图标到窗口打开图像，像在谷歌地图。

下面的Javascript脚本

var canvas = document.getElementsByTagName('canvas')[0];
canvas.width = 800;

canvas.height = 600;

var gkhead = new Image;
var gkhead2 = new Image;

window.onload = function(){     

        var ctx = canvas.getContext('2d');
        trackTransforms(ctx);


function redraw(){

      // Clear the entire canvas
      var p1 = ctx.transformedPoint(0,0);
      var p2 = ctx.transformedPoint(canvas.width,canvas.height);
      ctx.clearRect(p1.x,p1.y,p2.x-p1.x,p2.y-p1.y);

      ctx.save();
      ctx.setTransform(1,0,0,1,0,0);
      ctx.clearRect(0,0,canvas.width,canvas.height);
      ctx.restore();

      ctx.drawImage(gkhead,0,0,800,600);
      ctx.drawImage(gkhead2,300,100,10,10);


    }
    redraw();

  var lastX=canvas.width/2, lastY=canvas.height/2;

  var dragStart,dragged;

  canvas.addEventListener('mousedown',function(evt){
      document.body.style.mozUserSelect = document.body.style.webkitUserSelect = document.body.style.userSelect = 'none';
      lastX = evt.offsetX || (evt.pageX - canvas.offsetLeft);
      lastY = evt.offsetY || (evt.pageY - canvas.offsetTop);
      dragStart = ctx.transformedPoint(lastX,lastY);
      dragged = false;
  },false);

  canvas.addEventListener('mousemove',function(evt){
      lastX = evt.offsetX || (evt.pageX - canvas.offsetLeft);
      lastY = evt.offsetY || (evt.pageY - canvas.offsetTop);
      dragged = true;
      if (dragStart){
        var pt = ctx.transformedPoint(lastX,lastY);
        ctx.translate(pt.x-dragStart.x,pt.y-dragStart.y);
        redraw();
            }
  },false);

  canvas.addEventListener('mouseup',function(evt){
      dragStart = null;
      if (!dragged) zoom(evt.shiftKey ? -1 : 1 );
  },false);

  var scaleFactor = 1.1;

  var zoom = function(clicks){
      var pt = ctx.transformedPoint(lastX,lastY);
      ctx.translate(pt.x,pt.y);
      var factor = Math.pow(scaleFactor,clicks);
      ctx.scale(factor,factor);
      ctx.translate(-pt.x,-pt.y);
      redraw();
  }

  var handleScroll = function(evt){
      var delta = evt.wheelDelta ? evt.wheelDelta/40 : evt.detail ? -evt.detail : 0;
      if (delta) zoom(delta);
      return evt.preventDefault() && false;
  };

  canvas.addEventListener('DOMMouseScroll',handleScroll,false);
  canvas.addEventListener('mousewheel',handleScroll,false);
};

gkhead.src = 'map.jpg';
gkhead2.src = 'spyglass.png';

// Adds ctx.getTransform() - returns an SVGMatrix
// Adds ctx.transformedPoint(x,y) - returns an SVGPoint
function trackTransforms(ctx){
  var svg = document.createElementNS("http://www.w3.org/2000/svg",'svg');
  var xform = svg.createSVGMatrix();
  ctx.getTransform = function(){ return xform; };

  var savedTransforms = [];
  var save = ctx.save;
  ctx.save = function(){
      savedTransforms.push(xform.translate(0,0));
      return save.call(ctx);
  };
  var restore = ctx.restore;
  ctx.restore = function(){
    xform = savedTransforms.pop();
    return restore.call(ctx);
          };

  var scale = ctx.scale;
  ctx.scale = function(sx,sy){
    xform = xform.scaleNonUniform(sx,sy);
    return scale.call(ctx,sx,sy);
          };

  var rotate = ctx.rotate;
  ctx.rotate = function(radians){
      xform = xform.rotate(radians*180/Math.PI);
      return rotate.call(ctx,radians);
  };

  var translate = ctx.translate;
  ctx.translate = function(dx,dy){
      xform = xform.translate(dx,dy);
      return translate.call(ctx,dx,dy);
  };

  var transform = ctx.transform;
  ctx.transform = function(a,b,c,d,e,f){
      var m2 = svg.createSVGMatrix();
      m2.a=a; m2.b=b; m2.c=c; m2.d=d; m2.e=e; m2.f=f;
      xform = xform.multiply(m2);
      return transform.call(ctx,a,b,c,d,e,f);
  };

  var setTransform = ctx.setTransform;
  ctx.setTransform = function(a,b,c,d,e,f){
      xform.a = a;
      xform.b = b;
      xform.c = c;
      xform.d = d;
      xform.e = e;
      xform.f = f;
      return setTransform.call(ctx,a,b,c,d,e,f);
  };

  var pt  = svg.createSVGPoint();
  ctx.transformedPoint = function(x,y){
      pt.x=x; pt.y=y;
      return pt.matrixTransform(xform.inverse());
  }
}