topical media & game development

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graphic-canvas-util-reflection-reflection.js / js



  
reflection.js v2.0 http://cow.neondragon.net/stuff/reflection/ Freely distributable under MIT-style license.

  
   
  /* From prototype.js */
  if (!document.myGetElementsByClassName) {
          document.myGetElementsByClassName = function(className) {
                  var children = document.getElementsByTagName('*') || document.all;
                  var elements = new Array();
            
                  for (var i = 0; i < children.length; i++) {
                          var child = children[i];
                          var classNames = child.className.split(' ');
                          for (var j = 0; j < classNames.length; j++) {
                                  if (classNames[j] == className) {
                                          elements.push(child);
                                          break;
                                  }
                          }
                  }
                  return elements;
          }
  }
  
  var Reflection = {
          defaultHeight : 0.5,
          defaultOpacity: 0.5,
          
          add: function(image, options) {
                  Reflection.remove(image);
                  
                  doptions = { "height" : Reflection.defaultHeight, "opacity" : Reflection.defaultOpacity }
                  if (options) {
                          for (var i in doptions) {
                                  if (!options[i]) {
                                          options[i] = doptions[i];
                                  }
                          }
                  } else {
                          options = doptions;
                  }
          
                  try {
                          var d = document.createElement('div');
                          var p = image;
                          
                          var classes = p.className.split(' ');
                          var newClasses = '';
                          for (j=0;j<classes.length;j++) {
                                  if (classes[j] != "reflect") {
                                          if (newClasses) {
                                                  newClasses += ' '
                                          }
                                          
                                          newClasses += classes[j];
                                  }
                          }
  
                          var reflectionHeight = Math.floor(p.height*options['height']);
                          var divHeight = Math.floor(p.height*(1+options['height']));
                          
                          var reflectionWidth = p.width;
                          
                          if (document.all && !window.opera) {
                                  /* Fix hyperlinks */
                  if(p.parentElement.tagName == 'A') {
                          var d = document.createElement('a');
                          d.href = p.parentElement.href;
                  }  
                      
                                  /* Copy original image's classes & styles to div */
                                  d.className = newClasses;
                                  p.className = 'reflected';
                                  
                                  d.style.cssText = p.style.cssText;
                                  p.style.cssText = 'vertical-align: bottom';
                          
                                  var reflection = document.createElement('img');
                                  reflection.src = p.src;
                                  reflection.style.width = reflectionWidth+'px';
                                  reflection.style.display = 'block';
                                  reflection.style.height = p.height+"px";
                                  
                                  reflection.style.marginBottom = "-"+(p.height-reflectionHeight)+'px';
                                  reflection.style.filter = 'flipv progid:DXImageTransform.Microsoft.Alpha(opacity='+(options['opacity']*100)+', style=1, finishOpacity=0, startx=0, starty=0, finishx=0, finishy='+(options['height']*100)+')';
                                  
                                  d.style.width = reflectionWidth+'px';
                                  d.style.height = divHeight+'px';
                                  p.parentNode.replaceChild(d, p);
                                  
                                  d.appendChild(p);
                                  d.appendChild(reflection);
                          } else {
                                  var canvas = document.createElement('canvas');
                                  if (canvas.getContext) {
                                          /* Copy original image's classes & styles to div */
                                          d.className = newClasses;
                                          p.className = 'reflected';
                                          
                                          d.style.cssText = p.style.cssText;
                                          p.style.cssText = 'vertical-align: bottom';
                          
                                          var context = canvas.getContext("2d");
                                  
                                          canvas.style.height = reflectionHeight+'px';
                                          canvas.style.width = reflectionWidth+'px';
                                          canvas.height = reflectionHeight;
                                          canvas.width = reflectionWidth;
                                          
                                          d.style.width = reflectionWidth+'px';
                                          d.style.height = divHeight+'px';
                                          p.parentNode.replaceChild(d, p);
                                          
                                          d.appendChild(p);
                                          d.appendChild(canvas);
                                          
                                          context.save();
                                          
                                          context.translate(0,image.height-1);
                                          context.scale(1,-1);
                                          
                                          context.drawImage(image, 0, 0, reflectionWidth, image.height);
          
                                          context.restore();
                                          
                                          context.globalCompositeOperation = "destination-out";
                                          var gradient = context.createLinearGradient(0, 0, 0, reflectionHeight);
                                          
                                          gradient.addColorStop(1, "rgba(255, 255, 255, 1.0)");
                                          gradient.addColorStop(0, "rgba(255, 255, 255, "+(1-options['opacity'])+")");
                  
                                          context.fillStyle = gradient;
                                          context.rect(0, 0, reflectionWidth, reflectionHeight*2);
                                          context.fill();
                                  }
                          }
                  } catch (e) {
              }
          },
          
          remove : function(image) {
                  if (image.className == "reflected") {
                          image.className = image.parentNode.className;
                          image.parentNode.parentNode.replaceChild(image, image.parentNode);
                  }
          }
  }
  
  function addReflections() {
          var rimages = document.myGetElementsByClassName('reflect');
          for (i=0;i<rimages.length;i++) {
                  var rheight = null;
                  var ropacity = null;
                  
                  var classes = rimages[i].className.split(' ');
                  for (j=0;j<classes.length;j++) {
                          if (classes[j].indexOf("rheight") == 0) {
                                  var rheight = classes[j].substring(7)/100;
                          } else if (classes[j].indexOf("ropacity") == 0) {
                                  var ropacity = classes[j].substring(8)/100;
                          }
                  }
                  
                  Reflection.add(rimages[i], { height: rheight, opacity : ropacity});
          }
  }
  
  var previousOnload = window.onload;
  window.onload = function () { if(previousOnload) previousOnload(); addReflections(); }
  


(C) Æliens 20/2/2008

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