oCanvas 对象化 Canvas

oCanvas 可以帮助你很容易的在 HTML5 的 Canvas 标签上创建对象，并且创建这些对象的动画。支持包括 IE9 以及更新版本和其他包括 FF、Chrome、Safari 和 Opera 浏览器。

该库包含 9 部分：

1. oCanvas Object: which represents the HTML5 Canvas element itself, where everyThing will be built. 

2. Core: is the main instance which defines all other elements. 

3. Display Objects: representing the main predefined geometrical elements (lines, triANGLEs, rectangles, etc.). 

4. Background: sTores settings of object surfACE. 

5. Canvas.Timeline: facilitates the creation of loops for moving objects. 

6. Events: capturing the events that can occur with the keyboard, mouse, and touch. 

7. Scenes: We can group objects into independent "frames". 

8. ANimation: Lets you create short animations for each object. 

9. Draw: Module that allows you to clean or repaint the scenes.

示例代码：

Function createAnim() {
 
  //Block 1
  var tela = oCanvas.create({
    canvas: "#canvas",
    background: "#ccc"
  });
 
  //Block 2
  var quadrado = tela.display.rectangle({
    x: 25,
    y: 25,
    width: 20,
    height: 20, 
    fill: "#0aa",
    velocX: 4,
    velocY: 4
  });
  tela.addChild(quadrado);

  //Block 3
   
  tela.BIND("click tap", function() {
    quadrado.x = tela.mouse.x;
    quadrado.y = tela.mouse.y;
  });

  //Block 4
  tela.setLoop(function() {
    quadrado.x += quadrado.velocX;
    quadrado.y += quadrado.velocY;
    quadrado.rotation++;    
    if ((quadrado.x <= 0) || (quadrado.x >= (tela.width)))  
      quadrado.velocX = -quadrado.velocX;
    if ((quadrado.y < 20) || (quadrado.y > (tela.height - 20))) 
      quadrado.velocY = -quadrado.velocY;
  }).start();
 
}