KineticJS Canvas - 从中心点缩放组-前端问题

KineticJS Canvas - Scale group from center point(KineticJS Canvas - 从中心点缩放组)

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问题描述

我想扩展我的组(图像和其他内容).

group.setScale(zoom, zoom);

<!DOCTYPE HTML><html><头></头><身体><button id="larger">更大的</button><div id="container"></div><script src="http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v4.4.0.min.js"></script><script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script><脚本>$(函数(){var stage = new Kinetic.Stage({容器:'容器'，宽度:400，身高:400});var layer = new Kinetic.Layer();//一定要设置宽高//他们是这个方法工作所必需的var group = new Kinetic.Group({×:100，y: 100,宽度:100，高度:100});//存储原始组中心//这样我们就可以将组居中group.cx=group.getX()+group.getWidth()/2;group.cy=group.getY()+group.getHeight()/2;//自定义缩放功能//缩放组并使结果居中group.scale=function(x,y){group.setScale(x,y);group.setPosition(group.cx-group.getWidth()/2*group.getScale().x,group.cy-group.getHeight()/2*group.getScale().y);group.draw();}var box1 = new Kinetic.Rect({x: 0,y: 0,宽度:50，身高:50，填充:蓝色"，中风:'黑色'，行程宽度:4});group.add(box1);var box2 = new Kinetic.Rect({×:50，y: 50,宽度:50，身高:50，填写:绿色"，中风:'黑色'，行程宽度:4});group.add(box2);层.添加(组)；阶段.添加(层)；变比例因子=1；$("#larger").click(function(){比例因子+=0.10；group.scale(scaleFactor,scaleFactor);控制台.log(比例因子)；});});</脚本></身体></html>

I want to scale my group (image and something).

group.setScale(zoom, zoom);

http://jsfiddle.net/K8nK3/

But when i scale my group, I think it's not scale from center of my group. i think it like this

I want it scale from center like

I try more but it's not success. How can i do that, thanks.

解决方案

[Edited to better fit questioner's needs]

Here’s how to scale a Kinetic group from the centerpoint

First we store the centerX and centerY of the original group so we can keep the group centered there:

      group.cx=group.getX()+group.getWidth()/2;
      group.cy=group.getY()+group.getHeight()/2;

Then we write a custom scaling method that both scales the group and re-centers it:

      group.scale=function(x,y){
          group.setScale(x,y);
          group.setPosition(
              group.cx-group.getWidth()/2*group.getScale().x,
              group.cy-group.getHeight()/2*group.getScale().y);
          group.draw();
      }

Here’s code and a Fiddle: http://jsfiddle.net/m1erickson/dVGGz/

<!DOCTYPE HTML>
<html>
  <head></head>
  <body>
    <button id="larger">Larger</button>
    <div id="container"></div>
    <script src="http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v4.4.0.min.js"></script>
    <script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
    <script>
    $(function(){
      var stage = new Kinetic.Stage({
        container: 'container',
        width: 400,
        height: 400
      });
      var layer = new Kinetic.Layer();

      // Be sure to set width and height
      // They are required for this method to work
      var group = new Kinetic.Group({
        x: 100,
        y: 100,
        width:100,
        height:100
      });
      // store the original group center
      // so we can center the group there
      group.cx=group.getX()+group.getWidth()/2;
      group.cy=group.getY()+group.getHeight()/2;
      // custom scale function to both
      // scale the group and center the results
      group.scale=function(x,y){
          group.setScale(x,y);
          group.setPosition(
              group.cx-group.getWidth()/2*group.getScale().x,
              group.cy-group.getHeight()/2*group.getScale().y);
          group.draw();
      }

      var box1 = new Kinetic.Rect({
        x: 0,
        y: 0,
        width: 50,
        height: 50,
        fill: "blue",
        stroke: 'black',
        strokeWidth: 4
      });
      group.add(box1);

      var box2 = new Kinetic.Rect({
        x: 50,
        y: 50,
        width: 50,
        height: 50,
        fill: "green",
        stroke: 'black',
        strokeWidth: 4
      });
      group.add(box2);

      layer.add(group);
      stage.add(layer);

      var scaleFactor=1;
      $("#larger").click(function(){
          scaleFactor+=0.10;
          group.scale(scaleFactor,scaleFactor);
          console.log(scaleFactor);
      });

});

    </script>
  </body>
</html>

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