[GitHub] [incubator-echarts] szkissyh edited a comment on issue #11615: IOS 一个页面切换地理坐标图时报错：TypeError:null is not an object(evaluating 'this.ctx.dpr=this.dpr')

[GitBox <gi...@apache.org>]

szkissyh edited a comment on issue #11615: IOS 一个页面切换地理坐标图时报错：TypeError:null is not an object(evaluating 'this.ctx.dpr=this.dpr')
URL: https://github.com/apache/incubator-echarts/issues/11615#issuecomment-552393085
 
 
   > 一般这种错误是 dispose 后继续使用 chart 实例造成的，@szkissyh 建议再排查一下，同时也可以整理一个可以最小复现的 demo 发给我们
   
   我发现了问题，并且可以复现，问题的核心是同样一个世界地图模型，在横屏和竖屏模式下占用的内存相差很多。
   横屏模式占用内存较少，**为18M**
   ![image](https://user-images.githubusercontent.com/31839257/68581680-d9ebfc80-04b3-11ea-899c-c0d2fb66be30.png)
   竖屏模式占用内存较多，**为49M**
   ![image](https://user-images.githubusercontent.com/31839257/68581720-f1c38080-04b3-11ea-896e-e9b8159b7d25.png)
   
   而我们操作多为竖屏操作，多次操作后出现total canvas memory use exceeds the maximum limit，超出了safari支持的最大canvas内存支持（我的为384MB）
   
   释放代码为
   var chart = echarts.getInstanceByDom(document.getElementById("container"));
   if (chart) {
   	chart.dispose();
   	chart = null;
   }
   重新初始化代码为
    var chart=echarts.getInstanceByDom(document.getElementById("container"));
   if(!chart || chart.isDisposed()) {
   	chart = echarts.init(document.getElementById("container"));
   }
   
   同样的代码，竖屏多次操作，没有任何问题。但是横屏就会报出TypeError:null is not an object(evaluating 'this.ctx.dpr=this.dpr')
   

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