Wt

Added monkey patch for inspiration.

To try

1. Open https://webtoolkit.eu/widgets/trees-tables
2. Try zoom-in to ensure that devicePixelRatio is big.
3. Open console. and apply the monkey patch code.
4. Open the Graphics & Charts tab by click at the tab to avoid page reload.
5. Observe pie chart, scatter plot, and Category Chart.

  function DpiAwareCanvas(canvas) {
      var dpr = window.devicePixelRatio || 1;
      var rect = canvas.getBoundingClientRect();
      canvas.width = rect.width * dpr;
      canvas.height = rect.height * dpr;
      var ctx = canvas.__getContext('2d');
      ctx.__resetTransform();
      ctx.scale(dpr, dpr);
      canvas.style.width = rect.width + 'px';
      canvas.style.height = rect.height + 'px';
      return ctx;
    };

HTMLCanvasElement.prototype.__getContext = HTMLCanvasElement.prototype.getContext;

 HTMLCanvasElement.prototype.getContext = function(t, ...args) {

    if(t=== '2d')
    {
        return DpiAwareCanvas(this);
    }
    else
    {
        return this.__getContext(t, ...args);
    }

  }


  CanvasRenderingContext2D.prototype.__setTransform = CanvasRenderingContext2D.prototype.setTransform;


  CanvasRenderingContext2D.prototype.setTransform = function(...args) {

     console.dir(this);

     if(this.wtTransform)
     {

        console.log(this.wtTransform);
        this.wtTransform[4] =this.wtTransform[4] *(devicePixelRatio||1); 
        this.wtTransform[5] =this.wtTransform[5] *(devicePixelRatio||1); 

        this.__setTransform.apply(this, this.wtTransform);
        this.wtTransform = undefined;
        this.scale(devicePixelRatio || 1, devicePixelRatio || 1);
        return;

     }

     this.__setTransform(...args);
     this.scale(devicePixelRatio || 1, devicePixelRatio || 1);

  }



  CanvasRenderingContext2D.prototype.__resetTransform = CanvasRenderingContext2D.prototype.resetTransform;



  CanvasRenderingContext2D.prototype.resetTransform = function(...args) {


     this.resetTransform(...args);
     this.scale(devicePixelRatio || 1, devicePixelRatio || 1);

  }