react-konva set a shape at the center of stage

问题

I am using react-konva for drawing shapes on a stage and to edit them I select that shape and the shape has be set to focus on stage(i.e come to the center of the stage). On the click of a button I am updating the X,Y and scale of the stage but I am not getting the shape exactly at the center of the stage.

Please see this demo and share your inputs on this:

https://codesandbox.io/s/shapecenterdemo-o9hg2?file=/src/ShapeCenterDemo.jsx

PS: Can't remove the dragBoundFunc from the stage.

回答1:

Based on your demo:

  focusRect = () => {
    let { rect, stageWidth, stageHeight } = this.state;

    let newScale = 6;
    const rectWidth = 50 * newScale;
    const rectHeight = 50 * newScale;

  

    const x =  - rect.x * newScale + stageWidth / 2 - rectWidth / 2 ;
    const y =  - rect.y * newScale + stageHeight / 2 - rectHeight / 2;


    let pos = this.boundFunc({ x, y }, newScale);

    this.setState({
      stageX: pos.x,
      stageY: pos.y,
      stageScale: newScale
    });
  };

https://codesandbox.io/s/react-konva-center-a-shape-7ttts

来源：https://stackoverflow.com/questions/62954266/react-konva-set-a-shape-at-the-center-of-stage