Responsive canvas with React and Konva

Question

I use React and Konva libraries to draw a simple line. But when i resize the screen, the line stays out of the screen. So, how can I make it responsive?

This is my code:

import React from "react";
import { Stage, Layer,Line } from 'react-konva';

class App extends React.Component {

  constructor(props) {
    super(props);
  }

  render() {
    return (
        <div>
            <Stage width={window.innerWidth} height={window.innerHeight}>
                <Layer>
                    <Line
                        x={100}
                        y={100}
                        points={[0,0,576,456,509,403,20,15,300,207,111,222,293,177]}
                        stroke="black"
                        strokeWidth={5}
                        ref="line"
                    />
                </Layer>
            </Stage>
        </div>
    );
  }
}

export default App;

This may be helpful - https://konvajs.github.io/docs/sandbox/Responsive_Canvas.html — lavrton, Apr 20 '18 at 15:35
I will suggest that you use Konva only. Because whenever a state of the react component is updated, every layer/node is re-drawn which is useless. Separate canvas from react component. — Vidit, Apr 25 '18 at 07:30

lavrton · Accepted Answer · 2018-04-23T13:05:48.127

The "responsive logic" really depends on your app and on your desired UI goals. The simplest way you can add responsive here is to use scaling:

import React from "react";
import { Stage, Layer,Line } from 'react-konva';

class App extends React.Component {

  constructor(props) {
    super(props);
  }

  render() {
    // lets think you want to make all your objects visible in
    // 700x700 scene
    const CANVAS_VIRTUAL_WIDTH = 700;
    const CANVAS_VIRTUAL_HEIGHT = 700;

    // now you may want to make it visible even on small screens
    // we can just scale it
    const scale = Math.min(
      window.innerWidth / CANVAS_VIRTUAL_WIDTH,
      window.innerHeight / CANVAS_VIRTUAL_HEIGHT
    );

    return (
        <div>
            <Stage width={window.innerWidth} height={window.innerHeight} scaleX={scale} scaleY={scale}>
                <Layer>
                    <Line
                        x={100}
                        y={100}
                        points={[0,0,576,456,509,403,20,15,300,207,111,222,293,177]}
                        stroke="black"
                        strokeWidth={5}
                        ref="line"
                    />
                </Layer>
            </Stage>
        </div>
    );
  }
}

export default App;

Responsive canvas with React and Konva

1 Answers1

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