Animate Position Tutorial

To animate a shape's position with Konva, we can create a new animation with Konva.Animation which modifies the shape's position with each animation frame.

For a full list of attributes and methods, check out the Konva.Animation documentation.

Vanilla

import Konva from 'konva';

const stage = new Konva.Stage({
container: 'container',
width: window.innerWidth,
height: window.innerHeight,
});

const layer = new Konva.Layer();
stage.add(layer);

const circle = new Konva.Circle({
x: 50,
y: window.innerHeight / 2,
radius: 30,
fill: 'red',
stroke: 'black',
strokeWidth: 4,
});
layer.add(circle);

const amplitude = 100;
const period = 2000; // in milliseconds

const anim = new Konva.Animation(function(frame) {
circle.x(
amplitude * Math.sin((frame.time * 2 * Math.PI) / period) +
window.innerWidth / 2
);
}, layer);

anim.start();

React

import { Stage, Layer, Circle } from 'react-konva';
import { useEffect, useRef } from 'react';

const App = () => {
  const circleRef = useRef(null);

  useEffect(() => {
    const amplitude = 100;
    const period = 2000; // in milliseconds

    const anim = new Konva.Animation((frame) => {
      circleRef.current.x(
        amplitude * Math.sin((frame.time * 2 * Math.PI) / period) +
        window.innerWidth / 2
      );
    }, circleRef.current.getLayer());

    anim.start();

    return () => {
      anim.stop();
    };
  }, []);

  return (
    <Stage width={window.innerWidth} height={window.innerHeight}>
      <Layer>
        <Circle
          ref={circleRef}
          x={50}
          y={window.innerHeight / 2}
          radius={30}
          fill="red"
          stroke="black"
          strokeWidth={4}
        />
      </Layer>
    </Stage>
  );
};

export default App;

Vue

<template>
  <v-stage :config="stageSize">
    <v-layer ref="layerRef">
      <v-circle
        ref="circleRef"
        :config="circleConfig"
      />
    </v-layer>
  </v-stage>
</template>

<script setup>
import { ref, onMounted, onUnmounted } from 'vue';
import Konva from 'konva';

const stageSize = {
  width: window.innerWidth,
  height: window.innerHeight
};

const circleConfig = ref({
  x: 50,
  y: window.innerHeight / 2,
  radius: 30,
  fill: 'red',
  stroke: 'black',
  strokeWidth: 4
});

const layerRef = ref(null);
const circleRef = ref(null);
let anim = null;

onMounted(() => {
  const amplitude = 100;
  const period = 2000; // in milliseconds

  anim = new Konva.Animation((frame) => {
    circleRef.value.getNode().x(
      amplitude * Math.sin((frame.time * 2 * Math.PI) / period) +
      window.innerWidth / 2
    );
  }, layerRef.value.getNode());

  anim.start();
});

onUnmounted(() => {
  if (anim) {
    anim.stop();
  }
});
</script>