Canvas 光标样式——更改 HTML5 Canvas 图形上的鼠标光标

当用户将鼠标移到 HTML5 Canvas 图形上时，更改鼠标光标。Konva 可以监听各个图形上的鼠标事件，并对舞台容器应用任何 CSS 光标样式，例如 pointer、crosshair、grab、move 或自定义光标。

**操作说明：**将鼠标移到每个五边形上，查看光标变化。

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 pentagon1 = new Konva.RegularPolygon({
  x: 80,
  y: stage.height() / 2,
  sides: 5,
  radius: 30,
  fill: 'red',
  stroke: 'black',
  strokeWidth: 4,
});

pentagon1.on('mouseover', function (e) {
  e.target.getStage().container().style.cursor = 'pointer';
});
pentagon1.on('mouseout', function (e) {
  e.target.getStage().container().style.cursor = 'default';
});

const pentagon2 = new Konva.RegularPolygon({
  x: 180,
  y: stage.height() / 2,
  sides: 5,
  radius: 30,
  fill: 'green',
  stroke: 'black',
  strokeWidth: 4,
});

pentagon2.on('mouseover', function (e) {
  e.target.getStage().container().style.cursor = 'crosshair';
});
pentagon2.on('mouseout', function (e) {
  e.target.getStage().container().style.cursor = 'default';
});

const pentagon3 = new Konva.RegularPolygon({
  x: 280,
  y: stage.height() / 2,
  sides: 5,
  radius: 30,
  fill: 'blue',
  stroke: 'black',
  strokeWidth: 4,
});

pentagon3.on('mouseover', function (e) {
  e.target.getStage().container().style.cursor = 'move';
});
pentagon3.on('mouseout', function (e) {
  e.target.getStage().container().style.cursor = 'default';
});

layer.add(pentagon1);
layer.add(pentagon2);
layer.add(pentagon3);

React

import { Stage, Layer, RegularPolygon } from 'react-konva';
import { useState } from 'react';

// Separate component for polygon that changes cursor directly
const SpecialPolygon = ({ x, y }) => {
  // We use e.target approach here because this component doesn't have
  // access to the Stage's cursor state from the parent component
  const handleMouseOver = (e) => {
    e.target.getStage().container().style.cursor = 'pointer';
  };

  const handleMouseOut = (e) => {
    e.target.getStage().container().style.cursor = 'default';
  };

  return (
    <RegularPolygon
      x={x}
      y={y}
      sides={5}
      radius={30}
      fill="red"
      stroke="black"
      strokeWidth={4}
      onMouseOver={handleMouseOver}
      onMouseOut={handleMouseOut}
    />
  );
};

const App = () => {
  const [cursor, setCursor] = useState('default');

  return (
    <Stage 
      width={window.innerWidth} 
      height={window.innerHeight}
      style={{ cursor }}
    >
      <Layer>
        <SpecialPolygon
          x={80}
          y={window.innerHeight / 2}
        />
        <RegularPolygon
          x={180}
          y={window.innerHeight / 2}
          sides={5}
          radius={30}
          fill="green"
          stroke="black"
          strokeWidth={4}
          onMouseOver={() => setCursor('crosshair')}
          onMouseOut={() => setCursor('default')}
        />
        <RegularPolygon
          x={280}
          y={window.innerHeight / 2}
          sides={5}
          radius={30}
          fill="blue"
          stroke="black"
          strokeWidth={4}
          onMouseOver={() => setCursor('move')}
          onMouseOut={() => setCursor('default')}
        />
      </Layer>
    </Stage>
  );
};

export default App;

Vue

<template>
  <v-stage :config="stageSize">
    <v-layer>
      <v-regular-polygon
        v-for="(pentagon, i) in pentagons"
        :key="i"
        :config="pentagon"
        @mouseover="handleMouseOver($event, pentagon.cursor)"
        @mouseout="handleMouseOut"
      />
    </v-layer>
  </v-stage>
</template>

<script setup>
const stageSize = {
  width: window.innerWidth,
  height: window.innerHeight
};

const pentagons = [
  {
    x: 80,
    y: window.innerHeight / 2,
    sides: 5,
    radius: 30,
    fill: 'red',
    stroke: 'black',
    strokeWidth: 4,
    cursor: 'pointer'
  },
  {
    x: 180,
    y: window.innerHeight / 2,
    sides: 5,
    radius: 30,
    fill: 'green',
    stroke: 'black',
    strokeWidth: 4,
    cursor: 'crosshair'
  },
  {
    x: 280,
    y: window.innerHeight / 2,
    sides: 5,
    radius: 30,
    fill: 'blue',
    stroke: 'black',
    strokeWidth: 4,
    cursor: 'move'
  }
];

const handleMouseOver = (e, cursor) => {
  e.target.getStage().container().style.cursor = cursor;
};

const handleMouseOut = (e) => {
  e.target.getStage().container().style.cursor = 'default';
};
</script>