HTML5 Canvas 拖放教程

如需使用 Konva 拖放图形，请在创建图形时将 draggable 属性设置为 true。你也可以使用 draggable() 方法。

draggable() 方法会自动为桌面应用和移动应用启用拖放功能。

如需检测 Konva 拖放事件，请使用 on() 方法将 dragstart、dragmove 或 dragend 事件绑定到节点。

on() 方法需要事件类型和回调函数。事件发生时，Konva 会运行该函数。

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: stage.width() / 2,
  y: stage.height() / 2,
  radius: 70,
  fill: 'red',
  stroke: 'black',
  strokeWidth: 4,
  draggable: true,
});

// add cursor styling
circle.on('mouseover', function () {
  document.body.style.cursor = 'pointer';
});
circle.on('mouseout', function () {
  document.body.style.cursor = 'default';
});

layer.add(circle);

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React

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

const App = () => {
  const [position, setPosition] = useState({ x: window.innerWidth / 2, y: window.innerHeight / 2 });

  return (
    <Stage width={window.innerWidth} height={window.innerHeight}>
      <Layer>
        <Circle
          x={position.x}
          y={position.y}
          radius={70}
          fill="red"
          stroke="black"
          strokeWidth={4}
          draggable
          onMouseEnter={(e) => {
            document.body.style.cursor = 'pointer';
          }}
          onMouseLeave={(e) => {
            document.body.style.cursor = 'default';
          }}
          onDragEnd={(e) => {
            setPosition({
              x: e.target.x(),
              y: e.target.y()
            });
          }}
        />
      </Layer>
    </Stage>
  );
};

export default App;

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Vue

<template>
  <v-stage :config="stageSize">
    <v-layer>
      <v-circle
        :config="circleConfig"
        @mouseenter="handleMouseEnter"
        @mouseleave="handleMouseLeave"
      />
    </v-layer>
  </v-stage>
</template>

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

const circleConfig = {
  x: window.innerWidth / 2,
  y: window.innerHeight / 2,
  radius: 70,
  fill: 'red',
  stroke: 'black',
  strokeWidth: 4,
  draggable: true
};

const handleMouseEnter = () => {
  document.body.style.cursor = 'pointer';
};

const handleMouseLeave = () => {
  document.body.style.cursor = 'default';
};
</script>

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