HTML5 Canvas 使用 globalCompositeOperation 的混合模式教程

globalCompositeOperation 文档。

使用 Konva 框架，可以通过 globalCompositeOperation 属性设置 globalCompositeOperation 或混合模式操作。

操作说明：将红色矩形拖到绿色文本上，查看 XOR 混合效果。

Vanilla

import Konva from 'konva';

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

const layer = new Konva.Layer();

const text = new Konva.Text({
  text: 'Text Shadow!',
  fontFamily: 'Calibri',
  fontSize: 40,
  x: 20,
  y: 20,
  fill: 'green',
  shadowColor: 'white',
  shadowOffset: { x: 10, y: 10 }
});
layer.add(text);

const rect = new Konva.Rect({
  x: 50,
  y: 50,
  width: 100,
  height: 100,
  fill: 'red',
  draggable: true,
  globalCompositeOperation: 'xor'
});

layer.add(rect);
stage.add(layer);

React

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

const App = () => {
  const [position, setPosition] = useState({ x: 50, y: 50 });

  return (
    <Stage width={window.innerWidth} height={window.innerHeight}>
      <Layer>
        <Text
          text="Text Shadow!"
          fontFamily="Calibri"
          fontSize={40}
          x={20}
          y={20}
          fill="green"
          shadowColor="white"
          shadowOffset={{ x: 10, y: 10 }}
        />
        <Rect
          x={position.x}
          y={position.y}
          width={100}
          height={100}
          fill="red"
          draggable={true}
          onDragEnd={(e) => {
            setPosition({ x: e.target.x(), y: e.target.y() });
          }}
          globalCompositeOperation="xor"
        />
      </Layer>
    </Stage>
  );
};

export default App;

Vue

<template>
  <v-stage :config="stageSize">
    <v-layer>
      <v-text :config="textConfig" />
      <v-rect :config="rectConfig" />
    </v-layer>
  </v-stage>
</template>

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

const textConfig = {
  text: 'Text Shadow!',
  fontFamily: 'Calibri',
  fontSize: 40,
  x: 20,
  y: 20,
  fill: 'green',
  shadowColor: 'white',
  shadowOffset: { x: 10, y: 10 }
};

const rectConfig = {
  x: 50,
  y: 50,
  width: 100,
  height: 100,
  fill: 'red',
  draggable: true,
  globalCompositeOperation: 'xor'
};
</script>