HTML5 canvas 线条教程

使用 Konva 创建线条形状时，可以实例化一个 Konva.Line() 对象。线条可以通过不同配置创建各种形状，如简单线条、样条曲线、blob 和多边形。

欲查看完整属性和方法列表，请参考 Line API 参考。

简单线条

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 redLine = new Konva.Line({
  points: [5, 70, 140, 23, 250, 60, 300, 20],
  stroke: 'red',
  strokeWidth: 15,
  lineCap: 'round',
  lineJoin: 'round'
});

// 虚线
const greenLine = new Konva.Line({
  points: [5, 70, 140, 23, 250, 60, 300, 20],
  stroke: 'green',
  strokeWidth: 2,
  lineJoin: 'round',
  dash: [33, 10]
});

greenLine.y(50);
layer.add(redLine, greenLine);

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React

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

const App = () => {
  return (
    <Stage width={window.innerWidth} height={window.innerHeight}>
      <Layer>
        <Line
          points={[5, 70, 140, 23, 250, 60, 300, 20]}
          stroke="red"
          strokeWidth={15}
          lineCap="round"
          lineJoin="round"
        />
        <Line
          points={[5, 70, 140, 23, 250, 60, 300, 20]}
          stroke="green"
          strokeWidth={2}
          lineJoin="round"
          dash={[33, 10]}
          y={50}
        />
      </Layer>
    </Stage>
  );
};

export default App;

Open Sandbox

Vue

<template>
  <v-stage :config="stageSize">
    <v-layer>
      <v-line :config="redLineConfig" />
      <v-line :config="greenLineConfig" />
    </v-layer>
  </v-stage>
</template>

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

const redLineConfig = {
  points: [5, 70, 140, 23, 250, 60, 300, 20],
  stroke: 'red',
  strokeWidth: 15,
  lineCap: 'round',
  lineJoin: 'round'
};

const greenLineConfig = {
  points: [5, 70, 140, 23, 250, 60, 300, 20],
  stroke: 'green',
  strokeWidth: 2,
  lineJoin: 'round',
  dash: [33, 10],
  y: 50
};
</script>

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样条曲线（弯曲线条）

要创建弯曲的线条，添加 tension 属性：

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 line = new Konva.Line({
  points: [5, 70, 140, 23, 250, 60, 300, 20],
  stroke: 'red',
  strokeWidth: 15,
  lineCap: 'round',
  lineJoin: 'round',
  tension: 1
});

layer.add(line);

Open Sandbox

React

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

const App = () => {
  return (
    <Stage width={window.innerWidth} height={window.innerHeight}>
      <Layer>
        <Line
          points={[5, 70, 140, 23, 250, 60, 300, 20]}
          stroke="red"
          strokeWidth={15}
          lineCap="round"
          lineJoin="round"
          tension={1}
        />
      </Layer>
    </Stage>
  );
};

export default App;

Open Sandbox

Vue

<template>
  <v-stage :config="stageSize">
    <v-layer>
      <v-line :config="lineConfig" />
    </v-layer>
  </v-stage>
</template>

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

const lineConfig = {
  points: [5, 70, 140, 23, 250, 60, 300, 20],
  stroke: 'red',
  strokeWidth: 15,
  lineCap: 'round',
  lineJoin: 'round',
  tension: 1
};
</script>

Open Sandbox

多边形

要创建多边形，将 closed 属性设置为 true：

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 polygon = new Konva.Line({
  points: [73, 192, 73, 160, 340, 23, 500, 109, 499, 139, 342, 93],
  fill: '#00D2FF',
  stroke: 'black',
  strokeWidth: 5,
  closed: true
});

layer.add(polygon);

Open Sandbox

React

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

const App = () => {
  return (
    <Stage width={window.innerWidth} height={window.innerHeight}>
      <Layer>
        <Line
          points={[73, 192, 73, 160, 340, 23, 500, 109, 499, 139, 342, 93]}
          fill="#00D2FF"
          stroke="black"
          strokeWidth={5}
          closed
        />
      </Layer>
    </Stage>
  );
};

export default App;

Open Sandbox

Vue

<template>
  <v-stage :config="stageSize">
    <v-layer>
      <v-line :config="polygonConfig" />
    </v-layer>
  </v-stage>
</template>

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

const polygonConfig = {
  points: [73, 192, 73, 160, 340, 23, 500, 109, 499, 139, 342, 93],
  fill: '#00D2FF',
  stroke: 'black',
  strokeWidth: 5,
  closed: true
};
</script>

Open Sandbox

Blob（流体形状）

要创建 blob，结合使用 closed 和 tension 属性：

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 blob = new Konva.Line({
  points: [23, 20, 23, 160, 70, 93, 150, 109, 290, 139, 270, 93],
  fill: '#00D2FF',
  stroke: 'black',
  strokeWidth: 5,
  closed: true,
  tension: 0.3
});

layer.add(blob);

Open Sandbox

React

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

const App = () => {
  return (
    <Stage width={window.innerWidth} height={window.innerHeight}>
      <Layer>
        <Line
          points={[23, 20, 23, 160, 70, 93, 150, 109, 290, 139, 270, 93]}
          fill="#00D2FF"
          stroke="black"
          strokeWidth={5}
          closed
          tension={0.3}
        />
      </Layer>
    </Stage>
  );
};

export default App;

Open Sandbox

Vue

<template>
  <v-stage :config="stageSize">
    <v-layer>
      <v-line :config="blobConfig" />
    </v-layer>
  </v-stage>
</template>

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

const blobConfig = {
  points: [23, 20, 23, 160, 70, 93, 150, 109, 290, 139, 270, 93],
  fill: '#00D2FF',
  stroke: 'black',
  strokeWidth: 5,
  closed: true,
  tension: 0.3
};
</script>

Open Sandbox