mirror of
https://github.com/ialley-workshop-open/uni-halo.git
synced 2026-09-12 16:40:40 +08:00
小莫唐尼
100 lines
3.4 KiB
Markdown
100 lines
3.4 KiB
Markdown
# canvas
|
|
|
|
## Instructions
|
|
|
|
画布
|
|
|
|
属性说明
|
|
|
|
注意事项：
|
|
|
|
### Syntax
|
|
|
|
- 使用 `<canvas />`（或 `<canvas></canvas>`，当需要包裹子节点时）。
|
|
- 遇到平台差异时，建议使用条件编译（`#ifdef / #endif`）显式处理。
|
|
|
|
#### Properties
|
|
|
|
| 属性名 | 类型 | 默认值 | 说明 | 平台差异说明 |
|
|
| --- | --- | --- | --- | --- |
|
|
| type | String | | 指定 canvas 类型，支持 2d 和 webgl | 微信小程序2.7.0+ 、抖音小程序1.78.0+、支付宝小程序2.7.0+ |
|
|
| canvas-id | String | | canvas 组件的唯一标识符 | |
|
|
| disable-scroll | Boolean | false | 当在 canvas 中移动时且有绑定手势事件时，禁止屏幕滚动以及下拉刷新 | 抖音小程序与飞书小程序不支持 |
|
|
| hidpi | Boolean | true | 是否启用高清处理 | H5 (HBuilder X 3.4.0+)、App-vue (HBuilder X 3.4.0+) |
|
|
|
|
#### Events
|
|
|
|
| 事件名 | 类型 | 默认值 | 说明 | 平台差异说明 |
|
|
| --- | --- | --- | --- | --- |
|
|
| @touchstart | EventHandle | | 手指触摸动作开始 | 抖音小程序1.78.0+、小红书小程序 |
|
|
| @touchmove | EventHandle | | 手指触摸后移动 | 抖音小程序1.78.0+、小红书小程序 |
|
|
| @touchend | EventHandle | | 手指触摸动作结束 | 抖音小程序1.78.0+、小红书小程序 |
|
|
| @touchcancel | EventHandle | | 手指触摸动作被打断，如来电提醒，弹窗 | 抖音小程序1.78.0+ |
|
|
| @longtap | EventHandle | | 手指长按 500ms 之后触发，触发了长按事件后进行移动不会触发屏幕的滚动 | 抖音小程序与飞书小程序不支持 |
|
|
| @error | EventHandle | | 当发生错误时触发 error 事件，detail = {errMsg: 'something wrong'} | 抖音小程序与飞书小程序不支持 |
|
|
|
|
#### Platform Compatibility
|
|
|
|
See official docs for platform support table: `https://uniapp.dcloud.net.cn/component/canvas.html`
|
|
|
|
### Examples
|
|
|
|
### Example (Example 1)
|
|
|
|
```vue
|
|
<template>
|
|
<view>
|
|
<canvas style="width: 300px; height: 200px;" canvas-id="firstCanvas" id="firstCanvas"></canvas>
|
|
<canvas style="width: 400px; height: 500px;" canvas-id="secondCanvas" id="secondCanvas"></canvas>
|
|
<canvas style="width: 400px; height: 500px;" canvas-id="secondCanvas" id="secondCanvas" @error="canvasIdErrorCallback"></canvas>
|
|
</view>
|
|
</template>
|
|
```
|
|
|
|
### Example (Example 2)
|
|
|
|
```vue
|
|
<template>
|
|
<view>
|
|
<canvas style="width: 300px; height: 200px;" canvas-id="firstCanvas" id="firstCanvas"></canvas>
|
|
<canvas style="width: 400px; height: 500px;" canvas-id="secondCanvas" id="secondCanvas"></canvas>
|
|
<canvas style="width: 400px; height: 500px;" canvas-id="secondCanvas" id="secondCanvas" @error="canvasIdErrorCallback"></canvas>
|
|
</view>
|
|
</template>
|
|
```
|
|
|
|
### Example (Example 3)
|
|
|
|
```vue
|
|
<script>
|
|
export default {
|
|
onReady: function (e) {
|
|
var context = uni.createCanvasContext('firstCanvas')
|
|
context.setStrokeStyle("#00ff00")
|
|
context.setLineWidth(5)
|
|
context.rect(0, 0, 200, 200)
|
|
context.stroke()
|
|
context.setStrokeStyle("#ff0000")
|
|
context.setLineWidth(2)
|
|
context.moveTo(160, 100)
|
|
context.arc(100, 100, 60, 0, 2 * Math.PI, true)
|
|
context.moveTo(140, 100)
|
|
context.arc(100, 100, 40, 0, Math.PI, false)
|
|
context.moveTo(85, 80)
|
|
context.arc(80, 80, 5, 0, 2 * Math.PI, true)
|
|
context.moveTo(125, 80)
|
|
context.arc(120, 80, 5, 0, 2 * Math.PI, true)
|
|
context.stroke()
|
|
context.draw()
|
|
},
|
|
methods: {
|
|
canvasIdErrorCallback: function (e) {
|
|
console.error(e.detail.errMsg)
|
|
}
|
|
}
|
|
}
|
|
</script>
|
|
```
|
|
|
|
Reference: [Official Documentation](https://uniapp.dcloud.net.cn/component/canvas.html)
|