WeChat's small program API drawing uses setGlobalAlpha to set global brush transparency
May 19, 2021 WeChat Mini Program Development Document
Table of contents
Drawing interfaces and methods
canvasContext.setGlobalAlpha
Defined
Set global brush transparency.
Parameters
| Parameters | Type | Range | Description |
|---|---|---|---|
| alpha | Number | 0~1 | Transparency, 0 for full transparency, and 1 for total opacity |
Example
const ctx = wx.createCanvasContext('myCanvas')
ctx.setFillStyle('red')
ctx.fillRect(10, 10, 150, 100)
ctx.setGlobalAlpha(0.2)
ctx.setFillStyle('blue')
ctx.fillRect(50, 50, 150, 100)
ctx.setFillStyle('yellow')
ctx.fillRect(100, 100, 150, 100)
ctx.draw()
