How to achieve the effect of scratch card?
The idea is:
1. First determine the position and size of the winning picture or text
2. Start drawing the canvas, and match the position and size to the previous winning copy. The location remains consistent.
3. Cover the canvas with a gray mask to create the effect of the scratch card before it is scratched
The specific code is as follows
let left=0; this.data.awardCanvas.moveTo(left,0) this.data.awardCanvas.lineTo(left+400,0); this.data.awardCanvas.lineTo(left+400,150); this.data.awardCanvas.lineTo(left,150); this.data.awardCanvas.stroke() this.data.awardCanvas.setFillStyle('#ddd') this.data.awardCanvas.fill() this.data.awardCanvas.draw()
4. Start To make a scratch card action, define two triggered actions, bindtouchstart and bindtouchmove, on canvas
bindtouchstart is the first position where the finger starts to fall, and bindtouchmove is the position where the finger moves
One of the important canvas attributes is clearRect, which clears the content on the canvas
clearRect (clears the X coordinate of the position, clears the Y coordinate of the position, clears the width, clears the height)
The specific code is as follows :
this.data.awardCanvas.clearRect(x,y,15,15); this.data.awardCanvas.draw(true)
The specific code is athttps://github.com/zhaodengping/scratch-mini
Go and try it, maybe You can win the first prize~~
Recommended tutorial: "WeChat Mini Program"
The above is the detailed content of Implementation of scratch card in WeChat mini program. For more information, please follow other related articles on the PHP Chinese website!

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