PHP implements multi-touch techniques for WeChat mini programs

With the rapid development of mobile Internet, WeChat mini programs have become the choice of more and more enterprises and individuals. However, sometimes a single gesture operation makes users feel helpless, and multi-touch technology is one of the ways to solve this problem. In this article, we will introduce how to use PHP to implement multi-touch functionality in WeChat mini programs.

1. Create Canvas

First, create a Canvas in the applet page to display the positions of multiple fingers. This can be achieved through wxml code:

<canvas canvas-id="myCanvas"></canvas>

This code will create a canvas with the id "myCanvas" in the page.

2. Enable multi-touch events

Next, define multi-touch events in the mini program page. This can be achieved using the wx.onTouchEvent() function. This function can capture different gesture events by passing different parameters. For example, we can define the onTouchMove event to capture the position of the finger sliding:

wx.onTouchMove(function(e){
    console.log(e.touches);
})

The above code will print the position information of each finger to the console.

3. Drawing finger positions

We have successfully obtained the position information of each finger, and now we need to draw them to the canvas. In the applet page, you can use the wx.createCanvasContext() function to create a canvas context. Then, draw the finger's position by calling the beginPath(), moveTo(), lineTo(), and stroke() functions of that canvas context.

var ctx = wx.createCanvasContext('myCanvas');
wx.onTouchMove(function(e){
    ctx.beginPath();
    ctx.moveTo(e.touches[0].x, e.touches[0].y);
    for(var i=1;i<e.touches.length;i++){
        ctx.lineTo(e.touches[i].x, e.touches[i].y);
    }
    ctx.stroke();
    ctx.draw();
})

The above code will connect the positions of each finger to form multiple straight lines and properly handle the position information of each finger.

4. Achieve other functions based on gestures

Multi-touch can not only be used for drawing, but also for other functions. For example: implement gesture zoom. The relative position of each finger can be calculated in the callback function of the onTouchMove event, and then the gesture scaling ratio can be calculated. Then, the scaling of the UI interface can be achieved through the scaling ratio.

PHP is a powerful programming language that can be used to implement various functions. The method of using PHP to implement multi-touch functions in small programs is simple, easy to learn, and easy to use, and can provide users with a smoother and faster interactive experience.

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