How to use PHP to call the camera for QR code scanning-PHP Tutorial-php.cn

How to use PHP to call the camera for QR code scanning

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Release： 2023-07-30 12:54:01

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How to use PHP to call the camera to scan QR codes

Camera scanning QR codes is becoming more and more common in modern applications, and can provide convenient and fast information transmission and interaction methods. In the web application, we can use PHP to call the camera to scan the QR code, and use the scanned information for subsequent processing and display. This article will introduce how to use PHP to call the camera for QR code scanning, and provide corresponding code examples.

Preparation
Before starting, we need to configure the corresponding extension libraries and functions for the PHP environment. First, make sure your PHP version is 5.2.0 or above, because I will use the ZBar extension library of PHP 5.2 or above to implement the QR code scanning function. Secondly, you need to install the ZBar extension library and enable the corresponding extension in php.ini. For specific installation steps, please refer to the ZBar official website.

Implementation process
The following is a simple sample code that shows how to use PHP to call the camera for QR code scanning.

<!DOCTYPE html>
<html>
<head>
    <title>PHP调用摄像头进行二维码扫描</title>
    <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
    <style>
        #preview {
            width: 320px;
            height: 240px;
            border: 1px solid black;
            margin: 0 auto;
        }
    </style>
</head>
<body>
    <div id="preview"></div>

    <script>
        window.onload = function() {
            // 调用摄像头
            navigator.mediaDevices.getUserMedia({ video: { facingMode: "environment" } })
            .then(function (stream) {
                // 将视频流渲染到页面上
                var video = document.createElement("video");
                video.srcObject = stream;
                video.play();
                document.getElementById("preview").appendChild(video);

                // 定时扫描二维码
                setInterval(function() {
                    // 创建画布对象
                    var canvas = document.createElement("canvas");
                    canvas.width = video.videoWidth;
                    canvas.height = video.videoHeight;
                    var ctx = canvas.getContext("2d");
                    ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
                    // 获取二维码扫描结果
                    var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);                
                    var code = jsQR(imageData.data, canvas.width, canvas.height);
                    if (code) {
                        alert("扫描结果: " + code.data);
                    }
                }, 1000);
            })
            .catch(function (error) {
                console.error("摄像头调用失败:", error);
            });
        };
    </script>
</body>
</html>

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Code Analysis
The above code dynamically creates a video element for rendering the video stream of the camera. Then use the canvas element to intercept the picture of the video stream and convert it into an ImageData object. By calling the jsQR(imageData.data, canvas.width, canvas.height) function of the jsQR library, we can obtain the results of the QR code scan.

It should be noted that since the getUserMedia method returns a Promise object, we use .then and .catch to handle the success and failure callback functions respectively.

Conclusion
By using PHP to call the camera for QR code scanning, we can implement fast and convenient QR code scanning function in web applications. I hope this article will help you understand and practice it, and improve your application development skills.

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