PHP implements barcode design code

In modern commerce, barcodes have become a necessary tool for the unique identification of goods. Choosing a barcode code generation tool that suits your business needs can improve the efficiency of product identification and avoid related problems. Among them, PHP is a widely used programming language and one of the base languages ​​for many barcode code generators. Below, we will introduce how to implement barcode design code using PHP.

1. What is a barcode?

Generally speaking, a barcode is a graphic identification with certain encoding rules, which uses a certain combination of symbols and characters to represent physical information. The purpose is to convey information, such as sales information, inventory information, digital information and item numbers, etc., in a simple and efficient way.

2. PHP generates barcodes

PHP can generate multiple types of barcodes. Therefore, developers need to understand and be familiar with the required barcode specifications to best meet business needs. The two main tools for PHP to implement barcode design are the GD library and the BCMath function library.

1. GD library

GD The library is a free graphics processing library that exists as a PHP extension. It can process images in multiple formats and Generate many types of images, such as barcodes.

First you need to determine whether the GD library is open. If not, it needs to be enabled manually. Secondly, you need to install the GD version 2.x or above library. Use the GD library to generate images in the PHP environment, which can support images in various formats such as gif, jpeg, png, wbmp, xbm, etc.

The following is the extension method to enable GD:

<?php
if (!extension_loaded('gd')) {
  if (!dl('gd.so')) {
    exit('无法加载 GD 扩展！');
  }
}
?>

2. BCMath function library

BCMath function library is a high-precision mathematics for PHP Library that supports arbitrary precision numerical calculations. Developers need to use the BCMath function library to perform numerical calculations to efficiently generate barcode module data.

The following is a sample code to configure the BCMath function library:

<?php
$barcode_text = '123456789'; // 条形码文本信息
$barcode_width = 200; // 条形码图片宽度
$barcode_height = 50; // 条形码图片高度
$barcode_ratio = 2; // 缩放比例

// 设置 BCMath 函数库精度
$bcmath_precision = 3;
if (function_exists('bcscale')) {
  @bcscale($bcmath_precision);
}
?>

The bcscale function is used in the above code, which is used to set the precision of the math function library (BCMath) . The higher the precision setting, the higher the precision of the floating point number, but the higher the memory requirements.

3. Generate EAN-13 barcode

EAN-13 is a commonly used barcode standard, which contains information such as the country of the product, manufacturer, product number, check code and other information. To generate EAN-13 barcodes in PHP, you need to follow the relevant generation rules.

The following is a sample code to generate an EAN-13 barcode:

<?php
$barcode_text = '123456789012'; // 条形码文本信息
$barcode_width = 200; // 条形码图片宽度
$barcode_height = 50; // 条形码图片高度
$barcode_ratio = 2; // 缩放比例

// 设置 BCMath 函数库精度
$bcmath_precision = 3;
if (function_exists('bcscale')) {
  @bcscale($bcmath_precision);
}

//生成 EAN-13 条形码数据
$ean13_data = $this->getEan13Data($barcode_text);
$ean13_data_length = strlen($ean13_data);
$last = $ean13_data[$ean13_data_length - 1];

// 绘制条形码
$img = imagecreatetruecolor($barcode_width, $barcode_height);
$bg_color = imagecolorallocate($img, 255, 255, 255);
imagefill($img, 0, 0, $bg_color);

$xPos = 0;
$barWidth = $barcode_width / (7 + (7 * 6) + 7);
for ($i = 0; $i < $ean13_data_length - 1; $i++) {
    if (($i == 0) || ($i == 1) || ($i == 2) || ($i == 45) || ($i == 46) || ($i == 47)) {
        $code = $this->codingMapping($ean13_data[$i], true);
        $f = 1;
        for ($j = 0; $j < 7; $j++) {
            if (substr($code, $j, 1) == "1") {
                imagefilledrectangle($img, $xPos, 0, $xPos + ($barWidth * $barcode_ratio), $barcode_height, 0);
            }
            $xPos += ($barWidth * $barcode_ratio);
        }
    } else {
        $code_b = $this->codingMapping($ean13_data[$i], false);
        for ($j = 0; $j < 6; $j++) {
            if (substr($code_b, $j, 1) == "1") {
                imagefilledrectangle($img, $xPos, 0, $xPos + ($barWidth * $barcode_ratio), $barcode_height, 0);
            }
            $xPos += ($barWidth * $barcode_ratio);
        }
    }
}

//    输出给客户端
header('content-type:image/png');
imagepng($img);
imagedestroy($img);
?>

The above code generates specific encoding rules for the EAN-13 barcode, and generates the country, manufacturer number, and product number of the product. number, check code and other information, and draw the required barcode based on this. On this basis, the image is generated through the GD library.

4. Conclusion

The key role played by barcode technology in modern business is self-evident. As for the need to implement barcode design in PHP, it is relatively simple and effective. In actual development, you should master the basic knowledge of PHP, coding rules and the use of related underlying function libraries in order to better realize the functional requirements of barcode generation.

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