1. Class libraries used
1. phpqrcode (php library)
2. qrcode.js (javascript library)
2. Use of phpqrcode
Only uses the PHP class library, that is, the generation of QR codes is operated in the background. Because you want to generate a QR code with a logo in the background, you must first upload the logo image to the server (I used webuploader here)
How to use phpqrcode:
First download phpqrcode: http://phpqrcode.sourceforge.net/
Then remember to introduce the phpqrcode.php file before using it
$value = $url;//二维码内容 $errorCorrectionLevel = 'L';//设置容错级别 $matrixPointSize = $size;//生成图片大小 QRcode::png($value, 'public_files'.DIRECTORY_SEPARATOR .'code'.DIRECTORY_SEPARATOR .'qrcode.png', $errorCorrectionLevel, $matrixPointSize, 2);//生成二维码图片 无logo $logo = $tar_path;//上传至服务器的logo图片 $QR = 'public_files'.DIRECTORY_SEPARATOR .'code'.DIRECTORY_SEPARATOR .'qrcode.png';//已经生成的原始二维码图 if ($logo !== FALSE) { $QR = imagecreatefromstring(file_get_contents($QR)); $logo = imagecreatefromstring(file_get_contents($logo)); $QR_width = imagesx($QR);//二维码图片宽度 $QR_height = imagesy($QR);//二维码图片高度 $logo_width = imagesx($logo);//logo图片宽度 $logo_height = imagesy($logo);//logo图片高度 $logo_qr_width = $QR_width / 5; $scale = $logo_width/$logo_qr_width; $logo_qr_height = $logo_height/$scale; $from_width = ($QR_width - $logo_qr_width) / 2; imagecopyresampled($QR, $logo, $from_width, $from_width, 0, 0, $logo_qr_width, $logo_qr_height, $logo_width, $logo_height);}$name = time(); imagepng($QR, 'public_files'.DIRECTORY_SEPARATOR .'code'.DIRECTORY_SEPARATOR .$name.'.png');//输出带logo的二维码图片
3. Use of qrcode.js
Use qrcode.js To directly generate a QR code on the front end, you first need to download jquery.qrcode.js
The use of qrcode is also very simple:
var length = size*80;//设置二维码大小 length = parseInt(length); $("#code_img").qrcode({ //code_img是一个img标签的id render : "canvas", //设置渲染方式,有table和canvas,使用canvas方式渲染性能相对来说比较好 text : url, //扫描二维码后显示的内容,可以直接填一个网址,扫描二维码后自动跳向该链接 width : length, //二维码的宽度 height : length, background : "#ffffff", //二维码的后景色 foreground : "#000000", //二维码的前景色 src: $('#image').attr('src') //二维码中间的图片});
Introduce jquery.qrcode.js and then write this js code yourself , after execution, the QR code can be displayed and processed.
is mainly the logo reference format in the middle of the QR code. Generally, there are two formats for taking local pictures: one is the local URL, and the other is to convert the picture. Into base64 format
At first I tried the local URL format to reference images, but found that I could only reference images in the same directory as the js file, so the local URL format was not supported, so I adopted the latter method. .
Use
<input accept="image/*" type="file" id="file_input">
to upload and select local images, and then take their base64 format
var input = document.getElementById("file_input"); if(typeof FileReader==='undefined'){ input.setAttribute('disabled','disabled');}else{ input.addEventListener('change',readFile,false);} function readFile(){ var file = this.files[0]; if(!/image\/\w+/.test(file.type)){ alert("文件必须为图片!"); return false; } var reader = new FileReader(); reader.readAsDataURL(file); reader.onload = function(e){ $('#image').attr('src',this.result);//image为img标签的id }}
Read the file as a string of Data URL strings, and convert the small file Read the page directly into the URL address in a special format. This special format is base64
3. Comparison between two class libraries
Two class libraries, one operates in the background and the other operates directly in the front end.
phpqrcode generates QR codes and operates in the background, and the generated images are saved on the server. Generally, the generated QR code is saved directly to the local and then used directly. It is rare to go to the server to obtain it for a second time. Therefore, using phpqrcode will cause the accumulation of images in the server, taking up unnecessary space, and deleting it will also cost extra money. overhead. So using phpqrcode is not suitable for this QR code generation tool. Moreover, uploading images will also generate extra overhead.
qrcode.js operates directly on the front end. The uploaded images are directly saved in the browser, and the QR code is generated directly on the front end without any background interference, which reduces unnecessary costs. The necessary overhead will not cause the accumulation of images on the server and occupy unnecessary space.
The above is the summary of the (advanced) PHP method of generating QR codes with logos. For more related content, please pay attention to the PHP Chinese website (www.php.cn)!

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。


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