PHP generate barcode implementation program_PHP tutorial
Barcode is a graphical identifier that expresses a set of information by arranging multiple black bars and blanks of varying widths according to certain encoding rules. A common barcode is a pattern consisting of black bars (referred to as bars) and white bars (referred to as spaces) with very different reflectivities arranged in parallel lines. After having a general understanding of the above, we can re-integrate the code below to make it more convenient to use. it.
代码如下 | 复制代码 |
function UPCAbarcode($code) { $lw = 2; $hi = 100; $Lencode = array('0001101','0011001','0010011','0111101','0100011', '0110001','0101111','0111011','0110111','0001011'); $Rencode = array('1110010','1100110','1101100','1000010','1011100', '1001110','1010000','1000100','1001000','1110100'); $ends = '101'; $center = '01010'; /* UPC-A Must be 11 digits, we compute the checksum. */ if ( strlen($code) != 11 ) { die("UPC-A Must be 11 digits."); } /* Compute the EAN-13 Checksum digit */ $ncode = '0'.$code; $even = 0; $odd = 0; for ($x=0;$x { if ($x % 2) { $odd += $ncode[$x]; } else { $even += $ncode[$x]; } } $code.=(10 - (($odd * 3 + $even) % 10)) % 10; /* Create the bar encoding using a binary string */ $bars=$ends; $bars.=$Lencode[$code[0]]; for($x=1;$x { $bars.=$Lencode[$code[$x]]; } $bars.=$center; for($x=6;$x { $bars.=$Rencode[$code[$x]]; } $bars.=$ends; /* Generate the Barcode Image */ $img = ImageCreate($lw*95+30,$hi+30); $fg = ImageColorAllocate($img, 0, 0, 0); $bg = ImageColorAllocate($img, 255, 255, 255); ImageFilledRectangle($img, 0, 0, $lw*95+30, $hi+30, $bg); $shift=10; for ($x=0;$x if (($x=45 && $x=85)) { $sh=10; } else { $sh=0; } if ($bars[$x] == '1') { $color = $fg; } else { $color = $bg; } ImageFilledRectangle($img, ($x*$lw)+15,5,($x+1)*$lw+14,$hi+5+$sh,$color); } /* Add the Human Readable Label */ ImageString($img,4,5,$hi-5,$code[0],$fg); for ($x=0;$x { ImageString($img,5,$lw*(13+$x*6)+15,$hi+5,$code[$x+1],$fg); ImageString($img,5,$lw*(53+$x*6)+15,$hi+5,$code[$x+6],$fg); } ImageString($img,4,$lw*95+17,$hi-5,$code[11],$fg); /* Output the Header and Content. */ header("Content-Type: image/png"); ImagePNG($img); } UPCAbarcode('13322483157'); ?> |

PHPsessionscanstorestrings,numbers,arrays,andobjects.1.Strings:textdatalikeusernames.2.Numbers:integersorfloatsforcounters.3.Arrays:listslikeshoppingcarts.4.Objects:complexstructuresthatareserialized.

TostartaPHPsession,usesession_start()atthescript'sbeginning.1)Placeitbeforeanyoutputtosetthesessioncookie.2)Usesessionsforuserdatalikeloginstatusorshoppingcarts.3)RegeneratesessionIDstopreventfixationattacks.4)Considerusingadatabaseforsessionstoragei

Session regeneration refers to generating a new session ID and invalidating the old ID when the user performs sensitive operations in case of session fixed attacks. The implementation steps include: 1. Detect sensitive operations, 2. Generate new session ID, 3. Destroy old session ID, 4. Update user-side session information.

PHP sessions have a significant impact on application performance. Optimization methods include: 1. Use a database to store session data to improve response speed; 2. Reduce the use of session data and only store necessary information; 3. Use a non-blocking session processor to improve concurrency capabilities; 4. Adjust the session expiration time to balance user experience and server burden; 5. Use persistent sessions to reduce the number of data read and write times.

PHPsessionsareserver-side,whilecookiesareclient-side.1)Sessionsstoredataontheserver,aremoresecure,andhandlelargerdata.2)Cookiesstoredataontheclient,arelesssecure,andlimitedinsize.Usesessionsforsensitivedataandcookiesfornon-sensitive,client-sidedata.

PHPidentifiesauser'ssessionusingsessioncookiesandsessionIDs.1)Whensession_start()iscalled,PHPgeneratesauniquesessionIDstoredinacookienamedPHPSESSIDontheuser'sbrowser.2)ThisIDallowsPHPtoretrievesessiondatafromtheserver.

The security of PHP sessions can be achieved through the following measures: 1. Use session_regenerate_id() to regenerate the session ID when the user logs in or is an important operation. 2. Encrypt the transmission session ID through the HTTPS protocol. 3. Use session_save_path() to specify the secure directory to store session data and set permissions correctly.

PHPsessionfilesarestoredinthedirectoryspecifiedbysession.save_path,typically/tmponUnix-likesystemsorC:\Windows\TemponWindows.Tocustomizethis:1)Usesession_save_path()tosetacustomdirectory,ensuringit'swritable;2)Verifythecustomdirectoryexistsandiswrita


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SublimeText3 Linux new version
SublimeText3 Linux latest version

SublimeText3 Chinese version
Chinese version, very easy to use

Dreamweaver CS6
Visual web development tools

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

WebStorm Mac version
Useful JavaScript development tools
