Specifications

PHP AND MYSQL WEB DEVELOPMENT
Converting Between PHP and MySQL Date Formats ......................396
Date Calculations ................................................................................398
Using the Calendar Functions ............................................................399
Further Reading ..................................................................................400
Next ....................................................................................................400
19 Generating Images 401
Setting Up Image Support in PHP ......................................................402
Image Formats ....................................................................................403
JPEG ..............................................................................................403
PNG ..............................................................................................403
WBMP ..........................................................................................403
GIF ................................................................................................404
Creating Images ..................................................................................404
Creating a Canvas Image ..............................................................405
Drawing or Printing Text onto the Image ....................................406
Outputting the Final Graphic ........................................................408
Cleaning Up ..................................................................................410
Using Automatically Generated Images in Other Pages ....................410
Using Text and Fonts to Create Images ..............................................410
Setting Up the Base Canvas ..........................................................414
Fitting the Text onto the Button ....................................................415
Positioning the Text ......................................................................418
Writing the Text onto the Button ..................................................419
Finishing Up ..................................................................................419
Drawing Figures and Graphing Data ..................................................419
Other Image Functions ......................................................................428
Further Reading ..................................................................................428
Next ....................................................................................................428
20 Using Session Control in PHP 429
What Session Control Is ....................................................................430
Basic Session Functionality ................................................................430
What Is a Cookie? ........................................................................431
Setting Cookies from PHP ............................................................431
Using Cookies with Sessions ........................................................432
Storing the Session ID ..................................................................432
Implementing Simple Sessions ..........................................................433
Starting a Session ..........................................................................433
Registering Session Variables ........................................................433
Using Session Variables ................................................................434
Deregistering Variables and Destroying the Session ....................434
xvi
00 7842 FM 3/6/01 3:38 PM Page xvi