PHP using the GD library to paint and generate the code picture

First of all to determine whether the php.ini settings to open the GD extension function, the test is as follows

Print_r (Gd_info ());

If there is a printout of the contents below, then the GD function is open:

Array
(
    [GD Version] => bundled (2.0.34 compatible)
    [FreeType Support] => 1
    [FreeType linkage] =& Gt With FreeType
    [T1lib Support] => 1
    [gif Read Support] => 1
    [gif Create Support] => 1
    [JPG Support ] => 1
    [PNG Support] => 1
    [WBMP Support] => 1
    [XPM Support] => 
    [XBM Support] => 1
    [jis-mapped Japanese Font Support] => 
)

GD Paint general steps as follows:

1. Create a canvas resource

2. Create a color brush

3. Drawing

4. Save picture or Output picture

5. Destroying the Memory canvas resource

The test code is as follows:

!--? php header (content-type:image/jpeg);   $width = 400;  

Wide, high $height = 400; $image = Imagecreate ($width, $height);  First step: Create a blank image $white = imagecolorallocate ($image, 0, 0, 0); 

The first call to Imagecolorallocate () fills the background color of the palette-based image, which is the image created with Imagecreate (). $green = imagecolorallocate ($image, 0, 255, 0);  Step Two: Assign color to the image imageline ($image, 0, M, $green);  Step three: Draw line Imagerectangle ($image, 100,40,300,100, $green); Draw rectangular Imagearc ($image, 0, 360, $green); Draw round imagestring ($image, MB, M, PHP is Niubi honghong!, $green);
Write String $str =abcdefghjklmnpqrstuvwxyz23456789;
$randstr = substr (Str_shuffle ($STR), 0,4); Imagestring ($image, $randstr, $green); Verification Code Imagettftext ($image, 0, N, $green, & #39;/msjhbd.  ttf& #39, Chinese vsenglish);   Chinese validation//imagejpeg ($image, & #39;/test.jpg& #39;);  Save the picture under the current path as Test.jpg imagejpeg ($image);   Fourth step: Without file name, direct output to the Web page Imagedestroy ($image); Step Fifth: Destroy, Recycle resources?--> 

The test picture is as follows:

Note: GD library powerful can draw a variety of reports (such as histogram, pie chart, etc.), thumbnails, plus watermark and stock trend chart