gd2我们能做什么？

图像处理：

第一：创建一个图像资源 【创建一张画布或者是打开一张现有图片】

第二：分配颜色

第三：使用图像处理函数来操作这个图片资源。【画线，画点，画饼，画矩】

第四：输出header头【告诉浏览器，这是一张图片，可选】

第五：保存图片或者输出图片

第六：销毁图像资源

输出图像的时候：

Imagepng();

Imagejpeg();

Imagegif();

Imagwbmp();

如何写字：

Imagechar

Imagecharup

Imagestring

Imagestringup  

Imagettftext

GD.php

<?php 

  

//imagecreate();  它的画布颜色较少     256种 

// 

//imagecreatetruecolor();  它的画布颜色较多    65536 

  

  

$img=imagecreatetruecolor(500,500); 

  

  

$red=imagecolorallocate($img,255,0,0); 

  

$green=imagecolorallocate($img,0,255,0); 

  

$blue=imagecolorallocate($img,0,0,255); 

  

$pink=imagecolorallocate($img,255,102,204); 

  

  

  

imagefilledrectangle($img,0,0,500,500,$pink); 

  

  

imageline($img,0,0,500,500,$green); 

  

imageline($img,500,0,0,500,$green); 

  

  

imagefilledellipse($img,250,250,200,200,$red); 

  

imagefilledrectangle($img,180,180,320,320,$blue); 

//imagecharup($img,5,300,400,'',$green); 

//imagestringup($img,5,300,400,'我愿变成童话里',$red); 

  

  

imagettftext($img,50,0,0,200,$green,'STXINWEI.TTF','拼命赚钱，美貌如花'); 

  

  

header('Content-type:image/jpeg'); 

  

imagejpeg($img,'bcdc.jpeg'); 

  

imagedestroy($img); 

  

  

?> 

imgjoin.php

<?php  

  //将两张图片合并到一起 

//imagecreatefromjpeg  

//imagecreatefrompng  

//imagecreatefromwbmp  

//imagecreatefromgif  

//  

    

$src=imagecreatefromjpeg('zxy.jpg');  

    

$dst=imagecreatefromjpeg('yz.jpg');  

    

//imagecopy($dst,$src,440,512,215,25,376,446);  

    

//imagecopymerge($dst,$src,1130,466,267,174,238,292,20);  

    

//$newImg=imagecreatetruecolor(238,292);  

    

//imagecopymerge($newImg,$src,0,0,267,174,238,292,100);  

    

imagecopyresampled($dst,$src,700,704,267,187,100,100,230,281);  

    

imagepng($dst);  

    

?>

shuiyin.php

<?php 

  

//$y 原图 

//$w  水印图 

//$tm=透明度 

//$prefix 另存为文件时的前缀名 

  

water('yz.jpg','logo.gif',1,100,'wa1_'); 

water('yz.jpg','logo.gif',2,100,'wa2_'); 

water('yz.jpg','logo.gif',3,100,'wa3_'); 

water('yz.jpg','logo.gif',4,100,'wa4_'); 

water('yz.jpg','logo.gif',5,100,'wa5_'); 

water('yz.jpg','logo.gif',6,100,'wa6_'); 

water('yz.jpg','logo.gif',7,100,'wa7_'); 

water('yz.jpg','logo.gif',8,100,'wa8_'); 

water('yz.jpg','logo.gif',9,100,'wa9_'); 

water('yz.jpg','logo.gif',0,100,'wa0_'); 

  

  

  

  

function water($y,$w,$pos=0,$tm=100,$prefix='wa_'){ 

  

    $yInfo=getinfo($y); 

    $wInfo=getinfo($w); 

  

    if(!$yRes=wnOpen($y,$yInfo['type'])){ 

        exit('文件打开失败'); 

    } 

    if(!$wRes=wnOpen($w,$wInfo['type'])){ 

  

        exit('水印文件打开失败'); 

    } 

  

      

    switch($pos){ 

        case 1: 

            $x=0; 

            $y=0; 

            break; 

        case 2: 

            $x=ceil(($yInfo['width']-$wInfo['width'])/2); 

            $y=0; 

            break; 

        case 3: 

            $x=$yInfo['width']-$wInfo['width']; 

            $y=0; 

            break; 

        case 4: 

            $x=0; 

            $y=floor(($yInfo['height']-$wInfo['height'])/2); 

            break; 

        case 5: 

            $x=ceil(($yInfo['width']-$wInfo['width'])/2); 

            $y=floor(($yInfo['height']-$wInfo['height'])/2); 

            break; 

        case 6: 

            $x=$yInfo['width']-$wInfo['width']; 

            $y=floor(($yInfo['height']-$wInfo['height'])/2); 

            break; 

        case 7: 

            $x=0; 

            $y=$yInfo['height']-$wInfo['height']; 

            break; 

        case 8: 

            $x=ceil(($yInfo['width']-$wInfo['width'])/2); 

            $y=$yInfo['height']-$wInfo['height']; 

            break; 

        case 9: 

            $x=$yInfo['width']-$wInfo['width']; 

            $y=$yInfo['height']-$wInfo['height']; 

            break; 

        case 0: 

        default: 

          

            $x=mt_rand(0,$yInfo['width']-$wInfo['width']); 

            $y=mt_rand(0,$yInfo['height']-$wInfo['height']); 

            break; 

    } 

  

    imagecopymerge($yRes,$wRes,$x,$y,0,0,$wInfo['width'],$wInfo['height'],$tm); 

  

  

    wnSave($yRes,$yInfo,$prefix); 

  

    imagedestroy($yRes); 

    imagedestroy($wRes); 

  

  

} 

  

function wnSave($res,$info,$prefix){ 

      

    $newName=$prefix.$info['name']; 

  

    switch($info['type']){ 

        case 'image/png': 

        case 'image/x-png': 

            $res=imagepng($res,$newName); 

            break; 

        case 'image/jpeg': 

        case 'image/pjpeg': 

        case 'image/jpg': 

            $res=imagejpeg($res,$newName); 

            break; 

        case 'image/gif': 

            $res=imagegif($res,$newName); 

            break; 

        case 'image/wbmp': 

            $res=imagewbmp($res,$newName); 

            break; 

        default: 

            return false; 

  

    } 

    return $res; 

  

  

} 

  

function wnOpen($path,$type){ 

  

    switch($type){ 

        case 'image/png': 

        case 'image/x-png': 

            $res=imagecreatefrompng($path); 

            break; 

        case 'image/jpeg': 

        case 'image/pjpeg': 

        case 'image/jpg': 

            $res=imagecreatefromjpeg($path); 

            break; 

        case 'image/gif': 

            $res=imagecreatefromgif($path); 

            break; 

        case 'image/wbmp': 

            $res=imagecreatefromwbmp($path); 

            break; 

        default: 

            return false; 

  

    } 

    return $res; 

  

  

} 

  

  

function getInfo($path){ 

    $data=getimagesize($path); 

  

    //info是我随意命名的一个数组变量 

    $info['width']=$data[0]; 

    $info['height']=$data[1]; 

    $info['type']=$data['mime']; 

    $info['name']=basename($path); 

  

    return $info; 

  

} 

?> 

yzm.php

<?php 

  

//width=100 

//height=60 

//type  数字，字母，数字字母混合 

  

yzm(); 

  

function yzm($width=100,$height=60,$type=3,$length=4){ 

      

    $img=imagecreatetruecolor($width,$height); 

  

    imagefilledrectangle($img,0,0,$width,$height,qColor($img)); 

  

  

    switch($type){ 

        case 1: 

            $string=join('',array_rand(range(0,9),$length)); 

            break; 

        case 2: 

            $string=join('',array_rand(array_flip(range('a','z')),$length)); 

            break; 

  

        case 3: 

        default: 

            for($i=0;$i<$length;$i++){ 

                $rand=mt_rand(0,2); 

                switch($rand){ 

                    case 0: 

                        $as=mt_rand(48,57); //0-9 

                        break; 

                    case 1: 

                        $as=mt_rand(65,90); //A-Z 

                        break; 

                    case 2: 

                        $as=mt_rand(97,122);//a-z 

                        break; 

                } 

                $string.=chr($as); 

            } 

            break; 

      

    } 

  

    //干扰元素 

    for($i=0;$i<50;$i++){ 

  

        imagesetpixel($img,mt_rand(0,$width),mt_rand(0,$height),sColor($img)); 

              

    } 

    //随机直线，随机曲线 

  

    //写字 

    for($i=0;$i<$length;$i++){ 

  

        $x=$i*floor($width/$length); 

  

        $y=mt_rand(0,$height-15); 

  

        imagechar($img,5,$x,$y,$string[$i],sColor($img)); 

  

  

    } 

  

    header('content-type:image/png'); 

  

    imagepng($img); 

  

    imagedestroy($img); 

  

    //记住啊，把字符串返回回去，以后存到session里面使用 

    return $string; 

} 

  

//浅色，供背景使用 

//值越高，颜色越浅 

function qColor($img){ 

    return imagecolorallocate($img,mt_rand(130,255),mt_rand(130,255),mt_rand(130,255)); 

  

} 

  

function sColor($img){ 

    return imagecolorallocate($img,mt_rand(0,120),mt_rand(0,120),mt_rand(0,120)); 

  

} 

  

?>