PHP给图片增加水印得类

<?php
/*
+--------------------------------------------------------------------------
| 生成加水印的图片类 (支持水印为图片或者文字)
| ============================
| by JackMing （感谢Dash和其他不知道姓名的朋友支持，本类在这些朋友作品的基础上创建)
+--------------------------------------------------------------------------
*/

Class Gimage{
var $src_image_name = ""; //输入图片的文件名(必须包含路径名)
var $jpeg_quality = 90; //jpeg图片质量
var $save_image_file = ''; //输出文件名
var $wm_image_name = ""; //水印图片的文件名(必须包含路径名)
var $wm_image_pos = 1; //水印图片放置的位置
// 0 = middle
// 1 = top left
// 2 = top right
// 3 = bottom right
// 4 = bottom left
// 5 = top middle
// 6 = middle right
// 7 = bottom middle
// 8 = middle left
//other = 3
var $wm_image_transition = 20; //水印图片与原图片的融合度 (1=100)

var $wm_text = ""; //水印文字(支持中英文以及带有\r\n的跨行文字)
var $wm_text_size = 20; //水印文字大小
var $wm_text_angle = 4; //水印文字角度,这个值尽量不要更改
var $wm_text_pos = 3; //水印文字放置位置
var $wm_text_font = ""; //水印文字的字体
var $wm_text_color = "#cccccc"; //水印字体的颜色值

function create($filename="")
{
if ($filename) $this->src_image_name = strtolower(trim($filename));

$src_image_type = $this->get_type($this->src_image_name);
$src_image = $this->createImage($src_image_type,$this->src_image_name);
if (!$src_image) return;
$src_image_w=ImageSX($src_image);
$src_image_h=ImageSY($src_image);


if ($this->wm_image_name){
$this->wm_image_name = strtolower(trim($this->wm_image_name));
$wm_image_type = $this->get_type($this->wm_image_name);
$wm_image = $this->createImage($wm_image_type,$this->wm_image_name);
$wm_image_w=ImageSX($wm_image);
$wm_image_h=ImageSY($wm_image);
$temp_wm_image = $this->getPos($src_image_w,$src_image_h,$this->wm_image_pos,$wm_image);
$wm_image_x = $temp_wm_image["dest_x"];
$wm_image_y = $temp_wm_image["dest_y"];
imageCopyMerge($src_image, $wm_image,$wm_image_x,$wm_image_y,0,0,$wm_image_w,$wm_image_h,$this->wm_image_transition);
}

if ($this->wm_text){
$this->wm_text = $this->gb2utf8($this->wm_text);
$temp_wm_text = $this->getPos($src_image_w,$src_image_h,$this->wm_text_pos);
$wm_text_x = $temp_wm_text["dest_x"];
$wm_text_y = $temp_wm_text["dest_y"];
if(preg_match("/([a-f0-9][a-f0-9])([a-f0-9][a-f0-9])([a-f0-9][a-f0-9])/i", $this->wm_text_color, $color))
{
$red = hexdec($color[1]);
$green = hexdec($color[2]);
$blue = hexdec($color[3]);
$wm_text_color = imagecolorallocate($src_image, $red,$green,$blue);
}else{
$wm_text_color = imagecolorallocate($src_image, 255,255,255);
}

imagettftext($src_image, $this->wm_text_size, $this->wm_angle, $wm_text_x, $wm_text_y, $wm_text_color,$this->wm_text_font,$this->wm_text);
}

if ($this->save_file)
{
switch ($this->output_type){
case 'gif':$src_img=ImagePNG($src_image, $this->save_file); break;
case 'jpeg':$src_img=ImageJPEG($src_image, $this->save_file, $this->jpeg_quality); break;
case 'png':$src_img=ImagePNG($src_image, $this->save_file); break;
default:$src_img=ImageJPEG($src_image, $this->save_file, $this->jpeg_quality); break;
}
}
else
{
if ($src_image_type = "jpg") $src_image_type="jpeg";
header("Content-type: image/{$src_image_type}");
switch ($src_image_type){
case 'gif':$src_img=ImagePNG($src_image); break;
case 'jpg':$src_img=ImageJPEG($src_image, "", $this->jpeg_quality);break;
case 'png':$src_img=ImagePNG($src_image);break;
default:$src_img=ImageJPEG($src_image, "", $this->jpeg_quality);break;
}
}
imagedestroy($src_image);
}

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
/*
createImage 根据文件名和类型创建图片
内部函数

$type: 图片的类型，包括gif,jpg,png
$img_name:图片文件名，包括路径名，例如 " ./mouse.jpg"
*/
function createImage($type,$img_name){
if (!$type){
$type = $this->get_type($img_name);
}

switch ($type){
case 'gif':
if (function_exists('imagecreatefromgif'))
$tmp_img=@ImageCreateFromGIF($img_name);
break;
case 'jpg':
$tmp_img=ImageCreateFromJPEG($img_name);
break;
case 'png':
$tmp_img=ImageCreateFromPNG($img_name);
break;
default:
$tmp_img=ImageCreateFromString($img_name);
break;
}
return $tmp_img;
}

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
getPos 根据源图像的长、宽，位置代码，水印图片id来生成把水印放置到源图像中的位置
内部函数

$sourcefile_width: 源图像的宽
$sourcefile_height: 原图像的高
$pos: 位置代码
// 0 = middle
// 1 = top left
// 2 = top right
// 3 = bottom right
// 4 = bottom left
// 5 = top middle
// 6 = middle right
// 7 = bottom middle
// 8 = middle left
$wm_image: 水印图片ID
*/
function getPos($sourcefile_width,$sourcefile_height,$pos,$wm_image=""){
if($wm_image){
$insertfile_width = ImageSx($wm_image);
$insertfile_height = ImageSy($wm_image);
}else {
$lineCount = explode("\r\n",$this->wm_text);
$fontSize = imagettfbbox($this->wm_text_size,$this->wm_text_angle,$this->wm_text_font,$this->wm_text);
$insertfile_width = $fontSize[2] - $fontSize[0];
$insertfile_height = count($lineCount)*($fontSize[1] - $fontSize[3]);
}

switch ($pos){
case 0:
$dest_x = ( $sourcefile_width / 2 ) - ( $insertfile_width / 2 );
$dest_y = ( $sourcefile_height / 2 ) - ( $insertfile_height / 2 );
break;

case 1:
$dest_x = 0;
if ($this->wm_text){
$dest_y = $insertfile_height;
}else{
$dest_y = 0;
}
break;

case 2:
$dest_x = $sourcefile_width - $insertfile_width;
if ($this->wm_text){
$dest_y = $insertfile_height;
}else{
$dest_y = 0;
}
break;

case 3:
$dest_x = $sourcefile_width - $insertfile_width;
$dest_y = $sourcefile_height - $insertfile_height;
break;

case 4:
$dest_x = 0;
$dest_y = $sourcefile_height - $insertfile_height;
break;

case 5:
$dest_x = ( ( $sourcefile_width - $insertfile_width ) / 2 );
if ($this->wm_text){
$dest_y = $insertfile_height;
}else{
$dest_y = 0;
}
break;

case 6:
$dest_x = $sourcefile_width - $insertfile_width;
$dest_y = ( $sourcefile_height / 2 ) - ( $insertfile_height / 2 );
break;

case 7:
$dest_x = ( ( $sourcefile_width - $insertfile_width ) / 2 );
$dest_y = $sourcefile_height - $insertfile_height;
break;

case 8:
$dest_x = 0;
$dest_y = ( $sourcefile_height / 2 ) - ( $insertfile_height / 2 );
break;

default:
$dest_x = $sourcefile_width - $insertfile_width;
$dest_y = $sourcefile_height - $insertfile_height;
break;
}
return array("dest_x"=>$dest_x,"dest_y"=>$dest_y);
}

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
gb2utf8 指定的文字转换为UTF-8格式，包括中英文混合
内部函数
*/
function gb2utf8($gb)
{
if(!trim($gb))
return $gb;
$filename="./gb2312.txt";
$tmp=file($filename);
$codetable=array();
while(list($key,$value)=each($tmp))
$codetable[hexdec(substr($value,0,6))]=substr($value,7,6);

$utf8="";
while($gb)
{
if (ord(substr($gb,0,1))>127)
{
$tthis=substr($gb,0,2);
$gb=substr($gb,2,strlen($gb)-2);
$utf8.=$this->u2utf8(hexdec($codetable[hexdec(bin2hex($tthis))-0x8080]));
}
else
{
$tthis=substr($gb,0,1);
$gb=substr($gb,1,strlen($gb)-1);
$utf8.=$this->u2utf8($tthis);
}
}

return $utf8;
}

function u2utf8($c)
{
$str="";
if ($c < 0x80)
{
$str.=$c;
}
else if ($c < 0x800)
{
$str.=chr(0xC0 | $c>>6);
$str.=chr(0x80 | $c & 0x3F);
}
else if ($c < 0x10000)
{
$str.=chr(0xE0 | $c>>12);
$str.=chr(0x80 | $c>>6 & 0x3F);
$str.=chr(0x80 | $c & 0x3F);
}
else if ($c < 0x200000)
{
$str.=chr(0xF0 | $c>>18);
$str.=chr(0x80 | $c>>12 & 0x3F);
$str.=chr(0x80 | $c>>6 & 0x3F);
$str.=chr(0x80 | $c & 0x3F);
}
return $str;
}

/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
get_type 获得图片的格式，包括jpg,png,gif
内部函数

$img_name： 图片文件名，可以包括路径名
*/
function get_type($img_name)//获取图像文件类型
{
$name_array = explode(".",$img_name);
if (preg_match("/\.(jpg|jpeg|gif|png)$/", $img_name, $matches))
{
$type = strtolower($matches[1]);
}
else
{
$type = "string";
}
return $type;
}

}

?>

使用方法:
$img = new Gimage();
$img->wm_text = "www.discuz.com";
$img->wm_text_font = "./STXINWEI.TTF";
$img->create("./mouse.jpg");

就可以了，其中
mouse.jpg是你要在其上添加水印的图片名称，注意包含路径名
STXINWEI.TTF是字体文件的路径名＋文件名
这就是一个简单的测试。如果要调整更复杂的显示效果，只要修改一下类中的属性就可以了，例如把字体放大就可以
$img->wm_text_size = 20;
增加水印图片就可以
$img->wm_image_name="文件名";