php实现图片上传时添加文字和图片水印技巧

<?php
header('Content-Type:text/html;charset=utf-8');
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
//给图片添加水印
Class Water{
//开启水印
private $watermark_on = '1';

public $water_img;

//水印位置
public $pos = 1;

//压缩比
public $pct = 80;

//透明度
public $quality = 80;

public $text = '乐趣网zlblog.sinaapp.com';

public $size = 12;

public $color = '#000000';

public $font = 'font.ttf';

public function watermark( $img,$pos='',$out_img='',$water_img='',$text='' ){
if(!$this->check($img) || !$this->watermark_on) return false;

$water_img = $water_img ? $water_img : $this->water_img;
//水印的开启状态
$waterimg_on = $this->check($water_img) ? 1 : 0;
//判断是否在原图上操作
$out_img = $out_img ? $out_img : $img;
//判断水印的位置
$pos = $pos ? $pos : $this->pos;
//水印文字
$text = $text ? $text : $this->text;

$img_info = getimagesize($img);
$img_w = $img_info[0];
$img_h = $img_info[1];
//判断水印图片的类型

if( $waterimg_on ){
$w_info = getimagesize($water_img);
$w_w = $w_info[0];
$w_h = $w_info[1];
if ( $img_w < $w_w || $img_h < $w_h ) return false;
switch ( $w_info[2] ){
case 1:
$w_img = imagecreatefromgif($water_img);
break;
case 2:
$w_img = imagecreatefromjpeg($water_img);
break;
case 3:
$w_img = imagecreatefrompng($water_img);
break;
}
}else{
if( empty($text) || strlen($this->color)!=7 ) return FALSE;
$text_info = imagettfbbox($this->size, 0, $this->font, $text);
$w_w = $text_info[2] - $text_info[6];
$w_h = $text_info[3] - $text_info[7];
}

//建立原图资源

switch ( $img_info[2] ){
case 1:
$res_img = imagecreatefromgif($img);
break;
case 2:
$res_img = imagecreatefromjpeg($img);
break;
case 3:
$res_img = imagecreatefrompng($img);
break;
}
//确定水印的位置
switch ( $pos ){
case 1:
$x = $y =25;
break;
case 2:
$x = ($img_w - $w_w)/2;
$y = 25;
break;
case 3:
$x = $img_w - $w_w;
$y = 25;
break;
case 4:
$x = 25;
$y = ($img_h - $w_h)/2;
break;
case 5:
$x = ($img_w - $w_w)/2;
$y = ($img_h - $w_h)/2;
break;
case 6:
$x = $img_w - $w_w;
$y = ($img_h - $w_h)/2;
break;
case 7:
$x = 25;
$y = $img_h - $w_h;
break;
case 8:
$x = ($img_w - $w_w)/2;
$y = $img_h - $w_h;
break;
case 9:
$x = $img_w - $w_w;
$y = $img_h - $w_h;
break;
default :
$x = mt_rand(25, $img_w - $w_w);
$y = mt_rand(25, $img_h - $w_h);
}

//写入图片资源
if( $waterimg_on ){
imagecopymerge($res_img, $w_img, $x, $y, 0, 0, $w_w, $w_h, $this->pct);
}else{
$r = hexdec(substr($this->color, 1,2));
$g = hexdec(substr($this->color, 3,2));
$b = hexdec(substr($this->color, 5,2));
$color = imagecolorallocate($res_img, $r, $g, $b);
imagettftext($res_img, $this->size, 0, $x, $y, $color, $this->font, $text);
}

//生成图片类型
switch ( $img_info[2] ){
case 1:
imagecreatefromgif($res_img,$out_img);
break;
case 2:
//imagecreatefromjpeg($res_img,$out_img);
imagejpeg($res_img,$out_img);
break;
case 3:
imagejpeg($res_img,$out_img);
break;
}
if(isset($res_img)) imagedestroy ($res_img);
if(isset($w_img))  imagedestroy($w_img);
return TRUE;
}
//验证图片是否存在
private function check($img){
$type = array('.jpg','.jpeg','.png','.gif');
$img_type = strtolower(strrchr($img, '.'));
return extension_loaded('gd') && file_exists($img) && in_array($img_type, $type);
}
}

<?php

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
//header('Content-Type:text/html;charset=utf-8');
include 'water.class.php';
$image = new Water();
$image->watermark('12.jpg',5);
//$image->watermark('12.jpg',1);

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