php实现图片上传时添加文字和图片水印技巧

本文实现的功能特别适用于一些商城和图片站中，分享了图片在上传时添加文字和图片水印

本文实现的功能特别适用于一些商城和图片站中，分享了图片在上传时添加文字和图片水印的技巧，供大家参考，具体内容如下

1. water.class.php

<?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);
 } 
}

2. test1.php

<?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);

3.效果图

以上就是本文的全部内容，希望对大家学习PHP程序设计有所帮助。

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