下面给大家分享一下php给图片加上图片水印和文字水印实例，这也是网站经常用到的功能，把代码加上去，调用就很简单了。
核心代码：
1 function imagewatermark($groundimage, $waterpos = 0, $waterimage = "", $watertext = "", $textfont = 5, $textcolor = "#ff0000") {
2
3 $iswaterimage = false;
4
5 $formatmsg = "暂不支持该文件格式，请用图片处理软件将图片转换为gif、jpg、png格式。";
6
7 //读取水印文件
8
9 if (!empty($waterimage) && file_exists($waterimage)) {
10
11 $iswaterimage = true;
12
13 $water_info = getimagesize($waterimage);
14
15 $water_w = $water_info[0]; //取得水印图片的宽
16
17 $water_h = $water_info[1]; //取得水印图片的高
18
19 switch ($water_info[2]) {//取得水印图片的格式
20 case 1:$water_im = imagecreatefromgif($waterimage);
21 break;
22
23 case 2:$water_im = imagecreatefromjpeg($waterimage);
24 break;
25
26 case 3:$water_im = imagecreatefrompng($waterimage);
27 break;
28
29 default:die($formatmsg);
30 }
31 }
32
33 //读取背景图片
34
35 if (!empty($groundimage) && file_exists($groundimage)) {
36
37 $ground_info = getimagesize($groundimage);
38
39 $ground_w = $ground_info[0]; //取得背景图片的宽
40
41 $ground_h = $ground_info[1]; //取得背景图片的高
42
43 switch ($ground_info[2]) {//取得背景图片的格式
44 case 1:$ground_im = imagecreatefromgif($groundimage);
45 break;
46
47 case 2:$ground_im = imagecreatefromjpeg($groundimage);
48 break;
49
50 case 3:$ground_im = imagecreatefrompng($groundimage);
51 break;
52
53 default:die($formatmsg);
54 }
55 } else {
56
57 die("需要加水印的图片不存在！");
58 }
59
60 //水印位置
61
62 if ($iswaterimage) {//图片水印
63 $w = $water_w;
64
65 $h = $water_h;
66
67 $label = "图片的";
68 } else {//文字水印
69 $temp = imagettfbbox(ceil($textfont * 5), 0, "./cour.ttf", $watertext); //取得使用 truetype 字体的文本的范围
70
71 $w = $temp[2] - $temp[6];
72
73 $h = $temp[3] - $temp[7];
74
75 unset($temp);
76
77 $label = "文字区域";
78 }
79
80 if (($ground_w < $w) || ($ground_h < $h)) {
81
82 echo "需要加水印的图片的长度或宽度比水印" . $label . "还小，无法生成水印！";
83
84 return;
85 }
86
87 switch ($waterpos) {
88
89 case 0://随机
90
91 $posx = rand(0, ($ground_w - $w));
92
93 $posy = rand(0, ($ground_h - $h));
94
95 break;
96
97 case 1://1为顶端居左
98
99 $posx = 0;
100
101 $posy = 0;
102
103 break;
104
105 case 2://2为顶端居中
106
107 $posx = ($ground_w - $w) / 2;
108
109 $posy = 0;
110
111 break;
112
113 case 3://3为顶端居右
114
115 $posx = $ground_w - $w;
116
117 $posy = 0;
118
119 break;
120
121 case 4://4为中部居左
122
123 $posx = 0;
124
125 $posy = ($ground_h - $h) / 2;
126
127 break;
128
129 case 5://5为中部居中
130
131 $posx = ($ground_w - $w) / 2;
132
133 $posy = ($ground_h - $h) / 2;
134
135 break;
136
137 case 6://6为中部居右
138
139 $posx = $ground_w - $w;
140
141 $posy = ($ground_h - $h) / 2;
142
143 break;
144
145 case 7://7为底端居左
146
147 $posx = 0;
148
149 $posy = $ground_h - $h;
150
151 break;
152
153 case 8://8为底端居中
154
155 $posx = ($ground_w - $w) / 2;
156
157 $posy = $ground_h - $h;
158
159 break;
160
161 case 9://9为底端居右
162
163 $posx = $ground_w - $w - 10; // -10 是距离右侧10px 可以自己调节
164
165 $posy = $ground_h - $h - 10; // -10 是距离底部10px 可以自己调节
166
167 break;
168
169 default://随机
170
171 $posx = rand(0, ($ground_w - $w));
172
173 $posy = rand(0, ($ground_h - $h));
174
175 break;
176 }
177
178 //设定图像的混色模式
179
180 imagealphablending($ground_im, true);
181
182 if ($iswaterimage) {//图片水印
183 imagecopy($ground_im, $water_im, $posx, $posy, 0, 0, $water_w, $water_h); //拷贝水印到目标文件
184 } else {//文字水印
185 if (!emptyempty($textcolor) && (strlen($textcolor) == 7)) {
186
187 $r = hexdec(substr($textcolor, 1, 2));
188
189 $g = hexdec(substr($textcolor, 3, 2));
190
191 $b = hexdec(substr($textcolor, 5));
192 } else {
193
194 die("水印文字颜色格式不正确！");
195 }
196
197 imagestring($ground_im, $textfont, $posx, $posy, $watertext, imagecolorallocate($ground_im, $r, $g, $b));
198 }
199
200 //生成水印后的图片
201
202 @unlink($groundimage);
203
204 switch ($ground_info[2]) {//取得背景图片的格式
205 case 1:imagegif($ground_im, $groundimage);
206 break;
207
208 case 2:imagejpeg($ground_im, $groundimage);
209 break;
210
211 case 3:imagepng($ground_im, $groundimage);
212 break;
213
214 default:die($errormsg);
215 }
216
217 //释放内存
218
219 if (isset($water_info))
220 unset($water_info);
221
222 if (isset($water_im))
223 imagedestroy($water_im);
224
225 unset($ground_info);
226
227 imagedestroy($ground_im);
228 }
文字水印：
watertext('banner.jpg', 9, '','sucaihuo.com'); //背景图片,$waterpos水印位置,水印图片地址
图片水印：
imagewatermark('404.jpg', 9, 'logo.gif'); //背景图片,$waterpos水印位置,水印图片地址
注意：$waterimage 和 $watertext 最好不要同时使用，选其中之一即可，优先使用 $waterimage。
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文字水印
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