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：
function imageWaterMark($groundImage, $waterPos = 0, $waterImage = "", $waterText = "", $textFont = 5, $textColor = "#FF0000") {
$isWaterImage = FALSE;
$formatMsg = "暂不支持该文件格式，请用图片处理软件将图片转换为GIF、JPG、PNG格式。";
//读取水印文件
if (!empty($waterImage) && file_exists($waterImage)) {
$isWaterImage = TRUE;
$water_info = getimagesize($waterImage);
$water_w = $water_info[0]; //取得水印图片的宽
$water_h = $water_info[1]; //取得水印图片的高
switch ($water_info[2]) {//取得水印图片的格式
case 1:$water_im = imagecreatefromgif($waterImage);
break;
case 2:$water_im = imagecreatefromjpeg($waterImage);
break;
case 3:$water_im = imagecreatefrompng($waterImage);
break;
default:die($formatMsg);
}
}
//读取背景图片
if (!empty($groundImage) && file_exists($groundImage)) {
$ground_info = getimagesize($groundImage);
$ground_w = $ground_info[0]; //取得背景图片的宽
$ground_h = $ground_info[1]; //取得背景图片的高
switch ($ground_info[2]) {//取得背景图片的格式
case 1:$ground_im = imagecreatefromgif($groundImage);
break;
case 2:$ground_im = imagecreatefromjpeg($groundImage);
break;
case 3:$ground_im = imagecreatefrompng($groundImage);
break;
default:die($formatMsg);
}
} else {
die("需要加水印的图片不存在！");
}
//水印位置
if ($isWaterImage) {//图片水印
$w = $water_w;
$h = $water_h;
$label = "图片的";
} else {//文字水印
$temp = imagettfbbox(ceil($textFont * 5), 0, "./cour.ttf", $waterText); //取得使用 TrueType 字体的文本的范围
$w = $temp[2] - $temp[6];
$h = $temp[3] - $temp[7];
unset($temp);
$label = "文字区域";
}
if (($ground_w < $w) || ($ground_h < $h)) {
echo "需要加水印的图片的长度或宽度比水印" . $label . "还小，无法生成水印！";
return;
}
switch ($waterPos) {
case 0://随机
$posX = rand(0, ($ground_w - $w));
$posY = rand(0, ($ground_h - $h));
break;
case 1://1为顶端居左
$posX = 0;
$posY = 0;
break;
case 2://2为顶端居中
$posX = ($ground_w - $w) / 2;
$posY = 0;
break;
case 3://3为顶端居右
$posX = $ground_w - $w;
$posY = 0;
break;
case 4://4为中部居左
$posX = 0;
$posY = ($ground_h - $h) / 2;
break;
case 5://5为中部居中
$posX = ($ground_w - $w) / 2;
$posY = ($ground_h - $h) / 2;
break;
case 6://6为中部居右
$posX = $ground_w - $w;
$posY = ($ground_h - $h) / 2;
break;
case 7://7为底端居左
$posX = 0;
$posY = $ground_h - $h;
break;
case 8://8为底端居中
$posX = ($ground_w - $w) / 2;
$posY = $ground_h - $h;
break;
case 9://9为底端居右
$posX = $ground_w - $w - 10; // -10 是距离右侧10px 可以自己调节
$posY = $ground_h - $h - 10; // -10 是距离底部10px 可以自己调节
break;
default://随机
$posX = rand(0, ($ground_w - $w));
$posY = rand(0, ($ground_h - $h));
break;
}
//设定图像的混色模式
imagealphablending($ground_im, true);
if ($isWaterImage) {//图片水印
imagecopy($ground_im, $water_im, $posX, $posY, 0, 0, $water_w, $water_h); //拷贝水印到目标文件
} else {//文字水印
if (!emptyempty($textColor) && (strlen($textColor) == 7)) {
$R = hexdec(substr($textColor, 1, 2));
$G = hexdec(substr($textColor, 3, 2));
$B = hexdec(substr($textColor, 5));
} else {
die("水印文字颜色格式不正确！");
}
imagestring($ground_im, $textFont, $posX, $posY, $waterText, imagecolorallocate($ground_im, $R, $G, $B));
}
//生成水印后的图片
@unlink($groundImage);
switch ($ground_info[2]) {//取得背景图片的格式
case 1:imagegif($ground_im, $groundImage);
break;
case 2:imagejpeg($ground_im, $groundImage);
break;
case 3:imagepng($ground_im, $groundImage);
break;
default:die($errorMsg);
}
//释放内存
if (isset($water_info))
unset($water_info);
if (isset($water_im))
imagedestroy($water_im);
unset($ground_info);
imagedestroy($ground_im);
}
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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