php 使用GD库压缩图片，添加文字图片水印
先上一个工具类，提供了压缩，添加文字、图片水印等方法：image.class.php<?phpclass Image {private $info;private $image;public function __construct($src) {$info = getimagesize($src);$this -> info = array("width" => $info[0],"height" => $info[1],"type" => image_type_to_extension($info[2], false),"mime" => $info['mime']);$fun = "imagecreatefrom{$this->info['type']}";$this -> image = $fun($src);}public function thumb($width, $height) {$imageThumb = imagecreatetruecolor($width, $height);imagecopyresampled($imageThumb,$this -> image,0,0,0,0,$width,$height,$this -> info["width"],$this -> info["height"]);imagedestroy($this -> image);$this -> image = $imageThumb;}public function waterMarkText($text, $fontPath, $fontSize, $color, $x, $y, $angle) {$color = imagecolorallocatealpha($this -> image,$color[0],$color[1],$color[2],$color[3]);imagettftext($this -> image,$fontSize,$angle,$x,$y,$color,$fontPath,$text);}public function waterMarkImage($source, $x, $y, $alpha) {$markInfo = getimagesize($source);//3、获取水印图片类型$markType = image_type_to_extension($markInfo[2], false);//4、在内存创建图像$markCreateImageFunc = "imagecreatefrom{$markType}";//5、把水印图片复制到内存中$water = $markCreateImageFunc($source);//特别处理，设置透明$color=imagecolorallocate($water,255,255,255);imagefill($water,0,0,$color);imagecolortransparent($water,$color);//6、合并图片imagecopymerge($this -> image, $water, $x, $y, 0, 0, $markInfo[0], $markInfo[1], $alpha);}public function show() {header("Content-type:" . $this -> info['mime']);$outputfunc = "image{$this -> info['type']}";$outputfunc($this -> image);}public function save($newname) {$outputfunc = "image{$this -> info['type']}";$outputfunc($this -> image, $newname . '.' . $this -> info['type']);}public function __destruct() {imagedestroy($this -> image);}}?>调用：<?phprequire "image.class.php";$src = "aeroplane.jpg";$image = new Image($src);$source = "logo.png";$image -> waterMarkImage($source, 0, 0, 30);$image -> thumb(500, 500);$fontPath = "STXINGKA.ttf";$text = "文字图片水印";$image -> waterMarkText($text,$fontPath,60,array(255, 255, 255, 20),10,240,0);$image -> show();$image -> save("image_mark");?>上面用到的图片和字体都跟代码文件在同一个目录下。效果：
