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

<?php
    class 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：

<?php
    require "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：