PHP GD库 图片合成（在图片上添加文字）

一、这种是直接显示在浏览器上，并不保存

    function aaa(){
        $user_id = 168955;
        $bigImgPath = 'http://h-cdn.zealcdn.cn/20180706140903.png';   //原图，可以是本地力或者在线图片 
        $img = imagecreatefromstring(file_get_contents($bigImgPath));
        $font = './Public/ziti/dkzt.ttc';  //一定要有对应的字体文件
        $black = imagecolorallocate($img, 0,255,0);  //字体颜色 RGB
        $fontSize = 10;   //字体大小
        $circleSize = 0;  //旋转角度
        $left = 10;       //左边距
        $top = 20;       //顶边距
        =“要加的内容”;    //要加的
        imagefttext($img, $fontSize, $circleSize, $left, $top, $black, $font, $str);
        list($bgWidth, $bgHight, $bgType) = getimagesize($bigImgPath);
        switch ($bgType) {
            case 1: //gif
                header('Content-Type:image/gif');
                ob_clean();
                imagegif($img);
                break;
            case 2: //jpg
                header('Content-Type:image/jpg');
                ob_clean();
                imagejpeg($img);
                break;
            case 3: //jpg
                header('Content-Type:image/png');
                ob_clean();
                imagepng($img);
                break;
            default:
                break;
        }
        $insert['vip_id']=168955;
        $insert['download_time']=$time;
        $challenge_img = M("challenge_img")->add($insert);
        imagedestroy($img);
    }

二、这各在后边中路径和文件名的同保存到指定 的文件夹下

function img_id($img_url,$user_id){
        $img = imagecreatefromstring(file_get_contents($img_url));
        $font = 'public/dkzt.ttc';//字体文件
        $black = imagecolorallocate($img,255, 255, 255);//字体颜色 RGB
        $fontSize = 20;   //字体大小
        $circleSize = 0; //旋转角度
        $left = 50;      //左边距
        $top = 210;       //顶边距
        imagefttext($img, $fontSize, $circleSize, $left, $top, $black, $font, '要加的文字内容');
        list($bgWidth, $bgHight, $bgType) = getimagesize($bigImgPath);
        switch ($bgType) {
            case 1: //gif
                header('Content-Type:image/gif');
                ob_clean();
                imagegif($img,'public/img/666.gif');
                break;
            case 2: //jpg
                header('Content-Type:image/jpg');
                ob_clean();
                imagejpeg($img,'public/img/666.jpg');
                break;
            case 3: //jpg
            ob_clean();
                header('Content-Type:image/png');

                imagepng($img,'public/img/666.png');
                break;
            default:
                break;
        }
  imagedestroy($img);
  }