图像处理_等比例居中裁剪图片_可添加水印

//参数：图片路径,生成的宽度,生成的高度
//功能：切片图片不影响比例居中切片支持jpg,jpeg,png,gif,wbmp格式图片
function imgthumb($url,$w,$h,$str="",$print){
    try{
        // if(!file_exists($url))
        // {
        //     throw new Exception('文件不存在！');
        // }
        $ext=pathinfo($url,PATHINFO_EXTENSION);
        switch($ext){
            case 'jpg':
            case 'jpeg':
                $im=imagecreatefromjpeg($url);
            break;
            case 'png':
                $im=imagecreatefrompng($url);
            break;
            case 'gif':
                $im=imagecreatefromgif($url);
            break;
            case 'wbmp':
                $im=imagecreatefromwbmp($url);
            break;
            default:
                die('文件格式不支持');
        }
        
        $imarr=getimagesize($url);
        $height=$imarr[1];
        $width=$imarr[0];
        $pro=$height / $width;
        $targetpro=$h / $w;
        $trueimg=imagecreatetruecolor($w,$h);
        if($targetpro>$pro)
        {
        $ws=$h/$pro;
        $x=($ws-$w)/2;
        imagecopyresampled($trueimg,$im,0,0,$x,0,$ws,$h,$width,$height);
        }
        else{
            $hs=$w*$pro;
            $y=-($h-$hs)/2;
            imagecopyresampled($trueimg,$im,0,0,0,$y,$w,$hs,$width,$height);
        }
        if($print)
        {
        $trueimg=imgprint($trueimg,$str);
        }
        header('content-type:'.$imarr['mime']);
        switch($ext){
            case 'jpg':
            case 'jpeg':
            case 'png':
                imagejpeg($trueimg,null,100);
            break;
   
                imagepng($trueimg);
            break;
            case 'gif':
                imagegif($trueimg);
            break;
            case 'wbmp':
                image2wbmp($trueimg);
            break;
            default:
                return false;
        }
        imagedestroy($trueimg);
    }catch(Exception $e){
        echo $e->getMessage();
    }
}
function imgprint($to,$str)
{
    try{
       
        // 建立一幅的图像
        $im = imagecreate(200,40);
        // 白色背景和蓝色文本
        $bg = imagecolorallocate($im, 255, 255, 255);
        $textcolor = imagecolorallocate($im, 255, 0, 0);
        // 把字符串写在图像左上角
        imagestring($im,5, 30, 10, $str, $textcolor);
        #$toimg=imagecreatefromjpeg($to);
        $toimg=$to;
        imagecopymerge($toimg,$im,imagesx($toimg)-imagesx($im),imagesy($toimg)-imagesy($im),0,0,200,40,50);//修改位置
        return $toimg;
        #header('content-type:'.getimagesize($to)['mime']);
        #imagejpeg($toimg,null,100);
    }catch(Exception $e){
        echo $e->getMessage();
    }
}
$img=$_REQUEST['imgpath'];
$x=isset($_REQUEST['x'])?$_REQUEST['x']:300;
$y=isset($_REQUEST['y'])?$_REQUEST['y']:300;
$print=isset($_REQUEST['print'])?$_REQUEST['print']:false;
$str='xxxx';
imgthumb($img,$x,$y,$str,$print);