function resize($srcImage,$toFile,$maxWidth = 200,$maxHeight = 200,$imgQuality=75)

{

   

    list($width, $height, $type, $attr) = getimagesize($srcImage);

    if($width < $maxWidth  || $height < $maxHeight) return ;

    switch ($type) {

    case 1: $img = imagecreatefromgif($srcImage); break;

    case 2: $img = imagecreatefromjpeg($srcImage); break;

    case 3: $img = imagecreatefrompng($srcImage); break;

    }

    $scale = min($maxWidth/$width, $maxHeight/$height); //求出绽放比例

     

    if($scale < 1) {

    $newWidth = floor($scale*$width);

    $newHeight = floor($scale*$height);

    $newImg = imagecreatetruecolor($newWidth, $newHeight);

    imagecopyresampled($newImg, $img, 0, 0, 0, 0, $newWidth, $newHeight, $width, $height);

    $newName = "";

    $toFile = preg_replace("/(.gif|.jpg|.jpeg|.png)/i","",$toFile);

 

    switch($type) {

        case 1: if(imagegif($newImg, "$toFile$newName.gif", $imgQuality))

        return "$newName.gif"; break;

        case 2: if(imagejpeg($newImg, "$toFile$newName.jpg", $imgQuality))

        return "$newName.jpg"; break;

        case 3: if(imagepng($newImg, "$toFile$newName.jpg", 7))

        return "$newName.png"; break;

        default: if(imagejpeg($newImg, "$toFile$newName.jpg", $imgQuality))

        return "$newName.jpg"; break;

    }

    imagedestroy($newImg);

    }

    imagedestroy($img);

    return false;

}