php生成水印，包括位置和透明度(3)

                    return false;

            }

            // 裁剪图片

            if($cut == 0){ // 等比列

                    $scale = min($new_w/$old_w, $new_h/$old_h); // 计算缩放比例

                    $width  = (int)($old_w*$scale); // 缩略图尺寸

                    $height = (int)($old_h*$scale);

                    $start_w = $start_h = 0;

                    $end_w = $old_w;

                    $end_h = $old_h;

            } elseif($cut == 1){ // center center 裁剪

                        $scale1 = round($new_w/$new_h,2);

                        $scale2 = round($old_w/$old_h,2);

                        if($scale1 > $scale2){

                                $end_h = round($old_w/$scale1,2);

                                $start_h = ($old_h-$end_h)/2;

                                $start_w  = 0;

                                $end_w    = $old_w;

                        } else{

                                $end_w  = round($old_h*$scale1,2);