织梦生成漂亮整齐的缩略图如何实现

if($toWH<=$srcWH){ $ftoW=$toW; $ftoH=$ftoW*($srcH/$srcW);  } else{ $ftoH=$toH; $ftoW=$ftoH*($srcW/$srcH);  }

$ftoH=$toH; $ftoW=$toW; if ($toWH<=$srcWH) { $src_Y = 0; $src_X = ($srcW-$srcH*$toWH)/2;  $srcW = $srcH*$toWH; } else { $src_X = 0; $src_Y = ($srcH-$srcW/$toWH)/2;  $srcH = $srcW/$toWH; }

($ni,$im,0,0,0,0,$ftoW,$ftoH,$srcW,$srcH)

($ni,$im,0,0,$src_X,$src_Y,$ftoW,$ftoH,$srcW,$srcH)