<?php
//創(chuàng)建壓縮圖
function _create_thumbnail($srcFile, $toW, $toH, $toFile="")
{
  if ($toFile == "")
  {
    $toFile = $srcFile;
  }
  $info = "";
  $data = getimagesize($srcFile, $info);
  if (!$data)
    return false;
  //將文件載入到資源變量im中
  switch ($data[2])
  {
    case 1:
      $im = imagecreatefromgif($srcFile);
      break;
    case 2:
      $im = imagecreatefromjpeg($srcFile);
      break;
    case 3:
      $im = imagecreatefrompng($srcFile);
      break;
  }
  //計算縮略圖的寬高
  $srcW = imagesx($im);
  $srcH = imagesy($im);
  $toWH = $toW / $toH;
  $srcWH = $srcW / $srcH;
  if ($toWH <= $srcWH)
  {
    $ftoW = $toW;
    $ftoH = (int)($ftoW * ($srcH / $srcW));
  }
  else
  {
    $ftoH = $toH;
    $ftoW = (int)($ftoH * ($srcW / $srcH));
  }
  if (function_exists("imagecreatetruecolor"))
  {
    $ni = imagecreatetruecolor($ftoW, $ftoH); //新建一個真彩色圖像
    if ($ni)
    {
      //重采樣拷貝部分圖像并調(diào)整大小 可保持較好的清晰度
      imagecopyresampled($ni, $im, 0, 0, 0, 0, $ftoW, $ftoH, $srcW, $srcH);
    }
    else
    {
      //拷貝部分圖像并調(diào)整大小
      $ni = imagecreate($ftoW, $ftoH);
      imagecopyresized($ni, $im, 0, 0, 0, 0, $ftoW, $ftoH, $srcW, $srcH);
    }
  }
  else
  {
    $ni = imagecreate($ftoW, $ftoH);
    imagecopyresized($ni, $im, 0, 0, 0, 0, $ftoW, $ftoH, $srcW, $srcH);
  }
  //保存到文件 統(tǒng)一為.png格式
  imagepng($ni, $toFile); //以 PNG 格式將圖像輸出到瀏覽器或文件
  ImageDestroy($ni);
  ImageDestroy($im);
}
?>