php generate image thumbnail function

<?php

/*

 * Created on 2011-3-18

 *

 * To change the template for this generated file go to

 * Window - Preferences - PHPeclipse - PHP - Code Templates

*/

/*构造函数-生成缩略图+水印,参数说明:

$srcFile-图片文件名,

$dstFile-另存文件名,

$markwords-水印文字,

$markimage-水印图片,

$dstW-图片保存宽度,

$dstH-图片保存高度,

$rate-图片保存品质*/

makethumb("1.jpg", "aa/b.jpg", "50", "50");

function makethumb($srcFile, $dstFile, $dstW, $dstH, $rate = 100, $markwords = null, $markimage = null) {

  $data = GetImageSize($srcFile);

  switch ($data[2]) {

    case 1:

      $im = @ImageCreateFromGIF($srcFile);

    break;

    case 2:

      $im = @ImageCreateFromJPEG($srcFile);

    break;

    case 3:

      $im = @ImageCreateFromPNG($srcFile);

    break;

  }

  if (!$im) return False;

  $srcW = ImageSX($im);

  $srcH = ImageSY($im);

  $dstX = 0;

  $dstY = 0;

  if ($srcW * $dstH > $srcH * $dstW) {

    $fdstH = round($srcH * $dstW / $srcW);

    $dstY = floor(($dstH - $fdstH) / 2);

    $fdstW = $dstW;

  } else {

    $fdstW = round($srcW * $dstH / $srcH);

    $dstX = floor(($dstW - $fdstW) / 2);

    $fdstH = $dstH;

  }

  $ni = ImageCreateTrueColor($dstW, $dstH);

  $dstX = ($dstX < 0) ? 0 : $dstX;

  $dstY = ($dstX < 0) ? 0 : $dstY;

  $dstX = ($dstX > ($dstW / 2)) ? floor($dstW / 2) : $dstX;

  $dstY = ($dstY > ($dstH / 2)) ? floor($dstH / s) : $dstY;

  $white = ImageColorAllocate($ni, 255, 255, 255);

  $black = ImageColorAllocate($ni, 0, 0, 0);

  imagefilledrectangle($ni, 0, 0, $dstW, $dstH, $white); // 填充背景色

  ImageCopyResized($ni, $im, $dstX, $dstY, 0, 0, $fdstW, $fdstH, $srcW, $srcH);

  if ($markwords != null) {

    $markwords = iconv("gb2312", "UTF-8", $markwords);

    //转换文字编码

    ImageTTFText($ni, 20, 30, 450, 560, $black, "simhei.ttf", $markwords); //写入文字水印

    //参数依次为，文字大小|偏转度|横坐标|纵坐标|文字颜色|文字类型|文字内容

  } elseif ($markimage != null) {

    $wimage_data = GetImageSize($markimage);

    switch ($wimage_data[2]) {

      case 1:

        $wimage = @ImageCreateFromGIF($markimage);

      break;

      case 2:

        $wimage = @ImageCreateFromJPEG($markimage);

      break;

      case 3:

        $wimage = @ImageCreateFromPNG($markimage);

      break;

    }

    imagecopy($ni, $wimage, 500, 560, 0, 0, 88, 31); //写入图片水印,水印图片大小默认为88*31

    imagedestroy($wimage);

  }

  ImageJpeg($ni, $dstFile, $rate);

  ImageJpeg($ni, $srcFile, $rate);

  imagedestroy($im);

  imagedestroy($ni);

}

?>