php 生成缩略图代码

时间：2015-01-23 来源：西部数据作者：西部数据

这是一款经典实用的生成小图的php代码,有专业素语来讲就是php 生成缩略图代码,实例代码如下:

# 显示图形及连接

function showdir ($adirectory, $i)

{

  global $browsedir;

  $start = $i;

# 更改 $maxcols 及 $maximages 可改变每一页显示的小图的行数与列数。

  $maxcols = 2;

  $maximages = 6;

  $maximages = $i + ($maximages - 3);

# 更改 $imagemaxwidth 及 $imagemaxheight 可改变显示小图的宽度与高度。

  $imagemaxwidth = 100;

  $imagemaxheight = 100;



# 计算高度与宽度的比例。

  $imagemaxratio =  $imagemaxwidth / $imagemaxheight;



  $ndirectory = sizeof ($adirectory);

  echo (table_start);

  for ($i; $i<=$maximages;)

  {

     echo (row_start);

     for ($icols=1; $icols<=$maxcols; $icols++)

     {

       echo (col_start);

       $imagefilename = $adirectory[++$i];

       if (strlen($imagefilename)>0)

       {

         $imagepath = $browsedir."/".$imagefilename;

         $imagesize = getimagesize ($imagepath);

         if ($imagesize)

         {

           $imagewidth = $imagesize[0];

           $imageheight = $imagesize[1];

           $imageratio = $imagewidth / $imageheight;

           if ($imageratio > $imagemaxratio)

           {

              $imageoutputwidth = $imagemaxwidth;

              $imageoutputheight = ceil ($imagemaxwidth/$imagewidth*$imageheight);

           }

           else if ($imageratio < $imagemaxratio)

           {

              $imageoutputheight = $imagemaxheight;

              $imageoutputwidth = ceil ($imagemaxheight/$imageheight*$imagewidth);

           } else

           {

              $imageoutputwidth = $imagemaxwidth;

              $imageoutputheight = $imagemaxheight;

           }

# 显示图形

           echo (a_start.$imagepath.a_close);

           echo (img_start.$imagepath.img_width.$imageoutputwidth.img_height.$imageoutputheight.img_end);

           echo (line_break.$adirectory[$i]);

           echo (a_end);

         }

         echo (col_end);

       }

     }

     echo (row_end);

  }

  echo (table_end);

pagemenu ($browsedir, $ndirectory, $start);

}

function pagemenu ($browsedir, $ndirectory, $pg) {

echo "<br><center><font face="verdana, arial, helvetica, sans-serif" size="1" color="#000033">page:";

$pg_num = 1;

//开源代码phpfensi.com

for ($img_num = 0; $img_num <= $ndirectory;) {

    if ($pg == $img_num) {

    echo "<span class="menulink_1"><a href="thumb.php?browsedir=$browsedir&start=$img_num"> *$pg_num</a> <span>";

    } else {

    echo "<span class="menulink_2"><a href="thumb.php?browsedir=$browsedir&start=$img_num"> $pg_num</a> <span>";

    }

# 建立其他页次的连接, 每页显示四张图, 故页数 $pg_num 每加 1 , $img_num 就加 4 。

    $pg_num = $pg_num + 1;

    $img_num = $img_num + 4;

}

echo "</font> ";

}

function dirtoarray ($browsedir, $extensions)

{

  $nextensions = sizeof ($extensions);

  $idirectory = 0;

  $directory = dir($browsedir);



  while ($entry = $directory->read())

  {

      for ($i=1; $i<=$nextensions; $i++)

      {

         $compare = stristr ($entry, $extensions[$i]);

         if (strlen($compare) == strlen($extensions[$i]))

         {

            $adirectory[++$idirectory] = $entry;

            break;

         }

      }

  }

  $directory->close();

  return $adirectory;

}

#主程序

#变量 $browsedir 为图形文件放置的位置。

$browsedir="./images";

# 允许浏览的图形文件扩展名, 放置於数组中, 可自行增加。

$extensions[1] = "jpeg";

$extensions[2] = "jpg";

$extensions[3] = "gif";

$extensions[4] = "png";

showdir (dirtoarray ($browsedir, $extensions), $start);

define ("line_break", "<br>");

define ("table_start", "<table width=600> ");

define ("table_end", "</table> ");

define ("row_start", "  <tr> ");

define ("row_end", "  </tr> ");

define ("col_start", "   <td align=center>       ");

define ("col_end", "    </td> ");

define ("img_start", "<img src=");

define ("img_end", ">");

define ("img_width", " width=");

define ("img_height", " height=");

define ("a_start", '<a href="');

define ("a_close", '">');

define ("a_end", "</a>");