上传生成缩略图代码,PHP代码库,德仔网

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【PHP】上传生成缩略图
作者:dezai / 发布于2014/1/28/ 499
上传生成缩略图-等比例无损压缩，可填充补充色
<?php
error_reporting( E_ALL );

// 测试
imagezoom('1.jpg', '2.jpg', 400, 300, '#FFFFFF');

/*
  php缩略图函数：
    等比例无损压缩，可填充补充色 author: 华仔
  主持格式：
    bmp 、jpg 、gif、png
  param:
    @srcimage : 要缩小的图片
    @dstimage : 要保存的图片
    @dst_width: 缩小宽
    @dst_height: 缩小高
    @backgroundcolor: 补充色 如：#FFFFFF 支持 6位 不支持3位
*/
function imagezoom( $srcimage, $dstimage, $dst_width, $dst_height, $backgroundcolor ) {
   
    // 中文件名乱码
    if ( PHP_OS == 'WINNT' ) {
        $srcimage = iconv('UTF-8', 'GBK', $srcimage);
        $dstimage = iconv('UTF-8', 'GBK', $dstimage);
    }
 
  $dstimg = imagecreatetruecolor( $dst_width, $dst_height );
  $color = imagecolorallocate($dstimg
    , hexdec(substr($backgroundcolor, 1, 2))
    , hexdec(substr($backgroundcolor, 3, 2))
    , hexdec(substr($backgroundcolor, 5, 2))
  );
  imagefill($dstimg, 0, 0, $color);
 
  if ( !$arr=getimagesize($srcimage) ) {
        echo "要生成缩略图的文件不存在";
        exit;
    }
   
  $src_width = $arr[0];
  $src_height = $arr[1];
  $srcimg = null;
  $method = getcreatemethod( $srcimage );
  if ( $method ) {
    eval( '$srcimg = ' . $method . ';' );
  }
 
  $dst_x = 0;
  $dst_y = 0;
  $dst_w = $dst_width;
  $dst_h = $dst_height;
  if ( ($dst_width / $dst_height - $src_width / $src_height) > 0 ) {
    $dst_w = $src_width * ( $dst_height / $src_height );
    $dst_x = ( $dst_width - $dst_w ) / 2;
  } elseif ( ($dst_width / $dst_height - $src_width / $src_height) < 0 ) {
    $dst_h = $src_height * ( $dst_width / $src_width );
    $dst_y = ( $dst_height - $dst_h ) / 2;
  }

  imagecopyresampled($dstimg, $srcimg, $dst_x
    , $dst_y, 0, 0, $dst_w, $dst_h, $src_width, $src_height);
 
  // 保存格式
  $arr = array(
    'jpg' => 'imagejpeg'
    , 'jpeg' => 'imagejpeg'
    , 'png' => 'imagepng'
    , 'gif' => 'imagegif'
    , 'bmp' => 'imagebmp'
  );
  $suffix = strtolower( array_pop(explode('.', $dstimage ) ) );
  if (!in_array($suffix, array_keys($arr)) ) {
    echo "保存的文件名错误";
    exit;
  } else {
    eval( $arr[$suffix] . '($dstimg, "'.$dstimage.'");' );
  }
 
  imagejpeg($dstimg, $dstimage);
 
  imagedestroy($dstimg);
  imagedestroy($srcimg);
 
}


function getcreatemethod( $file ) {
    $arr = array(
        '474946' => "imagecreatefromgif('$file')"
        , 'FFD8FF' => "imagecreatefromjpeg('$file')"
        , '424D' => "imagecreatefrombmp('$file')"
        , '89504E' => "imagecreatefrompng('$file')"
    );
    $fd = fopen( $file, "rb" );
    $data = fread( $fd, 3 );
   
    $data = str2hex( $data );
   
    if ( array_key_exists( $data, $arr ) ) {
        return $arr[$data];
    } elseif ( array_key_exists( substr($data, 0, 4), $arr ) ) {
        return $arr[substr($data, 0, 4)];
    } else {
        return false;
    }
}

function str2hex( $str ) {
    $ret = "";
   
    for( $i = 0; $i < strlen( $str ) ; $i++ ) {
        $ret .= ord($str[$i]) >= 16 ? strval( dechex( ord($str[$i]) ) )
            : '0'. strval( dechex( ord($str[$i]) ) );
    }
   
    return strtoupper( $ret );
}

// BMP 创建函数 php本身无
function imagecreatefrombmp($filename)
{
 if (! $f1 = fopen($filename,"rb")) return FALSE;

 $FILE = unpack("vfile_type/Vfile_size/Vreserved/Vbitmap_offset", fread($f1,14));
 if ($FILE['file_type'] != 19778) return FALSE;

 $BMP = unpack('Vheader_size/Vwidth/Vheight/vplanes/vbits_per_pixel'.
        '/Vcompression/Vsize_bitmap/Vhoriz_resolution'.
        '/Vvert_resolution/Vcolors_used/Vcolors_important', fread($f1,40));
 $BMP['colors'] = pow(2,$BMP['bits_per_pixel']);
 if ($BMP['size_bitmap'] == 0) $BMP['size_bitmap'] = $FILE['file_size'] - $FILE['bitmap_offset'];
 $BMP['bytes_per_pixel'] = $BMP['bits_per_pixel']/8;
 $BMP['bytes_per_pixel2'] = ceil($BMP['bytes_per_pixel']);
 $BMP['decal'] = ($BMP['width']*$BMP['bytes_per_pixel']/4);
 $BMP['decal'] -= floor($BMP['width']*$BMP['bytes_per_pixel']/4);
 $BMP['decal'] = 4-(4*$BMP['decal']);
 if ($BMP['decal'] == 4) $BMP['decal'] = 0;
 
 $PALETTE = array();
 if ($BMP['colors'] < 16777216)
 {
  $PALETTE = unpack('V'.$BMP['colors'], fread($f1,$BMP['colors']*4));
 }
 
 $IMG = fread($f1,$BMP['size_bitmap']);
 $VIDE = chr(0);

 $res = imagecreatetruecolor($BMP['width'],$BMP['height']);
 $P = 0;
 $Y = $BMP['height']-1;
 while ($Y >= 0)
 {
    $X=0;
    while ($X < $BMP['width'])
    {
    if ($BMP['bits_per_pixel'] == 24)
      $COLOR = unpack("V",substr($IMG,$P,3).$VIDE);
    elseif ($BMP['bits_per_pixel'] == 16)
    { 
      $COLOR = unpack("n",substr($IMG,$P,2));
      $COLOR[1] = $PALETTE[$COLOR[1]+1];
    }
    elseif ($BMP['bits_per_pixel'] == 8)
    { 
      $COLOR = unpack("n",$VIDE.substr($IMG,$P,1));
      $COLOR[1] = $PALETTE[$COLOR[1]+1];
    }
    elseif ($BMP['bits_per_pixel'] == 4)
    {
      $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));
      if (($P*2)%2 == 0) $COLOR[1] = ($COLOR[1] >> 4) ; else $COLOR[1] = ($COLOR[1] & 0x0F);
      $COLOR[1] = $PALETTE[$COLOR[1]+1];
    }
    elseif ($BMP['bits_per_pixel'] == 1)
    {
      $COLOR = unpack("n",$VIDE.substr($IMG,floor($P),1));
      if   (($P*8)%8 == 0) $COLOR[1] = $COLOR[1]    >>7;
      elseif (($P*8)%8 == 1) $COLOR[1] = ($COLOR[1] & 0x40)>>6;
      elseif (($P*8)%8 == 2) $COLOR[1] = ($COLOR[1] & 0x20)>>5;
      elseif (($P*8)%8 == 3) $COLOR[1] = ($COLOR[1] & 0x10)>>4;
      elseif (($P*8)%8 == 4) $COLOR[1] = ($COLOR[1] & 0x8)>>3;
      elseif (($P*8)%8 == 5) $COLOR[1] = ($COLOR[1] & 0x4)>>2;
      elseif (($P*8)%8 == 6) $COLOR[1] = ($COLOR[1] & 0x2)>>1;
      elseif (($P*8)%8 == 7) $COLOR[1] = ($COLOR[1] & 0x1);
      $COLOR[1] = $PALETTE[$COLOR[1]+1];
    }
    else
      return FALSE;
    imagesetpixel($res,$X,$Y,$COLOR[1]);
    $X++;
    $P += $BMP['bytes_per_pixel'];
    }
    $Y--;
    $P+=$BMP['decal'];
 }
 fclose($f1);

return $res;
}
// BMP 保存函数，php本身无
function imagebmp ($im, $fn = false)
{
  if (!$im) return false;
     
  if ($fn === false) $fn = 'php://output';
  $f = fopen ($fn, "w");
  if (!$f) return false;
     
  $biWidth = imagesx ($im);
  $biHeight = imagesy ($im);
  $biBPLine = $biWidth * 3;
  $biStride = ($biBPLine + 3) & ~3;
  $biSizeImage = $biStride * $biHeight;
  $bfOffBits = 54;
  $bfSize = $bfOffBits + $biSizeImage;
     
  fwrite ($f, 'BM', 2);
  fwrite ($f, pack ('VvvV', $bfSize, 0, 0, $bfOffBits));
     
  fwrite ($f, pack ('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 24, 0, $biSizeImage, 0, 0, 0, 0));
     
  $numpad = $biStride - $biBPLine;
  for ($y = $biHeight - 1; $y >= 0; --$y)
  {
    for ($x = 0; $x < $biWidth; ++$x)
    {
      $col = imagecolorat ($im, $x, $y);
      fwrite ($f, pack ('V', $col), 3);
    }
    for ($i = 0; $i < $numpad; ++$i)
      fwrite ($f, pack ('C', 0));
  }
  fclose ($f);
  return true;
}

?>
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