PHP缩略图等比例无损压缩，可填充空白区域补充色
<div class="codetitle"><a style="CURSOR: pointer" data="21749" class="copybut" id="copybut21749" onclick="doCopy('code21749')"> 代码如下:
<div class="codebody" id="code21749">
<?
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( $srcimage,$ds
timage,$dst_width,$dst_height,$backgroundcolor ) {
// 中
文件名乱码
if (
PHP_OS == 'WINNT' ) {
$srcimage = iconv('UTF-8','GBK',$srcimage);
$ds
timage = iconv('UTF-8',$ds
timage);
}
$dstimg = imagecreatetruecolor( $dst_width,$dst_height );
$color = imagecolorallocate($dstimg
,hexdec(substr($backgroundcolor,1,2))
,3,5,2))
);
imagefill($dstimg,$color);
if ( !$arr=ge
timagesize($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 - $dst_h ) / 2;
}
image
copyresampled($dstimg,$srcimg,$dst_x
,$dst_y,$dst_w,$dst_h,$src_width,$src_height);
// 保存格式
$arr = array(
'jpg' => 'imagejpeg'
,'jpeg' => 'imagejpeg'
,'png' => 'imagepng'
,'gif' => 'imagegif'
,'bmp' => 'imagebmp'
);
$suffix = strtolower( array_pop(explode('.',$ds
timage ) ) );
if (!in_array($suffix,array_keys($arr)) ) {
echo "保存的
文件名
错误";
exit;
} else {
eval( $arr[$suffix] . '($dstimg,"'.$ds
timage.'");' );
}
imagejpeg($dstimg,$ds
timage);
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($data,4),$arr ) ) {
return $arr[substr($data,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 str
toupper( $ret );
}
// BMP 创建
函数 PHP本身无
function imagecreatefrombmp($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/vpla
nes/vbits_per_pixel'.
'/Vcompression/Vsize_bitmap/Vhoriz_resolution'.
'/Vvert_resolution/Vcolors_used/Vcolors_important',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'],$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",2));
$COLOR[1] = $PALETTE[$COLOR[1]+1];
}
elseif ($BMP['bits_per_pixel'] == 8)
{
$COLOR = unpack("n",$VIDE.substr($IMG,1));
$COLOR[1] = $PALETTE[$COLOR[1]+1];
}
elseif ($BMP['bits_per_pixel'] == 4)
{
$COLOR = unpack("n",floor($P),1));
if (($
P2)%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)
{
$COLOR = unpack("n",1));
if (($
P8)%8 == 0) $COLOR[1] = $COLOR[1] >>7;
elseif (($
P8)%8 == 1) $COLOR[1] = ($COLOR[1] & 0x40)>>6;
elseif (($
P8)%8 == 2) $COLOR[1] = ($COLOR[1] & 0x20)>>5;
elseif (($
P8)%8 == 3) $COLOR[1] = ($COLOR[1] & 0x10)>>4;
elseif (($
P8)%8 == 4) $COLOR[1] = ($COLOR[1] & 0x8)>>3;
elseif (($
P8)%8 == 5) $COLOR[1] = ($COLOR[1] & 0x4)>>2;
elseif (($
P8)%8 == 6) $COLOR[1] = ($COLOR[1] & 0x2)>>1;
elseif (($
P8)%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,$bfOffBits));
fwrite ($f,pack ('VVVvvVVVVVV',40,$biWidth,$biHeight,24,$biSizeImage,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;
}
?>
