远行者

/**
 * 从BMP文件或 URL 新建一图像
 *
 * @param string $sFileName   图像资源
 * @return resource
 */
function imagecreatefrombmp( $sFileName )
{
   if( !$binResources = fopen( $sFileName, "rb" ) )
   {
		return false;   
   }
 
   $FILE = unpack( "vfile_type/Vfile_size/Vreserved/Vbitmap_offset", fread( $binResources, 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( $binResources, 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( $binResources, $BMP['colors']*4 ) );
   }
 
   $IMG = fread($binResources,$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( $binResources );
   return $res;
}

/**
 * 创建bmp格式图片
 *
 * @param resource $im          图像资源
 * @param string   $filename    如果要另存为文件，请指定文件名，为空则直接在浏览器输出
 * @param integer  $bit         图像质量(1、4、8、16、24、32位)
 * @param integer  $compression 压缩方式，0为不压缩，1使用RLE8压缩算法进行压缩
 * @return integer
 */
function imagebmp(&$im, $filename = '', $bit = 8, $compression = 0)
{
    if ( !in_array( $bit, array( 1, 4, 8, 16, 24, 32 ) ) )
    {
        $bit = 8;
    }
    else if ( $bit == 32 ) 
    {
        $bit = 24;
    }
 
    $bits = pow( 2, $bit );
 
    // 调整调色板
    imagetruecolortopalette( $im, true, $bits );
    $width  = imagesx( $im );
    $height = imagesy( $im );
    $colors_num = imagecolorstotal( $im );
 
    if ( $bit <= 8 )
    {
        // 颜色索引
        $rgb_quad = '';
        for ( $i = 0; $i < $colors_num; $i ++ )
        {
            $colors = imagecolorsforindex( $im, $i );
            $rgb_quad .= chr( $colors['blue']) . chr($colors['green']) . chr($colors['red'] ) . "\0";
        }
 
        // 位图数据
        $bmp_data = '';
 
        // 非压缩
        if ( $compression == 0 || $bit < 8 )
        {
            if ( !in_array( $bit, array( 1, 4, 8 ) ) )
            {
                $bit = 8;
            }
 
            $compression = 0;
 
            // 每行字节数必须为4的倍数，补齐。
            $extra = '';
            $padding = 4 - ceil( $width / ( 8 / $bit ) ) % 4;
            if ( $padding % 4 != 0 )
            {
                $extra = str_repeat( "\0", $padding );
            }
 
            for ( $j = $height - 1; $j >= 0; $j -- )
            {
                $i = 0;
                while ( $i < $width )
                {
                    $bin = 0;
                    $limit = $width - $i < 8 / $bit ? ( 8 / $bit - $width + $i ) * $bit : 0;
 
                    for ( $k = 8 - $bit; $k >= $limit; $k -= $bit )
                    {
                        $index = imagecolorat( $im, $i, $j );
                        $bin |= $index << $k;
                        $i ++;
                    }
 
                    $bmp_data .= chr( $bin );
                }
 
                $bmp_data .= $extra; 
            }
        }
        // RLE8 压缩
        else if ( $compression == 1 && $bit == 8 )
        {
            for ( $j = $height - 1; $j >= 0; $j-- )
            {
                $last_index = "\0";
                $same_num   = 0;
                for ( $i = 0; $i <= $width; $i ++ )
                {
                    $index = imagecolorat( $im, $i, $j );
                    if ( $index !== $last_index || $same_num > 255 )
                    {
                        if ( $same_num != 0 )
                        {
                            $bmp_data .= chr( $same_num ) . chr( $last_index );
                        }
 
                        $last_index = $index;
                        $same_num = 1;
                    }
                    else
                    {
                        $same_num ++;
                    }
                }
 
                $bmp_data .= "\0\0";
            }
 
            $bmp_data .= "\0\1";
        }
 
        $size_quad = strlen( $rgb_quad );
        $size_data = strlen( $bmp_data );
    }
    else
    {
        // 每行字节数必须为4的倍数，补齐。
        $extra = '';
        $padding = 4 - ( $width * ( $bit / 8 ) ) % 4;
        if ( $padding % 4 != 0 )
        {
            $extra = str_repeat( "\0", $padding );
        }
 
        // 位图数据
        $bmp_data = '';
 
        for ( $j = $height - 1; $j >= 0; $j -- )
        {
            for ( $i = 0; $i < $width; $i ++ )
            {
                $index  = imagecolorat( $im, $i, $j );
                $colors = imagecolorsforindex( $im, $index );
 
                if ( $bit == 16 )
                {
                    $bin = 0 << $bit;
 
                    $bin |= ( $colors['red'] >> 3 ) << 10;
                    $bin |= ( $colors['green'] >> 3 ) << 5;
                    $bin |= $colors['blue'] >> 3;
 
                    $bmp_data .= pack( "v", $bin );
                }
                else
                {
                    $bmp_data .= pack( "c*", $colors['blue'], $colors['green'], $colors['red'] );
                }
 
                // todo: 32bit; 
            }
 
            $bmp_data .= $extra;
        }
 
        $size_quad = 0;
        $size_data = strlen( $bmp_data );
        $colors_num = 0;
    }
 
    // 位图文件头
    $file_header = "BM" . pack( "V3", 54 + $size_quad + $size_data, 0, 54 + $size_quad );
 
    // 位图信息头
    $info_header = pack( "V3v2V*", 0x28, $width, $height, 1, $bit, $compression, $size_data, 0, 0, $colors_num, 0 );
 
    // 写入文件
    if ( $filename != '' )
    {
        $fp = fopen( $filename, "wb" );
 
        fwrite( $fp, $file_header );
        fwrite( $fp, $info_header );
        fwrite( $fp, $rgb_quad );
        fwrite( $fp, $bmp_data );
        fclose( $fp );
 
        return 1;
    }
 
    // 浏览器输出
    header( "Content-Type: image/bmp" );
    echo $file_header . $info_header;
    echo $rgb_quad;
    echo $bmp_data;
 
    return 1;
}

$im = imagecreatefrombmp( 'test.bmp' ); //load bmp image
imagebmp( $im ); //print bmp $im

imagejpeg( $im ); //print jpeg $im
imagepng( $im ); //print png $im'