/lib/functions/imagecreatefrombmpstring.php

<?php
/**
 * Code taken from https://cerescp.svn.sourceforge.net/svnroot/cerescp/emblema.php
 * under the GNU General Public license version 2.
 *
 * @license GPLv2 <http://www.gnu.org/licenses/gpl-2.0.txt>
 */
function imagecreatefrombmpstring($im) {
	$header = unpack("vtype/Vsize/v2reserved/Voffset", substr($im, 0, 14));
	$info = unpack("Vsize/Vwidth/Vheight/vplanes/vbits/Vcompression/Vimagesize/Vxres/Vyres/Vncolor/Vimportant", substr($im, 14, 40));
	extract($info);
	extract($header);
	if($type != 0x4D42)
		return false;
	$palette_size = $offset - 54;
	$ncolor = $palette_size / 4;
	$imres=imagecreatetruecolor($width, $height);
	imagealphablending($imres, false);
	imagesavealpha($imres, true);
	$pal=array();
	if($palette_size) {
		$palette = substr($im, 54, $palette_size);
		$gd_palette = "";
		$j = 0; $n = 0;
		while($j < $palette_size) {
			$b = ord($palette{$j++});
			$g = ord($palette{$j++});
			$r = ord($palette{$j++});
			$a = ord($palette{$j++});
			if ( ($r & 0xf8 == 0xf8) && ($g == 0) && ($b & 0xf8 == 0xf8))
				$a = 127; // alpha = 255 on 0xFF00FF
			$pal[$n++] = imagecolorallocatealpha($imres, $r, $g, $b, $a);
		}
	}
	$scan_line_size = (($bits * $width) + 7) >> 3;
	$scan_line_align = ($scan_line_size & 0x03) ? 4 - ($scan_line_size & 0x03): 0;
	for($i = 0, $l = $height - 1; $i < $height; $i++, $l--) {
		$scan_line = substr($im, $offset + (($scan_line_size + $scan_line_align) * $l), $scan_line_size);
		if($bits == 24) {
			$j = 0; $n = 0;
			while($j < $scan_line_size) {
				$b = ord($scan_line{$j++});
				$g = ord($scan_line{$j++});
				$r = ord($scan_line{$j++});
				$a = 0;
				if ( ($r & 0xf8 == 0xf8) && ($g == 0) && ($b & 0xf8 == 0xf8))
					$a = 127; // alpha = 255 on 0xFF00FF
				$col=imagecolorallocatealpha($imres, $r, $g, $b, $a);
				imagesetpixel($imres, $n++, $i, $col);
			}
		}
		else if($bits == 8) {
			$j = 0;
			while($j < $scan_line_size) {
				$col = $pal[ord($scan_line{$j++})];
				imagesetpixel($imres, $j-1, $i, $col);
			}
		}
		else if($bits == 4) {
			$j = 0; $n = 0;
			while($j < $scan_line_size) {
				$byte = ord($scan_line{$j++});
				$p1 = $byte >> 4;
				$p2 = $byte & 0x0F;
				imagesetpixel($imres, $n++, $i, $pal[$p1]);
				imagesetpixel($imres, $n++, $i, $pal[$p2]);
			}
		}
		else if($bits == 1) {
			$j = 0; $n = 0;
			while($j < $scan_line_size) {
				$byte = ord($scan_line{$j++});
				$p1 = (int) (($byte & 0x80) != 0);
				$p2 = (int) (($byte & 0x40) != 0);
				$p3 = (int) (($byte & 0x20) != 0);
				$p4 = (int) (($byte & 0x10) != 0);
				$p5 = (int) (($byte & 0x08) != 0);
				$p6 = (int) (($byte & 0x04) != 0);
				$p7 = (int) (($byte & 0x02) != 0);
				$p8 = (int) (($byte & 0x01) != 0);
				imagesetpixel($imres, $n++, $i, $pal[$p1]);
				imagesetpixel($imres, $n++, $i, $pal[$p2]);
				imagesetpixel($imres, $n++, $i, $pal[$p3]);
				imagesetpixel($imres, $n++, $i, $pal[$p4]);
				imagesetpixel($imres, $n++, $i, $pal[$p5]);
				imagesetpixel($imres, $n++, $i, $pal[$p6]);
				imagesetpixel($imres, $n++, $i, $pal[$p7]);
				imagesetpixel($imres, $n++, $i, $pal[$p8]);
			}
		}
	}
	return $imres;
}

?>