Home > php教程 > PHP源码 > imagecreatefrombmp,GD库支持32位BMP图片.

imagecreatefrombmp,GD库支持32位BMP图片.

PHP中文网
Release: 2016-05-25 17:10:25
Original
1067 people have browsed it

php代码:

/**
 * BMP 创建函数
 * @author simon
 * @param string $filename path of bmp file
 * @example who use,who knows
 * @return resource of GD
 */ 
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[&#39;colors&#39;] < 16777216 ){
		$PALETTE = unpack( &#39;V&#39; . $BMP[&#39;colors&#39;], fread( $f1, $BMP[&#39;colors&#39;] * 4 ) );
	}
	
	$IMG = fread( $f1, $BMP[&#39;size_bitmap&#39;] );
	$VIDE = chr( 0 );
	
	$res = imagecreatetruecolor( $BMP[&#39;width&#39;], $BMP[&#39;height&#39;] );
	$P = 0;
	$Y = $BMP[&#39;height&#39;] - 1;
	while( $Y >= 0 ){
		$X = 0;
		while( $X < $BMP[&#39;width&#39;] ){
			if ( $BMP[&#39;bits_per_pixel&#39;] == 32 ){
				$COLOR = unpack( "V", substr( $IMG, $P, 3 ) );
				$B = ord(substr($IMG, $P,1));
				$G = ord(substr($IMG, $P+1,1));
				$R = ord(substr($IMG, $P+2,1));
				$color = imagecolorexact( $res, $R, $G, $B );
				if ( $color == -1 )
					$color = imagecolorallocate( $res, $R, $G, $B );
				$COLOR[0] = $R*256*256+$G*256+$B;
				$COLOR[1] = $color;
			}elseif ( $BMP[&#39;bits_per_pixel&#39;] == 24 )
				$COLOR = unpack( "V", substr( $IMG, $P, 3 ) . $VIDE );
			elseif ( $BMP[&#39;bits_per_pixel&#39;] == 16 ){
				$COLOR = unpack( "n", substr( $IMG, $P, 2 ) );
				$COLOR[1] = $PALETTE[$COLOR[1] + 1];
			}elseif ( $BMP[&#39;bits_per_pixel&#39;] == 8 ){
				$COLOR = unpack( "n", $VIDE . substr( $IMG, $P, 1 ) );
				$COLOR[1] = $PALETTE[$COLOR[1] + 1];
			}elseif ( $BMP[&#39;bits_per_pixel&#39;] == 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[&#39;bits_per_pixel&#39;] == 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[&#39;bytes_per_pixel&#39;];
		}
		$Y--;
		$P += $BMP[&#39;decal&#39;];
	}
	fclose( $f1 );
	
	return $res;
}
Copy after login


source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Popular Recommendations
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template