php 将bmp图片转为jpg等其他任意格式的图片

<? php
// 例子：
$path = root . ' upload/2009/06/03/124401282315771. ' ;
$pathall = $path . ' bmp ' ;
$mi = '' ;
$mi = imagecreatefrombmp( $pathall );
imagejpeg( $mi , $path . ' jpg ' );
// 函数如下：
function imagecreatefrombmp( $filename )
{
// ouverture du fichier en mode binaire
if ( ! $f1 = fopen ( $filename , " rb " )) return false ;
// 1 : chargement des ent�tes fichier
$file = unpack ( " vfile_type/vfile_size/vreserved/vbitmap_offset " , fread ( $f1 , 14 ));
if ( $file [ ' file_type ' ] != 19778 ) return false ;
// 2 : chargement des ent�tes bmp
$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 ;
// 3 : chargement des couleurs de la palette
$palette = array ();
if ( $bmp [ ' colors ' ] < 16777216 )
{
$palette = unpack ( ' v ' . $bmp [ ' colors ' ] , fread ( $f1 , $bmp [ ' colors ' ] * 4 ));
}
// 4 : cr�ation de l'image
$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 ' ];
}
// fermeture du fichier
fclose ( $f1 );
return $res ;
}
?>