Thank you! This was a huge help! This worked great after I changed
the png output to jpg. The png output made a properly sized image,
but it was filled with all light blue pixels. I switched the output
to jpg and it looks perfect!
Here are my changes:
$img = imagecreatefrombmp("test32bit.bmp");
imagealphablending($img, false);
imagesavealpha($img, true);
imagejpeg($img, "test.jpg");
Ken
?>
<img src="test.jpg">
"Chung Leong" <chernyshevsky@hotmail.com> wrote in message news:<PqOdneKYwOer60bdRVn-sA@comcast.com>...[color=blue]
> "Ken" <hanson_kenneth@yahoo.com> wrote in message
> news:ea8389b0.0406241003.151b8cea@posting.google.c om...[color=green]
> > I need to convert 32 bit Windows bitmaps to jpgs with PHP.
> >
> > I used the function from
http://groups.google.com/groups?
> > hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&selm=a164f4b5.0311302128.40fb37f4%
> > 40posting.google.com to convert bitmaps to jpgs.
> >
> > It works very well for my 24 bit bitmaps, but I cannot figure out how
> > to
> > get it to work with 32 bits. I tried adding an additional scan line
> > and
> > the image appears in the correct size, but the colors are way off and
> > some of the data is missing. I also tried putting $a in different
> > places within the $gd_scan_line string:
> >
> > This did not work:
> >
> > $b = $scan_line{$j++};
> > $g = $scan_line{$j++};
> > $r = $scan_line{$j++};
> > $a = $scan_line{$j++};
> > $gd_scan_line .= "\x$a$r$g$b";
> >
> > Can anyone help?
> >
> > Ken[/color]
>
> You were close. Should have been $gd_scan_line .= "$a$r$g$b". Actually, the
> GD library interprets the alpha value as transparency (255 = fully
> transparent) while Windows sees it as opacity (0 = fully transparent). So we
> actually need to substract $a from 255 to get the correct value.
>
> Here's the update code. Improved it a bit by avoiding the use of a temporary
> file.
>
> <?
>
> function ConvertBMP2GD($src, $dest = false) {
> if(!($src_f = fopen($src, "rb"))) {
> trigger_error("Can't open $src", E_WARNING);
> return false;
> }
> if(!($dest_f = fopen($dest, "wb"))) {
> trigger_error("Can't open $dest", E_WARNING);
> return false;
> }
> $header = unpack("vtype/Vsize/v2reserved/Voffset", fread($src_f, 14));
> $info =
> unpack("Vsize/Vwidth/Vheight/vplanes/vbits/Vcompression/Vimagesize/Vxres/Vyr
> es/Vncolor/Vimportant", fread($src_f, 40));
>
> extract($info);
> extract($header);
>
> if($type != 0x4D42) { // signature "BM"
> return false;
> }
>
> $palette_size = $offset - 54;
> $ncolor = $palette_size / 4;
> $gd_header = "";
> // true-color vs. palette
> $gd_header .= ($palette_size == 0) ? "\xFF\xFE" : "\xFF\xFF";
> $gd_header .= pack("n2", $width, $height);
> $gd_header .= ($palette_size == 0) ? "\x01" : "\x00";
> if($palette_size) {
> $gd_header .= pack("n", $ncolor);
> }
> // no transparency
> $gd_header .= "\xFF\xFF\xFF\xFF";
>
> fwrite($dest_f, $gd_header);
>
> if($palette_size) {
> $palette = fread($src_f, $palette_size);
> $gd_palette = "";
> $j = 0;
> while($j < $palette_size) {
> $b = $palette{$j++};
> $g = $palette{$j++};
> $r = $palette{$j++};
> $a = $palette{$j++};
> $gd_palette .= "$r$g$b$a";
> }
> $gd_palette .= str_repeat("\x00\x00\x00\x00", 256 - $ncolor);
> fwrite($dest_f, $gd_palette);
> }
>
> $scan_line_size = (($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++, $l--) {
> // BMP stores scan lines starting from bottom
> fseek($src_f, $offset + (($scan_line_size + $scan_line_align) * $l));
> $scan_line = fread($src_f, $scan_line_size);
> if($bits == 24) {
> $gd_scan_line = "";
> $j = 0;
> while($j < $scan_line_size) {
> $b = $scan_line{$j++};
> $g = $scan_line{$j++};
> $r = $scan_line{$j++};
> $gd_scan_line .= "\xFF$r$g$b";
> }
> }
> else if($bits == 32) {
> $gd_scan_line = "";
> $j = 0;
> while($j < $scan_line_size) {
> $b = $scan_line{$j++};
> $g = $scan_line{$j++};
> $r = $scan_line{$j++};
> $a = chr(255 - ord($scan_line{$j++}));
> $gd_scan_line .= "$a$r$g$b";
> }
> }
> else if($bits == 8) {
> $gd_scan_line = $scan_line;
> }
> else if($bits == 4) {
> $gd_scan_line = "";
> $j = 0;
> while($j < $scan_line_size) {
> $byte = ord($scan_line{$j++});
> $p1 = chr($byte >> 4);
> $p2 = chr($byte & 0x0F);
> $gd_scan_line .= "$p1$p2";
> } $gd_scan_line = substr($gd_scan_line, 0, $width);
> }
> else if($bits == 1) {
> $gd_scan_line = "";
> $j = 0;
> while($j < $scan_line_size) {
> $byte = ord($scan_line{$j++});
> $p1 = chr((int) (($byte & 0x80) != 0));
> $p2 = chr((int) (($byte & 0x40) != 0));
> $p3 = chr((int) (($byte & 0x20) != 0));
> $p4 = chr((int) (($byte & 0x10) != 0));
> $p5 = chr((int) (($byte & 0x08) != 0));
> $p6 = chr((int) (($byte & 0x04) != 0));
> $p7 = chr((int) (($byte & 0x02) != 0));
> $p8 = chr((int) (($byte & 0x01) != 0));
> $gd_scan_line .= "$p1$p2$p3$p4$p5$p6$p7$p8";
> } $gd_scan_line = substr($gd_scan_line, 0, $width);
> }
>
> fwrite($dest_f, $gd_scan_line);
> }
> fclose($src_f);
> fclose($dest_f);
> return true;
> }
>
>
> class MemoryStream {
> var $position;
> var $varname;
> var $buffer;
>
> function stream_open($path, $mode, $options, &$opened_path)
> {
> $url = parse_url($path);
> $this->varname = $url["host"];
> $this->position = 0;
> $this->buffer = @$GLOBALS[$this->varname];
>
> return true;
> }
>
> function stream_close()
> {
> $GLOBALS[$this->varname] = $this->buffer;
> }
>
> function stream_read($count)
> {
> $ret = substr($this->buffer, $this->position, $count);
> $this->position += strlen($ret);
> return $ret;
> }
>
> function stream_write($data)
> {
> $this->buffer .= $data;
> $this->position += strlen($data);
> return strlen($data);
> }
>
> function stream_tell()
> {
> return $this->position;
> }
>
> function stream_eof()
> {
> return $this->position >= strlen($this->buffer);
> }
>
> function stream_stat() {
> return array( 'size' => strlen($this->buffer) );
> }
> }
>
> function imagecreatefrombmp($filename) {
> // use a memory stream instead of a temp file
> // where possible
> if(function_exists('stream_wrapper_register')
> && stream_wrapper_register("mem", "MemoryStream")) {
> $tmp_name = "mem://GD_TMP_FILE";
> $del_tmp = false;
> }
> else {
> $tmp_name = tempnam("/tmp", "GD");
> $del_tmp = true;
> }
> if(ConvertBMP2GD($filename, $tmp_name)) {
> $img = imagecreatefromgd($tmp_name);
> if($del_tmp) {
> unlink($tmp_name);
> }
> return $img;
> } return false;
> }
>
> $img = imagecreatefrombmp("test32bit.bmp");
> imagealphablending($img, false);
> imagesavealpha($img, true);
> imagepng($img, "test.png");
>
> ?>
> <img src="test.png">[/color]
