BMP to GD (then to JPG) - 32 bits?

[Ken]

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=UT F-8&oe=UTF-8&safe=off&selm =a164f4b5.03113 02128.40fb37f4%
40posting.googl e.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

[Guest]

Re: BMP to GD (then to JPG) - 32 bits?

> ...convert bitmaps to jpgs.

Personally, my solution would be the following:
a. a command-line application that converts one format to another
b. file exists (check if the new file was created)
c. PHP function getimagesize() to get info -

"Index 2 is a flag indicating the type of the image: 1 = GIF, 2 = JPG, 3 =
PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF(intel byte order), 8 =
TIFF(motorola byte order), 9 = JPC, 10 = JP2, 11 = JPX, 12 = JB2, 13 = SWC,
14 = IFF, 15 = WBMP, 16 = XBM"

Hope this helps --

_______________ _______________ ______
Wil Moore III, MCP | Integrations Specialist

[Chung Leong]

Re: BMP to GD (then to JPG) - 32 bits?


"Ken" <hanson_kenneth @yahoo.com> wrote in message
news:ea8389b0.0 406241003.151b8 cea@posting.goo gle.com...[color=blue]
> 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=UT F-8&oe=UTF-8&safe=off&selm =a164f4b5.03113 02128.40fb37f4%
> 40posting.googl e.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_siz e) {
$gd_header .= pack("n", $ncolor);
}
// no transparency
$gd_header .= "\xFF\xFF\xFF\x FF";

fwrite($dest_f, $gd_header);

if($palette_siz e) {
$palette = fread($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("\x0 0\x00\x00\x00", 256 - $ncolor);
fwrite($dest_f, $gd_palette);
}

$scan_line_size = (($bits * $width) + 7) >> 3;
$scan_line_alig n = ($scan_line_siz e & 0x03) ? 4 - ($scan_line_siz e & 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_si ze + $scan_line_alig n) * $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$p4$p 5$p6$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($pa th, $mode, $options, &$opened_pat h)
{
$url = parse_url($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($co unt)
{
$ret = substr($this->buffer, $this->position, $count);
$this->position += strlen($ret);
return $ret;
}

function stream_write($d ata)
{
$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 imagecreatefrom bmp($filename) {
// use a memory stream instead of a temp file
// where possible
if(function_exi sts('stream_wra pper_register')
&& stream_wrapper_ register("mem", "MemoryStream") ) {
$tmp_name = "mem://GD_TMP_FILE";
$del_tmp = false;
}
else {
$tmp_name = tempnam("/tmp", "GD");
$del_tmp = true;
}
if(ConvertBMP2G D($filename, $tmp_name)) {
$img = imagecreatefrom gd($tmp_name);
if($del_tmp) {
unlink($tmp_nam e);
}
return $img;
} return false;
}

$img = imagecreatefrom bmp("test32bit. bmp");
imagealphablend ing($img, false);
imagesavealpha( $img, true);
imagepng($img, "test.png") ;

?>
<img src="test.png">

[Ken]

Re: BMP to GD (then to JPG) - 32 bits?

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:

$img = imagecreatefrom bmp("test32bit. bmp");
imagealphablend ing($img, false);
imagesavealpha( $img, true);
imagejpeg($img, "test.jpg") ;

Ken



?>
<img src="test.jpg">


"Chung Leong" <chernyshevsky@ hotmail.com> wrote in message news:<PqOdneKYw Oer60bdRVn-sA@comcast.com> ...[color=blue]
> "Ken" <hanson_kenneth @yahoo.com> wrote in message
> news:ea8389b0.0 406241003.151b8 cea@posting.goo gle.com...[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=UT F-8&oe=UTF-8&safe=off&selm =a164f4b5.03113 02128.40fb37f4%
> > 40posting.googl e.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_siz e) {
> $gd_header .= pack("n", $ncolor);
> }
> // no transparency
> $gd_header .= "\xFF\xFF\xFF\x FF";
>
> fwrite($dest_f, $gd_header);
>
> if($palette_siz e) {
> $palette = fread($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("\x0 0\x00\x00\x00", 256 - $ncolor);
> fwrite($dest_f, $gd_palette);
> }
>
> $scan_line_size = (($bits * $width) + 7) >> 3;
> $scan_line_alig n = ($scan_line_siz e & 0x03) ? 4 - ($scan_line_siz e & 0x03)
> : 0;
>
> for($i = 0, $l = $height - 1; $i < $height; $i++, $l--) {
> // BMP stores scan lines starting from bottom
> fseek($src_f, $offset + (($scan_line_si ze + $scan_line_alig n) * $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$p4$p 5$p6$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 $buffer;
>
> function stream_open($pa th, $mode, $options, &$opened_pat h)
> {
> $url = parse_url($path );
> $this->varname = $url["host"];
> $this->position = 0;
> $this->buffer = @$GLOBALS[$this->varname];
>
> return true;
> }
>
> function stream_close()
> {
> $GLOBALS[$this->varname] = $this->buffer;
> }
>
> function stream_read($co unt)
> {
> $ret = substr($this->buffer, $this->position, $count);
> $this->position += strlen($ret);
> return $ret;
> }
>
> function stream_write($d ata)
> {
> $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($this->buffer) );
> }
> }
>
> function imagecreatefrom bmp($filename) {
> // use a memory stream instead of a temp file
> // where possible
> if(function_exi sts('stream_wra pper_register')
> && stream_wrapper_ register("mem", "MemoryStream") ) {
> $tmp_name = "mem://GD_TMP_FILE";
> $del_tmp = false;
> }
> else {
> $tmp_name = tempnam("/tmp", "GD");
> $del_tmp = true;
> }
> if(ConvertBMP2G D($filename, $tmp_name)) {
> $img = imagecreatefrom gd($tmp_name);
> if($del_tmp) {
> unlink($tmp_nam e);
> }
> return $img;
> } return false;
> }
>
> $img = imagecreatefrom bmp("test32bit. bmp");
> imagealphablend ing($img, false);
> imagesavealpha( $img, true);
> imagepng($img, "test.png") ;
>
> ?>
> <img src="test.png">[/color]