imagecreatefromstring
AeroX created a nice example, but it only works at specific imagesizes because bmp uses fully 32-bit lines. To prevent failures (different colors, pixel-shifting per line), the solution is to skip the padding, inserted after color-pixels on the line. His implementation did cutting the padding into the image-data, causing wrong colors, pixel-shifting per line and also an large memory-consumption.
I improved this script to the next implementation. The readability of a image is checked by a other function, so it doesn't take part in this script.
Suggestions? Please let me know.
<?php
public function imagecreatefrombmp($p_sFile)
{
// Load the image into a string
$file = fopen($p_sFile,"rb");
$read = fread($file,10);
while(!feof($file)&&($read<>""))
$read .= fread($file,1024);
$temp = unpack("H*",$read);
$hex = $temp[1];
$header = substr($hex,0,108);
// Process the header
// Structure: http://www.fastgraph.com/help/bmp_header_format.html
if (substr($header,0,4)=="424d")
{
// Cut it in parts of 2 bytes
$header_parts = str_split($header,2);
// Get the width 4 bytes
$width = hexdec($header_parts[19].$header_parts[18]);
// Get the height 4 bytes
$height = hexdec($header_parts[23].$header_parts[22]);
// Unset the header params
unset($header_parts);
}
// Define starting X and Y
$x = 0;
$y = 1;
// Create newimage
$image = imagecreatetruecolor($width,$height);
// Grab the body from the image
$body = substr($hex,108);
// Calculate if padding at the end-line is needed
// Divided by two to keep overview.
// 1 byte = 2 HEX-chars
$body_size = (strlen($body)/2);
$header_size = ($width*$height);
// Use end-line padding? Only when needed
$usePadding = ($body_size>($header_size*3)+4);
// Using a for-loop with index-calculation instaid of str_split to avoid large memory consumption
// Calculate the next DWORD-position in the body
for ($i=0;$i<$body_size;$i+=3)
{
// Calculate line-ending and padding
if ($x>=$width)
{
// If padding needed, ignore image-padding
// Shift i to the ending of the current 32-bit-block
if ($usePadding)
$i += $width%4;
// Reset horizontal position
$x = 0;
// Raise the height-position (bottom-up)
$y++;
// Reached the image-height? Break the for-loop
if ($y>$height)
break;
}
// Calculation of the RGB-pixel (defined as BGR in image-data)
// Define $i_pos as absolute position in the body
$i_pos = $i*2;
$r = hexdec($body[$i_pos+4].$body[$i_pos+5]);
$g = hexdec($body[$i_pos+2].$body[$i_pos+3]);
$b = hexdec($body[$i_pos].$body[$i_pos+1]);
// Calculate and draw the pixel
$color = imagecolorallocate($image,$r,$g,$b);
imagesetpixel($image,$x,$height-$y,$color);
// Raise the horizontal position
$x++;
}
// Unset the body / free the memory
unset($body);
// Return image-object
return $image;
}
?>
imagecreatefromwbmp
(PHP 4 >= 4.0.1, PHP 5)
imagecreatefromwbmp — Create a new image from file or URL
Description
resource imagecreatefromwbmp
( string $filename
)
imagecreatefromwbmp() returns an image identifier representing the image obtained from the given filename.
Tip
A URL can be used as a filename with this function if the fopen wrappers have been enabled. See fopen() for more details on how to specify the filename. See the List of Supported Protocols/Wrappers for links to information about what abilities the various wrappers have, notes on their usage, and information on any predefined variables they may provide.
Parameters
- filename
-
Path to the WBMP image.
Return Values
Returns an image resource identifier on success, FALSE on errors.
Examples
Example #1 Example to handle an error during loading of a WBMP
<?php
function LoadWBMP($imgname)
{
/* Attempt to open */
$im = @imagecreatefromwbmp($imgname);
/* See if it failed */
if(!$im)
{
/* Create a blank image */
$im = imagecreatetruecolor (20, 20);
$bgc = imagecolorallocate($im, 255, 255, 255);
$tc = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 10, 10, $bgc);
/* Output an error message */
imagestring($im, 1, 5, 5, 'Error loading ' . $imgname, $tc);
}
return $im;
}
header('Content-Type: image/png');
$img = LoadPNG('bogus.image');
imagwbmp($img);
imagedestroy($img);
?>
Notes
Note: WBMP support is only available if PHP was compiled against GD-1.8 or later.
Warning
Windows versions of PHP prior to PHP 4.3.0 do not support access of remote files via this function, even if allow_url_fopen is enabled.
add a note
User Contributed Notesimagecreatefromwbmp
alexander at alexauto dot nl
08-Oct-2008 11:59
08-Oct-2008 11:59
d at bwdp dot org
14-Aug-2008 11:07
14-Aug-2008 11:07
why has php not made a predefined function like imagecreatefrombmp yet? surely there's more demand for it than there is for the wbmp function
AeroX @ aerox-studios
11-May-2008 09:54
11-May-2008 09:54
.bmp is just hex encoded RGB values.
All you need to do is open in binary mode and seperate the header from the body.
Decode the width and height from the header.
Then create the image pixel by pixel from the RGB values in the body.
function imagecreatefrombmp( $filename )
{
$file = fopen( $filename, "rb" );
$read = fread( $file, 10 );
while( !feof( $file ) && $read != "" )
{
$read .= fread( $file, 1024 );
}
$temp = unpack( "H*", $read );
$hex = $temp[1];
$header = substr( $hex, 0, 104 );
$body = str_split( substr( $hex, 108 ), 6 );
if( substr( $header, 0, 4 ) == "424d" )
{
$header = substr( $header, 4 );
// Remove some stuff?
$header = substr( $header, 32 );
// Get the width
$width = hexdec( substr( $header, 0, 2 ) );
// Remove some stuff?
$header = substr( $header, 8 );
// Get the height
$height = hexdec( substr( $header, 0, 2 ) );
unset( $header );
}
$x = 0;
$y = 1;
$image = imagecreatetruecolor( $width, $height );
foreach( $body as $rgb )
{
$r = hexdec( substr( $rgb, 4, 2 ) );
$g = hexdec( substr( $rgb, 2, 2 ) );
$b = hexdec( substr( $rgb, 0, 2 ) );
$color = imagecolorallocate( $image, $r, $g, $b );
imagesetpixel( $image, $x, $height-$y, $color );
$x++;
if( $x >= $width )
{
$x = 0;
$y++;
}
}
return $image;
}
nko38 dot fr at gmail dot com
02-Nov-2005 01:20
02-Nov-2005 01:20
for .bmp files, convert them with bmp2png, then you can use this files in gd
http://cetus.sakura.ne.jp/softlab/b2p-home/
clambert at whitecrown dot net
16-Jun-2001 08:47
16-Jun-2001 08:47
WBMP images are Wireless Bitmaps, not Windows Bitmaps. WBMP is used for bandwidth constrained, black and white, limited devices such as PDAs and Cell Phones.