imagecreatefromwbmp

(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)

imagecreatefromwbmp — Crea una nuova immagine da un file o una URL

Descrizione

imagecreatefromwbmp(string $filename): GdImage|false

imagecreatefromwbmp() returns an image identifier representing the image obtained from the given filename.

Nota: WBMP images are Wireless Bitmaps, not Windows Bitmaps. The latter can be loaded with imagecreatefrombmp().

Suggerimento

È possibile utilizzare una URL come un nome di file con questa funzione se fopen wrappers è stata abilitata. Vedere fopen() per maggiori informazioni su come specificare i nomi di file. Vedere Supported Protocols and Wrappers per i link verso le informazioni sulle capacità dei vari wrapper, note sul loro uso, informazioni sulle variabili predefinite che forniscono.

Elenco dei parametri

filename: Path to the WBMP image.

Valori restituiti

Restituisce un identificatore di risorsa immagine, false in caso di errore.

Log delle modifiche

Versione	Descrizione
8.0.0	On success, this function returns a GDImage instance now; previously, a resource was returned.

Esempi

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(150, 30);
        $bgc = imagecolorallocate($im, 255, 255, 255);
        $tc  = imagecolorallocate($im, 0, 0, 0);

        imagefilledrectangle($im, 0, 0, 150, 30, $bgc);

        /* Output an error message */
        imagestring($im, 1, 5, 5, 'Error loading ' . $imgname, $tc);
    }

    return $im;
}

header('Content-Type: image/vnd.wap.wbmp');

$img = LoadWBMP('bogus.image');

imagewbmp($img);
imagedestroy($img);
?>

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User Contributed Notes 4 notes

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clambert at whitecrown dot net ¶

23 years ago


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.

down

AeroX @ aerox-studios ¶

16 years ago


.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;
}

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alexander at alexauto dot nl ¶

16 years ago


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;

    }

?>

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-1

php at webdecker dot de ¶

14 years ago


To get the horizontal and vertical resolution you could add some lines to the previous code of alexander. BMP stores the resolution in pixels per meter. To get it as pixels per inch (dpi) you have to multiply the value by 0.0254.

<?php
    public function imagecreatefrombmp($p_sFile)
    {
            // ...
            // ... insert after the lines where you get width and height...

            //    Get the horz. resolution in pixel per meter, 4 bytes
            $dpix = hexdec($header_parts[39]. $header_parts[38]) * 0.0254;
            
            //    Get the vert. resolution in pixel per meter, 4 bytes
            $dpiy = hexdec($header_parts[43]. $header_parts[42]) * 0.0254;

            // ... rest of the code...

            return ($image, $dpix, $dpiy);
    }           
?>

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