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Ce document utilise Manuel du site Web PHP chinois Libérer
(PHP 4 >= 4.0.1, PHP 5, PHP 7)
imagecreatefromwbmp — 由文件或 URL 创建一个新图象。
$filename
)imagecreatefromwbmp() 返回一图像标识符,代表了从给定的文件名取得的图像。
如已启用fopen 包装器,在此函数中, URL 可作为文件名。关于如何指定文件名详见 fopen() 。各种 wapper 的不同功能请参见 支持的协议和封装协议,注意其用法及其可提供的预定义变量。
filename
WBMP 图像的路径。
成功后返回图象资源,失败后返回 FALSE
。
Example #1 处理创建 WBMP 过程中的错误
<?php
function LoadWBMP ( $imgname )
{
$im = @ imagecreatefromwbmp ( $imgname );
if(! $im )
{
$im = imagecreatetruecolor ( 150 , 30 );
$bgc = imagecolorallocate ( $im , 255 , 255 , 255 );
$tc = imagecolorallocate ( $im , 0 , 0 , 0 );
imagefilledrectangle ( $im , 0 , 0 , 150 , 30 , $bgc );
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 ( $img );
?>
Note: WBMP 支持仅在 PHP 与 GD-1.8 或更高版本一起编译时可用。
Windows 版本的 PHP 在 4.3.0 版之前不支持通过此函数访问远程文件,即使已经启用 allow_url_fopen.
[#1] php at webdecker dot de [2010-01-28 03:05:33]
To get the horizontal and vertical resolution you could add some lines to the previous code of alexander. BMP stores the resolution in pixels per meter. To get it as pixels per inch (dpi) you have to multiply the value by 0.0254.
<?php
public function imagecreatefrombmp($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, $dpiy);
}
?>
[#2] alexander at alexauto dot nl [2008-10-08 04:59:12]
AeroX created a nice example, but it only works at specific imagesizes because bmp uses fully 32-bit lines. To prevent failures (different colors, pixel-shifting per line), the solution is to skip the padding, inserted after color-pixels on the line. His implementation did cutting the padding into the image-data, causing wrong colors, pixel-shifting per line and also an large memory-consumption.
I improved this script to the next implementation. The readability of a image is checked by a other function, so it doesn't take part in this script.
Suggestions? Please let me know.
<?php
public function imagecreatefrombmp($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;
}
?>
[#3] AeroX @ aerox-studios [2008-05-11 02:54:04]
.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;
}
[#4] clambert at whitecrown dot net [2001-06-16 13:47:56]
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.