imagecreatefrompng
(PHP 4, PHP 5)
imagecreatefrompng — Create a new image from file or URL
Description
imagecreatefrompng() returns an image identifier representing the image obtained from the given filename.
imagecreatefrompng() returns an empty string on failure. It also outputs an error message, which unfortunately displays as a broken link in a browser. To ease debugging the following example will produce an error PNG:
Example#1 Example to handle an error during creation
<?php
function LoadPNG($imgname)
{
$im = @imagecreatefrompng($imgname); /* Attempt to open */
if (!$im) { /* See if it failed */
$im = imagecreatetruecolor(150, 30); /* Create a blank image */
$bgc = imagecolorallocate($im, 255, 255, 255);
$tc = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 150, 30, $bgc);
/* Output an errmsg */
imagestring($im, 1, 5, 5, "Error loading $imgname", $tc);
}
return $im;
}
header("Content-Type: image/png");
$img = LoadPNG("bogus.image");
imagepng($img);
?>
The above example will output something similar to:

如果 fopen wrappers 已啟動,則可藉此函數把檔名當成URL使用。參考 fopen() 有更多關於如何指定檔名的細節和List of Supported Protocols/Wrappers支援URL協定的列表。
Parameters
- filename
-
Path to the PNG image
Return Values
Returns an image resource identifier on success, FALSE on errors.
Notes
PHP 4.3.0 之前的 Windows PHP版本不支援由此函數存取遠端檔案,即使啟動allow_url_fopen選項。