imagecreatefrompng

(PHP 3>= 3.0.13, PHP 4 , PHP 5)

imagecreatefrompng -- Create a new image from file or URL

Description

resource imagecreatefrompng ( string filename )

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:

範例 1. Example to handle an error during creation (courtesy vic at zymsys dot com)

<?php
function LoadPNG($imgname)
{
    
$im = @imagecreatefrompng($imgname); /* Attempt to open */
    
if (!$im) { /* See if it failed */
        
$im  = imagecreate(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;
}
?>

提示: 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附錄 L支援URL協定的列表。

警告

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。