GD and Image 函数
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imagetypes

(PHP 4 >= 4.0.2, PHP 5)

imagetypes返回当前 PHP 版本所支持的图像类型

说明

int imagetypes ( void )

本函数以比特字段方式返回与当前 PHP 版本关联的 GD 库所支持的图像格式。将返回以下结果,IMG_GIF | IMG_JPG | IMG_PNG | IMG_WBMP| IMG_XPM。 例如要检查是否支持 PNG,这样做:

Example #1 imagetypes() 例子

<?php
if (imagetypes() & IMG_PNG) {
    echo 
"PNG Support is enabled";
}
?>


GD and Image 函数
在线手册:中文  英文

用户评论:

ThunderCrew (2007-07-30 19:38:32)

Im not a smart man but this seemd to be the simplest code and it worked.
Its at the very top of this directory.

<?php
var_dump
(gd_info());
?> 

Returned image info and more.

array(11) { ["GD Version"]=> string(27) "bundled (2.0.28 compatible)" ["FreeType Support"]=> bool(true) ["FreeType Linkage"]=> string(13) "with freetype" ["T1Lib Support"]=> bool(false) ["GIF Read Support"]=> bool(true) ["GIF Create Support"]=> bool(true) ["JPG Support"]=> bool(true) ["PNG Support"]=> bool(true) ["WBMP Support"]=> bool(true) ["XBM Support"]=> bool(true) ["JIS-mapped Japanese Font Support"]=> bool(false) }

enyo (2003-11-05 19:32:12)

Why not use this function?

<?php
function getSupportedImageTypes() {
    
$aSupportedTypes = array();

    
$aPossibleImageTypeBits = array(
        
IMG_GIF=>'GIF',
        
IMG_JPG=>'JPG',
        
IMG_PNG=>'PNG',
        
IMG_WBMP=>'WBMP'
    
);

    foreach (
$aPossibleImageTypeBits as $iImageTypeBits => $sImageTypeString) {
        if (
imagetypes() & $iImageTypeBits) {
            
$aSupportedTypes[] = $sImageTypeString;
        }
    }

    return 
$aSupportedTypes;
}
?>

jocke at selincite dot IHATESP4M dot com (2003-10-16 14:56:29)

I wrote this function that returns an array with the supported image types

<?php
function getSupportedImageTypes() {
        
$aSupportedTypes = array();
        
        
$aPossibleImageTypeBits = array(
                
"IMG_GIF",
                
"IMG_JPG",
                
"IMG_PNG"
                
"IMG_WBMP"
            
);
            
        foreach (
$aPossibleImageTypeBits as $iIndex => $sImageTypeBits) {
            
            
$sEval  "if (";
            
$sEval .= "imagetypes() & " $sImageTypeBits "";
            
$sEval .= ") { return TRUE; } else { return FALSE; }";
            
            if (eval(
$sEval)) {
                
$aSupportedTypes[] = str_replace("IMG_"""$sImageTypeBits);
            }
        }
        
        return 
$aSupportedTypes;
    }
?>
Hope that helps someone :) 

/Jocke Selin

PS, if you know of a better way that doesn't include eval(), please let me know.

jaldinger (at) consulturdorado (dot) com (2003-01-08 12:31:14)

Please note that if only "GIF Read Support" is enabled, the
IMG_GIF bit will not be returned (at least on my system:
PHP 4.3.0/RH Linux 7.2).
To work around this issue, and also the issue that there is no
function that can tell me what image format a GD resource ID
refers to, I use the following switch statement to map the exif
IMAGETYPE_* constants to the GD IMG_* constants:
switch (exif_imagetype($file['tmp_name'])) {
case IMAGETYPE_GIF:
$image_type = IMG_GIF;
break;
case IMAGETYPE_JPEG:
$image_type = IMG_JPG;
break;
case IMAGETYPE_PNG:
$image_type = IMG_PNG;
break;
case IMAGETYPE_WBMP:
$image_type = IMG_WBMP;
break;
default:
$image_type = 0;
break;
}
store this value together with the image data in a database
and later use the following IF statement to see if I can work
with that image (create a thumbnail, etc...)
if ($image_type & (imagetypes() | IMG_GIF)) {
return $this->createJpegThumbailFromString($data, 46, 27);
} else {
return file_get_contents($_SERVER['DOCUMENT_ROOT'] .
'/gfx/no-thumbnail.jpg');
}
HTH anybody...
Joerg.

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