How does PHP determine whether a gif image is an animated image?
Example
| The code is as follows |
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| 代码如下 |
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/*
* 判断图片是否为动态图片（动画）
*/
function isAnimatedGif($filename) {
$fp=fopen($filename,'rb');
$filecontent=fread($fp,filesize($filename));
fclose($fp);
return strpos($filecontent,chr(0x21).chr(0xff).chr(0x0b).'NETSCAPE2.0')===FALSE?0:1;
}
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/*
* Determine whether the picture is a dynamic picture (animation)
*/
function isAnimatedGif($filename) {
| 代码如下 |
|
function IsAnimatedGif($filename)
{
$fp = fopen($filename, 'rb');
$filecontent = fread($fp, filesize($filename));
fclose($fp);
return strpos($filecontent,chr(0x21).chr(0xff).chr(0x0b).'NETSCAPE2.0') === FALSE?0:1;
}
echo IsAnimatedGif("51windows.gif");
?> |
$fp=fopen($filename,'rb');
$filecontent=fread($fp,filesize($filename));
fclose($fp);
return strpos($filecontent,chr(0x21).chr(0xff).chr(0x0b).'NETSCAPE2.0')===FALSE?0:1;
}
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Or do this
Use PHP to determine whether a gif image is animated (multi-frame)
| 代码如下 |
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function check($image){
$content= file_get_contents($image);
if(preg_match("/".chr(0x21).chr(0xff).chr(0x0b).'NETSCAPE2.0'."/",$content)){
return true;
}else{
return false;
}
}
if(check('/home/lyy/luoyinyou/2.gif')){
echo'真是动画';
}else{
echo'不是动画';
}
?>
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| The code is as follows |
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function IsAnimatedGif($filename)
{
$fp = fopen($filename, 'rb');
$filecontent = fread($fp, filesize($filename));
fclose($fp);
return strpos($filecontent,chr(0x21).chr(0xff).chr(0x0b).'NETSCAPE2.0') === FALSE?0:1;
}
echo IsAnimatedGif("51windows.gif");
?> |
Example 2
The gif animation is in gif89 format, and it was found that the beginning of the file is gif89. But many transparent pictures also use the gif89 format,
GOOGLE: You can check whether the file contains: chr(0×21).chr(0xff).chr(0×0b).'NETSCAPE2.0'
chr(0×21).chr(0xff) is the header of the extended function segment in the gif image, 'NETSCAPE2.0' is the program name for the extended function execution
The program code is as follows:
| The code is as follows |
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function check($image){
$content= file_get_contents($image);
if(preg_match("/".chr(0x21).chr(0xff).chr(0x0b).'NETSCAPE2.0'."/",$content)){
return true;
return false;<🎜>
}<🎜>
}<🎜>
if(check('/home/lyy/luoyinyou/2.gif')){<🎜>
echo'It's really animated';<🎜>
}else{<🎜>
echo'Not an animation';<🎜>
}<🎜>
?>
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The test found that reading 1024 bytes is enough, because the data stream read at this time exactly contains chr(0×21).chr(0xff).chr(0×0b).'NETSCAPE2.0'
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