PHP Verify Uploaded Image Size_PHP Tutorial-PHP Tutorial-php.cn

PHP Verify Uploaded Image Size_PHP Tutorial

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Release： 2016-07-13 10:29:29

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getimagesize function Get image size (PHP 4, PHP 5)

array getimagesize ( string filename [, array &imageinfo] ) //Note that ￥imageinfo no longer requires the preceding & when using it.

Description
The getimagesize() function will determine the size of any GIF, JPG, PNG, SWF, SWC, PSD, TIFF, BMP, IFF, JP2, JPX, JB2, JPC, XBM or WBMP image file And returns the dimensions of the image as well as the file type and a height/width text string that can be used in an IMG tag in a normal HTML file.

If the image specified by filename cannot be accessed or is not a valid image, getimagesize() will return FALSE and generate an E_WARNING level error.

Note:
Support for JPC, JP2, JPX, JB2, XBM and WBMP is available since PHP 4.3.2. Support for SWC is available since PHP 4.3.0. Support for TIFF was added in PHP 4.2.0, and PHP 5.3 added support for ICON

Note:
JPEG 2000 support was added in PHP 4.3.2. Note that JPC and JP2 can have different color depth components. In this case, the value of "bits" is the highest bit depth encountered. Additionally, a JP2 file may contain multiple JPEG 2000 code streams, in which case getimagesize() returns the value of the first code stream encountered in the top level of the file.

Note:
This function does not require the GD image library.

Returns an array with four cells. Index 0 contains the pixel values for the width of the image, and index 1 contains the pixel values for the height of the image. Index 2 is the tag of the image type: 1 = GIF, 2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF(intel byte order), 8 = TIFF(motorola byte order), 9 = JPC, 10 = JP2, 11 = JPX, 12 = JB2, 13 = SWC, 14 = IFF, 15 = WBMP, 16 = XBM, 17 = ICO, 18 = COUNT. These tags correspond to the new IMAGETYPE constant added in PHP 4.3.0. Index 3 is a text string with the content "height="yyy" width="xxx"" and can be used directly in the IMG tag.

Example getimagesize(file)
list($width, $height, $type, $attr) = getimagesize("img/flag.jpg");
echo "width={$width}, height={$height}, type={$type}, attr={$attr}";
?>
URL support was added in PHP 4.0.5.

Example getimagesize(URL)
$size = getimagesize("http://www.example.com/gifs/logo.gif");

// if the file name has space in it, encode it properly
$size = getimagesize("http://www.example.com/gifs/logo.gif");

?>
For JPG images, two more indices are returned: channels and bits. channels has a value of 3 for RGB images and 4 for CMYK images. bits is the number of bits per color.

As of PHP 4.3.0, bits and channels also exist for other image types. But these values can be confusing. For example, GIFs always use 3 channels per pixel, but for animated GIFs the number of bits per pixel cannot be calculated from the global color table.

Some formats may contain no images or contain multiple images. In this case, getimagesize() may not be used to accurately determine the size of the image. At this point getimagesize() will return zero for width and height.

Since PHP 4.3.0, getimagesize() also returns an additional parameter mime, conforming to the MIME type of the image. This information can be used to send the correct information in the HTTP Content-type header:

Example getimagesize() and MIME type
$size = getimagesize($filename);
$fp=fopen($filename, "rb");
if ($size && $fp) {
header("Content-type: {$size['mime']}");
fpassthru($fp);
exit;
} else {
// error
}
?>
The optional imageinfo parameter allows extracting some extended information from the image file. Currently this will return the different JPG APP IDs in an associative array. Some programs use these APP identifiers to embed textual information in images. A very common one is the IPTC » http://www.iptc.org/ information embedded in the APP13 logo. The iptcparse() function can be used to parse the binary APP13 identifier into readable information.

Example getimagesize() returns IPTC
$size = getimagesize("testimg.jpg", $info);
if (isset($info["APP13" ])) {
$iptc = iptcparse($info["APP13"]);
var_dump($iptc);
}
?>