imageresolution

(PHP 7 >= 7.2.0)

imageresolutionGet or set the resolution of the image

설명

mixed imageresolution ( resource $image [, int $res_x [, int $res_y ]] )

imageresolution() allows to set and get the resolution of an image in DPI (dots per inch). If none of the optional parameters is given, the current resolution is returned as indexed array. If only res_x is given, the horizontal and vertical resolution are set to this value. If both optional parameters are given, the horizontal and vertical resolution are set to these values, respectively.

The resolution is only used as meta information when images are read from and written to formats supporting this kind of information (curently PNG and JPEG). It does not affect any drawing operations. The default resolution for new images is 96 DPI.

인수

image

imagecreatetruecolor() 등의 이미지 생성 함수에서 반환한 이미지 자원.

res_x

The horizontal resolution in DPI.

res_y

The vertical resolution in DPI.

반환값

When used as getter (that is without the optional parameters), it returns TRUE on success, 실패 시 FALSE를 반환합니다. When used as setter (that is with one or both optional parameters given), it returns an indexed array of the horizontal and vertical resolution on success, 실패 시 FALSE를 반환합니다.

예제

Example #1 Setting and getting the resolution of an image

<?php
$im 
imagecreatetruecolor(100100);
imageresolution($im200);
print_r(imageresolution($im));
imageresolution($im30072);
print_r(imageresolution($im));
?>

위 예제의 출력:

Array
(
    [0] => 200
    [1] => 200
)
Array
(
    [0] => 300
    [1] => 72
)
add a note add a note

User Contributed Notes 1 note

up
1
fernando dot fonseca at afteryou dot pt
11 months ago
It should be clear that the set version of the function doesn't change the image it self, just the resource in memory, which probably is fine if you didn't save the image yet. If your use case is for an image that is already on disk,  image you should always do something like:

imageresolution($img, 300, 300);
imagepng($img, $filname, $quality);
To Top