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imageresolution

(PHP 7 >= 7.2.0, PHP 8)

imageresolution — Get or set the resolution of the image

说明

imageresolution(GdImage $image, ?int $resolution_x = null, ?int $resolution_y = null): array|true

imageresolution() allows to set and get the resolution of an image in DPI (dots per inch). If the optional parameters are null, the current resolution is returned as an indexed array. If only resolution_x is not null, the horizontal and vertical resolution are set to this value. If none of the optional parameters are null, 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.

参数

image

由图象创建函数(例如imagecreatetruecolor())返回的 GdImage 对象。

resolution_x

The horizontal resolution in DPI.

resolution_y

The vertical resolution in DPI.

返回值

When used as getter, it returns an indexed array of the horizontal and vertical resolution on success. When used as setter, it always returns true.

更新日志

版本 说明
8.0.0 resolution_x and resolution_y are now nullable.

示例

示例 #1 Setting and getting the resolution of an image

<?php
$im = imagecreatetruecolor(100, 100);
imageresolution($im, 200);
print_r(imageresolution($im));
imageresolution($im, 300, 72);
print_r(imageresolution($im));
?>

以上示例会输出：

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