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|bool

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, 或者在失败时返回 false. When used as setter, it returns true on success, 或者在失败时返回 false.

更新日志

版本	说明
8.0.0	`resolution_x` and `resolution_y` are now nullable.

范例

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));
?>

以上例程会输出：

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

add a note

User Contributed Notes 1 note

down

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);

add a note

官方地址：https://www.php.net/manual/en/function.imageresolution.php

有任何技术问题请点击这里网站运营推广招聘

IT PHP 编程语言 Linux 开发编程科技 Elasticsearch HTML/CSS/XML 网络数据库 JAVA 面试 NoSQL C/C++ Golang Git 算法操作系统正则表达式 Redis 互联网 MySql JavaScript 运维软件国际架构设计 Mac OS TCP/IP Excel Vim Windows Socket Oracle VR MongoDB Python 运营 MemCache 商业硬件电子娱乐设计 nginx 摄影游戏 WordPress HTTP 团建数码电器

php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 [PHP] inet_pton/inet_ntop IP地址转换函数 [鸟哥]PHP_INT_MIN 和 -9223372036854775808 PHP 8.1 adodb手册 ADORecordSet对象 opcache预加载 Composer的Packagist资源 array_multisort() 多字段排序 PHPMailer设置utf8 PHPMailer字符集CharSet PHP json解析（json_decode）页面工具 mysql面试题纯php实现DES以及TripleDES加密算法 php 修改图片大小 Packagist / Composer 中国全量镜像利用PHP SOAP实现WEB SERVICE [原创]诡异的php-fpm超时问题两千行PHP学习笔记

略微加速

PHP官方手册 - 互联网笔记

imageresolution

说明

参数

返回值

更新日志

范例

User Contributed Notes 1 note