原因
真正的原因是IDEA系列的新版增加了高清缩放模式
解决
禁用缩放即可
禁用方法 ，打开 (Help | Edit Custom VM Options)
增加一行配置 -Dsun.java2d.uiScale.enabled=false
参考原文：
HiDPI modes JRE-managed HiDPI mode (default on macOS since JDK7, on Windows since 2018.2/JBR8, on Linux since 2019.2/JBR11). JBR stands for JetBrains Runtime, Java runtime based on OpenJDK and maintained by JetBrains.
Enabled via the VM option: -Dsun.java2d.uiScale.enabled=true (Help | Edit Custom VM Options).
In this mode the UI scaling is defined by the product of the two scale factors: the user scale (managed by the IDE) and the system scale (managed by the JBR).
IDE-managed HiDPI mode (legacy mode).
Enabled via the VM option: -Dsun.java2d.uiScale.enabled=false (Help | Edit Custom VM Options).
In this mode the UI scaling is defined only by the user scale factor (managed by the IDE).
