ChangeDisplaySettingsEx

ChangeDisplaySettings is a function in the Windows operating system that allows applications to modify display-related configurations programmatically. Introduced as part of the Windows API, it provides developers with a way to adjust settings such as screen resolution, color depth, refresh rate, and display orientation without requiring user interaction. This function is commonly used in applications that need to dynamically adapt to different display environments, such as games, video players, or multimedia software.

The function is part of the Windows Graphics Device Interface (GDI) and is typically called via the `ChangeDisplaySettings` API, which is defined in the `wingdi.h` header file. It accepts a pointer to a `DEVMODE` structure containing the desired display settings and a flag indicating whether the changes should be applied immediately or saved for future use. If successful, the function returns `DISP_CHANGE_SUCCESSFUL`, indicating that the settings were applied without issues. Other return values, such as `DISP_CHANGE_RESTART`, `DISP_CHANGE_FAILED`, or `DISP_CHANGE_BADMODE`, indicate different outcomes, such as requiring a system restart or an invalid configuration.

While useful for developers, improper use of `ChangeDisplaySettings` can lead to instability, particularly if conflicting settings are applied across multiple applications. Modern Windows versions also provide alternative methods, such as the Windows Display Driver Model (WDDM) and DirectX, which offer more controlled and safer ways to manage display settings. Additionally, user account control (UAC) may restrict certain applications from modifying display settings without explicit permission. Developers should ensure their applications handle errors gracefully and provide fallback options when changes cannot be applied.