DPI_AWARENESS enumeration (windef.h)

Article
01/31/2022

Identifies the dots per inch (dpi) setting for a thread, process, or window.

Syntax

typedef enum DPI_AWARENESS {
  DPI_AWARENESS_INVALID = -1,
  DPI_AWARENESS_UNAWARE = 0,
  DPI_AWARENESS_SYSTEM_AWARE = 1,
  DPI_AWARENESS_PER_MONITOR_AWARE = 2
} ;

Constants


`DPI_AWARENESS_INVALID` Value: -1 Invalid DPI awareness. This is an invalid DPI awareness value.
`DPI_AWARENESS_UNAWARE` Value: 0 DPI unaware. This process does not scale for DPI changes and is always assumed to have a scale factor of 100% (96 DPI). It will be automatically scaled by the system on any other DPI setting.
`DPI_AWARENESS_SYSTEM_AWARE` Value: 1 System DPI aware. This process does not scale for DPI changes. It will query for the DPI once and use that value for the lifetime of the process. If the DPI changes, the process will not adjust to the new DPI value. It will be automatically scaled up or down by the system when the DPI changes from the system value.
`DPI_AWARENESS_PER_MONITOR_AWARE` Value: 2 Per monitor DPI aware. This process checks for the DPI when it is created and adjusts the scale factor whenever the DPI changes. These processes are not automatically scaled by the system.

Remarks

In previous versions of Windows, DPI values were only set once for an entire application. For those apps, the PROCESS_DPI_AWARENESS type determined the type of DPI awareness for the entire application. Currently, the DPI awareness is defined on an individual thread, window, or process level and is indicated by the DPI_AWARENESS type. While the focus shifted from a process level to a thread level, the different kinds of DPI awareness are the same: unaware, system aware, and per monitor aware. For detailed descriptions and some examples of the different DPI kinds, see PROCESS_DPI_AWARENESS.

The old recommendation was to define the DPI awareness level in the application manifest using the setting dpiAware as explained in PROCESS_DPI_AWARENESS. Now that the DPI awareness is tied to threads and windows instead of an entire application, a new windows setting is added to the app manifest. This setting is dpiAwareness and will override any dpiAware setting if both of them are present in the manifest. While it is still recommended to use the manifest, you can now change the DPI awareness while the app is running by using SetThreadDpiAwarenessContext.

It is important to note that if your application has a DPI_AWARENESS_PER_MONITOR_AWARE window, you are responsible for keeping track of the DPI by responding to WM_DPICHANGED messages.

Examples

This snippet demonstrates how to set a value of DPI_AWARENESS_SYSTEM_AWARE in your application manifest.

<dpiAwareness>System</dpiAwareness>

This snippet demonstrates how to set a value of DPI_AWARENESS_PER_MONITOR_AWARE in your application manifest.

<dpiAwareness>PerMonitor</dpiAwareness>

Requirements

Requirement	Value
Minimum supported client	Windows 10 [desktop apps only]
Minimum supported server	None supported
Header	windef.h