wx.DPIChangedEvent

Event sent when the display scale factor or pixel density (measured in dots-per-inch, or DPI) of the monitor a window is on changes.

The event is sent to each wx.TopLevelWindow affected by the change, and all its children recursively (post-order traversal). For example, this event is sent to the window when it is moved, by the user, from a display using some DPI value to another display using a different DPI value. It also sent to all program windows on the given display if its DPI changes due to a change in the system settings.

If you define an event handler for this event, you should almost always call event.Skip() in it in order to allow the base class handler to execute, as many controls rely on processing this event in order to update their appearance when the DPI changes. However the default handler for the top level window itself only sets the new window size, by scaling the current size by the DPI ratio – e.g. doubling it if the DPI has changed from normal to “high”, i.e. 200%, one – and also ensuring that the window is still bigger than its best size, as returned by wx.Window.GetBestSize . Note that in some cases this may cause the window size to grow unexpectedly and you may prefer to call wx.Window.SetSize in your handler of this event for the top level window and not call event.Skip() to prevent the default handler from resizing the window.

Currently this event is generated by wxMSW port if only and only if the MSW application runs under Windows 10 Creators Update (v1703) or later and is marked as being “per-monitor DPI aware”, i.e. contains a dpiAwareness tag with the value “PerMonitorV2” in its manifest (see Microsoft “Application Manifests” documentation for more details).

Events Emitted by this Class

Handlers bound for the following event types will receive a wx.DPIChangedEvent parameter.

• EVT_DPI_CHANGED: Process a wxEVT_DPI_CHANGED event.

Added in version 4.1/wxWidgets-3.1.3.

See also

Events and Event Handling

Class Hierarchy

Inheritance diagram for class DPIChangedEvent:

Methods Summary

GetNewDPI	Returns the new DPI.
GetOldDPI	Returns the old DPI.
Scale	Rescale a value in pixels to match the new DPI.
ScaleX	Rescale horizontal component to match the new DPI.
ScaleY	Rescale vertical component to match the new DPI.

Properties Summary

NewDPI	See GetNewDPI
OldDPI	See GetOldDPI

Class API

class wx.DPIChangedEvent(Event)

Event sent when the display scale factor or pixel density (measured in dots-per-inch, or DPI) of the monitor a window is on changes.

Methods

GetNewDPI(self)

Returns the new DPI.

Return type:

wx.Size

---

GetOldDPI(self)

Returns the old DPI.

Return type:

wx.Size

---

Scale(self, sz)

Rescale a value in pixels to match the new DPI.

This is a convenience function to use in wxEVT_DPI_CHANGED event handlers, as they often need to update some sizes to the new DPI. It simply calls MulDivInt32 with new and old DPI values, but is more readable and less error-prone.

For example, the returned value will be twice bigger than the original one when switching from normal (96) DPI to high (2x, 192) DPI.

Parameters:

sz (wx.Size)

Return type:

wx.Size

Added in version 4.1/wxWidgets-3.1.6.

---

ScaleX(self, x)

Rescale horizontal component to match the new DPI.

This is the same as Scale , but for the horizontal component only.

Parameters:

x (int)

Return type:

int

Added in version 4.1/wxWidgets-3.1.6.

---

ScaleY(self, y)

Rescale vertical component to match the new DPI.

This is the same as Scale , but for the vertical component only.

Parameters:

y (int)

Return type:

int

Added in version 4.1/wxWidgets-3.1.6.

Properties

NewDPI

See GetNewDPI

---

OldDPI

See GetOldDPI