Re: What is the correct way to response to the wxEVT_DPI_CHANGED event?

Hi, everyone, I still have question about the DPI change handling.

Here is the patch I made to the "display" sample code:

diff --git a/samples/display/display.cpp b/samples/display/display.cpp
index 58f18de..fb028ef 100644
--- a/samples/display/display.cpp
+++ b/samples/display/display.cpp
@@ -356,6 +356,10 @@ void MyFrame::PopuplateWithDisplayInfo()
         sizer->Add(new wxStaticText(page, wxID_ANY, "Current: "));
         sizer->Add(new wxStaticText(page, Display_CurrentMode, 
currentMode));
 
+        wxSize dpi = GetDPI();
+        wxSize newSize = wxWindow::FromDIP(wxSize(250,50));
+        sizer->Add(new wxButton(page, wxID_ANY, _T("Hello World"), 
wxDefaultPosition, newSize));
+
         sizerTop->Add(new wxButton(page, Display_ResetMode, "&Reset mode"),
                       wxSizerFlags().Centre().Border());
 #endif // wxUSE_DISPLAY


And now I try to set two breakpoints. The breakpoint1 in the above code, in 
the line of Add() function call. The breakpoint2 is set inside the function:

void MyFrame::OnDPIChanged(wxDPIChangedEvent& event)
{
    wxLogStatus(this, "DPI changed: was %d*%d, now %d*%d",
                event.GetOldDPI().x, event.GetOldDPI().y,
                event.GetNewDPI().x, event.GetNewDPI().y);

    event.Skip();
}
Now, I try to run the executable when the initial DPI scaling is 100%, I 
first got breakpoint1 hit, and I see the "newSize" is 250*50. Now, I try to 
change the DPI scaling to 150%, and after that, I got breakpoint1 hit 
again, I see the value of "newSize" is still 250*50. After that I got the 
breakpoint2 hit.

I expect that when the second time the breakpoint1 got hit, the newSize 
value should be 375*75, because I have already changed the DPI scaling.
Also, I expect that the breakpoint2 should be hit before the breakpoint1 
after the DPI changes?

Any one can explain this?

Thanks.
Asmwarrior

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