From 10ac26d6e5639cb2ccc394a965feae57d2fe7908 Mon Sep 17 00:00:00 2001
From: Maarten Bent <MaartenBent@users.noreply.github.com>
Date: Fri, 10 Jul 2020 20:41:35 +0200
Subject: [PATCH] Fix DPI of wxTipWindow

Take care to use the DPI of the display the window will be actually
displayed on and not that of its parent window, which can be different.
---
 src/generic/tipwin.cpp | 39 +++++++++++++++++++++++++++++++++------
 1 file changed, 33 insertions(+), 6 deletions(-)

diff --git a/src/generic/tipwin.cpp b/src/generic/tipwin.cpp
index 0e45e87c20..2ecb4b206b 100644
--- a/src/generic/tipwin.cpp
+++ b/src/generic/tipwin.cpp
@@ -33,6 +33,7 @@
     #include "wx/settings.h"
 #endif // WX_PRECOMP
 
+#include "wx/display.h"
 #include "wx/vector.h"
 
 // ----------------------------------------------------------------------------
@@ -116,19 +117,45 @@ wxTipWindow::wxTipWindow(wxWindow *parent,
     SetForegroundColour(wxSystemSettings::GetColour(wxSYS_COLOUR_INFOTEXT));
     SetBackgroundColour(wxSystemSettings::GetColour(wxSYS_COLOUR_INFOBK));
 
-    // set size, position and show it
-    m_view = new wxTipWindowView(this);
-    m_view->Adjust(text, maxLength);
-
     int x, y;
     wxGetMousePosition(&x, &y);
 
-    // we want to show the tip below the mouse, not over it
+    // move to the center of the target display so wxTipWindowView will use the
+    // correct DPI
+    wxPoint posScreen;
+    wxSize sizeScreen;
+
+    const int displayNum = wxDisplay::GetFromPoint(wxPoint(x, y));
+    if ( displayNum != wxNOT_FOUND )
+    {
+        const wxRect rectScreen = wxDisplay(displayNum).GetGeometry();
+        posScreen = rectScreen.GetPosition();
+        sizeScreen = rectScreen.GetSize();
+    }
+    else // outside of any display?
+    {
+        // just use the primary one then
+        posScreen = wxPoint(0, 0);
+        sizeScreen = wxGetDisplaySize();
+    }
+    wxPoint center(posScreen.x + sizeScreen.GetWidth() / 2,
+                   posScreen.y + sizeScreen.GetHeight() / 2);
+    Move(center, wxSIZE_NO_ADJUSTMENTS);
+
+    // set size, position and show it
+    m_view = new wxTipWindowView(this);
+    m_view->Adjust(text, FromDIP(parent->ToDIP(maxLength)) );
+
+    // we want to show the tip below the mouse, not over it, make sure to not
+    // overflow into the next display
     //
     // NB: the reason we use "/ 2" here is that we don't know where the current
     //     cursors hot spot is... it would be nice if we could find this out
     //     though
-    y += wxSystemSettings::GetMetric(wxSYS_CURSOR_Y, this) / 2;
+    int cursorOffset = wxSystemSettings::GetMetric(wxSYS_CURSOR_Y, this) / 2;
+    if (y + cursorOffset >= posScreen.y + sizeScreen.GetHeight())
+        cursorOffset = posScreen.y + sizeScreen.GetHeight() - y - 1;
+    y += cursorOffset;
 
     Position(wxPoint(x, y), wxSize(0,0));
     Popup(m_view);