From 8ceadd3029024b827464010985221e2276585b54 Mon Sep 17 00:00:00 2001
From: Maarten Bent <MaartenBent@users.noreply.github.com>
Date: Tue, 8 Oct 2019 21:07:43 +0200
Subject: [PATCH] Improve wxD2DContext::GetDPI and wxGDIPlusContext::GetDPI

If there is a valid wxWindow, use its DPI. Otherwise use a dedicated function
of the context to get the DPI. Don't use the common wxGraphicsContext::GetDPI
because this will return hard-coded 72 when there is no valid wxWindow.
---
 src/msw/graphics.cpp    | 21 +++++++++++++++++++++
 src/msw/graphicsd2d.cpp | 23 +++++++++++++++++++----
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/src/msw/graphics.cpp b/src/msw/graphics.cpp
index 6bbf407a73..d3a981c60d 100644
--- a/src/msw/graphics.cpp
+++ b/src/msw/graphics.cpp
@@ -458,6 +458,7 @@ public:
     virtual void GetPartialTextExtents(const wxString& text, wxArrayDouble& widths) const wxOVERRIDE;
     virtual bool ShouldOffset() const wxOVERRIDE;
     virtual void GetSize( wxDouble* width, wxDouble *height );
+    virtual void GetDPI(wxDouble* dpiX, wxDouble* dpiY) const wxOVERRIDE;
 
     Graphics* GetGraphics() const { return m_context; }
 
@@ -2397,6 +2398,26 @@ void wxGDIPlusContext::GetSize( wxDouble* width, wxDouble *height )
     *height = m_height;
 }
 
+void wxGDIPlusContext::GetDPI(wxDouble* dpiX, wxDouble* dpiY) const
+{
+    if ( GetWindow() )
+    {
+        const wxSize dpi = GetWindow()->GetDPI();
+
+        if ( dpiX )
+            *dpiX = dpi.x;
+        if ( dpiY )
+            *dpiY = dpi.y;
+    }
+    else
+    {
+        if ( dpiX )
+            *dpiX = GetGraphics()->GetDpiX();
+        if ( dpiY )
+            *dpiY = GetGraphics()->GetDpiY();
+    }
+}
+
 //-----------------------------------------------------------------------------
 // wxGDIPlusPrintingContext implementation
 //-----------------------------------------------------------------------------
diff --git a/src/msw/graphicsd2d.cpp b/src/msw/graphicsd2d.cpp
index ce6aaeeedc..b84bfa0d1d 100644
--- a/src/msw/graphicsd2d.cpp
+++ b/src/msw/graphicsd2d.cpp
@@ -4576,10 +4576,25 @@ void wxD2DContext::Flush()
 
 void wxD2DContext::GetDPI(wxDouble* dpiX, wxDouble* dpiY) const
 {
-    FLOAT x, y;
-    GetRenderTarget()->GetDpi(&x, &y);
-    if (dpiX != NULL) *dpiX = x;
-    if (dpiY != NULL) *dpiY = y;
+    if ( GetWindow() )
+    {
+        const wxSize dpi = GetWindow()->GetDPI();
+
+        if ( dpiX )
+            *dpiX = dpi.x;
+        if ( dpiY )
+            *dpiY = dpi.y;
+    }
+    else
+    {
+        FLOAT x, y;
+        GetRenderTarget()->GetDpi(&x, &y);
+
+        if ( dpiX )
+            *dpiX = x;
+        if ( dpiY )
+            *dpiY = y;
+    }
 }
 
 //-----------------------------------------------------------------------------