From f95d6463d34d71f04296734b124167f4044db8c3 Mon Sep 17 00:00:00 2001
From: Artur Wieczorek <artwik@wp.pl>
Date: Fri, 10 Apr 2020 20:33:16 +0200
Subject: [PATCH] Fix sizing wxBitmapButton used as wxPropertyGrid editor
 button

Since wxBitmapButton doesn't rescale embedded bitmap we need
to do this on our own to display entire bitmap even the button
is small.

Closes #18715.
---
 src/propgrid/editors.cpp  | 52 ++++++++++++++++++++++++++++++++++++---
 src/propgrid/propgrid.cpp |  4 +--
 2 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/src/propgrid/editors.cpp b/src/propgrid/editors.cpp
index 23642c2e3c..64eab238f9 100644
--- a/src/propgrid/editors.cpp
+++ b/src/propgrid/editors.cpp
@@ -2138,9 +2138,55 @@ void wxPGMultiButton::Add( const wxBitmap& bitmap, int itemid )
 {
     itemid = GenId(itemid);
     wxSize sz = GetSize();
-    wxButton* button = new wxBitmapButton( this, itemid, bitmap,
-                                           wxPoint(sz.x, 0),
-                                           wxSize(sz.y, sz.y) );
+
+    // Internal margins around the bitmap inside the button
+    const int margins =
+#if defined(__WXMSW__)
+            2*4;
+#elif defined(__WXGTK3__)
+            2*4;
+#elif defined(__WXGTK__)
+            2*8;
+#elif defined(__WXOSX__)
+            2*3;
+#else
+            0;
+#endif
+    // Maximal heigth of the bitmap
+    const int hMax = sz.y - margins;
+
+    wxBitmap scaledBmp;
+    // Scale bitmap down if necessary
+    if ( bitmap.GetHeight() > hMax )
+    {
+        double scale = (double)hMax / bitmap.GetHeight();
+        int w = wxRound(bitmap.GetWidth()*scale);
+        int h = wxRound(bitmap.GetHeight()*scale);
+#if wxUSE_IMAGE
+        // Here we use high-quality wxImage scaling functions available
+        wxImage img = bitmap.ConvertToImage();
+        img.Rescale(w, h, wxIMAGE_QUALITY_HIGH);
+        scaledBmp = img;
+#else // !wxUSE_IMAGE
+        scaledBmp.Create(w, h, bitmap.GetDepth());
+#if defined(__WXMSW__) || defined(__WXOSX__)
+        // wxBitmap::UseAlpha() is used only on wxMSW and wxOSX.
+        scaledBmp.UseAlpha(bitmap.HasAlpha());
+#endif // __WXMSW__ || __WXOSX__
+        {
+            wxMemoryDC dc(scaledBmp);
+            dc.SetUserScale(scale, scale);
+            dc.DrawBitmap(bitmap, 0, 0);
+        }
+#endif // wxUSE_IMAGE/!wxUSE_IMAGE
+    }
+    else
+    {
+        scaledBmp = bitmap;
+    }
+
+    wxBitmapButton* button = new wxBitmapButton(this, itemid, scaledBmp,
+                           wxPoint(sz.x, 0), wxSize(wxDefaultCoord, sz.y));
     DoAddButton( button, sz );
 }
 #endif
diff --git a/src/propgrid/propgrid.cpp b/src/propgrid/propgrid.cpp
index faf9e1763d..b31b49d42d 100644
--- a/src/propgrid/propgrid.cpp
+++ b/src/propgrid/propgrid.cpp
@@ -1331,9 +1331,7 @@ void wxPropertyGrid::CalculateFontAndBitmapStuff( int vspacing )
     GetTextExtent(wxS("jG"), &x, &y, 0, 0, &m_captionFont);
 
     m_lineHeight = m_fontHeight+(2*m_spacingy)+1;
-#if defined(__WXGTK3__)
-    m_lineHeight = wxMax(35, m_lineHeight);
-#endif
+
     // button spacing
     m_buttonSpacingY = (m_lineHeight - m_iconHeight) / 2;
     if ( m_buttonSpacingY < 0 ) m_buttonSpacingY = 0;