From b234a1b7a7cce7f536608b34f67d31ca2bc54f6e Mon Sep 17 00:00:00 2001
From: Vojtech Kral <vojtech@kral.hk>
Date: Fri, 17 May 2019 19:12:52 +0200
Subject: [PATCH] Use mac_max_scaling_factor() in create_scaled_bitmap()

---
 src/slic3r/GUI/wxExtensions.cpp | 12 +++++++++++-
 src/slic3r/Utils/MacDarkMode.mm |  7 +++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/slic3r/GUI/wxExtensions.cpp b/src/slic3r/GUI/wxExtensions.cpp
index fa8942c545..103a9ecf0c 100644
--- a/src/slic3r/GUI/wxExtensions.cpp
+++ b/src/slic3r/GUI/wxExtensions.cpp
@@ -1,6 +1,7 @@
 #include "wxExtensions.hpp"
 
 #include <stdexcept>
+#include <cmath>
 
 #include "libslic3r/Utils.hpp"
 #include "libslic3r/Model.hpp"
@@ -19,6 +20,7 @@
 #include "libslic3r/GCode/PreviewData.hpp"
 #include "I18N.hpp"
 #include "GUI_Utils.hpp"
+#include "../Utils/MacDarkMode.hpp"
 
 using Slic3r::GUI::from_u8;
 
@@ -389,7 +391,15 @@ wxBitmap create_scaled_bitmap(wxWindow *win, const std::string& bmp_name_in,
     static Slic3r::GUI::BitmapCache cache;
 
 #ifdef __APPLE__
-    const float scale_factor = win != nullptr ? win->GetContentScaleFactor() : 1.0f;
+    // Note: win->GetContentScaleFactor() is not used anymore here because it tends to
+    // return bogus results quite often (such as 1.0 on Retina or even 0.0).
+    // We're using the max scaling factor across all screens because it's very likely to be good enough.
+
+    static float max_scaling_factor = NAN;
+    if (std::isnan(max_scaling_factor)) {
+        max_scaling_factor = Slic3r::GUI::mac_max_scaling_factor();
+    }
+    const float scale_factor = win != nullptr ? max_scaling_factor : 1.0f;
 #else
     (void)(win);
     const float scale_factor = 1.0f;
diff --git a/src/slic3r/Utils/MacDarkMode.mm b/src/slic3r/Utils/MacDarkMode.mm
index 514b6e7d3f..adbd72aabd 100644
--- a/src/slic3r/Utils/MacDarkMode.mm
+++ b/src/slic3r/Utils/MacDarkMode.mm
@@ -1,6 +1,9 @@
 #import "MacDarkMode.hpp"
 
+#import <algorithm>
+
 #import <Foundation/Foundation.h>
+#import <AppKit/NSScreen.h>
 
 
 @implementation MacDarkMode
@@ -19,12 +22,12 @@ double mac_max_scaling_factor()
 {
     double scaling = 1.;
     if ([NSScreen screens] == nil) {
-        scalign = [[NSScreen mainScreen] backingScaleFactor];
+        scaling = [[NSScreen mainScreen] backingScaleFactor];
     } else {
 	    for (int i = 0; i < [[NSScreen screens] count]; ++ i)
 	    	scaling = std::max<double>(scaling, [[[NSScreen screens] objectAtIndex:0] backingScaleFactor]);
 	}
-    return scalign;
+    return scaling;
 }
 
 }