[dasher] Correctly fall back system font when no Dasher Font has been selected in preferences (fixes #173) (#

[Patrick Welche <pwelche src gnome org>]

commit 0f9d07c690759177a2e6592f5b5b872bcbee8506
Author: sebwills <sw sebwills com>
Date:   Tue Apr 14 22:13:32 2020 +0100

    Correctly fall back system font when no Dasher Font has been selected in preferences (fixes #173) (#174)

 Src/MacOSX/DasherViewOpenGL.mm | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
---
diff --git a/Src/MacOSX/DasherViewOpenGL.mm b/Src/MacOSX/DasherViewOpenGL.mm
index e5368dc8..0451767f 100755
--- a/Src/MacOSX/DasherViewOpenGL.mm
+++ b/Src/MacOSX/DasherViewOpenGL.mm
@@ -57,7 +57,7 @@ protected:
 
     //white text on (default) transparent background means that when we texture
     //a surface using a colour, the text appears in that colour...
-    NSDictionary *attrs = [NSDictionary dictionaryWithObjectsAndKeys:[NSFont 
fontWithName:dasherView.cachedFontName size:iFontSize], NSFontAttributeName, [NSColor whiteColor], 
NSForegroundColorAttributeName, nil];
+    NSDictionary *attrs = [NSDictionary dictionaryWithObjectsAndKeys:Font(iFontSize), NSFontAttributeName, 
[NSColor whiteColor], NSForegroundColorAttributeName, nil];
     //dictionaryWith...: does an autorelease - only "alloc" methods do not.
     
     if (bWrap)
@@ -68,10 +68,16 @@ protected:
   }
   
   CGSize TextSize(NSString *str, unsigned int iFontSize, bool bWrap) {
-    NSFont *font=[NSFont fontWithName:dasherView.cachedFontName size:iFontSize];
-    NSDictionary *attrs =[NSDictionary dictionaryWithObject:(font ? font : [NSFont 
systemFontOfSize:iFontSize]) forKey:NSFontAttributeName];
+    NSDictionary *attrs =[NSDictionary dictionaryWithObject:(Font(iFontSize)) forKey:NSFontAttributeName];
     return NSSizeToCGSize(bWrap ? ([str boundingRectWithSize:NSMakeSize(GetWidth(), CGFLOAT_MAX) 
options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs].size) : ([str sizeWithAttributes:attrs]));
   }
+  
+private:
+  NSFont* Font(const unsigned int iFontSize) {
+    NSFont *font=[NSFont fontWithName:dasherView.cachedFontName size:iFontSize];
+    font = font ? font : [NSFont systemFontOfSize:iFontSize];
+    return font;
+  }
 };
 
 @implementation DasherViewOpenGL