OSX use fontAttributes for better emulation of bold fonts (#501)

* using fontAttributes dictionary allows for better emulation of bold typefaces, also switch to using color from context, this allows keeping the same dict throughout, as a side effect fix font caching

* reverting in order to maintain crossplatform compatibility

* applying review suggestions

* applying review suggestions

include/wx/defs.h

@@ -2943,6 +2943,7 @@ typedef const void * CFTypeRef;
 
 DECLARE_WXOSX_OPAQUE_CONST_CFREF( CFString )
 typedef struct __CFString * CFMutableStringRef;
+DECLARE_WXOSX_OPAQUE_CONST_CFREF( CFDictionary )
 
 DECLARE_WXOSX_OPAQUE_CFREF( CFRunLoopSource )
 DECLARE_WXOSX_OPAQUE_CONST_CFREF( CTFont )

include/wx/osx/font.h

@@ -144,6 +144,7 @@ public:
 #endif
 
     CTFontRef OSXGetCTFont() const;
+    CFDictionaryRef OSXGetCTFontAttributes() const;
 
 #if wxOSX_USE_COCOA
     WX_NSFont OSXGetNSFont() const;

src/osx/carbon/font.cpp

@@ -158,6 +158,7 @@ protected:
 public:
     bool            m_fontValid;
     wxCFRef<CTFontRef> m_ctFont;
+    wxCFRef<CFDictionaryRef> m_ctFontAttributes;
     wxCFRef<CGFontRef> m_cgFont;
 #if wxOSX_USE_COCOA
     WX_NSFont       m_nsFont;
@@ -176,6 +177,7 @@ wxFontRefData::wxFontRefData(const wxFontRefData& data) : wxGDIRefData()
     m_info = data.m_info;
     m_fontValid = data.m_fontValid;
     m_ctFont = data.m_ctFont;
+    m_ctFontAttributes = data.m_ctFontAttributes;
     m_cgFont = data.m_cgFont;
 #if wxOSX_USE_COCOA
     m_nsFont = (NSFont*) wxMacCocoaRetain(data.m_nsFont);
@@ -271,6 +273,11 @@ wxFontRefData::wxFontRefData(wxOSXSystemFont font, int size)
                 break;
         }
         m_ctFont.reset(CTFontCreateUIFontForLanguage( uifont, (CGFloat) size, NULL ));
+        CFMutableDictionaryRef dict = CFDictionaryCreateMutable(kCFAllocatorDefault, 0,&kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
+        m_ctFontAttributes.reset(dict);
+        CFDictionarySetValue(dict, kCTFontAttributeName, m_ctFont.get() );
+        CFDictionarySetValue(dict, kCTForegroundColorFromContextAttributeName, kCFBooleanTrue);
+
         wxCFRef<CTFontDescriptorRef> descr;
         descr.reset( CTFontCopyFontDescriptor( m_ctFont ) );
         m_info.Init(descr);
@@ -288,6 +295,16 @@ wxFontRefData::wxFontRefData(wxOSXSystemFont font, int size)
 
 static const CGAffineTransform kSlantTransform = CGAffineTransformMake( 1, 0, tan(wxDegToRad(11)), 1, 0, 0 );
 
+namespace
+{
+    
+struct CachedFontEntry {
+    wxCFRef< CTFontRef > font;
+    wxCFRef< CFDictionaryRef > fontAttributes;
+} ;
+    
+} // anonymous namespace
+
 void wxFontRefData::MacFindFont()
 {
     if ( m_fontValid )
@@ -306,10 +323,19 @@ void wxFontRefData::MacFindFont()
         // use font caching
         wxString lookupnameWithSize = wxString::Format( "%s_%u_%d", m_info.m_faceName, traits, m_info.m_pointSize );
 
-        static std::map< std::wstring , wxCFRef< CTFontRef > > fontcache ;
+        static std::map< wxString, CachedFontEntry > fontcache ;
-        m_ctFont = fontcache[ std::wstring(lookupnameWithSize.wc_str()) ];
+        
-        if ( !m_ctFont )
+        CachedFontEntry& entry = fontcache[ lookupnameWithSize ];
+        m_ctFont = entry.font;
+        m_ctFontAttributes = entry.fontAttributes;
+        if ( m_ctFont )
         {
+            // use cached version
+        }
+        else
+        {
+            CFMutableDictionaryRef dict = CFDictionaryCreateMutable(kCFAllocatorDefault, 0,&kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
+            m_ctFontAttributes.reset(dict);
             
             wxStringToStringHashMap::const_iterator it = gs_FontFamilyToPSName.find(m_info.m_faceName);
             
@@ -350,11 +376,23 @@ void wxFontRefData::MacFindFont()
                                 fontWithTraits = CTFontCreateCopyWithSymbolicTraits( m_ctFont, 0, remainingTransform, remainingTraits, remainingTraits );
                                 if ( fontWithTraits == NULL )
                                 {
-                                    // give in on the bold, try native oblique
+                                    // try native oblique, emulate bold later
                                     fontWithTraits = CTFontCreateCopyWithSymbolicTraits( m_ctFont, 0, NULL, kCTFontItalicTrait, kCTFontItalicTrait );
                                 }
+                                else
+                                {
+                                    remainingTraits &= ~kCTFontBoldTrait;
+                                }
                             }
                         }
+                        
+                        // we have to emulate bold
+                        if ( remainingTraits & kCTFontBoldTrait )
+                        {
+                            // 3 times as thick, negative value because we want effect on stroke and fill (not only stroke)
+                            const float strokewidth = -3.0;
+                            CFDictionarySetValue(dict, kCTStrokeWidthAttributeName, CFNumberCreate( NULL, kCFNumberFloatType, &strokewidth));
+                        }
 
                         if ( fontWithTraits == NULL )
                         {
@@ -366,6 +404,11 @@ void wxFontRefData::MacFindFont()
                         m_ctFont.reset(fontWithTraits);
                 }
             }
+            CFDictionarySetValue(dict, kCTFontAttributeName, m_ctFont.get() );
+            CFDictionarySetValue(dict, kCTForegroundColorFromContextAttributeName, kCFBooleanTrue);
+            
+            entry.font = m_ctFont;
+            entry.fontAttributes = m_ctFontAttributes;
         }
 
         m_cgFont.reset(CTFontCopyGraphicsFont(m_ctFont, NULL));
@@ -378,7 +421,7 @@ void wxFontRefData::MacFindFont()
 #endif
     m_fontValid = true;
 }
-
+    
 bool wxFontRefData::IsFixedWidth() const
 {
     CTFontSymbolicTraits traits = CTFontGetSymbolicTraits(m_ctFont);
@@ -659,6 +702,16 @@ CTFontRef wxFont::OSXGetCTFont() const
     return (CTFontRef)(M_FONTDATA->m_ctFont);
 }
 
+CFDictionaryRef wxFont::OSXGetCTFontAttributes() const
+{
+    wxCHECK_MSG( M_FONTDATA != NULL , NULL, wxT("invalid font") );
+    
+    // cast away constness otherwise lazy font resolution is not possible
+    const_cast<wxFont *>(this)->RealizeResource();
+    
+    return (CFDictionaryRef)(M_FONTDATA->m_ctFontAttributes);
+}
+
 #if wxOSX_USE_COCOA_OR_CARBON
 
 CGFontRef wxFont::OSXGetCGFont() const

src/osx/carbon/graphics.cpp

@@ -824,6 +824,7 @@ public:
     ~wxMacCoreGraphicsFontData();
 
     CTFontRef OSXGetCTFont() const { return m_ctFont ; }
+    CFDictionaryRef OSXGetCTFontAttributes() const { return m_ctFontAttributes; }
     wxColour GetColour() const { return m_colour ; }
 
     bool GetUnderlined() const { return m_underlined ; }
@@ -837,6 +838,7 @@ private :
     bool m_underlined,
          m_strikethrough;
     wxCFRef< CTFontRef > m_ctFont;
+    wxCFRef< CFDictionaryRef > m_ctFontAttributes;
 #if wxOSX_USE_IPHONE
     UIFont*  m_uiFont;
 #endif
@@ -849,6 +851,7 @@ wxMacCoreGraphicsFontData::wxMacCoreGraphicsFontData(wxGraphicsRenderer* rendere
     m_strikethrough = font.GetStrikethrough();
 
     m_ctFont.reset( wxMacCreateCTFont( font ) );
+    m_ctFontAttributes.reset( wxCFRetain( font.OSXGetCTFontAttributes() ) );
 #if wxOSX_USE_IPHONE
     m_uiFont = CreateUIFont(font);
     wxMacCocoaRetain( m_uiFont );
@@ -2220,21 +2223,10 @@ void wxMacCoreGraphicsContext::DoDrawText( const wxString &str, wxDouble x, wxDo
 
     wxMacCoreGraphicsFontData* fref = (wxMacCoreGraphicsFontData*)m_font.GetRefData();
     wxCFStringRef text(str, wxLocale::GetSystemEncoding() );
-    CTFontRef font = fref->OSXGetCTFont();
     CGColorRef col = wxMacCreateCGColor( fref->GetColour() );
-#if 0
+    CTFontRef font = fref->OSXGetCTFont();
-    // right now there's no way to get continuous underlines, only words, so we emulate it
+
-    CTUnderlineStyle ustyle = fref->GetUnderlined() ? kCTUnderlineStyleSingle : kCTUnderlineStyleNone ;
+    wxCFRef<CFAttributedStringRef> attrtext( CFAttributedStringCreate(kCFAllocatorDefault, text, fref->OSXGetCTFontAttributes()) );
-    wxCFRef<CFNumberRef> underlined( CFNumberCreate(NULL, kCFNumberSInt32Type, &ustyle) );
-     CFStringRef keys[] = { kCTFontAttributeName , kCTForegroundColorAttributeName, kCTUnderlineStyleAttributeName };
-    CFTypeRef values[] = { font, col, underlined };
-#else
-    CFStringRef keys[] = { kCTFontAttributeName , kCTForegroundColorAttributeName };
-    CFTypeRef values[] = { font, col };
-#endif
-    wxCFRef<CFDictionaryRef> attributes( CFDictionaryCreate(kCFAllocatorDefault, (const void**) &keys, (const void**) &values,
-                                                    WXSIZEOF( keys ), &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks) );
-    wxCFRef<CFAttributedStringRef> attrtext( CFAttributedStringCreate(kCFAllocatorDefault, text, attributes) );
     wxCFRef<CTLineRef> line( CTLineCreateWithAttributedString(attrtext) );
 
     y += CTFontGetAscent(font);
@@ -2246,6 +2238,7 @@ void wxMacCoreGraphicsContext::DoDrawText( const wxString &str, wxDouble x, wxDo
     CGContextScaleCTM(m_cgContext, 1, -1);
     CGContextSetTextMatrix(m_cgContext, CGAffineTransformIdentity);
 
+    CGContextSetFillColorWithColor( m_cgContext, col );
     CTLineDraw( line, m_cgContext );
 
     if ( fref->GetUnderlined() ) {
@@ -2316,14 +2309,10 @@ void wxMacCoreGraphicsContext::GetTextExtent( const wxString &str, wxDouble *wid
         strToMeasure = wxS(" ");
 
     wxMacCoreGraphicsFontData* fref = (wxMacCoreGraphicsFontData*)m_font.GetRefData();
-    CTFontRef font = fref->OSXGetCTFont();
 
     wxCFStringRef text(strToMeasure, wxLocale::GetSystemEncoding() );
-    CFStringRef keys[] = { kCTFontAttributeName  };
+    
-    CFTypeRef values[] = { font };
+    wxCFRef<CFAttributedStringRef> attrtext( CFAttributedStringCreate(kCFAllocatorDefault, text, fref->OSXGetCTFontAttributes() ) );
-    wxCFRef<CFDictionaryRef> attributes( CFDictionaryCreate(kCFAllocatorDefault, (const void**) &keys, (const void**) &values,
-                                                            WXSIZEOF( keys ), &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks) );
-    wxCFRef<CFAttributedStringRef> attrtext( CFAttributedStringCreate(kCFAllocatorDefault, text, attributes) );
     wxCFRef<CTLineRef> line( CTLineCreateWithAttributedString(attrtext) );
 
     CGFloat a, d, l, w;
@@ -2336,7 +2325,6 @@ void wxMacCoreGraphicsContext::GetTextExtent( const wxString &str, wxDouble *wid
         if ( height )
             *height = a+d+l;
     }
-
     if ( descent )
         *descent = d;
     if ( externalLeading )
@@ -2355,14 +2343,9 @@ void wxMacCoreGraphicsContext::GetPartialTextExtents(const wxString& text, wxArr
         return;
 
     wxMacCoreGraphicsFontData* fref = (wxMacCoreGraphicsFontData*)m_font.GetRefData();
-    CTFontRef font = fref->OSXGetCTFont();
 
     wxCFStringRef t(text, wxLocale::GetSystemEncoding() );
-    CFStringRef keys[] = { kCTFontAttributeName  };
+    wxCFRef<CFAttributedStringRef> attrtext( CFAttributedStringCreate(kCFAllocatorDefault, t, fref->OSXGetCTFontAttributes()) );
-    CFTypeRef values[] = { font };
-    wxCFRef<CFDictionaryRef> attributes( CFDictionaryCreate(kCFAllocatorDefault, (const void**) &keys, (const void**) &values,
-                                                            WXSIZEOF( keys ), &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks) );
-    wxCFRef<CFAttributedStringRef> attrtext( CFAttributedStringCreate(kCFAllocatorDefault, t, attributes) );
     wxCFRef<CTLineRef> line( CTLineCreateWithAttributedString(attrtext) );
 
     widths.reserve(text.length());