Add wxGraphicsRenderer::CreateFontAtDPI to support font with fractional pixel-size

include/wx/graphics.h

@@ -727,7 +727,7 @@ public:
     }
 
     // returns the resolution of the graphics context in device points per inch
-    virtual void GetDPI( wxDouble* dpiX, wxDouble* dpiY);
+    virtual void GetDPI( wxDouble* dpiX, wxDouble* dpiY) const;
 
 #if 0
     // sets the current alpha on this context
@@ -1038,6 +1038,9 @@ public:
                                       const wxString& facename,
                                       int flags = wxFONTFLAG_DEFAULT,
                                       const wxColour& col = *wxBLACK) = 0;
+    virtual wxGraphicsFont CreateFontAtDPI(const wxFont& font,
+                                           const wxRealPoint& dpi,
+                                           const wxColour& col = *wxBLACK) = 0;
 
     // create a native bitmap representation
     virtual wxGraphicsBitmap CreateBitmap( const wxBitmap &bitmap ) = 0;

interface/wx/graphics.h

@@ -1116,7 +1116,7 @@ public:
     /**
        Returns the resolution of the graphics context in device points per inch.
     */
-    virtual void GetDPI( wxDouble* dpiX, wxDouble* dpiY);
+    virtual void GetDPI( wxDouble* dpiX, wxDouble* dpiY) const;
 
     /**
         Returns the associated window if any.
@@ -1459,6 +1459,17 @@ public:
                                       int flags = wxFONTFLAG_DEFAULT,
                                       const wxColour& col = *wxBLACK) = 0;
 
+    /**
+        Creates a native graphics font from a wxFont and a text colour.
+
+        The specified DPI is used to convert the (fractional) wxFont point-size
+        to a fractional pixel-size.
+
+        @since 3.1.3
+    */
+    virtual wxGraphicsFont CreateFontAtDPI(const wxFont& font,
+                                           const wxRealPoint& dpi,
+                                           const wxColour& col = *wxBLACK) = 0;
 
     /**
         Creates a native brush with a linear gradient.

src/common/graphcmn.cpp

@@ -619,7 +619,7 @@ wxDouble wxGraphicsContext::GetAlpha() const
 }
 #endif
 
-void wxGraphicsContext::GetDPI( wxDouble* dpiX, wxDouble* dpiY)
+void wxGraphicsContext::GetDPI( wxDouble* dpiX, wxDouble* dpiY) const
 {
     if ( m_window )
     {
@@ -944,7 +944,9 @@ wxGraphicsContext::CreateRadialGradientBrush(
 
 wxGraphicsFont wxGraphicsContext::CreateFont( const wxFont &font , const wxColour &col ) const
 {
-    return GetRenderer()->CreateFont(font,col);
+    wxRealPoint dpi;
+    GetDPI(&dpi.x, &dpi.y);
+    return GetRenderer()->CreateFontAtDPI(font, dpi, col);
 }
 
 wxGraphicsFont

src/generic/graphicc.cpp

@@ -3009,6 +3009,9 @@ public :
                                       const wxString& facename,
                                       int flags = wxFONTFLAG_DEFAULT,
                                       const wxColour& col = *wxBLACK) wxOVERRIDE;
+    virtual wxGraphicsFont CreateFontAtDPI(const wxFont& font,
+                                           const wxRealPoint& dpi,
+                                           const wxColour& col) wxOVERRIDE;
 
     // create a native bitmap representation
     virtual wxGraphicsBitmap CreateBitmap( const wxBitmap &bitmap ) wxOVERRIDE;
@@ -3238,6 +3241,14 @@ wxCairoRenderer::CreateFont(double sizeInPixels,
     return font;
 }
 
+wxGraphicsFont
+wxCairoRenderer::CreateFontAtDPI(const wxFont& font,
+                                 const wxRealPoint& WXUNUSED(dpi),
+                                 const wxColour& col)
+{
+    return CreateFont(font, col);
+}
+
 wxGraphicsBitmap wxCairoRenderer::CreateBitmap( const wxBitmap& bmp )
 {
     wxGraphicsBitmap p;

src/msw/graphics.cpp

@@ -342,6 +342,7 @@ class wxGDIPlusFontData : public wxGraphicsObjectRefData
 public:
     wxGDIPlusFontData( wxGraphicsRenderer* renderer,
                        const wxFont &font,
+                       const wxRealPoint& dpi,
                        const wxColour& col );
     wxGDIPlusFontData(wxGraphicsRenderer* renderer,
                       const wxString& name,
@@ -661,6 +662,10 @@ public :
                                       int flags = wxFONTFLAG_DEFAULT,
                                       const wxColour& col = *wxBLACK) wxOVERRIDE;
 
+    virtual wxGraphicsFont CreateFontAtDPI(const wxFont& font,
+                                           const wxRealPoint& dpi,
+                                           const wxColour& col) wxOVERRIDE;
+
     // create a graphics bitmap from a native bitmap
     virtual wxGraphicsBitmap CreateBitmapFromNativeBitmap( void* bitmap ) wxOVERRIDE;
 
@@ -1144,6 +1149,7 @@ wxGDIPlusFontData::Init(const wxString& name,
 
 wxGDIPlusFontData::wxGDIPlusFontData( wxGraphicsRenderer* renderer,
                                       const wxFont &font,
+                                      const wxRealPoint& dpi,
                                       const wxColour& col )
     : wxGraphicsObjectRefData( renderer )
 {
@@ -1157,7 +1163,11 @@ wxGDIPlusFontData::wxGDIPlusFontData( wxGraphicsRenderer* renderer,
     if ( font.GetWeight() == wxFONTWEIGHT_BOLD )
         style |= FontStyleBold;
 
-    Init(font.GetFaceName(), (REAL)(font.GetPixelSize().GetHeight()), style, col);
+    REAL fontSize = (REAL)(!dpi.y
+        ? font.GetPixelSize().GetHeight()
+        : (font.GetFractionalPointSize() * dpi.y / 72.0f));
+
+    Init(font.GetFaceName(), fontSize, style, col);
 }
 
 wxGDIPlusFontData::wxGDIPlusFontData(wxGraphicsRenderer* renderer,
@@ -2720,15 +2730,7 @@ wxGraphicsFont
 wxGDIPlusRenderer::CreateFont( const wxFont &font,
                                const wxColour &col )
 {
-    ENSURE_LOADED_OR_RETURN(wxNullGraphicsFont);
+    return CreateFontAtDPI(font, wxRealPoint(), col);
-    if ( font.IsOk() )
-    {
-        wxGraphicsFont p;
-        p.SetRefData(new wxGDIPlusFontData( this, font, col ));
-        return p;
-    }
-    else
-        return wxNullGraphicsFont;
 }
 
 wxGraphicsFont
@@ -2756,6 +2758,22 @@ wxGDIPlusRenderer::CreateFont(double sizeInPixels,
     return f;
 }
 
+wxGraphicsFont
+wxGDIPlusRenderer::CreateFontAtDPI(const wxFont& font,
+                                   const wxRealPoint& dpi,
+                                   const wxColour& col)
+{
+    ENSURE_LOADED_OR_RETURN(wxNullGraphicsFont);
+    if ( font.IsOk() )
+    {
+        wxGraphicsFont p;
+        p.SetRefData(new wxGDIPlusFontData( this, font, dpi, col ));
+        return p;
+    }
+    else
+        return wxNullGraphicsFont;
+}
+
 wxGraphicsBitmap wxGDIPlusRenderer::CreateBitmap( const wxBitmap &bitmap )
 {
     ENSURE_LOADED_OR_RETURN(wxNullGraphicsBitmap);

src/msw/graphicsd2d.cpp

@@ -2792,7 +2792,7 @@ wxD2DPenData* wxGetD2DPenData(const wxGraphicsPen& pen)
 class wxD2DFontData : public wxGraphicsObjectRefData
 {
 public:
-    wxD2DFontData(wxGraphicsRenderer* renderer, const wxFont& font, const wxColor& color);
+    wxD2DFontData(wxGraphicsRenderer* renderer, const wxFont& font, const wxRealPoint& dpi, const wxColor& color);
 
     wxCOMPtr<IDWriteTextLayout> CreateTextLayout(const wxString& text) const;
 
@@ -2817,7 +2817,7 @@ private:
     bool m_strikethrough;
 };
 
-wxD2DFontData::wxD2DFontData(wxGraphicsRenderer* renderer, const wxFont& font, const wxColor& color) :
+wxD2DFontData::wxD2DFontData(wxGraphicsRenderer* renderer, const wxFont& font, const wxRealPoint& dpi, const wxColor& color) :
     wxGraphicsObjectRefData(renderer), m_brushData(renderer, wxBrush(color)),
     m_underlined(font.GetUnderlined()), m_strikethrough(font.GetStrikethrough())
 {
@@ -2870,13 +2870,17 @@ wxD2DFontData::wxD2DFontData(wxGraphicsRenderer* renderer, const wxFont& font, c
     hr = familyNames->GetString(0, name, length+1);
     wxCHECK_HRESULT_RET(hr);
 
+    FLOAT fontSize = (FLOAT)(!dpi.y
+        ? font.GetPixelSize().GetHeight()
+        : (font.GetFractionalPointSize() * dpi.y / 72.0f));
+
     hr = wxDWriteFactory()->CreateTextFormat(
         name,
         NULL,
         m_font->GetWeight(),
         m_font->GetStyle(),
         m_font->GetStretch(),
-        (FLOAT)(font.GetPixelSize().GetHeight()),
+        fontSize,
         L"en-us",
         &m_textFormat);
 
@@ -3644,7 +3648,7 @@ public:
 
     void Flush() wxOVERRIDE;
 
-    void GetDPI(wxDouble* dpiX, wxDouble* dpiY) wxOVERRIDE;
+    void GetDPI(wxDouble* dpiX, wxDouble* dpiY) const wxOVERRIDE;
 
     wxD2DContextSupplier::ContextType GetContext() wxOVERRIDE
     {
@@ -4570,7 +4574,7 @@ void wxD2DContext::Flush()
     GetRenderTarget()->SetTransform(&currTransform);
 }
 
-void wxD2DContext::GetDPI(wxDouble* dpiX, wxDouble* dpiY)
+void wxD2DContext::GetDPI(wxDouble* dpiX, wxDouble* dpiY) const
 {
     FLOAT x, y;
     GetRenderTarget()->GetDpi(&x, &y);
@@ -4653,6 +4657,10 @@ public :
         int flags = wxFONTFLAG_DEFAULT,
         const wxColour& col = *wxBLACK) wxOVERRIDE;
 
+    virtual wxGraphicsFont CreateFontAtDPI(const wxFont& font,
+                                           const wxRealPoint& dpi,
+                                           const wxColour& col) wxOVERRIDE;
+
     // create a graphics bitmap from a native bitmap
     wxGraphicsBitmap CreateBitmapFromNativeBitmap(void* bitmap) wxOVERRIDE;
 
@@ -4886,7 +4894,30 @@ wxImage wxD2DRenderer::CreateImageFromBitmap(const wxGraphicsBitmap& bmp)
 
 wxGraphicsFont wxD2DRenderer::CreateFont(const wxFont& font, const wxColour& col)
 {
-    wxD2DFontData* fontData = new wxD2DFontData(this, font, col);
+    return CreateFontAtDPI(font, wxRealPoint(), col);
+}
+
+wxGraphicsFont wxD2DRenderer::CreateFont(
+    double sizeInPixels, const wxString& facename,
+    int flags,
+    const wxColour& col)
+{
+    // Use the same DPI as wxFont will use in SetPixelSize, so these cancel
+    // each other out and we are left with the actual pixel size.
+    ScreenHDC hdc;
+    wxRealPoint dpi(::GetDeviceCaps(hdc, LOGPIXELSX),
+                    ::GetDeviceCaps(hdc, LOGPIXELSY));
+
+    return CreateFontAtDPI(
+        wxFontInfo(wxSize(sizeInPixels, sizeInPixels)).AllFlags(flags).FaceName(facename),
+        dpi, col);
+}
+
+wxGraphicsFont wxD2DRenderer::CreateFontAtDPI(const wxFont& font,
+                                              const wxRealPoint& dpi,
+                                              const wxColour& col)
+{
+    wxD2DFontData* fontData = new wxD2DFontData(this, font, dpi, col);
     if ( !fontData->GetFont() )
     {
         // Apparently a non-TrueType font is given and hence
@@ -4901,16 +4932,6 @@ wxGraphicsFont wxD2DRenderer::CreateFont(const wxFont& font, const wxColour& col
     return graphicsFont;
 }
 
-wxGraphicsFont wxD2DRenderer::CreateFont(
-    double sizeInPixels, const wxString& facename,
-    int flags,
-    const wxColour& col)
-{
-    return CreateFont(
-        wxFontInfo(wxSize(sizeInPixels, sizeInPixels)).AllFlags(flags).FaceName(facename),
-        col);
-}
-
 // create a sub-image from a native image representation
 wxGraphicsBitmap wxD2DRenderer::CreateSubBitmap(const wxGraphicsBitmap& bitmap, wxDouble x, wxDouble y, wxDouble w, wxDouble h)
 {

src/osx/carbon/graphics.cpp

@@ -2778,6 +2778,9 @@ public :
                                       const wxString& facename,
                                       int flags = wxFONTFLAG_DEFAULT,
                                       const wxColour& col = *wxBLACK) wxOVERRIDE;
+    virtual wxGraphicsFont CreateFontAtDPI(const wxFont& font,
+                                           const wxRealPoint& dpi,
+                                           const wxColour& col) wxOVERRIDE;
 
     // create a native bitmap representation
     virtual wxGraphicsBitmap CreateBitmap( const wxBitmap &bitmap ) wxOVERRIDE ;
@@ -3073,6 +3076,14 @@ wxMacCoreGraphicsRenderer::CreateFont(double sizeInPixels,
     return f;
 }
 
+wxGraphicsFont
+wxMacCoreGraphicsRenderer::CreateFontAtDPI(const wxFont& font,
+                                           const wxRealPoint& WXUNUSED(dpi),
+                                           const wxColour& col)
+{
+    return CreateFont(font, col);
+}
+
 //
 // CoreGraphics Helper Methods
 //

src/qt/graphics.cpp

@@ -1154,6 +1154,9 @@ public:
         const wxString& facename,
         int flags = wxFONTFLAG_DEFAULT,
         const wxColour& col = *wxBLACK) wxOVERRIDE;
+    virtual wxGraphicsFont CreateFontAtDPI(const wxFont& font,
+                                           const wxRealPoint& dpi,
+                                           const wxColour& col) wxOVERRIDE;
 
     // create a native bitmap representation
     virtual wxGraphicsBitmap CreateBitmap(const wxBitmap& bitmap) wxOVERRIDE;
@@ -1321,6 +1324,14 @@ wxGraphicsFont wxQtGraphicsRenderer::CreateFont(
     return font;
 }
 
+wxGraphicsFont
+wxQtGraphicsRenderer::CreateFontAtDPI(const wxFont& font,
+                                      const wxRealPoint& WXUNUSED(dpi),
+                                      const wxColour& col)
+{
+    return CreateFont(font, col);
+}
+
 wxGraphicsBitmap wxQtGraphicsRenderer::CreateBitmap(const wxBitmap& bmp)
 {
     wxGraphicsBitmap p;