diff --git a/include/wx/dc.h b/include/wx/dc.h index aa6b39e260..a06217ab45 100644 --- a/include/wx/dc.h +++ b/include/wx/dc.h @@ -114,6 +114,27 @@ enum wxMappingMode wxMM_POINTS }; +// Description of text characteristics. +struct wxFontMetrics +{ + wxFontMetrics() + { + height = + ascent = + descent = + internalLeading = + externalLeading = + averageWidth = 0; + } + + int height, // Total character height. + ascent, // Part of the height above the baseline. + descent, // Part of the height below the baseline. + internalLeading, // Intra-line spacing. + externalLeading, // Inter-line spacing. + averageWidth; // Average font width, a.k.a. "x-width". +}; + #if WXWIN_COMPATIBILITY_2_8 //----------------------------------------------------------------------------- @@ -375,6 +396,18 @@ public: virtual wxCoord GetCharHeight() const = 0; virtual wxCoord GetCharWidth() const = 0; + + // The derived classes should really override DoGetFontMetrics() to return + // the correct values in the future but for now provide a default + // implementation in terms of DoGetTextExtent() to avoid breaking the + // compilation of all other ports as wxMSW is the only one to implement it. + virtual void DoGetFontMetrics(int *height, + int *ascent, + int *descent, + int *internalLeading, + int *externalLeading, + int *averageWidth) const; + virtual void DoGetTextExtent(const wxString& string, wxCoord *x, wxCoord *y, wxCoord *descent = NULL, @@ -840,6 +873,15 @@ public: wxCoord GetCharWidth() const { return m_pimpl->GetCharWidth(); } + wxFontMetrics GetFontMetrics() const + { + wxFontMetrics fm; + m_pimpl->DoGetFontMetrics(&fm.height, &fm.ascent, &fm.descent, + &fm.internalLeading, &fm.externalLeading, + &fm.averageWidth); + return fm; + } + void GetTextExtent(const wxString& string, wxCoord *x, wxCoord *y, wxCoord *descent = NULL, diff --git a/include/wx/msw/dc.h b/include/wx/msw/dc.h index e8205c4a21..b99da69a1d 100644 --- a/include/wx/msw/dc.h +++ b/include/wx/msw/dc.h @@ -165,6 +165,12 @@ protected: void RealizeScaleAndOrigin(); public: + virtual void DoGetFontMetrics(int *height, + int *ascent, + int *descent, + int *internalLeading, + int *externalLeading, + int *averageWidth) const; virtual void DoGetTextExtent(const wxString& string, wxCoord *x, wxCoord *y, wxCoord *descent = NULL, diff --git a/interface/wx/dc.h b/interface/wx/dc.h index 582474020b..3c0b009072 100644 --- a/interface/wx/dc.h +++ b/interface/wx/dc.h @@ -79,6 +79,28 @@ enum wxMappingMode wxMM_POINTS }; +/** + Simple collection of various font metrics. + + This object is returned by wxDC::GetFontMetrics(). + + @since 2.9.2 + + @library{wxcore} + @category{dc,gdi} + */ +struct wxFontMetrics +{ + /// Constructor initializes all fields to 0. + wxFontMetrics(); + + int height, ///< Total character height. + ascent, ///< Part of the height above the baseline. + descent, ///< Part of the height below the baseline. + internalLeading, ///< Intra-line spacing. + externalLeading, ///< Inter-line spacing. + averageWidth; ///< Average font width, a.k.a. "x-width". +}; /** @@ -773,6 +795,21 @@ public: */ wxCoord GetCharWidth() const; + /** + Returns the various font characteristics. + + This method allows to retrieve some of the font characteristics not + returned by GetTextExtent(), notably internal leading and average + character width. + + Currently this method returns correct results only under wxMSW, in the + other ports the internal leading will always be 0 and the average + character width will be computed as the width of the character 'x'. + + @since 2.9.2 + */ + wxFontMetrics GetFontMetrics() const; + /** Gets the dimensions of the string using the currently selected font. @a string is the text string to measure, @e heightLine, if non @NULL, diff --git a/src/common/dcbase.cpp b/src/common/dcbase.cpp index dd745d02fb..3dea79e650 100644 --- a/src/common/dcbase.cpp +++ b/src/common/dcbase.cpp @@ -1134,6 +1134,27 @@ void wxDCImpl::InheritAttributes(wxWindow *win) SetLayoutDirection(win->GetLayoutDirection()); } +void wxDCImpl::DoGetFontMetrics(int *height, + int *ascent, + int *descent, + int *internalLeading, + int *externalLeading, + int *averageWidth) const +{ + // Average width is typically the same as width of 'x'. + wxCoord h, d; + DoGetTextExtent("x", averageWidth, &h, &d, externalLeading); + + if ( height ) + *height = h; + if ( ascent ) + *ascent = h - d; + if ( descent ) + *descent = d; + if ( internalLeading ) + *internalLeading = 0; +} + //----------------------------------------------------------------------------- // wxDC //----------------------------------------------------------------------------- diff --git a/src/msw/dc.cpp b/src/msw/dc.cpp index b5f8cd1298..81fdb55587 100644 --- a/src/msw/dc.cpp +++ b/src/msw/dc.cpp @@ -1722,6 +1722,31 @@ wxCoord wxMSWDCImpl::GetCharWidth() const return lpTextMetric.tmAveCharWidth; } +void wxMSWDCImpl::DoGetFontMetrics(int *height, + int *ascent, + int *descent, + int *internalLeading, + int *externalLeading, + int *averageWidth) const +{ + TEXTMETRIC tm; + + GetTextMetrics(GetHdc(), &tm); + + if ( height ) + *height = tm.tmHeight; + if ( ascent ) + *ascent = tm.tmAscent; + if ( descent ) + *descent = tm.tmDescent; + if ( internalLeading ) + *internalLeading = tm.tmInternalLeading; + if ( externalLeading ) + *externalLeading = tm.tmExternalLeading; + if ( averageWidth ) + *averageWidth = tm.tmAveCharWidth; +} + void wxMSWDCImpl::DoGetTextExtent(const wxString& string, wxCoord *x, wxCoord *y, wxCoord *descent, wxCoord *externalLeading, const wxFont *font) const @@ -1791,13 +1816,7 @@ void wxMSWDCImpl::DoGetTextExtent(const wxString& string, wxCoord *x, wxCoord *y if ( descent || externalLeading ) { - TEXTMETRIC tm; - ::GetTextMetrics(GetHdc(), &tm); - - if (descent) - *descent = tm.tmDescent; - if (externalLeading) - *externalLeading = tm.tmExternalLeading; + DoGetFontMetrics(NULL, NULL, descent, NULL, externalLeading, NULL); } if ( hfontOld )