From: Vadim Zeitlin Date: Sun, 27 Feb 2011 12:48:13 +0000 (+0000) Subject: Add wxDC::GetFontMetrics() and implement it for wxMSW. X-Git-Url: https://git.saurik.com/wxWidgets.git/commitdiff_plain/e29bf4b0567856d5a40d6b47ce31762ca1960bc9 Add wxDC::GetFontMetrics() and implement it for wxMSW. Add a new wxDC method allowing to retrieve the font characteristics not available from GetTextExtent(), notably the internal leading (and also the average font width). Currently this is implemented for wxMSW only, the internal leading is always 0 in the other ports. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67063 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775 --- 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 )