1 ///////////////////////////////////////////////////////////////////////////////
2 // Name: wx/private/textmeasure.h
3 // Purpose: declaration of wxTextMeasure class
4 // Author: Manuel Martin
7 // Copyright: (c) 1997-2012 wxWidgets team
8 // Licence: wxWindows licence
9 ///////////////////////////////////////////////////////////////////////////////
11 #ifndef _WX_PRIVATE_TEXTMEASURE_H_
12 #define _WX_PRIVATE_TEXTMEASURE_H_
14 class WXDLLIMPEXP_FWD_CORE wxDC
;
15 class WXDLLIMPEXP_FWD_CORE wxFont
;
16 class WXDLLIMPEXP_FWD_CORE wxWindow
;
18 // ----------------------------------------------------------------------------
19 // wxTextMeasure: class used to measure text extent.
20 // ----------------------------------------------------------------------------
22 class wxTextMeasureBase
25 // The first ctor argument must be non-NULL, i.e. each object of this class
26 // is associated with either a valid wxDC or a valid wxWindow.
27 wxTextMeasureBase(const wxDC
*dc
, const wxFont
*theFont
);
28 wxTextMeasureBase(const wxWindow
*win
, const wxFont
*theFont
);
30 // Even though this class is not supposed to be used polymorphically, give
31 // it a virtual dtor to avoid compiler warnings.
32 virtual ~wxTextMeasureBase() { }
35 // Return the extent of a single line string.
36 void GetTextExtent(const wxString
& string
,
39 wxCoord
*descent
= NULL
,
40 wxCoord
*externalLeading
= NULL
);
42 // The same for a multiline (with '\n') string.
43 void GetMultiLineTextExtent(const wxString
& text
,
46 wxCoord
*heightOneLine
= NULL
);
48 // Find the dimensions of the largest string.
49 wxSize
GetLargestStringExtent(size_t n
, const wxString
* strings
);
50 wxSize
GetLargestStringExtent(const wxArrayString
& strings
)
52 return GetLargestStringExtent(strings
.size(), &strings
[0]);
55 // Fill the array with the widths for each "0..N" substrings for N from 1
58 // The scaleX argument is the horizontal scale used by wxDC and is only
59 // used in the generic implementation.
60 bool GetPartialTextExtents(const wxString
& text
,
65 // These functions are called by our public methods before and after each
66 // call to DoGetTextExtent(). Derived classes may override them to prepare
67 // for -- possibly several -- subsequent calls to DoGetTextExtent().
69 // As these calls must be always paired, they're never called directly but
70 // only by our friend MeasuringGuard class.
72 // NB: They're public only to allow VC6 to compile this code, there doesn't
73 // seem to be any way to give MeasuringGuard access to them (FIXME-VC6)
74 virtual void BeginMeasuring() { }
75 virtual void EndMeasuring() { }
78 // RAII wrapper for the two methods above.
82 MeasuringGuard(wxTextMeasureBase
& tm
) : m_tm(tm
)
84 m_tm
.BeginMeasuring();
93 wxTextMeasureBase
& m_tm
;
97 // The main function of this class, to be implemented in platform-specific
98 // way used by all our public methods.
100 // The width and height pointers here are never NULL and the input string
102 virtual void DoGetTextExtent(const wxString
& string
,
105 wxCoord
*descent
= NULL
,
106 wxCoord
*externalLeading
= NULL
) = 0;
108 // The real implementation of GetPartialTextExtents().
110 // On input, widths array contains text.length() zero elements and the text
111 // is guaranteed to be non-empty.
112 virtual bool DoGetPartialTextExtents(const wxString
& text
,
116 // Call either DoGetTextExtent() or wxDC::GetTextExtent() depending on the
117 // value of m_useDCImpl.
119 // This must be always used instead of calling DoGetTextExtent() directly!
120 void CallGetTextExtent(const wxString
& string
,
123 wxCoord
*descent
= NULL
,
124 wxCoord
*externalLeading
= NULL
);
127 // Exactly one of m_dc and m_win is non-NULL for any given object of this
129 const wxDC
* const m_dc
;
130 const wxWindow
* const m_win
;
132 // If this is true, simply forward to wxDC::GetTextExtent() from our
133 // CallGetTextExtent() instead of calling our own DoGetTextExtent().
135 // We need this because our DoGetTextExtent() typically only works with
136 // native DCs, i.e. those having an HDC under Windows or using Pango under
137 // GTK+. However wxTextMeasure object can be constructed for any wxDC, not
138 // necessarily a native one and in this case we must call back into the DC
139 // implementation of text measuring itself.
142 // This one can be NULL or not.
143 const wxFont
* const m_font
;
145 wxDECLARE_NO_COPY_CLASS(wxTextMeasureBase
);
148 // Include the platform dependant class declaration, if any.
149 #if defined(__WXGTK20__)
150 #include "wx/gtk/private/textmeasure.h"
151 #elif defined(__WXMSW__)
152 #include "wx/msw/private/textmeasure.h"
153 #else // no platform-specific implementation of wxTextMeasure yet
154 #include "wx/generic/private/textmeasure.h"
156 #define wxUSE_GENERIC_TEXTMEASURE 1
159 #ifndef wxUSE_GENERIC_TEXTMEASURE
160 #define wxUSE_GENERIC_TEXTMEASURE 0
163 #endif // _WX_PRIVATE_TEXTMEASURE_H_