Upgrade WX to r74856, mainly to support @2x.

Externals/wxWidgets3/include/wx/private/textmeasure.h

@@ -0,0 +1,174 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/private/textmeasure.h
+// Purpose:     declaration of wxTextMeasure class
+// Author:      Manuel Martin
+// Created:     2012-10-05
+// Copyright:   (c) 1997-2012 wxWidgets team
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_PRIVATE_TEXTMEASURE_H_
+#define _WX_PRIVATE_TEXTMEASURE_H_
+
+class WXDLLIMPEXP_FWD_CORE wxDC;
+class WXDLLIMPEXP_FWD_CORE wxFont;
+class WXDLLIMPEXP_FWD_CORE wxWindow;
+
+// ----------------------------------------------------------------------------
+// wxTextMeasure: class used to measure text extent.
+// ----------------------------------------------------------------------------
+
+class wxTextMeasureBase
+{
+public:
+    // The first ctor argument must be non-NULL, i.e. each object of this class
+    // is associated with either a valid wxDC or a valid wxWindow. The font can
+    // be NULL to use the current DC/window font or can be specified explicitly.
+    wxTextMeasureBase(const wxDC *dc, const wxFont *theFont);
+    wxTextMeasureBase(const wxWindow *win, const wxFont *theFont);
+
+    // Even though this class is not supposed to be used polymorphically, give
+    // it a virtual dtor to avoid compiler warnings.
+    virtual ~wxTextMeasureBase() { }
+
+
+    // Return the extent of a single line string.
+    void GetTextExtent(const wxString& string,
+                       wxCoord *width,
+                       wxCoord *height,
+                       wxCoord *descent = NULL,
+                       wxCoord *externalLeading = NULL);
+
+    // The same for a multiline (with '\n') string.
+    void GetMultiLineTextExtent(const wxString& text,
+                                wxCoord *width,
+                                wxCoord *height,
+                                wxCoord *heightOneLine = NULL);
+
+    // Find the dimensions of the largest string.
+    wxSize GetLargestStringExtent(size_t n, const wxString* strings);
+    wxSize GetLargestStringExtent(const wxArrayString& strings)
+    {
+        return GetLargestStringExtent(strings.size(), &strings[0]);
+    }
+
+    // Fill the array with the widths for each "0..N" substrings for N from 1
+    // to text.length().
+    //
+    // The scaleX argument is the horizontal scale used by wxDC and is only
+    // used in the generic implementation.
+    bool GetPartialTextExtents(const wxString& text,
+                               wxArrayInt& widths,
+                               double scaleX);
+
+
+    // These functions are called by our public methods before and after each
+    // call to DoGetTextExtent(). Derived classes may override them to prepare
+    // for -- possibly several -- subsequent calls to DoGetTextExtent().
+    //
+    // As these calls must be always paired, they're never called directly but
+    // only by our friend MeasuringGuard class.
+    //
+    // NB: They're public only to allow VC6 to compile this code, there doesn't
+    //     seem to be any way to give MeasuringGuard access to them (FIXME-VC6)
+    virtual void BeginMeasuring() { }
+    virtual void EndMeasuring() { }
+
+    // This is another method which is only used by MeasuringGuard.
+    bool IsUsingDCImpl() const { return m_useDCImpl; }
+
+protected:
+    // RAII wrapper for the two methods above.
+    class MeasuringGuard
+    {
+    public:
+        MeasuringGuard(wxTextMeasureBase& tm) : m_tm(tm)
+        {
+            // BeginMeasuring() should only be called if we have a native DC,
+            // so don't call it if we delegate to a DC of unknown type.
+            if ( !m_tm.IsUsingDCImpl() )
+                m_tm.BeginMeasuring();
+        }
+
+        ~MeasuringGuard()
+        {
+            if ( !m_tm.IsUsingDCImpl() )
+                m_tm.EndMeasuring();
+        }
+
+    private:
+        wxTextMeasureBase& m_tm;
+    };
+
+
+    // The main function of this class, to be implemented in platform-specific
+    // way used by all our public methods.
+    //
+    // The width and height pointers here are never NULL and the input string
+    // is not empty.
+    virtual void DoGetTextExtent(const wxString& string,
+                                 wxCoord *width,
+                                 wxCoord *height,
+                                 wxCoord *descent = NULL,
+                                 wxCoord *externalLeading = NULL) = 0;
+
+    // The real implementation of GetPartialTextExtents().
+    //
+    // On input, widths array contains text.length() zero elements and the text
+    // is guaranteed to be non-empty.
+    virtual bool DoGetPartialTextExtents(const wxString& text,
+                                         wxArrayInt& widths,
+                                         double scaleX) = 0;
+
+    // Call either DoGetTextExtent() or wxDC::GetTextExtent() depending on the
+    // value of m_useDCImpl.
+    //
+    // This must be always used instead of calling DoGetTextExtent() directly!
+    void CallGetTextExtent(const wxString& string,
+                           wxCoord *width,
+                           wxCoord *height,
+                           wxCoord *descent = NULL,
+                           wxCoord *externalLeading = NULL);
+
+    // Return a valid font: if one was given to us in the ctor, use this one,
+    // otherwise use the current font of the associated wxDC or wxWindow.
+    wxFont GetFont() const;
+
+
+    // Exactly one of m_dc and m_win is non-NULL for any given object of this
+    // class.
+    const wxDC* const m_dc;
+    const wxWindow* const m_win;
+
+    // If this is true, simply forward to wxDC::GetTextExtent() from our
+    // CallGetTextExtent() instead of calling our own DoGetTextExtent().
+    //
+    // We need this because our DoGetTextExtent() typically only works with
+    // native DCs, i.e. those having an HDC under Windows or using Pango under
+    // GTK+. However wxTextMeasure object can be constructed for any wxDC, not
+    // necessarily a native one and in this case we must call back into the DC
+    // implementation of text measuring itself.
+    bool m_useDCImpl;
+
+    // This one can be NULL or not.
+    const wxFont* const m_font;
+
+    wxDECLARE_NO_COPY_CLASS(wxTextMeasureBase);
+};
+
+// Include the platform dependant class declaration, if any.
+#if defined(__WXGTK20__)
+    #include "wx/gtk/private/textmeasure.h"
+#elif defined(__WXMSW__)
+    #include "wx/msw/private/textmeasure.h"
+#else // no platform-specific implementation of wxTextMeasure yet
+    #include "wx/generic/private/textmeasure.h"
+
+    #define wxUSE_GENERIC_TEXTMEASURE 1
+#endif
+
+#ifndef wxUSE_GENERIC_TEXTMEASURE
+    #define wxUSE_GENERIC_TEXTMEASURE 0
+#endif
+
+#endif // _WX_PRIVATE_TEXTMEASURE_H_