extracted wxWrapSizer in separate files and somewhat improved it (heavily modified patch 1876663)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@53500 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/wrapsizer.h

@@ -0,0 +1,101 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        wx/wrapsizer.h
+// Purpose:     provide wrapping sizer for layout (wxWrapSizer)
+// Author:      Arne Steinarson
+// Created:     2008-05-08
+// RCS-ID:      $Id$
+// Copyright:   (c) Arne Steinarson
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_WRAPSIZER_H_
+#define _WX_WRAPSIZER_H_
+
+#include "wx/sizer.h"
+
+// flags for wxWrapSizer
+enum
+{
+    wxEXTEND_LAST_ON_EACH_LINE = 1,
+    // don't leave spacers in the beginning of a new row
+    wxREMOVE_LEADING_SPACES = 2,
+
+    wxWRAPSIZER_DEFAULT_FLAGS = wxEXTEND_LAST_ON_EACH_LINE |
+                                wxREMOVE_LEADING_SPACES
+};
+
+// ----------------------------------------------------------------------------
+// A box sizer that can wrap items on several lines when sum of widths exceed
+// available line width.
+// ----------------------------------------------------------------------------
+
+class WXDLLEXPORT wxWrapSizer : public wxBoxSizer
+{
+public:
+    wxWrapSizer(int orient = wxHORIZONTAL, int flags = wxWRAPSIZER_DEFAULT_FLAGS);
+    virtual ~wxWrapSizer();
+
+    // override base class virtual methods
+    virtual wxSize CalcMin();
+    virtual void RecalcSizes();
+
+protected:
+    // This method is called to decide if an item represents empty space or
+    // not. We do this to avoid having space-only items first or last on a
+    // wrapped line (left alignment).
+    //
+    // By default only spacers are considered to be empty items but a derived
+    // class may override this item if some other kind of sizer elements should
+    // be also considered empty for some reason.
+    virtual bool IsSpaceItem(wxSizerItem *item) const
+    {
+        return item->IsSpacer();
+    }
+
+    virtual bool InformFirstDirection(int direction,
+                                      int size,
+                                      int availableOtherDir );
+
+    // helpers of CalcMin()
+    void CalcMinFromMinor(int totMinor);
+    void CalcMinFromMajor(int totMajor);
+    void CalcMinUsingCurrentLayout();
+    void CalcMinFittingSize(const wxSize& szBoundary);
+    void CalcMaxSingleItemSize();
+
+    // temporarily change the proportion of the last item of the N-th row to
+    // extend to the end of line if the appropriate flag is set
+    void AdjustLastRowItemProp(size_t n, wxSizerItem *itemLast);
+
+    // remove all the items from m_rows
+    void ClearRows();
+
+    // return the N-th row sizer from m_rows creating it if necessary
+    wxSizer *GetRowSizer(size_t n);
+
+    // should be called after completion of each row
+    void FinishRow(size_t n, int rowMajor, int rowMinor, wxSizerItem *itemLast);
+
+
+    const int m_flags;       // Flags specified in the ctor
+
+    int m_dirInform;         // Direction for size information
+    int m_availSize;         // Size available in m_dirInform direction
+    int m_availableOtherDir; // Size available in the other direction
+    bool m_lastUsed;         // Indicates whether value from InformFirst... has
+                             //  been used yet
+
+    // The sizes below are computed by RecalcSizes(), i.e. they don't have
+    // valid values during the initial call to CalcMin() and they are only
+    // valid for the current layout (i.e. the current number of rows)
+    int m_minSizeMinor;      // Min size in minor direction
+    int m_maxSizeMajor;      // Size of longest row
+    int m_minItemMajor;      // Size of smallest item in major direction
+
+    wxBoxSizer m_rows;       // Sizer containing multiple rows of our items
+
+private:
+    DECLARE_DYNAMIC_CLASS_NO_COPY(wxWrapSizer);
+};
+
+#endif // _WX_WRAPSIZER_H_