treectrl.cpp

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/////////////////////////////////////////////////////////////////////////////
// Name:        src/msw/treectrl.cpp
// Purpose:     wxTreeCtrl
// Author:      Julian Smart
// Modified by: Vadim Zeitlin to be less MSW-specific on 10.10.98
// Created:     1997
// RCS-ID:      $Id: treectrl.cpp,v 1.208.2.1 2005/12/01 11:05:31 ABX Exp $
// Copyright:   (c) Julian Smart
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// ============================================================================
// declarations
// ============================================================================

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------

#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
    #pragma implementation "treectrl.h"
#endif

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

#if wxUSE_TREECTRL

#include "wx/msw/private.h"

// include <commctrl.h> "properly"
#include "wx/msw/wrapcctl.h"

#include "wx/msw/missing.h"

// Set this to 1 to be _absolutely_ sure that repainting will work for all
// comctl32.dll versions
#define wxUSE_COMCTL32_SAFELY 0

#include "wx/app.h"
#include "wx/log.h"
#include "wx/dynarray.h"
#include "wx/imaglist.h"
#include "wx/settings.h"
#include "wx/msw/treectrl.h"
#include "wx/msw/dragimag.h"

// macros to hide the cast ugliness
// --------------------------------

// ptr is the real item id, i.e. wxTreeItemId::m_pItem
#define HITEM_PTR(ptr)     (HTREEITEM)(ptr)

// item here is a wxTreeItemId
#define HITEM(item)     HITEM_PTR((item).m_pItem)

// the native control doesn't support multiple selections under MSW and we
// have 2 ways to emulate them: either using TVS_CHECKBOXES style and let
// checkboxes be the selection status (checked == selected) or by really
// emulating everything, i.e. intercepting mouse and key events &c. The first
// approach is much easier but doesn't work with comctl32.dll < 4.71 and also
// looks quite ugly.
#define wxUSE_CHECKBOXES_IN_MULTI_SEL_TREE 0

// ----------------------------------------------------------------------------
// private functions
// ----------------------------------------------------------------------------

// wrapper for TreeView_HitTest
static HTREEITEM GetItemFromPoint(HWND hwndTV, int x, int y)
{
    TV_HITTESTINFO tvht;
    tvht.pt.x = x;
    tvht.pt.y = y;

    return (HTREEITEM)TreeView_HitTest(hwndTV, &tvht);
}

#if !wxUSE_CHECKBOXES_IN_MULTI_SEL_TREE

// wrappers for TreeView_GetItem/TreeView_SetItem
static bool IsItemSelected(HWND hwndTV, HTREEITEM hItem)
{

    TV_ITEM tvi;
    tvi.mask = TVIF_STATE | TVIF_HANDLE;
    tvi.stateMask = TVIS_SELECTED;
    tvi.hItem = hItem;

    if ( !TreeView_GetItem(hwndTV, &tvi) )
    {
        wxLogLastError(wxT("TreeView_GetItem"));
    }

    return (tvi.state & TVIS_SELECTED) != 0;
}

static bool SelectItem(HWND hwndTV, HTREEITEM hItem, bool select = true)
{
    TV_ITEM tvi;
    tvi.mask = TVIF_STATE | TVIF_HANDLE;
    tvi.stateMask = TVIS_SELECTED;
    tvi.state = select ? TVIS_SELECTED : 0;
    tvi.hItem = hItem;

    if ( TreeView_SetItem(hwndTV, &tvi) == -1 )
    {
        wxLogLastError(wxT("TreeView_SetItem"));
        return false;
    }

    return true;
}

static inline void UnselectItem(HWND hwndTV, HTREEITEM htItem)
{
    SelectItem(hwndTV, htItem, false);
}

static inline void ToggleItemSelection(HWND hwndTV, HTREEITEM htItem)
{
    SelectItem(hwndTV, htItem, !IsItemSelected(hwndTV, htItem));
}

// helper function which selects all items in a range and, optionally,
// unselects all others
static void SelectRange(HWND hwndTV,
                        HTREEITEM htFirst,
                        HTREEITEM htLast,
                        bool unselectOthers = true)
{
    // find the first (or last) item and select it
    bool cont = true;
    HTREEITEM htItem = (HTREEITEM)TreeView_GetRoot(hwndTV);
    while ( htItem && cont )
    {
        if ( (htItem == htFirst) || (htItem == htLast) )
        {
            if ( !IsItemSelected(hwndTV, htItem) )
            {
                SelectItem(hwndTV, htItem);
            }

            cont = false;
        }
        else
        {
            if ( unselectOthers && IsItemSelected(hwndTV, htItem) )
            {
                UnselectItem(hwndTV, htItem);
            }
        }

        htItem = (HTREEITEM)TreeView_GetNextVisible(hwndTV, htItem);
    }

    // select the items in range
    cont = htFirst != htLast;
    while ( htItem && cont )
    {
        if ( !IsItemSelected(hwndTV, htItem) )
        {
            SelectItem(hwndTV, htItem);
        }

        cont = (htItem != htFirst) && (htItem != htLast);

        htItem = (HTREEITEM)TreeView_GetNextVisible(hwndTV, htItem);
    }

    // unselect the rest
    if ( unselectOthers )
    {
        while ( htItem )
        {
            if ( IsItemSelected(hwndTV, htItem) )
            {
                UnselectItem(hwndTV, htItem);
            }

            htItem = (HTREEITEM)TreeView_GetNextVisible(hwndTV, htItem);
        }
    }

    // seems to be necessary - otherwise the just selected items don't always
    // appear as selected
    UpdateWindow(hwndTV);
}

// helper function which tricks the standard control into changing the focused
// item without changing anything else (if someone knows why Microsoft doesn't
// allow to do it by just setting TVIS_FOCUSED flag, please tell me!)
static void SetFocus(HWND hwndTV, HTREEITEM htItem)
{
    // the current focus
    HTREEITEM htFocus = (HTREEITEM)TreeView_GetSelection(hwndTV);

    if ( htItem )
    {
        // set the focus
        if ( htItem != htFocus )
        {
            // remember the selection state of the item
            bool wasSelected = IsItemSelected(hwndTV, htItem);

            if ( htFocus && IsItemSelected(hwndTV, htFocus) )
            {
                // prevent the tree from unselecting the old focus which it
                // would do by default (TreeView_SelectItem unselects the
                // focused item)
                TreeView_SelectItem(hwndTV, 0);
                SelectItem(hwndTV, htFocus);
            }

            TreeView_SelectItem(hwndTV, htItem);

            if ( !wasSelected )
            {
                // need to clear the selection which TreeView_SelectItem() gave
                // us
                UnselectItem(hwndTV, htItem);
            }
            //else: was selected, still selected - ok
        }
        //else: nothing to do, focus already there
    }
    else
    {
        if ( htFocus )
        {
            bool wasFocusSelected = IsItemSelected(hwndTV, htFocus);

            // just clear the focus
            TreeView_SelectItem(hwndTV, 0);

            if ( wasFocusSelected )
            {
                // restore the selection state
                SelectItem(hwndTV, htFocus);
            }
        }
        //else: nothing to do, no focus already
    }
}

#endif // wxUSE_CHECKBOXES_IN_MULTI_SEL_TREE

// ----------------------------------------------------------------------------
// private classes
// ----------------------------------------------------------------------------

// a convenient wrapper around TV_ITEM struct which adds a ctor
#ifdef __VISUALC__
#pragma warning( disable : 4097 ) // inheriting from typedef
#endif

struct wxTreeViewItem : public TV_ITEM
{
    wxTreeViewItem(const wxTreeItemId& item,    // the item handle
                   UINT mask_,                  // fields which are valid
                   UINT stateMask_ = 0)         // for TVIF_STATE only
    {
        wxZeroMemory(*this);

        // hItem member is always valid
        mask = mask_ | TVIF_HANDLE;
        stateMask = stateMask_;
        hItem = HITEM(item);
    }
};

// wxVirutalNode is used in place of a single root when 'hidden' root is
// specified.
class wxVirtualNode : public wxTreeViewItem
{
public:
    wxVirtualNode(wxTreeItemData *data)
        : wxTreeViewItem(TVI_ROOT, 0)
    {
        m_data = data;
    }

    ~wxVirtualNode()
    {
        delete m_data;
    }

    wxTreeItemData *GetData() const { return m_data; }
    void SetData(wxTreeItemData *data) { delete m_data; m_data = data; }

private:
    wxTreeItemData *m_data;

    DECLARE_NO_COPY_CLASS(wxVirtualNode)
};

#ifdef __VISUALC__
#pragma warning( default : 4097 )
#endif

// a macro to get the virtual root, returns NULL if none
#define GET_VIRTUAL_ROOT() ((wxVirtualNode *)m_pVirtualRoot)

// returns true if the item is the virtual root
#define IS_VIRTUAL_ROOT(item) (HITEM(item) == TVI_ROOT)

// a class which encapsulates the tree traversal logic: it vists all (unless
// OnVisit() returns false) items under the given one
class wxTreeTraversal
{
public:
    wxTreeTraversal(const wxTreeCtrl *tree)
    {
        m_tree = tree;
    }

    // do traverse the tree: visit all items (recursively by default) under the
    // given one; return true if all items were traversed or false if the
    // traversal was aborted because OnVisit returned false
    bool DoTraverse(const wxTreeItemId& root, bool recursively = true);

    // override this function to do whatever is needed for each item, return
    // false to stop traversing
    virtual bool OnVisit(const wxTreeItemId& item) = 0;

protected:
    const wxTreeCtrl *GetTree() const { return m_tree; }

private:
    bool Traverse(const wxTreeItemId& root, bool recursively);

    const wxTreeCtrl *m_tree;

    DECLARE_NO_COPY_CLASS(wxTreeTraversal)
};

// internal class for getting the selected items
class TraverseSelections : public wxTreeTraversal
{
public:
    TraverseSelections(const wxTreeCtrl *tree,
                       wxArrayTreeItemIds& selections)
        : wxTreeTraversal(tree), m_selections(selections)
        {
            m_selections.Empty();

            if (tree->GetCount() > 0)
                DoTraverse(tree->GetRootItem());
        }

    virtual bool OnVisit(const wxTreeItemId& item)
    {
        // can't visit a virtual node.
        if ( (GetTree()->GetRootItem() == item) && (GetTree()->GetWindowStyle() & wxTR_HIDE_ROOT))
        {
            return true;
        }

#if wxUSE_CHECKBOXES_IN_MULTI_SEL_TREE
        if ( GetTree()->IsItemChecked(item) )
#else
        if ( ::IsItemSelected(GetHwndOf(GetTree()), HITEM(item)) )
#endif
        {
            m_selections.Add(item);
        }

        return true;
    }

    size_t GetCount() const { return m_selections.GetCount(); }

private:
    wxArrayTreeItemIds& m_selections;

    DECLARE_NO_COPY_CLASS(TraverseSelections)
};

// internal class for counting tree items
class TraverseCounter : public wxTreeTraversal
{
public:
    TraverseCounter(const wxTreeCtrl *tree,
                    const wxTreeItemId& root,
                    bool recursively)
        : wxTreeTraversal(tree)
        {
            m_count = 0;

            DoTraverse(root, recursively);
        }

    virtual bool OnVisit(const wxTreeItemId& WXUNUSED(item))
    {
        m_count++;

        return true;
    }

    size_t GetCount() const { return m_count; }

private:
    size_t m_count;

    DECLARE_NO_COPY_CLASS(TraverseCounter)
};

// ----------------------------------------------------------------------------
// This class is needed for support of different images: the Win32 common
// control natively supports only 2 images (the normal one and another for the
// selected state). We wish to provide support for 2 more of them for folder
// items (i.e. those which have children): for expanded state and for expanded
// selected state. For this we use this structure to store the additional items
// images.
//
// There is only one problem with this: when we retrieve the item's data, we
// don't know whether we get a pointer to wxTreeItemData or
// wxTreeItemIndirectData. So we always set the item id to an invalid value
// in this class and the code using the client data checks for it and retrieves
// the real client data in this case.
// ----------------------------------------------------------------------------

class wxTreeItemIndirectData : public wxTreeItemData
{
public:
    // ctor associates this data with the item and the real item data becomes
    // available through our GetData() method
    wxTreeItemIndirectData(wxTreeCtrl *tree, const wxTreeItemId& item)
    {
        for ( size_t n = 0; n < WXSIZEOF(m_images); n++ )
        {
            m_images[n] = -1;
        }

        // save the old data
        m_data = tree->GetItemData(item);