Geografic-Information-System/gui/wxpython/gui_modules/wxgui_utils.py

"""!
@package wxgui_utils.py

@brief Utility classes for GRASS wxPython GUI. Main functions include
tree control for GIS map layer management, command console, and
command parsing.

Classes:
 - AbstractLayer
 - Layer
 - LayerTree

(C) 2007-2009 by the GRASS Development Team
This program is free software under the GNU General Public
License (>=v2). Read the file COPYING that comes with GRASS
for details.
 
@author Michael Barton (Arizona State University)
@author Jachym Cepicky (Mendel University of Agriculture)
@author Martin Landa <landa.martin gmail.com>
"""

import os
import sys
import string

import wx
import wx.lib.customtreectrl as CT
import wx.combo
import wx.lib.newevent
import wx.lib.buttons  as  buttons

from grass.script import core as grass

import gdialogs
import globalvar
import menuform
import toolbars
import mapdisp
import render
import histogram
import utils
import profile
from debug import Debug as Debug
from icon import Icons as Icons
from preferences import globalSettings as UserSettings
from vdigit import haveVDigit
try:
    import subprocess
except:
    from compat import subprocess
    
try:
    import treemixin 
except ImportError:
    from wx.lib.mixins import treemixin


TREE_ITEM_HEIGHT = 25

class LayerTree(treemixin.DragAndDrop, CT.CustomTreeCtrl):
    """
    Creates layer tree structure
    """
    def __init__(self, parent,
                 id=wx.ID_ANY, pos=wx.DefaultPosition,
                 size=wx.DefaultSize, style=wx.SUNKEN_BORDER,
                 ctstyle=CT.TR_HAS_BUTTONS | CT.TR_HAS_VARIABLE_ROW_HEIGHT |
                 CT.TR_HIDE_ROOT | CT.TR_ROW_LINES | CT.TR_FULL_ROW_HIGHLIGHT |
                 CT.TR_MULTIPLE,**kargs):
        self.items = []
        self.itemCounter = 0
        super(LayerTree, self).__init__(parent, id, pos, size, style=style, ctstyle=ctstyle)
        self.SetName("LayerTree")

        ### SetAutoLayout() causes that no vertical scrollbar is displayed
        ### when some layers are not visible in layer tree
        # self.SetAutoLayout(True)
        self.SetGradientStyle(1)
        self.EnableSelectionGradient(True)
        self.SetFirstGradientColour(wx.Colour(100, 100, 100))
        self.SetSecondGradientColour(wx.Colour(150, 150, 150))

        self.Map = render.Map()    # instance of render.Map to be associated with display
        self.root = None           # ID of layer tree root node
        self.groupnode = 0         # index value for layers
        self.optpage = {}          # dictionary of notebook option pages for each map layer
        self.layer_selected = None # ID of currently selected layer
        self.saveitem = {}         # dictionary to preserve layer attributes for drag and drop
        self.first = True          # indicates if a layer is just added or not
        self.flag = ''             # flag for drag and drop hittest
        self.disp_idx = kargs['idx']
        self.lmgr = kargs['lmgr']
        self.notebook = kargs['notebook']   # GIS Manager notebook for layer tree
        self.treepg = parent        # notebook page holding layer tree
        self.auimgr = kargs['auimgr']       # aui manager
        self.rerender = False       # layer change requires a rerendering if auto render
        self.reorder = False        # layer change requires a reordering

        # init associated map display
        pos = wx.Point((self.disp_idx + 1) * 25, (self.disp_idx + 1) * 25)
        self.mapdisplay = mapdisp.MapFrame(self,
                                           id=wx.ID_ANY, pos=pos,
                                           size=globalvar.MAP_WINDOW_SIZE,
                                           style=wx.DEFAULT_FRAME_STYLE,
                                           tree=self, notebook=self.notebook,
                                           lmgr=self.lmgr, page=self.treepg,
                                           Map=self.Map, auimgr=self.auimgr)

        # title
        self.mapdisplay.SetTitle(_("GRASS GIS Map Display: %d  - Location: %s") % \
                                     (self.disp_idx + 1, grass.gisenv()["LOCATION_NAME"]))
        
        # show new display
        if kargs['showMapDisplay'] is True:
            self.mapdisplay.Show()
            self.mapdisplay.Refresh()
            self.mapdisplay.Update()

        self.root = self.AddRoot(_("Map Layers"))
        self.SetPyData(self.root, (None,None))
        self.items = []

        #create image list to use with layer tree
        il = wx.ImageList(16, 16, mask=False)

        trart = wx.ArtProvider.GetBitmap(wx.ART_FOLDER_OPEN, wx.ART_OTHER, (16, 16))
        self.folder_open = il.Add(trart)
        trart = wx.ArtProvider.GetBitmap(wx.ART_FOLDER, wx.ART_OTHER, (16, 16))
        self.folder = il.Add(trart)

        bmpsize = (16, 16)
        trgif = Icons["addrast"].GetBitmap(bmpsize)
        self.rast_icon = il.Add(trgif)

        trgif = Icons["addrast3d"].GetBitmap(bmpsize)
        self.rast3d_icon = il.Add(trgif)

        trgif = Icons["addrgb"].GetBitmap(bmpsize)
        self.rgb_icon = il.Add(trgif)
        
        trgif = Icons["addhis"].GetBitmap(bmpsize)
        self.his_icon = il.Add(trgif)

        trgif = Icons["addshaded"].GetBitmap(bmpsize)
        self.shaded_icon = il.Add(trgif)

        trgif = Icons["addrarrow"].GetBitmap(bmpsize)
        self.rarrow_icon = il.Add(trgif)

        trgif = Icons["addrnum"].GetBitmap(bmpsize)
        self.rnum_icon = il.Add(trgif)

        trgif = Icons["addvect"].GetBitmap(bmpsize)
        self.vect_icon = il.Add(trgif)

        trgif = Icons["addthematic"].GetBitmap(bmpsize)
        self.theme_icon = il.Add(trgif)

        trgif = Icons["addchart"].GetBitmap(bmpsize)
        self.chart_icon = il.Add(trgif)

        trgif = Icons["addgrid"].GetBitmap(bmpsize)
        self.grid_icon = il.Add(trgif)

        trgif = Icons["addgeodesic"].GetBitmap(bmpsize)
        self.geodesic_icon = il.Add(trgif)

        trgif = Icons["addrhumb"].GetBitmap(bmpsize)
        self.rhumb_icon = il.Add(trgif)

        trgif = Icons["addlabels"].GetBitmap(bmpsize)
        self.labels_icon = il.Add(trgif)

        trgif = Icons["addcmd"].GetBitmap(bmpsize)
        self.cmd_icon = il.Add(trgif)

        self.AssignImageList(il)

        # use when groups implemented
        ## self.tree.SetItemImage(self.root, fldridx, wx.TreeItemIcon_Normal)
        ## self.tree.SetItemImage(self.root, fldropenidx, wx.TreeItemIcon_Expanded)

        self.Bind(wx.EVT_TREE_ITEM_EXPANDING,   self.OnExpandNode)
        self.Bind(wx.EVT_TREE_ITEM_COLLAPSED,   self.OnCollapseNode)
        self.Bind(wx.EVT_TREE_ITEM_ACTIVATED,   self.OnActivateLayer)
        self.Bind(wx.EVT_TREE_SEL_CHANGED,      self.OnChangeSel)
        self.Bind(CT.EVT_TREE_ITEM_CHECKED,     self.OnLayerChecked)
        self.Bind(wx.EVT_TREE_DELETE_ITEM,      self.OnDeleteLayer)
        self.Bind(wx.EVT_TREE_ITEM_RIGHT_CLICK, self.OnLayerContextMenu)
        #self.Bind(wx.EVT_TREE_BEGIN_DRAG,       self.OnDrag)
        self.Bind(wx.EVT_TREE_END_DRAG,         self.OnEndDrag)
        #self.Bind(wx.EVT_TREE_END_LABEL_EDIT,   self.OnChangeLayerName)
        self.Bind(wx.EVT_KEY_UP,                self.OnKeyUp)
        # self.Bind(wx.EVT_CLOSE, self.OnCloseWindow)
        self.Bind(wx.EVT_IDLE,                  self.OnIdle)
                
    def OnIdle(self, event):
        """
        Only re-order and re-render a composite map image from GRASS during
        idle time instead of multiple times during layer changing.
        """
        if self.rerender:
            if self.mapdisplay.statusbarWin['render'].GetValue():
                self.mapdisplay.MapWindow.UpdateMap(render=True)

        event.Skip()
        
    def OnKeyUp(self, event):
        """!Key pressed"""
        key = event.GetKeyCode()
        if key == wx.WXK_DELETE and self.lmgr:
            self.lmgr.OnDeleteLayer(None)

        event.Skip()

    #def OnChangeLayerName (self, event):
    #    """!Change layer name"""
    #    Debug.msg (3, "LayerTree.OnChangeLayerName: name=%s" % event.GetLabel())

    def OnLayerContextMenu (self, event):
        """!Contextual menu for item/layer"""
        if not self.layer_selected:
            event.Skip()
            return

        ltype = self.GetPyData(self.layer_selected)[0]['type']

        Debug.msg (4, "LayerTree.OnContextMenu: layertype=%s" % \
                       ltype)

        if not hasattr (self, "popupID1"):
            self.popupID1 = wx.NewId()
            self.popupID2 = wx.NewId()
            self.popupID3 = wx.NewId()
            self.popupID4 = wx.NewId()
            self.popupID5 = wx.NewId()
            self.popupID6 = wx.NewId()
            self.popupID7 = wx.NewId()
            self.popupID8 = wx.NewId()
            self.popupID9 = wx.NewId()
            self.popupID10 = wx.NewId()
            self.popupID11 = wx.NewId() # nviz
            self.popupID12 = wx.NewId()
            self.popupID13 = wx.NewId()
            self.popupID14 = wx.NewId()
            self.popupID15 = wx.NewId()

        self.popupMenu = wx.Menu()

        numSelected = len(self.GetSelections())
        
        # general item
        self.popupMenu.Append(self.popupID1, text=_("Remove"))
        self.Bind(wx.EVT_MENU, self.lmgr.OnDeleteLayer, id=self.popupID1)

        if ltype != "command": # rename
            self.popupMenu.Append(self.popupID2, text=_("Rename"))
            self.Bind(wx.EVT_MENU, self.RenameLayer, id=self.popupID2)
            if numSelected > 1:
                self.popupMenu.Enable(self.popupID2, False)
            
        # map layer items
        if ltype != "group" and \
                ltype != "command":
            self.popupMenu.AppendSeparator()
            self.popupMenu.Append(self.popupID8, text=_("Change opacity level"))
            self.Bind(wx.EVT_MENU, self.OnPopupOpacityLevel, id=self.popupID8)
            self.popupMenu.Append(self.popupID3, text=_("Properties"))
            self.Bind(wx.EVT_MENU, self.OnPopupProperties, id=self.popupID3)
            if ltype in ('raster', 'vector'):
                self.popupMenu.Append(self.popupID9, text=_("Zoom to selected map(s)"))
                self.Bind(wx.EVT_MENU, self.mapdisplay.MapWindow.OnZoomToMap, id=self.popupID9)
                self.popupMenu.Append(self.popupID10, text=_("Set computational region from selected map(s)"))
                self.Bind(wx.EVT_MENU, self.OnSetCompRegFromMap, id=self.popupID10)
            if numSelected > 1:
                self.popupMenu.Enable(self.popupID8, False)
                self.popupMenu.Enable(self.popupID3, False)
            
        # specific items
        try:
            mltype = self.GetPyData(self.layer_selected)[0]['type']
        except:
            mltype = None
        #
        # vector layers (specific items)
        #
        if mltype and mltype == "vector":
            self.popupMenu.AppendSeparator()
            self.popupMenu.Append(self.popupID4, text=_("Show attribute data"))
            self.Bind (wx.EVT_MENU, self.lmgr.OnShowAttributeTable, id=self.popupID4)

            self.popupMenu.Append(self.popupID5, text=_("Start editing"))
            self.popupMenu.Append(self.popupID6, text=_("Stop editing"))
            self.popupMenu.Enable(self.popupID6, False)
            self.Bind (wx.EVT_MENU, self.OnStartEditing, id=self.popupID5)
            self.Bind (wx.EVT_MENU, self.OnStopEditing,  id=self.popupID6)

            layer = self.GetPyData(self.layer_selected)[0]['maplayer']
            # enable editing only for vector map layers available in the current mapset
            digitToolbar = self.mapdisplay.toolbars['vdigit']
            if digitToolbar:
                # background vector map
                self.popupMenu.Append(self.popupID14,
                                      text=_("Use as background vector map"),
                                      kind=wx.ITEM_CHECK)
                self.Bind(wx.EVT_MENU, self.OnSetBgMap, id=self.popupID14)
                if UserSettings.Get(group='vdigit', key='bgmap', subkey='value',
                                    internal=True) == layer.GetName():
                    self.popupMenu.Check(self.popupID14, True)
            
            if layer.GetMapset() != grass.gisenv()['MAPSET']:
                # only vector map in current mapset can be edited
                self.popupMenu.Enable (self.popupID5, False)
                self.popupMenu.Enable (self.popupID6, False)
            elif digitToolbar and digitToolbar.GetLayer():
                # vector map already edited
                vdigitLayer = digitToolbar.GetLayer()
                if vdigitLayer is layer:
                    # disable 'start editing'
                    self.popupMenu.Enable (self.popupID5, False)
                    # enable 'stop editing'
                    self.popupMenu.Enable(self.popupID6, True)
                    # disable 'remove'
                    self.popupMenu.Enable(self.popupID1, False)
                    # disable 'bgmap'
                    self.popupMenu.Enable(self.popupID14, False)
                else:
                    # disable 'start editing'
                    self.popupMenu.Enable(self.popupID5, False)
                    # disable 'stop editing'
                    self.popupMenu.Enable(self.popupID6, False)
                    # enable 'bgmap'
                    self.popupMenu.Enable(self.popupID14, True)
            
            self.popupMenu.Append(self.popupID7, _("Metadata"))
            self.Bind (wx.EVT_MENU, self.OnMetadata, id=self.popupID7)
            if numSelected > 1:
                self.popupMenu.Enable(self.popupID4, False)
                self.popupMenu.Enable(self.popupID5, False)
                self.popupMenu.Enable(self.popupID6, False)
                self.popupMenu.Enable(self.popupID7, False)
                self.popupMenu.Enable(self.popupID14, False)
        
        #
        # raster layers (specific items)
        #
        elif mltype and mltype == "raster":
            self.popupMenu.Append(self.popupID12, text=_("Zoom to selected map(s) (ignore NULLs)"))
            self.Bind(wx.EVT_MENU, self.mapdisplay.MapWindow.OnZoomToRaster, id=self.popupID12)
            self.popupMenu.Append(self.popupID13, text=_("Set computational region from selected map(s) (ignore NULLs)"))
            self.Bind(wx.EVT_MENU, self.OnSetCompRegFromRaster, id=self.popupID13)
            self.popupMenu.AppendSeparator()
            self.popupMenu.Append(self.popupID15, _("Set color table"))
            self.Bind (wx.EVT_MENU, self.OnColorTable, id=self.popupID15)
            self.popupMenu.Append(self.popupID4, _("Histogram"))
            self.Bind (wx.EVT_MENU, self.OnHistogram, id=self.popupID4)
            self.popupMenu.Append(self.popupID5, _("Profile"))
            self.Bind (wx.EVT_MENU, self.OnProfile, id=self.popupID5)
            self.popupMenu.Append(self.popupID6, _("Metadata"))
            self.Bind (wx.EVT_MENU, self.OnMetadata, id=self.popupID6)
            if self.mapdisplay.toolbars['nviz']:
                self.popupMenu.Append(self.popupID11, _("Nviz properties"))
                self.Bind (wx.EVT_MENU, self.OnNvizProperties, id=self.popupID11)

            if numSelected > 1:
                self.popupMenu.Enable(self.popupID12, False)
                self.popupMenu.Enable(self.popupID13, False)
                self.popupMenu.Enable(self.popupID15, False)
                self.popupMenu.Enable(self.popupID4, False)
                self.popupMenu.Enable(self.popupID5, False)
                self.popupMenu.Enable(self.popupID6, False)
                self.popupMenu.Enable(self.popupID11, False)
        
        ## self.PopupMenu(self.popupMenu, pos)
        self.PopupMenu(self.popupMenu)
        self.popupMenu.Destroy()

    def OnMetadata(self, event):
        """!Print metadata of raster/vector map layer
        TODO: Dialog to modify metadata
        """
        mapLayer = self.GetPyData(self.layer_selected)[0]['maplayer']
        mltype = self.GetPyData(self.layer_selected)[0]['type']

        if mltype == 'raster':
            cmd = ['r.info']
        elif mltype == 'vector':
            cmd = ['v.info']
        cmd.append('map=%s' % mapLayer.name)

        # print output to command log area
        self.lmgr.goutput.RunCmd(cmd, switchPage=True)

    def OnSetCompRegFromRaster(self, event):
        """!Set computational region from selected raster map (ignore NULLs)"""
        mapLayer = self.GetPyData(self.layer_selected)[0]['maplayer']
        
        cmd = ['g.region',
               '-p',
               'zoom=%s' % mapLayer.name]
        
        # print output to command log area
        self.lmgr.goutput.RunCmd(cmd)
         
    def OnSetCompRegFromMap(self, event):
        """!Set computational region from selected raster/vector map"""
        rast = []
        vect = []
        rast3d = []
        for layer in self.GetSelections():
            mapLayer = self.GetPyData(layer)[0]['maplayer']
            mltype = self.GetPyData(layer)[0]['type']
                
            if mltype == 'raster':
                rast.append(mapLayer.name)
            elif mltype == 'vector':
                vect.append(mapLayer.name)
            elif mltype == '3d-raster':
                rast3d.append(mapLayer.name)

        cmd = ['g.region']
        if rast:
            cmd.append('rast=%s' % ','.join(rast))
        if vect:
            cmd.append('vect=%s' % ','.join(vect))
        if rast3d:
            cmd.append('rast3d=%s' % ','.join(rast3d))
        
        # print output to command log area
        if len(cmd) > 1:
            cmd.append('-p')
            self.lmgr.goutput.RunCmd(cmd)
        
    def OnProfile(self, event):
        """!Plot profile of given raster map layer"""
        mapLayer = self.GetPyData(self.layer_selected)[0]['maplayer']
        if not mapLayer.name:
            wx.MessageBox(parent=self,
                          message=_("Unable to create profile of "
                                    "raster map."),
                          caption=_("Error"), style=wx.OK | wx.ICON_ERROR | wx.CENTRE)
            return False

        if not hasattr (self, "profileFrame"):
            self.profileFrame = None

        if hasattr (self.mapdisplay, "profile") and self.mapdisplay.profile:
            self.profileFrame = self.mapdisplay.profile

        if not self.profileFrame:
            self.profileFrame = profile.ProfileFrame(self.mapdisplay,
                                                     id=wx.ID_ANY, pos=wx.DefaultPosition, size=(700,300),
                                                     style=wx.DEFAULT_FRAME_STYLE, rasterList=[mapLayer.name])
            # show new display
            self.profileFrame.Show()
        
    def OnColorTable(self, event):
        """!Set color table for raster map"""
        name = self.GetPyData(self.layer_selected)[0]['maplayer'].name
        menuform.GUI().ParseCommand(['r.colors',
                                     'map=%s' % name],
                                    parentframe=self)
        
    def OnHistogram(self, event):
        """
        Plot histogram for given raster map layer
        """
        mapLayer = self.GetPyData(self.layer_selected)[0]['maplayer']
        if not mapLayer.name:
            wx.MessageBox(parent=self,
                          message=_("Unable to display histogram of "
                                    "raster map."),
                          caption=_("Error"), style=wx.OK | wx.ICON_ERROR | wx.CENTRE)
            return False

        if not hasattr (self, "histogramFrame"):
            self.histogramFrame = None

        if hasattr (self.mapdisplay, "histogram") and self.mapdisplay.histogram:
            self.histogramFrame = self.mapdisplay.histogram

        if not self.histogramFrame:
            self.histogramFrame = histogram.HistFrame(self,
                                                      id=wx.ID_ANY,
                                                      pos=wx.DefaultPosition, size=globalvar.HIST_WINDOW_SIZE,
                                                      style=wx.DEFAULT_FRAME_STYLE)
            # show new display
            self.histogramFrame.Show()

        self.histogramFrame.SetHistLayer(mapLayer.name)
        self.histogramFrame.HistWindow.UpdateHist()
        self.histogramFrame.Refresh()
        self.histogramFrame.Update()

        return True

    def OnStartEditing(self, event):
        """
        Start editing vector map layer requested by the user
        """
        if not haveVDigit:
            from vdigit import errorMsg
            msg = _("Unable to start vector digitizer.\nThe VDigit python extension "
                    "was not found or loaded properly.\n"
                    "Switching back to 2D display mode.\n\nDetails: %s" % errorMsg)
            
            self.mapdisplay.toolbars['map'].combo.SetValue (_("2D view"))
            wx.MessageBox(parent=self.mapdisplay,
                          message=msg,
                          caption=_("Error"),
                          style=wx.OK | wx.ICON_ERROR | wx.CENTRE)
            return
        
        try:
            maplayer = self.GetPyData(self.layer_selected)[0]['maplayer']
        except:
            event.Skip()
            return

        if not self.mapdisplay.toolbars['vdigit']: # enable tool
            self.mapdisplay.AddToolbar('vdigit')
        else: # tool already enabled
            pass

        # mark layer as 'edited'
        self.mapdisplay.toolbars['vdigit'].StartEditing (maplayer)

    def OnStopEditing(self, event):
        """
        Stop editing the current vector map layer
        """
        maplayer = self.GetPyData(self.layer_selected)[0]['maplayer']
        
        self.mapdisplay.toolbars['vdigit'].OnExit()
        self.mapdisplay.imgVectorMap = None
        
    def OnSetBgMap(self, event):
        """!Set background vector map for editing sesstion"""
        if event.IsChecked():
            mapName = self.GetPyData(self.layer_selected)[0]['maplayer'].GetName()
            UserSettings.Set(group='vdigit', key='bgmap', subkey='value',
                             value=str(mapName), internal=True)
        else:
            UserSettings.Set(group='vdigit', key='bgmap', subkey='value',
                             value='', internal=True)
        
    def OnPopupProperties (self, event):
        """!Popup properties dialog"""
        self.PropertiesDialog(self.layer_selected)

    def OnPopupOpacityLevel(self, event):
        """!Popup opacity level indicator"""
        if not self.GetPyData(self.layer_selected)[0]['ctrl']:
            return

        #win = self.FindWindowById(self.GetPyData(self.layer_selected)[0]['ctrl'])
        #type = win.GetName()
        #
        #self.layer_selected.DeleteWindow()

        maplayer = self.GetPyData(self.layer_selected)[0]['maplayer']
        current_opacity = maplayer.GetOpacity()
        
        dlg = gdialogs.SetOpacityDialog(self, opacity=current_opacity,
                                        title=_("Set opacity <%s>") % maplayer.GetName())
        dlg.CentreOnParent()

        if dlg.ShowModal() == wx.ID_OK:
            new_opacity = dlg.GetOpacity() # string
            self.Map.ChangeOpacity(maplayer, new_opacity)
            maplayer.SetOpacity(new_opacity)
            opacity_pct = int(new_opacity * 100)
            layername = self.GetItemText(self.layer_selected)
            layerbase = layername.split('(')[0].strip()
            self.SetItemText(self.layer_selected,
                             layerbase + ' (opacity: ' + str(opacity_pct) + '%)')
            
            # vector layer currently edited
            if self.mapdisplay.toolbars['vdigit'] and \
                    self.mapdisplay.toolbars['vdigit'].GetLayer() == maplayer:   
                alpha = int(new_opacity * 255)
                self.mapdisplay.digit.driver.UpdateSettings(alpha)
                
            # redraw map if auto-rendering is enabled
            self.rerender = True
            self.reorder = True
            #if self.mapdisplay.statusbarWin['render'].GetValue():
            #    print "*** Opacity OnRender *****"
            #    self.mapdisplay.OnRender(None)

    def OnNvizProperties(self, event):
        """!Nviz-related properties (raster/vector/volume)

        @todo vector/volume
        """
        if not self.mapdisplay.nvizToolWin.IsShown():
            self.mapdisplay.nvizToolWin.Show()

        self.mapdisplay.nvizToolWin.SetPage('surface')

    def RenameLayer (self, event):
        """!Rename layer"""
        self.EditLabel(self.layer_selected)

    def AddLayer(self, ltype, lname=None, lchecked=None,
                 lopacity=1.0, lcmd=None, lgroup=None, lvdigit=None, lnviz=None):
        """!Add new item to the layer tree, create corresponding MapLayer instance.
        Launch property dialog if needed (raster, vector, etc.)

        @param ltype layer type (raster, vector, 3d-raster, ...)
        @param lname layer name
        @param lchecked if True layer is checked
        @param lopacity layer opacity level
        @param lcmd command (given as a list)
        @param lgroup group name or None
        @param lvdigit vector digitizer settings (eg. geometry attributes)
        @param lnviz layer Nviz properties
        """
        self.first = True
        params = {} # no initial options parameters

        # deselect active item
        if self.layer_selected:
            self.SelectItem(self.layer_selected, select=False)

        Debug.msg (3, "LayerTree().AddLayer(): ltype=%s" % (ltype))
        
        if ltype == 'command':
            # generic command item
            ctrl = wx.TextCtrl(self, id=wx.ID_ANY, value='',
                               pos=wx.DefaultPosition, size=(self.GetSize()[0]-100,25),
                               # style=wx.TE_MULTILINE|wx.TE_WORDWRAP)
                               style=wx.TE_PROCESS_ENTER | wx.TE_DONTWRAP)
            ctrl.Bind(wx.EVT_TEXT_ENTER, self.OnCmdChanged)
            # ctrl.Bind(wx.EVT_TEXT,       self.OnCmdChanged)
        elif ltype == 'group':
            # group item
            ctrl = None
            grouptext = _('Layer group:') + str(self.groupnode)
            self.groupnode += 1
        else:
            btnbmp = Icons["layeropts"].GetBitmap((16,16))
            ctrl = buttons.GenBitmapButton(self, id=wx.ID_ANY, bitmap=btnbmp, size=(24,24))
            ctrl.SetToolTipString(_("Click to edit layer settings"))
            self.Bind(wx.EVT_BUTTON, self.OnLayerContextMenu, ctrl)
        # add layer to the layer tree
        if self.layer_selected and self.layer_selected != self.GetRootItem():
            if self.GetPyData(self.layer_selected)[0]['type'] == 'group' \
                and self.IsExpanded(self.layer_selected):
                # add to group (first child of self.layer_selected) if group expanded
                layer = self.PrependItem(parent=self.layer_selected,
                                         text='', ct_type=1, wnd=ctrl)
            else:
                # prepend to individual layer or non-expanded group
                if lgroup is False:
                    # -> last child of root (loading from workspace)
                    layer = self.AppendItem(parentId=self.root,
                                            text='', ct_type=1, wnd=ctrl)
                elif lgroup is True:
                    # -> last child of group (loading from workspace)
                    parent = self.GetItemParent(self.layer_selected)
                    if parent is self.root: # first item in group
                        parent=self.layer_selected
                    layer = self.AppendItem(parentId=parent,
                                            text='', ct_type=1, wnd=ctrl)
                elif lgroup is None:
                    # -> previous sibling of selected layer
                    parent = self.GetItemParent(self.layer_selected)
                    layer = self.InsertItem(parentId=parent,
                                            input=self.GetPrevSibling(self.layer_selected),
                                            text='', ct_type=1, wnd=ctrl)
        else: # add first layer to the layer tree (first child of root)
            layer = self.PrependItem(parent=self.root, text='', ct_type=1, wnd=ctrl)

        # layer is initially unchecked as inactive (beside 'command')
        # use predefined value if given
        if lchecked is not None:
            checked = lchecked
        else:
            checked = True

        self.CheckItem(layer, checked=checked)

        # select new item
        self.SelectItem(layer, select=True)
        self.layer_selected = layer
        
        # add text and icons for each layer ltype
        if ltype == 'raster':
            self.SetItemImage(layer, self.rast_icon)
            self.SetItemText(layer, '%s %s' % (_('raster'), _('(double click to set properties)')))
        elif ltype == '3d-raster':
            self.SetItemImage(layer, self.rast3d_icon)
            self.SetItemText(layer, '%s %s' % (_('3d raster'), _('(double click to set properties)')))
        elif ltype == 'rgb':
            self.SetItemImage(layer, self.rgb_icon)
            self.SetItemText(layer, '%s %s' % (_('RGB'), _('(double click to set properties)')))
        elif ltype == 'his':
            self.SetItemImage(layer, self.his_icon)
            self.SetItemText(layer, '%s %s' % (_('HIS'), _('(double click to set properties)')))
        elif ltype == 'shaded':
            self.SetItemImage(layer, self.shaded_icon)
            self.SetItemText(layer, '%s %s' % (_('Shaded relief'), _('(double click to set properties)')))
        elif ltype == 'rastnum':
            self.SetItemImage(layer, self.rnum_icon)
            self.SetItemText(layer, '%s %s' % (_('raster cell numbers'), _('(double click to set properties)')))
        elif ltype == 'rastarrow':
            self.SetItemImage(layer, self.rarrow_icon)
            self.SetItemText(layer, '%s %s' % (_('raster flow arrows'), _('(double click to set properties)')))
        elif ltype == 'vector':
            self.SetItemImage(layer, self.vect_icon)
            self.SetItemText(layer, '%s %s' % (_('vector'), _('(double click to set properties)')))
        elif ltype == 'thememap':
            self.SetItemImage(layer, self.theme_icon)
            self.SetItemText(layer, '%s %s' % (_('thematic map'), _('(double click to set properties)')))
        elif ltype == 'themechart':
            self.SetItemImage(layer, self.chart_icon)
            self.SetItemText(layer, '%s %s' % (_('thematic charts'), _('(double click to set properties)')))
        elif ltype == 'grid':
            self.SetItemImage(layer, self.grid_icon)
            self.SetItemText(layer, '%s %s' % (_('grid'), _('(double click to set properties)')))
        elif ltype == 'geodesic':
            self.SetItemImage(layer, self.geodesic_icon)
            self.SetItemText(layer, '%s %s' % (_('geodesic line'), _('(double click to set properties)')))
        elif ltype == 'rhumb':
            self.SetItemImage(layer, self.rhumb_icon)
            self.SetItemText(layer, '%s %s' % (_('rhumbline'), _('(double click to set properties)')))
        elif ltype == 'labels':
            self.SetItemImage(layer, self.labels_icon)
            self.SetItemText(layer, '%s %s' % (_('vector labels'), _('(double click to set properties)')))
        elif ltype == 'command':
            self.SetItemImage(layer, self.cmd_icon)
        elif ltype == 'group':
            self.SetItemImage(layer, self.folder)
            self.SetItemText(layer, grouptext)

        self.first = False

        if ltype != 'group':
            if lcmd and len(lcmd) > 1:
                cmd = lcmd
                render = False
                name = utils.GetLayerNameFromCmd(lcmd)
            else:
                cmd = []
                if ltype == 'command' and lname:
                    for c in lname.split(';'):
                        cmd.append(c.split(' '))
                
                render = False
                name = None

            if ctrl:
                ctrlId = ctrl.GetId()
            else:
                ctrlId = None
                
            # add a data object to hold the layer's command (does not apply to generic command layers)
            self.SetPyData(layer, ({'cmd'      : cmd,
                                    'type'     : ltype,
                                    'ctrl'     : ctrlId,
                                    'maplayer' : None,
                                    'vdigit'   : lvdigit,
                                    'nviz'     : lnviz,
                                    'propwin'  : None}, 
                                   None))
            
            # find previous map layer instance 
            prevItem = self.GetFirstChild(self.root)[0]
            prevMapLayer = None 
            pos = -1
            while prevItem and prevItem.IsOk() and prevItem != layer: 
                if self.GetPyData(prevItem)[0]['maplayer']: 
                    prevMapLayer = self.GetPyData(prevItem)[0]['maplayer'] 
                
                prevItem = self.GetNextSibling(prevItem) 
                
                if prevMapLayer: 
                    pos = self.Map.GetLayerIndex(prevMapLayer)
                else: 
                    pos = -1
            
            maplayer = self.Map.AddLayer(pos=pos,
                                         type=ltype, command=self.GetPyData(layer)[0]['cmd'], name=name,
                                         l_active=checked, l_hidden=False,
                                         l_opacity=lopacity, l_render=render)
            self.GetPyData(layer)[0]['maplayer'] = maplayer

            # run properties dialog if no properties given
            if len(cmd) == 0:
                self.PropertiesDialog(layer, show=True)
                
            if ltype == '3d-raster' and \
                    not self.mapdisplay.toolbars['nviz']:
                self.EnableItem(layer, False)
            
        else: # group
            self.SetPyData(layer, ({'cmd': None,
                                    'type' : ltype,
                                    'ctrl' : None,
                                    'maplayer' : None,
                                    'propwin' : None}, 
                                   None))

        # use predefined layer name if given
        if lname:
            if ltype == 'group':
                self.SetItemText(layer, lname)
            elif ltype == 'command':
                ctrl.SetValue(lname)
            else:
                name = lname + ' (opacity: ' + \
                       str(self.GetPyData(layer)[0]['maplayer'].GetOpacity()) + '%)'
                self.SetItemText(layer, name)
                
        # updated progress bar range (mapwindow statusbar)
        if checked is True:
            self.mapdisplay.statusbarWin['progress'].SetRange(len(self.Map.GetListOfLayers(l_active=True)))

        # layer.SetHeight(TREE_ITEM_HEIGHT)

        return layer

    def PropertiesDialog (self, layer, show=True):
        """!Launch the properties dialog"""
        if self.GetPyData(layer)[0].has_key('propwin') and \
                self.GetPyData(layer)[0]['propwin'] is not None:
            # recycle GUI dialogs
            win = self.GetPyData(layer)[0]['propwin']
            # update properties (columns, layers)
            win.notebookpanel.OnUpdateSelection(None)
            if win.IsShown():
                win.SetFocus()
            else:
                win.Show()
            
            return
        
        completed = ''
        params = self.GetPyData(layer)[1]
        ltype  = self.GetPyData(layer)[0]['type']
                
        Debug.msg (3, "LayerTree.PropertiesDialog(): ltype=%s" % \
                   ltype)

        if self.GetPyData(layer)[0]['cmd']:
            cmdValidated = menuform.GUI().ParseCommand(self.GetPyData(layer)[0]['cmd'],
                                                       completed=(self.GetOptData,layer,params),
                                                       parentframe=self, show=show)
            self.GetPyData(layer)[0]['cmd'] = cmdValidated
        elif ltype == 'raster':
            cmd = ['d.rast']
            
            if UserSettings.Get(group='cmd', key='rasterOpaque', subkey='enabled'):
                cmd.append('-n')
            menuform.GUI().ParseCommand(cmd, completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == '3d-raster':
            cmd = ['d.rast3d']
            menuform.GUI().ParseCommand(cmd, completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'rgb':
            menuform.GUI().ParseCommand(['d.rgb'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'his':
            menuform.GUI().ParseCommand(['d.his'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'shaded':
            menuform.GUI().ParseCommand(['d.shadedmap'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'rastarrow':
            menuform.GUI().ParseCommand(['d.rast.arrow'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'rastnum':
            menuform.GUI().ParseCommand(['d.rast.num'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'vector':
            types = ''
            for type in UserSettings.Get(group='cmd', key='showType').keys():
                if UserSettings.Get(group='cmd', key='showType', subkey=[type, 'enabled']):
                    types += type + ','
            types = types.rstrip(',')
            
            menuform.GUI().ParseCommand(['d.vect', 'type=%s' % types],
                                         completed=(self.GetOptData,layer,params),
                                         parentframe=self)
        elif ltype == 'thememap':
            # -s flag requested, otherwise only first thematic category is displayed
            # should be fixed by C-based d.thematic.* modules
            menuform.GUI().ParseCommand(['d.vect.thematic', '-s'], 
                                        completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'themechart':
            menuform.GUI().ParseCommand(['d.vect.chart'],
                                        completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'grid':
            menuform.GUI().ParseCommand(['d.grid'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'geodesic':
            menuform.GUI().ParseCommand(['d.geodesic'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'rhumb':
            menuform.GUI().ParseCommand(['d.rhumbline'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'labels':
            menuform.GUI().ParseCommand(['d.labels'], completed=(self.GetOptData,layer,params),
                                        parentframe=self)
        elif ltype == 'cmdlayer':
            pass
        elif ltype == 'group':
            pass
        
    def OnActivateLayer(self, event):
        """!Double click on the layer item.
        Launch property dialog, or expand/collapse group of items, etc."""
        
        layer = event.GetItem()
        self.layer_selected = layer

        self.PropertiesDialog (layer)

        if self.GetPyData(layer)[0]['type'] == 'group':
            if self.IsExpanded(layer):
                self.Collapse(layer)
            else:
                self.Expand(layer)

    def OnDeleteLayer(self, event):
        """!Remove selected layer item from the layer tree"""

        item = event.GetItem()

        try:
            item.properties.Close(True)
        except:
            pass

        if item != self.root:
            Debug.msg (3, "LayerTree.OnDeleteLayer(): name=%s" % \
                           (self.GetItemText(item)))
        else:
            self.root = None

        # unselect item
        self.Unselect()
        self.layer_selected = None

        try:
            if self.GetPyData(item)[0]['type'] != 'group':
                self.Map.DeleteLayer( self.GetPyData(item)[0]['maplayer'])
        except:
            pass

        # redraw map if auto-rendering is enabled
        self.rerender = True
        self.reorder = True
        #if self.mapdisplay.statusbarWin['render'].GetValue():
        #    print "*** Delete OnRender *****"
        #    self.mapdisplay.OnRender(None)

        if self.mapdisplay.toolbars['vdigit']:
            self.mapdisplay.toolbars['vdigit'].UpdateListOfLayers (updateTool=True)

        # update progress bar range (mapwindow statusbar)
        self.mapdisplay.statusbarWin['progress'].SetRange(len(self.Map.GetListOfLayers(l_active=True)))

        event.Skip()

    def OnLayerChecked(self, event):
        """!Enable/disable data layer"""
        item    = event.GetItem()
        checked = item.IsChecked()

        digitToolbar = self.mapdisplay.toolbars['vdigit']
        if self.first == False:
            # change active parameter for item in layers list in render.Map
            if self.GetPyData(item)[0]['type'] == 'group':
                child, cookie = self.GetFirstChild(item)
                while child:
                    self.CheckItem(child, checked)
                    mapLayer = self.GetPyData(child)[0]['maplayer']
                    if not digitToolbar or \
                           (digitToolbar and digitToolbar.GetLayer() != mapLayer):
                        # ignore when map layer is edited
                        self.Map.ChangeLayerActive(mapLayer, checked)
                    child = self.GetNextSibling(child)
            else:
                mapLayer = self.GetPyData(item)[0]['maplayer']
                if not digitToolbar or \
                       (digitToolbar and digitToolbar.GetLayer() != mapLayer):
                    # ignore when map layer is edited
                    self.Map.ChangeLayerActive(mapLayer, checked)

        #
        # update progress bar range (mapwindow statusbar)
        #
        self.mapdisplay.statusbarWin['progress'].SetRange(len(self.Map.GetListOfLayers(l_active=True)))

        #
        # nviz
        #
        if self.mapdisplay.toolbars['nviz'] and \
                self.GetPyData(item) is not None:
            # nviz - load/unload data layer
            mapLayer = self.GetPyData(item)[0]['maplayer']

            self.mapdisplay.SetStatusText(_("Please wait, updating data..."), 0)

            if checked: # enable
                if mapLayer.type == 'raster':
                    self.mapdisplay.MapWindow.LoadRaster(item)
                elif mapLayer.type == '3d-raster':
                    self.mapdisplay.MapWindow.LoadRaster3d(item)
                elif mapLayer.type == 'vector':
                    self.mapdisplay.MapWindow.LoadVector(item)

            else: # disable
                data = self.GetPyData(item)[0]['nviz']

                if mapLayer.type == 'raster':
                    self.mapdisplay.MapWindow.UnloadRaster(item)
                elif mapLayer.type == '3d-raster':
                    self.mapdisplay.MapWindow.UnloadRaster3d(item)
                elif mapLayer.type == 'vector':
                    self.mapdisplay.MapWindow.UnloadVector(item)
                    
                    if hasattr(self.mapdisplay, "nvizToolWin"):
                        toolWin = self.mapdisplay.nvizToolWin
                        # remove vector page
                        if toolWin.notebook.GetSelection() == toolWin.page['vector']['id']:
                            toolWin.notebook.RemovePage(toolWin.page['vector']['id'])
                            toolWin.page['vector']['id'] = -1
                            toolWin.page['settings']['id'] = 1

            self.mapdisplay.SetStatusText("", 0)

        # redraw map if auto-rendering is enabled
        self.rerender = True
        self.reorder = True
        #if self.mapdisplay.statusbarWin['render'].GetValue():
        #    print "*** Checked OnRender *****"
        #    self.mapdisplay.OnRender(None)

    def OnCmdChanged(self, event):
        """!Change command string"""
        ctrl = event.GetEventObject().GetId()
        cmd = event.GetString()
        
        layer = self.GetFirstVisibleItem()

        while layer and layer.IsOk():
            if self.GetPyData(layer)[0]['ctrl'] == ctrl:
                break
            
            layer = self.GetNextVisible(layer)

        # change parameters for item in layers list in render.Map
        self.ChangeLayer(layer)
        
        event.Skip()

    def OnChangeSel(self, event):
        """!Selection changed"""
        oldlayer = event.GetOldItem()
        layer = event.GetItem()
        if layer == oldlayer:
            event.Veto()
            return
        
        self.layer_selected = layer
        
        try:
            self.RefreshLine(oldlayer)
            self.RefreshLine(layer)
        except:
            pass

        #
        # update statusbar -> show command string
        #
        if self.GetPyData(layer) and self.GetPyData(layer)[0]['maplayer']:
            cmd = self.GetPyData(layer)[0]['maplayer'].GetCmd(string=True)
            if len(cmd) > 0:
                self.lmgr.SetStatusText(cmd)

        # set region if auto-zooming is enabled
        if self.GetPyData(layer) and self.GetPyData(layer)[0]['cmd'] and \
               UserSettings.Get(group = 'display', key = 'autoZooming', subkey = 'enabled'):
            mapLayer = self.GetPyData(layer)[0]['maplayer']
            if mapLayer.GetType() in ('raster', 'vector'):
                render = self.mapdisplay.statusbarWin['render'].IsChecked()
                self.mapdisplay.MapWindow.ZoomToMap(layers = [mapLayer,],
                                                    render = render)
        
        #
        # update nviz tools
        #
        if self.mapdisplay.toolbars['nviz'] and \
                self.GetPyData(self.layer_selected) is not None:

            if self.layer_selected.IsChecked():
                # update Nviz tool window
                type = self.GetPyData(self.layer_selected)[0]['maplayer'].type

                if type == 'raster':
                    self.mapdisplay.nvizToolWin.UpdatePage('surface')
                    self.mapdisplay.nvizToolWin.SetPage('surface')
                elif type == 'vector':
                    self.mapdisplay.nvizToolWin.UpdatePage('vector')
                    self.mapdisplay.nvizToolWin.SetPage('vector')
                elif type == '3d-raster':
                    self.mapdisplay.nvizToolWin.UpdatePage('volume')
                    self.mapdisplay.nvizToolWin.SetPage('volume')
            else:
                for page in ('surface', 'vector', 'volume'):
                    pageId = self.mapdisplay.nvizToolWin.page[page]['id']
                    if pageId > -1:
                        self.mapdisplay.nvizToolWin.notebook.RemovePage(pageId)
                        self.mapdisplay.nvizToolWin.page[page]['id'] = -1
                        self.mapdisplay.nvizToolWin.page['settings']['id'] = 1 

    def OnCollapseNode(self, event):
        """
        Collapse node
        """
        if self.GetPyData(self.layer_selected)[0]['type'] == 'group':
            self.SetItemImage(self.layer_selected, self.folder)

    def OnExpandNode(self, event):
        """
        Expand node
        """
        self.layer_selected = event.GetItem()
        if self.GetPyData(self.layer_selected)[0]['type'] == 'group':
            self.SetItemImage(self.layer_selected, self.folder_open)
    
    def OnEndDrag(self, event):
        self.StopDragging()
        dropTarget = event.GetItem()
        self.flag = self.HitTest(event.GetPoint())[1]
        if self.IsValidDropTarget(dropTarget):
            self.UnselectAll()
            if dropTarget != None:
                self.SelectItem(dropTarget)
            self.OnDrop(dropTarget, self._dragItem)
        elif dropTarget == None:
            self.OnDrop(dropTarget, self._dragItem)

    def OnDrop(self, dropTarget, dragItem):
        # save everthing associated with item to drag
        try:
            old = dragItem  # make sure this member exists
        except:
            return

        Debug.msg (4, "LayerTree.OnDrop(): layer=%s" % \
                   (self.GetItemText(dragItem)))
        
        # recreate data layer, insert copy of layer in new position, and delete original at old position
        newItem  = self.RecreateItem (dragItem, dropTarget)

        # if recreated layer is a group, also recreate its children
        if  self.GetPyData(newItem)[0]['type'] == 'group':
            (child, cookie) = self.GetFirstChild(dragItem)
            if child:
                while child:
                    self.RecreateItem(child, dropTarget, parent=newItem)
                    self.Delete(child)
                    child = self.GetNextChild(old, cookie)[0]
            #self.Expand(newItem)

        # delete layer at original position
        try:
            self.Delete(old) # entry in render.Map layers list automatically deleted by OnDeleteLayer handler
        except AttributeError:
            # FIXME being ugly (item.SetWindow(None))
            pass

        # reorder layers in render.Map to match new order after drag and drop
        #self.ReorderLayers()

        # redraw map if auto-rendering is enabled
        self.rerender = True
        self.reorder = True
        #if self.mapdisplay.statusbarWin['render'].GetValue():
        #    print "*** Drop OnRender *****"
        #    self.mapdisplay.OnRender(None)

        # select new item
        self.SelectItem(newItem)
        
    def RecreateItem (self, dragItem, dropTarget, parent=None):
        """
        Recreate item (needed for OnEndDrag())
        """
        Debug.msg (4, "LayerTree.RecreateItem(): layer=%s" % \
                   self.GetItemText(dragItem))

        # fetch data (dragItem)
        checked = self.IsItemChecked(dragItem)
        image   = self.GetItemImage(dragItem, 0)
        text    = self.GetItemText(dragItem)
        if self.GetPyData(dragItem)[0]['ctrl']:
            # recreate data layer
            btnbmp = Icons["layeropts"].GetBitmap((16,16))
            newctrl = buttons.GenBitmapButton(self, id=wx.ID_ANY, bitmap=btnbmp, size=(24, 24))
            newctrl.SetToolTipString(_("Click to edit layer settings"))
            self.Bind(wx.EVT_BUTTON, self.OnLayerContextMenu, newctrl)
            data    = self.GetPyData(dragItem)
        
        elif self.GetPyData(dragItem)[0]['type'] == 'command':
            # recreate command layer
            oldctrl = None
            newctrl = wx.TextCtrl(self, id=wx.ID_ANY, value='',
                                  pos=wx.DefaultPosition, size=(250,25),
                                  style=wx.TE_MULTILINE|wx.TE_WORDWRAP)
            try:
                newctrl.SetValue(self.GetPyData(dragItem)[0]['maplayer'].GetCmd(string=True))
            except:
                pass
            newctrl.Bind(wx.EVT_TEXT_ENTER, self.OnCmdChanged)
            newctrl.Bind(wx.EVT_TEXT,       self.OnCmdChanged)
            data    = self.GetPyData(dragItem)

        elif self.GetPyData(dragItem)[0]['type'] == 'group':
            # recreate group
            newctrl = None
            data    = None
            
        # decide where to put recreated item
        if dropTarget != None and dropTarget != self.GetRootItem():
            if parent:
                # new item is a group
                afteritem = parent
            else:
                # new item is a single layer
                afteritem = dropTarget

            # dragItem dropped on group
            if  self.GetPyData(afteritem)[0]['type'] == 'group':
                newItem = self.PrependItem(afteritem, text=text, \
                                      ct_type=1, wnd=newctrl, image=image, \
                                      data=data)
                self.Expand(afteritem)
            else:
                #dragItem dropped on single layer
                newparent = self.GetItemParent(afteritem)
                newItem = self.InsertItem(newparent, self.GetPrevSibling(afteritem), \
                                       text=text, ct_type=1, wnd=newctrl, \
                                       image=image, data=data)
        else:
            # if dragItem not dropped on a layer or group, append or prepend it to the layer tree
            if self.flag & wx.TREE_HITTEST_ABOVE:
                newItem = self.PrependItem(self.root, text=text, \
                                      ct_type=1, wnd=newctrl, image=image, \
                                      data=data)
            elif (self.flag &  wx.TREE_HITTEST_BELOW) or (self.flag & wx.TREE_HITTEST_NOWHERE) \
                     or (self.flag & wx.TREE_HITTEST_TOLEFT) or (self.flag & wx.TREE_HITTEST_TORIGHT):
                newItem = self.AppendItem(self.root, text=text, \
                                      ct_type=1, wnd=newctrl, image=image, \
                                      data=data)

        #update new layer 
        self.SetPyData(newItem, self.GetPyData(dragItem))
        if newctrl:
            self.GetPyData(newItem)[0]['ctrl'] = newctrl.GetId()
        else:
            self.GetPyData(newItem)[0]['ctrl'] = None
            
        self.CheckItem(newItem, checked=checked) # causes a new render

        # newItem.SetHeight(TREE_ITEM_HEIGHT)

        return newItem

    def GetOptData(self, dcmd, layer, params, propwin):
        """!Process layer data"""
        # set layer text to map name
        if dcmd:
            mapLayer = self.GetPyData(layer)[0]['maplayer']
            opacity = int(mapLayer.GetOpacity(float=True) * 100)
            mapname = utils.GetLayerNameFromCmd(dcmd, layerType=mapLayer.type,
                                                fullyQualified=True)
            if not mapname:
                wx.MessageBox(parent=self,
                              message=_("Map <%s> not found.") % utils.GetLayerNameFromCmd(dcmd),
                              caption=_("Error"),
                              style=wx.OK | wx.ICON_ERROR | wx.CENTRE)

                return
            
            self.SetItemText(layer, mapname + ' (opacity: ' + str(opacity) + '%)')
        
        # update layer data
        if params:
            self.SetPyData(layer, (self.GetPyData(layer)[0], params))
        if dcmd:
            self.GetPyData(layer)[0]['cmd'] = dcmd
        self.GetPyData(layer)[0]['propwin'] = propwin
        
        # change parameters for item in layers list in render.Map
        self.ChangeLayer(layer)

        # set region if auto-zooming is enabled
        if dcmd and UserSettings.Get(group = 'display', key = 'autoZooming', subkey = 'enabled'):
            mapLayer = self.GetPyData(layer)[0]['maplayer']
            if mapLayer.GetType() in ('raster', 'vector'):
                render = UserSettings.Get(group = 'display', key = 'autoRendering', subkey = 'enabled')
                self.mapdisplay.MapWindow.ZoomToMap(layers = [mapLayer,],
                                                    render = render)
        
        if self.mapdisplay.toolbars['nviz'] and dcmd:
            # update nviz session
            mapLayer = self.GetPyData(layer)[0]['maplayer']
            mapWin = self.mapdisplay.MapWindow
            if len(mapLayer.GetCmd()) > 0:
                id = -1
                if mapLayer.type == 'raster':
                    if mapWin.IsLoaded(layer):
                        mapWin.UnloadRaster(layer)
                    
                    mapWin.LoadRaster(layer)
                    
                elif mapLayer.type == '3d-raster':
                    if mapWin.IsLoaded(layer):
                        mapWin.UnloadRaster3d(layer)
                    
                    mapWin.LoadRaster3d(layer)
                    
                elif mapLayer.type == 'vector':
                    if mapWin.IsLoaded(layer):
                        mapWin.UnloadVector(layer)
                    
                    mapWin.LoadVector(layer)

                # reset view when first layer loaded
                nlayers = len(mapWin.Map.GetListOfLayers(l_type=('raster', 'vector'),
                                                         l_active=True))
                if nlayers < 2:
                    mapWin.ResetView()
        
    def ReorderLayers(self):
        """!Add commands from data associated with
        any valid layers (checked or not) to layer list in order to
        match layers in layer tree."""

        # make a list of visible layers
        treelayers = []

        vislayer = self.GetFirstVisibleItem()

        if not vislayer or self.GetPyData(vislayer) is None:
            return

        itemList = ""

        for item in range(self.GetCount()):
            itemList += self.GetItemText(vislayer) + ','
            if self.GetPyData(vislayer)[0]['type'] != 'group':
                treelayers.append(self.GetPyData(vislayer)[0]['maplayer'])

            if not self.GetNextVisible(vislayer):
                break
            else:
                vislayer = self.GetNextVisible(vislayer)

        Debug.msg (4, "LayerTree.ReorderLayers(): items=%s" % \
                   (itemList))

        # reorder map layers
        treelayers.reverse()
        self.Map.ReorderLayers(treelayers)
        self.reorder = False

    def ChangeLayer(self, item):
        """!Change layer"""
        type = self.GetPyData(item)[0]['type']
        layerName = None
        
        if type == 'command':
            win = self.FindWindowById(self.GetPyData(item)[0]['ctrl'])
            if win.GetValue() != None:
                cmd = win.GetValue().split(';')
                cmdlist = []
                for c in cmd:
                    cmdlist.append(c.split(' '))
                opac = 1.0
                chk = self.IsItemChecked(item)
                hidden = not self.IsVisible(item)
        elif type != 'group':
            if self.GetPyData(item)[0] is not None:
                cmdlist = self.GetPyData(item)[0]['cmd']
                opac = self.GetPyData(item)[0]['maplayer'].GetOpacity(float=True)
                chk = self.IsItemChecked(item)
                hidden = not self.IsVisible(item)
                # determine layer name
                layerName = utils.GetLayerNameFromCmd(cmdlist, fullyQualified=True)
                if not layerName:
                    layerName = self.GetItemText(item)
        
        maplayer = self.Map.ChangeLayer(layer=self.GetPyData(item)[0]['maplayer'], type=type,
                                        command=cmdlist, name=layerName,
                                        l_active=chk, l_hidden=hidden, l_opacity=opac, l_render=False)
        
        self.GetPyData(item)[0]['maplayer'] = maplayer
        
        # if digitization tool enabled -> update list of available vector map layers
        if self.mapdisplay.toolbars['vdigit']:
            self.mapdisplay.toolbars['vdigit'].UpdateListOfLayers(updateTool=True)
        
        # redraw map if auto-rendering is enabled
        self.rerender = True
        self.reorder = True
        #if self.mapdisplay.statusbarWin['render'].GetValue():
        #    print "*** Change OnRender *****"
        #    self.mapdisplay.OnRender(None)
        
    def OnCloseWindow(self, event):
        pass
        # self.Map.Clean()

    def FindItemByData(self, key, value):
        """!Find item based on key and value (see PyData[0])"""
        item = self.GetFirstChild(self.root)[0]
        return self.__FindSubItemByData(item, key, value)

    def EnableItemType(self, type, enable=True):
        """!Enable/disable items in layer tree"""
        item = self.GetFirstChild(self.root)[0]
        while item and item.IsOk():
            mapLayer = self.GetPyData(item)[0]['maplayer']
            if mapLayer and type == mapLayer.type:
                self.EnableItem(item, enable)
            
            item = self.GetNextSibling(item)
        
    def __FindSubItemByData(self, item, key, value):
        """!Support method for FindItemByValue"""
        while item and item.IsOk():
            itemValue = self.GetPyData(item)[0][key]
            if value == itemValue:
                return item
            if self.GetPyData(item)[0]['type'] == 'group':
                subItem = self.GetFirstChild(item)[0]
                found = self.__FindSubItemByData(subItem, key, value)
                if found:
                    return found
            item = self.GetNextSibling(item)

        return None