Geografic-Information-System/gui/wxpython/gui_core/mapwindow.py

"""!
@package gui_core.mapwindow

@brief Map display canvas - base class for buffered window.

Classes:
 - MapWindow

(C) 2006-2011 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 Martin Landa <landa.martin gmail.com>
@author Michael Barton
@author Jachym Cepicky
"""

import wx

from core.settings import UserSettings

class MapWindow(object):
    """!Abstract map display window class
    
    Superclass for BufferedWindow class (2D display mode), and GLWindow
    (3D display mode).
    
    Subclasses have to define
     - _bindMouseEvents method which binds MouseEvent handlers
     - Pixel2Cell
     - Cell2Pixel (if it is possible)
    
    """
    def __init__(self, parent, id = wx.ID_ANY,
                 Map = None, tree = None, lmgr = None, **kwargs):
        self.parent = parent # MapFrame
        self.Map    = Map
        self.tree   = tree
        self.lmgr   = lmgr
        
        # mouse attributes -- position on the screen, begin and end of
        # dragging, and type of drawing
        self.mouse = {
            'begin': [0, 0], # screen coordinates
            'end'  : [0, 0],
            'use'  : "pointer",
            'box'  : "point"
            }
        # last east, north coordinates, changes on mouse motion
        self.lastEN = None 
        
        # stores overridden cursor
        self._overriddenCursor = None

    def RegisterMouseEventHandler(self, event, handler, cursor = None):
        """!Binds event handler
        
        Call event.Skip() in handler to allow default processing in MapWindow.
        
        @code
        # your class methods
        def OnButton(self, event):
            # current map display's map window
            # expects LayerManager to be the parent
            self.mapwin = self.parent.GetLayerTree().GetMapDisplay().GetWindow()
            if self.mapwin.RegisterMouseEventHandler(wx.EVT_LEFT_DOWN, self.OnMouseAction,
                                                     wx.StockCursor(wx.CURSOR_CROSS)):
                self.parent.GetLayerTree().GetMapDisplay().Raise()
            else:
                # handle that you cannot get coordinates
        
        def OnMouseAction(self, event):
            # get real world coordinates of mouse click
            coor = self.mapwin.Pixel2Cell(event.GetPositionTuple()[:])
            self.text.SetLabel('Coor: ' + str(coor))
            self.mapwin.UnregisterMouseEventHandler(wx.EVT_LEFT_DOWN)
            event.Skip()
        @endcode
        
        @param event one of mouse events
        @param handler function to handle event
        @param cursor cursor which temporary overrides current cursor
        
        @return True if successful
        @return False if event cannot be bind
        """
        
        # if it is a VDigitWindow it cannot be used
        # hasattr is ugly
        if hasattr(self, "digit"):
            return False
        
        self.Bind(event, handler)
        self.mouse['useBeforeGenericEvent'] = self.mouse['use']
        self.mouse['use'] = 'genericEvent'
        
        if cursor:
            self._overriddenCursor = self.GetCursor()
            self.SetCursor(cursor)
        
        return True


    def UnregisterMouseEventHandler(self, event):
        """!Unbinds event handler a restores previous state
        
        You should unbind to restore normal MapWindow behaviour.
        Note that this operation will unbind any other external (non-MapWindow) handlers.
        
        @param event event to unbind
        
        @return True if successful
        @return False if event cannot be unbind
        """
        if hasattr(self, "digit"):
            return False
        
        # it is not yet possible in wxPython to unbind exact event
        ret = self.Unbind(event)
        
        # restore bind state
        self._bindMouseEvents()
        
        # restore mouse use (previous state)
        self.mouse['use'] = self.mouse['useBeforeGenericEvent']
        
        # restore overridden cursor
        if self._overriddenCursor:
            self.SetCursor(self._overriddenCursor)
        
        return ret
    
    def Pixel2Cell(self, (x, y)):
        raise NotImplementedError()
    
    def Cell2Pixel(self, (east, north)):
        raise NotImplementedError()

    def OnMotion(self, event):
        """!Tracks mouse motion and update statusbar
        
        @see GetLastEN
        """
        try:
            self.lastEN = self.Pixel2Cell(event.GetPositionTuple())
        except (ValueError):
            self.lastEN = None
        # FIXME: special case for vdigit and access to statusbarManager
        if self.parent.statusbarManager.GetMode() == 0: # Coordinates            
            updated = False
            if hasattr(self, "digit"):
                precision = int(UserSettings.Get(group = 'projection', key = 'format',
                                             subkey = 'precision'))
                updated = self._onMotion(self.lastEN, precision)

            if not updated:
                self.parent.CoordinatesChanged()
        
        event.Skip()

    def GetLastEN(self):
        """!Returns last coordinates of mouse cursor.
        
        @see OnMotion
        """
        return self.lastEN
    
    def GetLayerByName(self, name, mapType, dataType = 'layer'):
        """!Get layer from layer tree by nam
        
        @param name layer name
        @param type 'item' / 'layer' / 'nviz'

        @return layer / map layer properties / nviz properties
        @return None
        """
        if not self.tree:
            return None
        
        try:
            mapLayer = self.Map.GetListOfLayers(l_type = mapType, l_name = name)[0]
        except IndexError:
            return None
        
        if dataType == 'layer':
            return mapLayer
        item = self.tree.FindItemByData('maplayer', mapLayer)
        if not item:
            return None
        if dataType == 'nviz':
            return self.tree.GetPyData(item)[0]['nviz']
        
        return item
        
    def GetSelectedLayer(self, type = 'layer', multi = False):
        """!Get selected layer from layer tree
        
        @param type 'item' / 'layer' / 'nviz'
        @param multi return first selected layer or all
        
        @return layer / map layer properties / nviz properties
        @return None / [] on failure
        """
        ret = []
        if not self.tree or \
                not self.tree.GetSelection():
            if multi:
                return []
            else:
                return None
        
        if multi and \
                type == 'item':
            return self.tree.GetSelections()
        
        for item in self.tree.GetSelections():
            if not item.IsChecked():
                if multi:
                    continue
                else:
                    return None

            if type == 'item': # -> multi = False
                return item
        
            try:
                if type == 'nviz':
                    layer = self.tree.GetPyData(item)[0]['nviz']
                else:
                    layer = self.tree.GetPyData(item)[0]['maplayer']
            except:
                layer = None

            if multi:
                ret.append(layer)
            else:
                return layer
            
        return ret