#!/usr/bin/env python
# -*- coding: utf-8 -*-

#This file is part of PLCOpenEditor, a library implementing an IEC 61131-3 editor
#based on the plcopen standard. 
#
#Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD
#
#See COPYING file for copyrights details.
#
#This library is free software; you can redistribute it and/or
#modify it under the terms of the GNU General Public
#License as published by the Free Software Foundation; either
#version 2.1 of the License, or (at your option) any later version.
#
#This library is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#General Public License for more details.
#
#You should have received a copy of the GNU General Public
#License along with this library; if not, write to the Free Software
#Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

import wx

from graphics.GraphicCommons import GetScaledEventPosition

#-------------------------------------------------------------------------------
#                               Viewer RubberBand
#-------------------------------------------------------------------------------

"""
Class that implements a rubberband for graphic Viewers
"""

class RubberBand:
    
    def __init__(self, viewer):
        """
        Constructor
        @param viewer: Viewer on which rubberband must be drawn
        """
        self.Viewer = viewer
        
        # wx.Panel on which rubberband will be drawn
        self.DrawingSurface = viewer.Editor
        
        self.Reset()
    
    def Reset(self):
        """
        Initialize internal attributes of rubberband
        """
        self.StartPoint = None
        self.CurrentBBox = None
        self.LastBBox = None
    
    def IsShown(self):
        """
        Indicate if rubberband is drawn on viewer
        @return: True if rubberband is drawn
        """
        return self.CurrentBBox != None
    
    def GetCurrentExtent(self):
        """
        Return the rubberband bounding box
        @return: Rubberband bounding box (wx.Rect object)
        """
        # In case of rubberband not shown, return the last rubberband
        # bounding box
        if self.IsShown():
            return self.CurrentBBox
        return self.LastBBox
    
    def OnLeftDown(self, event, dc, scaling):
        """
        Called when left mouse is pressed on Viewer. Starts to edit a new
        rubberband bounding box
        @param event: Mouse event
        @param dc: Device Context of Viewer
        @param scaling: PLCOpen scaling applied on Viewer
        """
        # Save the point where mouse was pressed in Viewer unit, position may
        # be modified by scroll and zoom applied on viewer
        self.StartPoint = GetScaledEventPosition(event, dc, scaling)
        
        # Initialize rubberband bounding box
        self.CurrentBBox = wx.Rect(self.StartPoint.x, self.StartPoint.y, 0, 0)
        
        # Change viewer mouse cursor to reflect a rubberband bounding box is
        # edited
        self.DrawingSurface.SetCursor(wx.StockCursor(wx.CURSOR_CROSS))
        
        self.Redraw()
    
    def OnMotion(self, event, dc, scaling):
        """
        Called when mouse is dragging over Viewer. Update the current edited
        rubberband bounding box
        @param event: Mouse event
        @param dc: Device Context of Viewer
        @param scaling: PLCOpen scaling applied on Viewer
        """
        # Get mouse position in Viewer unit, position may be modified by scroll
        # and zoom applied on viewer
        pos = GetScaledEventPosition(event, dc, scaling)
        
        # Save the last bounding box drawn for erasing it later
        self.LastBBox = wx.Rect(0, 0, 0, 0)
        self.LastBBox.Union(self.CurrentBBox)
        
        # Calculate new position and size of the box 
        self.CurrentBBox.x = min(pos.x, self.StartPoint.x)
        self.CurrentBBox.y = min(pos.y, self.StartPoint.y)
        self.CurrentBBox.width = abs(pos.x - self.StartPoint.x) + 1
        self.CurrentBBox.height = abs(pos.y - self.StartPoint.y) + 1
        
        self.Redraw()
    
    def OnLeftUp(self, event, dc, scaling):
        """
        Called when mouse is release from Viewer. Erase the current edited
        rubberband bounding box
        @param event: Mouse event
        @param dc: Device Context of Viewer
        @param scaling: PLCOpen scaling applied on Viewer
        """
        # Change viewer mouse cursor to default
        self.DrawingSurface.SetCursor(wx.NullCursor)
        
        # Save the last edited bounding box
        self.LastBBox = self.CurrentBBox
        self.CurrentBBox = None
        
        self.Redraw()
    
    def DrawBoundingBoxes(self, bboxes, dc=None):
        """
        Draw a list of bounding box on Viewer in the order given using XOR 
        logical function
        @param bboxes: List of bounding boxes to draw on viewer
        @param dc: Device Context of Viewer (default None)
        """
        # Get viewer Device Context if not given
        if dc is None:
            dc = self.Viewer.GetLogicalDC()
        
        # Save current viewer scale factors before resetting them in order to
        # avoid rubberband pen to be scaled
        scalex, scaley = dc.GetUserScale()
        dc.SetUserScale(1, 1)
        
        # Set DC drawing style
        dc.SetPen(wx.Pen(wx.WHITE, style=wx.DOT))
        dc.SetBrush(wx.TRANSPARENT_BRUSH)
        dc.SetLogicalFunction(wx.XOR)
        
        # Draw the bounding boxes using viewer scale factor
        for bbox in bboxes:
            if bbox is not None:
                dc.DrawRectangle(
                    bbox.x * scalex, bbox.y * scaley, 
                    bbox.width * scalex, bbox.height * scaley)
        
        dc.SetLogicalFunction(wx.COPY)
        
        # Restore Viewer scale factor
        dc.SetUserScale(scalex, scaley)
    
    def Redraw(self, dc = None):
        """
        Redraw rubberband on Viewer
        @param dc: Device Context of Viewer (default None)
        """
        # Erase last bbox and draw current bbox
        self.DrawBoundingBoxes([self.LastBBox, self.CurrentBBox], dc)
    
    def Erase(self, dc = None):
        """
        Erase rubberband from Viewer
        @param dc: Device Context of Viewer (default None)
        """
        # Erase last bbox
        self.DrawBoundingBoxes([self.LastBBox], dc)

    def Draw(self, dc = None):
        """
        Draw rubberband on Viewer
        @param dc: Device Context of Viewer (default None)
        """
        # Erase last bbox and draw current bbox
        self.DrawBoundingBoxes([self.CurrentBBox], dc)