import wx
from mappanel import MapPanel

class DraggableMapPanel(MapPanel):
    def __init__(self, *args, **kwargs):
        MapPanel.__init__(self, *args, **kwargs)
        
        self.Bind(wx.EVT_MOUSE_EVENTS, self.MouseEvent)
        
        self.drag = None
    
    def MouseEvent(self, evt):
        # Handle zoom
        if evt.GetWheelRotation():
            tile_w, tile_h = self.tilecache.tilesize
            mouse_x, mouse_y = evt.GetPosition()
            
            # Old map position at the cursor
            old_x = self.mapx + float(mouse_x) / tile_w
            old_y = self.mapy + float(mouse_y) / tile_h
            oldzoom = self.mapzoom
            
            self.mapzoom += evt.GetWheelRotation() // evt.GetWheelDelta()
            
            zoomratio = 2 ** (self.mapzoom - oldzoom)
            
            self.mapx = old_x * zoomratio - float(mouse_x) / tile_w
            self.mapy = old_y * zoomratio - float(mouse_y) / tile_h
            
            self.Reposition()
        
        # Handle drag
        if evt.LeftDown():
            self.drag = evt.GetPosition()
        elif evt.Dragging() or evt.LeftUp() and self.drag:
            delta = evt.GetPosition() - self.drag
            tile_w, tile_h = self.tilecache.tilesize
            self.mapx -= float(delta.x) / tile_w
            self.mapy -= float(delta.y) / tile_h
            self.Reposition()
            self.drag = evt.GetPosition()
        
        if evt.LeftUp():
            self.drag = None