""" A point-to-point drawn polygon. """ # Enthought library imports. from enable.primitives.api import Polygon from traits.api import Int, Instance from drawing_tool import DrawingTool class PointPolygon(DrawingTool): """ A point-to-point drawn polygon. """ # The actual polygon primitive we are editing. polygon = Instance(Polygon, args=()) # The pixel distance from a vertex that is considered 'on' the vertex. proximity_distance = Int(4) # Override the default value of this inherited trait draw_mode = "overlay" # The index of the vertex being dragged, if any. _dragged = Int def reset(self): self.polygon.model.reset() self.event_state = "normal" return #------------------------------------------------------------------------ # "complete" state #------------------------------------------------------------------------ def complete_draw(self, gc): """ Draw a closed polygon. """ self.polygon.border_dash = None self.polygon._draw_closed(gc) return def complete_left_down(self, event): """ Handle the left mouse button coming up in the 'complete' state. """ # Ignore the click if it contains modifiers we do not handle. polygon = self.polygon if event.shift_down or event.alt_down: event.handled = False else: # If we are over a point, we will either move it or remove it. over = self._over_point(event, polygon.model.points) if over is not None: # Control down means remove it. if event.control_down: del polygon.model.points[over] # Otherwise, prepare to drag it. else: self._dragged = over event.window.set_pointer('right arrow') self.event_state = 'drag_point' self.request_redraw() return def complete_mouse_move(self, event): """ Handle the mouse moving in the 'complete' state. """ # If we are over a point, then we have to prepare to move it. over = self._over_point(event, self.polygon.model.points) if over is not None: if event.control_down: event.window.set_pointer('bullseye') else: event.window.set_pointer('right arrow') else: event.handled = False event.window.set_pointer('arrow') self.request_redraw() return #------------------------------------------------------------------------ # "drag_point" state #------------------------------------------------------------------------ def drag_point_draw(self, gc): """ Draw the polygon in the 'drag_point' state. """ self.complete_draw(gc) return def drag_point_left_up(self, event): """ Handle the left mouse coming up in the 'drag_point' state. """ self.event_state = 'complete' self.request_redraw() return def drag_point_mouse_move(self, event): """ Handle the mouse moving in the 'drag_point' state. """ # Only worry about the event if it's inside our bounds. polygon = self.polygon dragged_point = polygon.model.points[self._dragged] # If the point has actually moved, update it. if dragged_point != (event.x, event.y): polygon.model.points[self._dragged] = \ (event.x + self.x, event.y - self.y) self.request_redraw() return #------------------------------------------------------------------------ # "incomplete" state #------------------------------------------------------------------------ def incomplete_draw(self, gc): """ Draw the polygon in the 'incomplete' state. """ self.polygon.border_dash = (4.0, 2.0) self.polygon._draw_open(gc) return def incomplete_left_dclick(self, event): """ Handle a left double-click in the incomplete state. """ # Remove the point that was placed by the first mouse up, since # another one will be placed on the up stroke of the double click. del self.polygon.model.points[-1] event.window.set_pointer('right arrow') self.event_state = 'complete' self.complete = True self.request_redraw() return def incomplete_left_up(self, event): """ Handle the left mouse button coming up in incomplete state. """ # If the click was over the start vertex, we are done. if self._is_over_start( event ): del self.polygon.model.points[-1] self.event_state = 'complete' event.window.set_pointer('right arrow') self.complete = True # Otherwise, add the point and move on. else: self.polygon.model.points.append((event.x + self.x, event.y - self.y)) self.request_redraw() return def incomplete_mouse_move(self, event): """ Handle the mouse moving in incomplete state. """ # If we move over the initial point, then we change the cursor. if self._is_over_start( event ): event.window.set_pointer('bullseye') else: event.window.set_pointer('pencil') # If the point has actually changed, then we need to update our model. if self.polygon.model.points != (event.x + self.x, event.y - self.y): self.polygon.model.points[-1] = (event.x + self.x, event.y - self.y) self.request_redraw() return #------------------------------------------------------------------------ # "normal" state #------------------------------------------------------------------------ def normal_left_up(self, event): """ Handle the left button up in the 'normal' state. """ # Append the current point twice, because we need to have the starting # point and the current point be separate, since the current point # will be moved with the mouse from now on. pt = (event.x + self.x, event.y - self.y) self.polygon.model.points.append(pt) self.polygon.model.points.append(pt) self.event_state = 'incomplete' return def normal_mouse_move(self, event): """ Handle the mouse moving in the 'normal' state. """ event.window.set_pointer('pencil') return #------------------------------------------------------------------------ # private methods #------------------------------------------------------------------------ def _is_near_point(self, point, event): """ Determine if the pointer is near a specified point. """ event_point = (event.x + self.x, event.y - self.y) return ((abs(point[0] - event_point[0]) + \ abs(point[1] - event_point[1])) <= self.proximity_distance) def _is_over_start(self, event): """ Test if the event is 'over' the starting vertex. """ return (len(self.polygon.model.points) > 0 and self._is_near_point(self.polygon.model.points[0], event)) def _over_point(self, event, points): """ Return the index of a point in points that event is 'over'. Returns none if there is no such point. """ for i, point in enumerate(points): if self._is_near_point(point, event): result = i break else: result = None return result # EOF