""" A point-to-point drawn polygon. """ from __future__ import with_statement from enable.api import cursor_style_trait, Line from traits.api import Event, Int, Instance from drawing_tool import DrawingTool class PointLine(DrawingTool): """ A point-to-point drawn line. """ # Our contained "Line" instance; it stores the points and does the actual # drawing. line = Instance(Line, args=()) # Override the draw_mode value we inherit from DrawingTool draw_mode = "overlay" # The pixel distance from a vertex that is considered 'on' the vertex. proximity_distance = Int(4) # The cursor shapes to use for various modes normal_cursor = cursor_style_trait('arrow') drawing_cursor = cursor_style_trait('pencil') delete_cursor = cursor_style_trait('bullseye') move_cursor = cursor_style_trait('sizing') # The index of the vertex being dragged, if any. _dragged = Int complete = Event def add_point(self, point): """ Add the point. """ self.line.points.append(point) return def get_point(self, index): """ Get the point at the specified index. """ return self.line.points[ index ] def set_point(self, index, point): """ Set the point at the specified index to point. """ self.line.points[index] = point return def remove_point(self, index): """ Remove the point with the specified index. """ del self.line.points[index] return #------------------------------------------------------------------------ # DrawingTool interface #------------------------------------------------------------------------ def reset(self): self.line.points = [] self.event_state = "normal" return #------------------------------------------------------------------------ # "complete" state #------------------------------------------------------------------------ def complete_draw(self, gc): # Draw the completed line self.line.line_dash = None with gc: self.line._draw_mainlayer(gc) return def complete_left_down(self, event): """ Handle the left mouse button going down in the 'complete' state. """ # Ignore the click if it contains modifiers we do not handle. 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, self.line.points) if over is not None: # Control down means remove it. if event.control_down: self.remove_point(over) self.updated = self # Otherwise, prepare to drag it. else: self._dragged = over event.window.set_pointer(self.move_cursor) 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.line.points) if over is not None: if event.control_down: event.window.set_pointer(self.delete_cursor) else: event.window.set_pointer(self.move_cursor) else: event.handled = False event.window.set_pointer(self.normal_cursor) self.request_redraw() return #------------------------------------------------------------------------ # "drag" state #------------------------------------------------------------------------ def drag_point_draw(self, gc): """ Draw the polygon in the 'drag_point' state. """ self.line._draw_mainlayer(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.updated = self 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. dragged_point = self.get_point(self._dragged) # If the point has actually moved, update it. if dragged_point != (event.x, event.y): self.set_point(self._dragged, (event.x, event.y)) self.request_redraw() return #------------------------------------------------------------------------ # "incomplete" state #------------------------------------------------------------------------ def incomplete_draw(self, gc): """ Draw the line in the 'incomplete' state. """ with gc: gc.set_fill_color((0, 0, 0, 0)) gc.rect(50, 50, 100, 100) self.line._draw_mainlayer(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 down, since # another one will be placed on the down stroke of the double click. self.remove_point(-1) event.window.set_pointer(self.move_cursor) self.event_state = 'complete' self.complete = True self.request_redraw() return def incomplete_left_down(self, event): """ Handle the left mouse button coming up in incomplete state. """ # Add the point. self.add_point((event.x, event.y)) self.updated = self 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. event.window.set_pointer(self.drawing_cursor) # If the point has actually changed, then we need to update our model. if self.get_point(-1) != (event.x, event.y): self.set_point(-1, (event.x, event.y)) self.request_redraw() return #------------------------------------------------------------------------ # "normal" state #------------------------------------------------------------------------ def normal_left_down(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. self.add_point((event.x, event.y)) self.add_point((event.x, event.y)) self.event_state = 'incomplete' self.updated = self self.line_dash = (4.0, 2.0) return def normal_mouse_move(self, event): """ Handle the mouse moving in the 'normal' state. """ event.window.set_pointer(self.drawing_cursor) return #------------------------------------------------------------------------ # Private interface #------------------------------------------------------------------------ def _updated_fired(self, event): # The self.updated trait is used by point_line and can be used by # others to indicate that the model has been updated. For now, the # only action taken is to do a redraw. self.request_redraw() def _is_near_point(self, point, event): """ Determine if the pointer is near a specified point. """ event_point = (event.x, event.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.points) > 0 and self._is_near_point(self.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