SelectableGraphicView.py 文件源码

def mousePressEvent(self, event: QMouseEvent):
        if self.scene() is None:
            return

        cursor = self.cursor().shape()
        has_shift_modifier = event.modifiers() == Qt.ShiftModifier
        is_in_shift_mode = (has_shift_modifier and self.hold_shift_to_drag) \
                           or (not has_shift_modifier and not self.hold_shift_to_drag) \
                              and cursor != Qt.SplitHCursor and cursor != Qt.SplitVCursor

        if event.buttons() == Qt.LeftButton and is_in_shift_mode:
            self.setCursor(Qt.ClosedHandCursor)
            self.grab_start = event.pos()
        elif event.buttons() == Qt.LeftButton:
            if self.is_pos_in_separea(self.mapToScene(event.pos())):
                self.separation_area_moving = True
                self.setCursor(Qt.SplitVCursor)

            elif self.selection_area.is_empty or self.selection_area.selected_edge is None:
                # Create new selection
                self.mouse_press_pos = event.pos()
                self.mouse_pos = event.pos()
                scene_pos = self.mapToScene(self.mouse_press_pos)
                self.__set_selection_area(x=scene_pos.x(), y=scene_pos.y(), w=0, h=0)
                self.selection_area.finished = False

            elif self.selection_area.selected_edge is not None:
                self.selection_area.resizing = True