RegionBox

The region box displays the names of each geographic region in the data set, with a checkbox next to the name.

When the user clicks on one of the checkboxes several actions are triggered: the set of selected regions is updated, the budget widget is notified so it can update the maximum budget (based on the total cost of all barriers in the current selection), and the map is updated by zooming in to a level that contains only the barriers in the selected regions.

Parameters:	`project` – the Project object that has region names `map` – the TGMap object that will be updated when regions are selected `budget` – the BudgetBox object to update when regions are selected

Source code in src/tidegates/widgets.py

def __init__(self, project, map, budget):
    """
    Create the grid of checkboxes and set up the callback function.

    Arguments:
      project:  the Project object that has region names
      map:  the TGMap object that will be updated when regions are selected
      budget:  the BudgetBox object to update when regions are selected
    """
    super(RegionBox, self).__init__(margin=(10,0,10,5))
    self.totals = project.totals
    self.map = map
    self.budget_box = budget
    boxes = []
    for name in project.regions:
        box = pn.widgets.Checkbox(name=name, styles=box_styles, stylesheets=[box_style_sheet])
        box.param.watch(self.cb, ['value'])
        boxes.append(box)
    self.grid = pn.GridBox(*boxes, ncols=3)
    self.selected = set()
    self.external_cb = None
    self.append(self.grid)

`add_external_callback(f)`

Save a reference to an external function to call when a region box is clicked.

Parameters:	`f` – aditional function to call when a checkbox is clicked

src/tidegates/widgets.py

def add_external_callback(self, f):
    """
    Save a reference to an external function to call when a region box is clicked.

    Arguments:
      f: aditional function to call when a checkbox is clicked
    """
    self.external_cb = f

`cb(*events)`

Callback function invoked when one of the checkboxes is clicked. If the new state of the checkbox is 'selected' the region is added to the set of selected regions, otherwise it is removed. After updating the set notify the map widget and any other widgets that have been registered as external callbacks.

src/tidegates/widgets.py

def cb(self, *events):
    """
    Callback function invoked when one of the checkboxes is clicked.  If the new state
    of the checkbox is 'selected' the region is added to the set of selected regions,
    otherwise it is removed.  After updating the set notify the map widget and any
    other widgets that have been registered as external callbacks.
    """
    for e in events:
        if e.type == 'changed':
            r = e.obj.name
            if e.new:
                self.selected.add(r)
            else:
                self.selected.remove(r)
            amount = sum(self.totals[x] for x in self.selected)
            self.budget_box.set_budget_max(amount)
    self.map.display_regions(self.selected)
    self.map.zoom(self.selected)
    if self.external_cb:
        self.external_cb()

`selection()`

Return a list of the names of currently selected regions.

src/tidegates/widgets.py

def selection(self) -> list[str]:
    """
    Return a list of the names of currently selected regions.
    """
    return self.selected