@spec apply_data_buffer(t(), [entry() | term()], Drafter.Widget.rect() | nil) :: t()

Replaces :data with a non-empty list of slice entries.

Unlike the other data-driven widgets this expects a plain list rather than a Drafter.RingBuffer: {label, value} and {label, value, color} tuples pass through, and anything else becomes {"", term}. An empty list or a value that is not a list returns state unchanged.

iex> state = Drafter.Widget.PieChart.mount(%{})
iex> Drafter.Widget.PieChart.apply_data_buffer(state, [{"A", 1}, 7], nil).data
[{"A", 1}, {"", 7}]

iex> state = Drafter.Widget.PieChart.mount(%{data: [{"A", 1}]})
iex> Drafter.Widget.PieChart.apply_data_buffer(state, [], nil).data
[{"A", 1}]

@spec component_tag() :: :pie_chart

The component tag this widget registers under.

iex> Drafter.Widget.PieChart.component_tag()
:pie_chart

@spec from_component_opts(
  term(),
  keyword()
) :: Drafter.Widget.props()

Builds the props map for a {:pie_chart, data, opts} element.

data becomes :data when it is a non-empty list that is not a keyword list; otherwise opts[:data] is used, defaulting to []. :class is normalised into :classes and :__app_module__ becomes :app_module.

iex> props = Drafter.Widget.PieChart.from_component_opts([{"A", 1}], show_legend: false)
iex> {props.data, props.show_legend, props.renderer}
{[{"A", 1}], false, :text}

iex> Drafter.Widget.PieChart.from_component_opts(nil, data: [{"B", 2}]).data
[{"B", 2}]

@spec handle_event(Drafter.Event.t(), t()) :: {:bubble, t()}

Ignores every event and returns {:bubble, state}, letting it continue to the parent widget and then to the app.

@spec image_active?(t()) :: boolean()

Whether this pie chart is drawing a transmitted image rather than cells.

@spec image_raster(t() | Drafter.Widget.props(), Drafter.Widget.rect()) ::
  Drafter.Render.Picture.t() | nil

The pie, without its legend, as a Drafter.Render.Picture at the left of rect, or nil when the pie is not drawn as an image.

@spec mount(Drafter.Widget.props()) :: t()

Builds the widget state from props.

Every option listed in the module doc is read here with the default stated there.

iex> state = Drafter.Widget.PieChart.mount(%{data: [{"A", 60}, {"B", 40}]})
iex> {state.data, state.show_legend, state.show_percentages, state.renderer}
{[{"A", 60}, {"B", 40}], true, true, :text}

iex> Drafter.Widget.PieChart.mount(%{}).colors |> length()
8

@spec preferred_height(
  term(),
  keyword()
) :: pos_integer()

The number of rows the element asks for: opts[:height], default 10.

iex> Drafter.Widget.PieChart.preferred_height(nil, [])
10

iex> Drafter.Widget.PieChart.preferred_height(nil, height: 20)
20

@spec render(t() | Drafter.Widget.props(), Drafter.Widget.rect()) :: [
  Drafter.Draw.Strip.t()
]

Draws the chart into rect, always returning exactly rect.height strips.

state may be a plain props map, in which case it is passed through mount/1 first. Slices are laid out clockwise starting at twelve o'clock. This is the cell renderer and is used whatever :renderer says; image/3 is the graphics path.

Callback implementation for Drafter.Widget.unmount/1.

@spec update(Drafter.Widget.props(), t()) :: t()

Replaces the state fields named in props, keeping the current value for any key that is absent.

Accepts :data, :show_legend, :show_percentages, :colors, :style, :classes, :app_module and :renderer.

iex> state = Drafter.Widget.PieChart.mount(%{data: [{"A", 1}]})
iex> updated = Drafter.Widget.PieChart.update(%{show_legend: false}, state)
iex> {updated.data, updated.show_legend}
{[{"A", 1}], false}

@spec update_props_from_mount(Drafter.Widget.props(), term(), keyword()) ::
  Drafter.Widget.props()

Passes the mount props through unchanged, so every option is live-updatable through the component tree.

iex> props = Drafter.Widget.PieChart.from_component_opts([{"A", 1}], [])
iex> Drafter.Widget.PieChart.update_props_from_mount(props, %{}, []) == props
true