PadController

class PadController(**properties: Any)

Superclasses: EventController, Object

GtkPadController is an event controller for the pads found in drawing tablets.

Pads are the collection of buttons and tactile sensors often found around the stylus-sensitive area.

These buttons and sensors have no implicit meaning, and by default they perform no action. GtkPadController is provided to map those to Action objects, thus letting the application give them a more semantic meaning.

Buttons and sensors are not constrained to triggering a single action, some %GDK_SOURCE_TABLET_PAD devices feature multiple “modes”. All these input elements have one current mode, which may determine the final action being triggered.

Pad devices often divide buttons and sensors into groups. All elements in a group share the same current mode, but different groups may have different modes. See get_n_groups and get_group_n_modes.

Each of the actions that a given button/strip/ring performs for a given mode is defined by a PadActionEntry. It contains an action name that will be looked up in the given ActionGroup and activated whenever the specified input element and mode are triggered.

A simple example of GtkPadController usage: Assigning button 1 in all modes and pad devices to an “invert-selection” action:

GtkPadActionEntry *pad_actions[] = {
  { GTK_PAD_ACTION_BUTTON, 1, -1, "Invert selection", "pad-actions.invert-selection" },
  …
};

…
action_group = g_simple_action_group_new ();
action = g_simple_action_new ("pad-actions.invert-selection", NULL);
g_signal_connect (action, "activate", on_invert_selection_activated, NULL);
g_action_map_add_action (G_ACTION_MAP (action_group), action);
…
pad_controller = gtk_pad_controller_new (action_group, NULL);

The actions belonging to rings/strips will be activated with a parameter of type %G_VARIANT_TYPE_DOUBLE bearing the value of the given axis, it is required that those are made stateful and accepting this GVariantType.

Constructors

class PadController
classmethod new(group: ActionGroup, pad: Device | None = None) → PadController

Creates a new GtkPadController that will associate events from pad to actions.

A None pad may be provided so the controller manages all pad devices generically, it is discouraged to mix GtkPadController objects with None and non-None pad argument on the same toplevel window, as execution order is not guaranteed.

The GtkPadController is created with no mapped actions. In order to map pad events to actions, use set_action_entries or set_action.

Be aware that pad events will only be delivered to GtkWindow’s, so adding a pad controller to any other type of widget will not have an effect.

Parameters:

  • group – GActionGroup to trigger actions from

  • pad – A %GDK_SOURCE_TABLET_PAD device, or None to handle all pads

Methods

class PadController
set_action(type: PadActionType, index: int, mode: int, label: str, action_name: str) → None

Adds an individual action to controller.

This action will only be activated if the given button/ring/strip number in index is interacted while the current mode is mode. -1 may be used for simple cases, so the action is triggered on all modes.

The given label should be considered user-visible, so internationalization rules apply. Some windowing systems may be able to use those for user feedback.

Parameters:

  • type – the type of pad feature that will trigger this action

  • index – the 0-indexed button/ring/strip number that will trigger this action

  • mode – the mode that will trigger this action, or -1 for all modes.

  • label – Human readable description of this action, this string should be deemed user-visible.

  • action_name – action name that will be activated in the GActionGroup

set_action_entries(entries: Sequence[PadActionEntry]) → None

A convenience function to add a group of action entries on controller.

See PadActionEntry and set_action.

Parameters:

entries – the action entries to set on controller

Properties

class PadController
props.action_group: ActionGroup
props.pad: Device