/ 
Term-Fabulous-0.01
/ Term::Fabulous::Widget::Dialog::Backdrop

NAME

Term::Fabulous::Widget::Dialog::Backdrop - The screen-filling layer behind an open dialog

DESCRIPTION

This class is internal to Term::Fabulous::Widget::Dialog. When a dialog opens, it creates one Backdrop, puts itself inside it and adds the Backdrop to the root widget. The Backdrop

  • floats over the whole screen (attached to the root, grown to its size, with the dialog's z_index), painted in the dialog's backdrop_color with the glyphs below showing through, and centers the dialog in itself;

  • catches every mouse event outside the dialog, whatever its color, since it covers every cell of the screen: the Mouse and MouseMove events are fired on the Backdrop and bubble to the root widget, its parent, not to the widgets behind it. Clay treats it as a floating element that captures the pointer, so nothing below it is hovered or pressed;

  • can take the keyboard focus, so a click outside the dialog focuses the Backdrop instead of a widget behind it;

  • decides the Tab order while the focus is inside the dialog (Clay::UI::Role::Interaction::HasFocusOrder): Tab and Shift+Tab cycle through the focusable widgets inside the dialog, and through the Backdrop alone when there are none;

  • stops every key that the widgets inside the dialog let bubble, so the widgets and key bindings behind the dialog see none; it closes the dialog on Escape, when the dialog's close_on_escape is set;

  • takes the focus itself when the focused widget inside the dialog loses it without another widget getting it (it is disabled or removed, or the program focuses nothing), so keys and Tab stay inside the dialog. It learns about that from the OnBlur event bubbling up from the widget, so an OnBlur listener inside the dialog must let it bubble (return Clay::UI::Enum::Result->CONTINUE).

METHODS

dialog

The Term::Fabulous::Widget::Dialog this Backdrop belongs to.

get_next_focus, get_previous_focus

The Clay::UI::Role::Interaction::HasFocusOrder methods: the widget after or before the focused one among the widgets inside the dialog that can take the focus now, in tree order (also those a widget keeps below an internal child, such as the items of a Term::Fabulous::Widget::VirtualList), wrapping around. They are the tracker's default order limited to the dialog (default_next_focus( within => $dialog ), see "default_next_focus" in Clay::UI::Interaction). From the Backdrop itself, Tab goes to the first widget and Shift+Tab to the last; with no focusable widget inside, both return the Backdrop.

SEE ALSO

Term::Fabulous::Widget::Dialog.