View Layout Arrangement

Terminal.Gui provides a feature of Layout known as Arrangement, which controls how the user can use the mouse and keyboard to arrange views and enables either Tiled or Overlapped layouts. Arrangement is a sub-topic of Layout.

• Arrangement - Describes the feature of Layout which controls how the user can use the mouse and keyboard to arrange views and enables either Tiled or Overlapped layouts.

• Arrange Mode - The Arrange Modes are set via the Arrangement property. When a user presses Ctrl+F5 (configurable via the ArrangeKey property) the application goes into Arrange Mode. In this mode, indicators are displayed on an arrangeable view indicating which aspect of the View can be arranged. If Movable, a ◊ will be displayed in the top-left corner of the Border. If Resizable, pressing Tab (or Shift+Tab) will cycle to an an indictor in the bottom-right corner of the Border. The up/down/left/right cursor keys will act appropriately. Esc, Ctrl+F5 or clicking outside of the Border will exit Arrange Mode.

• Modal - A modal view is one that is run as an "application" via Run(Func<Exception, bool>?, IConsoleDriver?) where Modal == true. Dialog, Messagebox, and Wizard are the prototypical examples. When run this way, there IS a z-order but it is highly-constrained: the modal view has a z-order of 1 and everything else is at 0.

• Movable - Describes a View that can be moved by the user using the keyboard or mouse. Movable is enabled on a per-View basis by setting the Movable flag on Arrangement. Dragging on the top Border of a View will move such a view. Pressing Ctrl+F5 will activate Arrange Mode letting the user move the view with the up/down/left/right cursor keys.

• Overlapped - A form of layout where SubViews of a View are visually arranged such that their Frames overlap. In Overlap view arrangements there is a Z-axis (Z-order) in addition to the X and Y dimension. The Z-order indicates which Views are shown above other views. Overlapped is enabled on a per-View basis by setting the Overlapped flag on Arrangement.

• Sizable - Describes a View that can be sized by the user using the keyboard or mouse. Sizable is enabled on a per-View basis by setting the Resizable flag on Arrangement. Dragging on the left, right, or bottom Border of a View will size that side of such a view. Pressing Ctrl+F5 will activate Arrange Mode letting the user size the view with the up/down/left/right cursor keys.

• Tiled - A form of layout where SubViews of a View are visually arranged such that their Frames do not typically overlap. With Tiled views, there is no 'z-order` to the Subviews of a View. In most use-cases, subviews do not overlap with each other (the exception being when it's done intentionally to create some visual effect). As a result, the default layout for most TUI apps is "tiled", and by default Arrangement is set to Fixed.

• Runnable - Today, Overlapped and Runnable are intrinsically linked. A runnable view is one where Application.Run(Toplevel) is called. Each Runnable view where (Modal == false) has it's own RunState and is, effectively, a self-contained "application". Application.Run() non-preemptively dispatches events (screen, keyboard, mouse , Timers, and Idle handlers) to the associated Toplevel. It is possible for such a Toplevel to create a thread and call Application.Run(someotherToplevel) on that thread, enabling pre-emptive user-interface multitasking (BackgroundWorkerCollection does this).