Define a dialog library

[inexorabletash]

There are hints of this in the common dialogs in DeskTop (used for file copy/delete and selector entry add/edit), but it could be formalized.

Introduce a declarative format like the following:

dialog_resource := num_controls controls...
control := rect | label | push_button | check_box | radio_button | text_input 
rect := pen_mode, left, top, right, bottom
label := left, top, string
push_button := id, left, top, right, bottom, string
check_button := id, state, left, top
radio_button := id, state, left, top
text_input := id, max_length, left, top, right, bottom

A handful of calls would be needed:

• GetTextInputString(id, pbuffer)
• SetTextInputString(id, str)
• GetButtonState(id, pstate)
• SetButtonState(id, pstate)

... and a custom event loop that provides for clicks on buttons (reporting ids) and keys (Enter, Escape, Apple-x).

[inexorabletash]

This could follow the Control Manager and linked control list style from the IIgs toolbox.

[inexorabletash]

Started this very incrementally in 7f4be7f

[inexorabletash]

Just an update here:

• Added Button ToolKit (BTK) which provide push buttons, check boxes, and radio buttons, with control records and an MLI-style API.
• Added LineEdit ToolKit (LETK) which provides single-line text inputs, with control records and an MLI-style API.
• Added GetNextEvent (a lib) which synthesizes mouse move events.
• Added OptionPicker (a lib) which handles a grid of options; this requires the client to have members in a well-known namespace rather than defining a control record.
• Added ListBox (a lib) which provides a scrolling list of options; same namespace requirement as OptionPicker.

To provide a full dialog library we'd need something like:

• Convert OptionPicker to be implemented with an MLI-style API and control record definition.
• Convert ListBox to be implemented with an MLI-style API and control record definition.
• Define a general control struct which has (1) control ID, (2) control type, (3) pointer to next control, followed by the control record, allowing a linked list of controls to be defined.
• A DialogManager call that takes the linked list of controls and handles all of the basics - hit testing and tracking, key input and filtering, etc.

Doable, but not urgent as doing it by hand isn't that bad.