libui/doc/windows-controls.md

Controls on Windows

Overview

TODO

Reference

uiControlOSVtable

typedef struct uiControlOSVtable uiControlOSVtable;
struct uiControlOSVtable {
	size_t Size;
	HWND (*Handle)(uiControl *c, void *implData);
};

uiControlOSVtable describes the set of functions that control implementations on Windows need to implement. When registering your control type, you pass this in as a parameter to uiRegisterControlType(). Each method here is required.

You are responsible for allocating and initializing this struct. To do so, you simply zero the memory for this struct and set its Size field to sizeof (uiControlOSVtable). (TODO put this in a common place)

Each method takes at least two parameters. The first, c, is the uiControl itself. The second, implData, is the implementation data pointer; it is the same as the pointer returned by uiControlImplData(c), and is provided here as a convenience.

Each method is named for the uiWindowsControl function that it implements. As such, details on how to implement these methods are documented alongside those functions. For instance, instructions on implementing Handle() are given under the documentation for uiWindowsControlHandle().

uiWindowsControlHandle()

uiprivExtern HWND uiWindowsControlHandle(uiControl *c);

uiWindowsControlHandle() returns the window handle that underpins c, or NULL if c does not have any underlying window handle associated with it when called.

The window returned by uiWindowsControlHandle() is owned by c; you do not receive a reference to it at all. The window is valid until either c is destroyed or until c decides to destroy the window; you can handle the latter by catching TODO. In general, you should not store the returned window handle directly for later use. Instead, use the returned handle immediately if you have to, or follow TODO if you need to adjust properties of the handle that should persist across handle destruction/creation.

uiWindows have a single window that is created when the uiWindow is created and destroyed when the uiWindow is destroyed. Despite this, you should still follow the best practices described above. The window is of a special libui-internal window class.

For all other uiControls defined by libui, the returned window is of the appropriate window class:

• TODO

It is a programmer error to pass NULL for c. TODO a non-uiControl?