libui/doc/controls.md

Controls

Overview

TODO

Reference

uiControl

typedef struct uiControl uiControl;
uint32_t uiControlType(void);
#define uiControl(obj) ((uiControl *) uiCheckControlType((obj), uiControlType()))

uiControl is an opaque type that describes a control.

uiControlType() is the type identifier of a uiControl as passed to uiControlCheckType(). You rarely need to call this directly; the uiControl() conversion macro does this for you.

uiControlVtable

typedef struct uiControlVtable uiControlVtable;
struct uiControlVtable {
	void (*Free)(uiControl *c, void *implData);
};

uiControlVtable describes the set of functions that control implementations need to implement. When registering your control type, you pass this in as part of the OS-specific counterpart vtable. Each method here is required.

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 uiControl function that it implements. As such, details on how to implement these methods are documented alongside those functions. For instance, instructions on implementing Free() are given under the documentation for uiControlFree().

uiControlFree()

void uiControlFree(uiControl *c);

uiControlFree() frees the given control.

If c has children, those children are also freed. It is a programmer error to free a control that is itself a child of another control.

If c has any registered events, those event handlers will be set to be no longer run via uiEventInvalidateSender(). The registered handlers themselves will not be removed, to avoid the scenario of another uiControl being created with the same pointer value later triggering your handler unexpectedly.

It is a programmer error to specify NULL for c.

For control implementations: This function calls your vtable's Free() method. Parameter validity checks are already performed, uiControlEventOnFree() handlers have been called, and uiControl-specific events have been invalidated. Your Free() should invalidate any events that are specific to your controls, call uiControlFree() on all the children of this control, and free dynamically allocated memory that is part of your implementation data. Once your Free() method returns, libui will take care of freeing the implementation data memory block itself.