Class MCoeControlContext

MCoeControlContext

Support

Supported from 5.0

Description

Interface to allow sharing of graphics settings between controls.

The interface provides functions to set the graphics context of a control before drawing. If a control has its iContext member set, the UI Control Framework calls functions defined by this interface when a control is about to be drawn. Developers must implement PrepareContext(), which is called by the framework, to initialise the control’s window with the required graphics settings.

To use control contexts, a control should inherit from an MCoeControlContext-derived class. To share the context between controls, this control should then be set as the context for all controls that wish to share it. This is done by setting the iContext member of each of the controls — using CCoeControl::SetControlContext() and CCoeControl::CopyControlContextFrom().

Defined in MCoeControlContext:
ActivateContext(), PrepareContext(), ResetContext()

virtual void ActivateContext(CWindowGc& aGc,RDrawableWindow& aWindow) const;

Description

Activates a graphics context for the specified window.

This function is called whenever a control is about to be drawn. Its default implementation activates the graphics context given by aGc for the window given by aWindow, and calls PrepareContext().

This function may be overridden by derived classes.

Parameters

CWindowGc& aGc The graphics context to activate. When called from CCoeControl::ActivateGc(), this is the system graphics context. RDrawableWindow& aWindow The window for which the graphics context is to be activated.

virtual void PrepareContext(CWindowGc& aGc) const;

Description

Initialises graphics context settings.

This function should be implemented by derived classes to initialise the graphics context, given by aGc, with the required settings. The default implementation is empty.

Parameters

CWindowGc& aGc The graphics context to be initialised.

virtual void ResetContext(CWindowGc& aGc) const;

Description

Resets the control context.

The default implementation first resets the graphics context given by aGc, and then calls PrepareContext(). The function may be overridden by derived classes.

Parameters

CWindowGc& aGc The graphics context to be reset.