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PtUpdateVisibility()

Tell the widget library about a change in visibility

Synopsis:

PtUpdateVisibility( PtWidget_t *widget, 
                    PhRect_t *rect );

Arguments:

widget

A pointer to a container widget whose visibility has changed.

rect

A pointer to a PhRect_t structure that defines the area over which the visibility has changed.

Description:

This function tells the widget library that a change has occurred that may affect the visibility of widgets that intersect with the provided rect in the given container widget. This change may make the intersecting widgets completely obscured, completely unobscured, or partially obscured. This information is used to optimize refreshing the screen:

• Widgets that are completely obscured aren't drawn (since you wouldn't see them anyway).
• Widgets that are completely unobscured are drawn and don't cause widgets above them to be repaired (a completely unobscured widget has no intersecting widgets above it).
• Otherwise a widget is drawn when damaged and causes all intersecting widgets above it to be repaired.

Returns:

0 on success; -1 if widget isn't a container.

Classification:

Photon

Safety:
Interrupt handler	No
Signal handler	No
Thread	No

See also:

PhRect_t in the Photon Library Reference

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