NPN_InvalidateRect

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Summary

Invalidates the specified portion of the plugin's drawing area, adding it to the region that needs to be redrawn when the plugin next repaints its contents.

Syntax

#include <npapi.h>
 
void NPN_InvalidateRect(NPP instance,
                        NPRect *invalidRect);

Parameters

The function has the following parameters:

instance
Pointer to the plug-in instance to invalidate a portion of.
invalidRect
The area to invalidate, specified in a coordinate system that originates at the top left of the plug-in's content area.

Description

Before a windowless plug-in can repaint or refresh part of its drawing area, the plug-in must first invalidate the area with either NPN_InvalidateRect() or NPN_InvalidateRegion().

NPN_InvalidateRect() causes the NPP_HandleEvent() method to pass an update event or a paint message to the plug-in. After calling this method, the plug-in receives a paint message asynchronously.

The browser redraws invalid areas of the document and any windowless plug-ins at regularly timed intervals. To immediately send a paint message, the plug-in can call NPN_ForceRedraw() after calling this method.

See also