NPN InvalidateRect
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[edit] Summary
Invalidates specified drawing area prior to repainting or refreshing a windowless plug-in.
[edit] Syntax
#include <npapi.h>
void NPN_InvalidateRect(NPP instance,
NPRect *invalidRect);
[edit] Parameters
The function has the following parameters:
- instance
- Pointer to the current plug-in instance.
- invalidRect
- The area to invalidate, specified in a coordinate system that originates at the top left of the plug-in.
[edit] 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 force a paint message, the plug-in can call NPN_ForceRedraw after calling this method.