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.
#include <npapi.h> void NPN_InvalidateRect(NPP instance, NPRect *invalidRect);
The function has the following parameters:
- Pointer to the plug-in instance to invalidate a portion of.
- The area to invalidate, specified in a coordinate system that originates at the top left of the plug-in's content area.
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.