Input: 2.3 Mouse Input: Large Mouse Events

Applications and visible objects that use large documents (32-bit coordinate spaces) receive special versions of the mouse input messages. These special messages pass the pointer position differently; otherwise, they pass the same flags as passed by their normal counterparts.

Large mouse messages take the form MSG_META_LARGE_... . There is one large mouse event for each of the normal pointer, button, and drag events; note, however, that no large events exist for pre-passive or post-passive grabs. For the full list of large mouse events, see MSG_META_LARGE_PTR MSG_META_LARGE_START_SELECT MSG_META_LARGE_END_SELECT MSG_META_LARGE_START_MOVE_COPY MSG_META_LARGE_END_MOVE_COPY MSG_META_LARGE_START_FEATURES MSG_META_LARGE_END_FEATURES MSG_META_LARGE_START_OTHER MSG_META_LARGE_END_OTHER MS .

One special note about large events: Any object that handles large mouse events should also be prepared to handle normal mouse events. The visible parent of the large object can only send out one type (large or normal) of event at a time to its children; if it has any normal children at all, it will send out the normal event. If the large object should handle the normal event and doesn't, the event will be lost or passed on to another child.

For full information on handling large mouse events within a visible object tree, see the VisClass chapter. (This information also applies to Process objects acting as the contents of GenViews.)

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