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It is possible to disable some of the gesture code by removing the #define ENABLE_DOLLAR in SDL_gesture.c.
This reduces the overhead a bit [1] and prevents spamming of SDL_GetError() with "ERROR: NumPoints = 0" for every touch if you no gestures are used at all.

[1] The path's length in dollarNormalize() is calculated for every touch even though there is comment that it is not (change in HG from 2010-11-30)?

(In reply to comment #0)
> For Android, the following statements don't work:
> 
>   SDL_EventState(SDL_DOLLARGESTURE,SDL_IGNORE);
>   SDL_EventState(SDL_DOLLARRECORD,SDL_IGNORE);
>   SDL_EventState(SDL_MULTIGESTURE,SDL_IGNORE);
> 
> The are still present, which is a pity because the take much CPU time.
> I work with the latest hg distribution.

Small erratum:
SDL_EventState(SDL_DOLLARGESTURE,SDL_IGNORE) actually does work.

Big new complaint:
I tried an SDL app that works correctly on my Android 4.0 tablet on several other 4.0 and 4.1 tablets. I went to a big store where you can play with many tablets, and downloaded the apk file that I placed on a website beforehand. And guess what... none of them worked. The initial screen of the app did appear correctly, but as soon as the screen was touched it went black. If I touched some area where I knew there was a widget, that widget re-appeared. Widgets that should be sensitive to SDL_FINGERDOWN only, also seemed to receive SDL_FINGERMOTION events.

Summarizing: I looks as if the typing of events is broken for several Android devices.

In order to save Mr Lantinga some work, here is my solution for the ignore problem. I do not include a patch file, for events/SDL_gesture.c seems to be 'work in progress' because of the many out-commented source lines.

So:

In events/SDL_events.c, line 380:
    if (SDL_GetEventState(SDL_DOLLARGESTURE) == SDL_ENABLE ||
        SDL_GetEventState(SDL_DOLLARRECORD) == SDL_ENABLE ||
        SDL_GetEventState(SDL_MULTIGESTURE) == SDL_ENABLE) {
          SDL_GestureProcessEvent(event);
    }

In events/SDL_gesture.c, function SDL_GestureProcessEvent:
add to declarations:
    SDL_bool dollar = SDL_GetEventState(SDL_DOLLARRECORD) == SDL_ENABLE ||
                      SDL_GetEventState(SDL_DOLLARGESTURE) == SDL_ENABLE;
    SDL_bool multigesture = SDL_GetEventState(SDL_MULTIGESTURE) == SDL_ENABLE;

replace:
#ifdef ENABLE_DOLLAR
with:
   if (dollar) {

line 629 becomes:
   if (multigesture)
         SDL_SendGestureMulti(inTouch,dtheta,dDist);

Created attachment 3000 [details]
patch

simple patch

- make use of SDL_GetEventState() to send events if desired.
  in case of SDL_MULTIGESTURE, it also skips some computation for gesture recognition. 

- place SDL_QUERY use-case at first, since it is the most frequent

- fix a warning in SDL_events.c


From the previous comments : 
- I am not sure that the whole GestureProcessEvent should be disabled since it does some internal processing. if you enable/disable very quickly, the gesture you can miss some detection. of course, a corner case.

Fixed https://hg.libsdl.org/SDL/rev/7693573f862d
this makes the SDL_SetEventState work for SDL_DOLLARGESTURE, SDL_DOLLARRECORD,SDL_MULTIGESTURE.
It doesn't remove the processing though.