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annotate README.gesture @ 4902:50d0bff24d81

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Make the union nameless to reduce the complexity of the API. (Are there any compilers still in use that don't support this?)
author Sam Lantinga <slouken@libsdl.org>
date Wed, 29 Sep 2010 21:13:52 -0700
parents 2ede56a19f2f
children
rev   line source
4689
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
Jim Grandpre <jim.tla@gmail.com>
parents:
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1 ===========================================================================
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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2 Dollar Gestures
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3 ===========================================================================
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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4 SDL Provides an implementation of the $1 gesture recognition system. This allows for recording, saving, loading, and performing single stroke gestures.
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6 Gestures can be performed with any number of fingers (the centroid of the fingers must follow the path of the gesture), but the number of fingers must be constant (a finger cannot go down in the middle of a gesture). The path of a gesture is considered the path from the time when the final finger went down, to the first time any finger comes up.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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baf8195aeb92 Updated README's
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parents: 4689
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8 Dollar gestures are assigned an Id based on a hash function. This is guaranteed to remain constant for a given gesture. There is a (small) chance that two different gestures will be assigned the same ID. In this case, simply re-recording one of the gestures should result in a different ID.
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
Jim Grandpre <jim.tla@gmail.com>
parents:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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10 Recording:
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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11 ----------
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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12 To begin recording on a touch device call:
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13 SDL_RecordGesture(SDL_TouchID touchId), where touchId is the id of the touch device you wish to record on, or -1 to record on all connected devices.
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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15 Recording terminates as soon as a finger comes up. Recording is acknowledged by an SDL_DOLLARRECORD event.
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16 A SDL_DOLLARRECORD event is a dgesture with the following fields:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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18 event.dgesture.touchId - the Id of the touch used to record the gesture.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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19 event.dgesture.gestureId - the unique id of the recoreded gesture.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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22 Performing:
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
Jim Grandpre <jim.tla@gmail.com>
parents:
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23 -----------
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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24 As long as there is a dollar gesture assigned to a touch, every finger-up event will also cause an SDL_DOLLARGESTURE event with the following fields:
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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25
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
Jim Grandpre <jim.tla@gmail.com>
parents:
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26 event.dgesture.touchId - the Id of the touch which performed the gesture.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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27 event.dgesture.gestureId - the unique id of the closest gesture to the performed stroke.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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28 event.dgesture.error - the difference between the gesture template and the actual performed gesture. Lower error is a better match.
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29 event.dgesture.numFingers - the number of fingers used to draw the stroke.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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31 Most programs will want to define an appropriate error threshold and check to be sure taht the error of a gesture is not abnormally high (an indicator that no gesture was performed).
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
Jim Grandpre <jim.tla@gmail.com>
parents:
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35 Saving:
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
Jim Grandpre <jim.tla@gmail.com>
parents:
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36 -------
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
Jim Grandpre <jim.tla@gmail.com>
parents:
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37 To save a template, call SDL_SaveDollarTemplate(gestureId, src) where gestureId is the id of the gesture you want to save, and src is an SDL_RWops pointer to the file where the gesture will be stored.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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38
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2ede56a19f2f Fixed some typos in the documentation
Sam Lantinga <slouken@libsdl.org>
parents: 4690
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39 To save all currently loaded templates, call SDL_SaveAllDollarTemplates(src) where source is an SDL_RWops pointer to the file where the gesture will be stored.
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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41 Both functions return the number of gestures sucessfully saved.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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44 Loading:
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
Jim Grandpre <jim.tla@gmail.com>
parents:
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45 --------
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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46 To load templates from a file, call SDL_LoadDollarTemplates(touchId,src) where touchId is the id of the touch to load to (or -1 to load to all touch devices), and src is an SDL_RWops pointer to a gesture save file.
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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48 SDL_LoadDollarTemplates returns the number of templates sucessfully loaded.
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parents:
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parents:
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Jim Grandpre <jim.tla@gmail.com>
parents:
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52 ===========================================================================
f9ab8df6d45a Added README.touch and README.gesture. Moved touchtest/gestureSDLTest to test/testgesture
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parents:
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53 Multi Gestures
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54 ===========================================================================
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baf8195aeb92 Updated README's
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55 SDL provides simple support for pinch/rotate/swipe gestures.
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56 Every time a finger is moved an SDL_MULTIGESTURE event is sent with the following fields:
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58 event.mgesture.touchId - the Id of the touch on which the gesture was performed.
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59 event.mgesture.x - the normalized x cooridinate of the gesture. (0..1)
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60 event.mgesture.y - the normalized y cooridinate of the gesture. (0..1)
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61 event.mgesture.dTheta - the amount that the fingers rotated during this motion.
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62 event.mgesture.dDist - the amount that the fingers pinched during this motion.
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parents:
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63 event.mgesture.numFingers - the number of fingers used in the gesture.
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66 ===========================================================================
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67 Notes
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68 ===========================================================================
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69 For a complete example see test/testgesture.c
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71 Please direct questions/comments to:
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2ede56a19f2f Fixed some typos in the documentation
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parents: 4690
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72 jim.tla+sdl_touch@gmail.com