README-touch.txt
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     1 ===========================================================================
       
     2 System Specific Notes
       
     3 ===========================================================================
       
     4 Linux:
       
     5 The linux touch system is currently based off event streams, and proc/bus/devices. The active user must be given permissions to read /dev/input/TOUCHDEVICE, where TOUCHDEVICE is the event stream for your device. Currently only Wacom tablets are supported. If you have an unsupported tablet contact me at jim.tla+sdl_touch@gmail.com and I will help you get support for it.
       
     6 
       
     7 ac: 
       
     8 The Mac and iPhone APIs are pretty. If your touch device supports them then you'll be fine. If it doesn't, then there isn't much we can do.
       
     9 
       
    10 iPhone: 
       
    11 Works out of box.
       
    12 
       
    13 Windows:
       
    14 Unfortunately there is no windows support as of yet. Support for Windows 7 is planned, but we currently have no way to test. If you have a Windows 7 WM_TOUCH supported device, and are willing to help test please contact me at jim.tla+sdl_touch@gmail.com
       
    15 
       
    16 ===========================================================================
       
    17 Events
       
    18 ===========================================================================
       
    19 SDL_FINGERDOWN:
       
    20 Sent when a finger (or stylus) is placed on a touch device.
       
    21 Fields:
       
    22 event.tfinger.touchId  - the Id of the touch device.
       
    23 event.tfinger.fingerId - the Id of the finger which just went down.
       
    24 event.tfinger.x        - the x coordinate of the touch (0..1)
       
    25 event.tfinger.y        - the y coordinate of the touch (0..1)
       
    26 event.tfinger.pressure - the pressure of the touch (0..1)
       
    27 
       
    28 SDL_FINGERMOTION:
       
    29 Sent when a finger (or stylus) is moved on the touch device.
       
    30 Fields:
       
    31 Same as SDL_FINGERDOWN but with additional:
       
    32 event.tfinger.dx       - change in x coordinate during this motion event.
       
    33 event.tfinger.dy       - change in y coordinate during this motion event.
       
    34 
       
    35 SDL_FINGERUP:
       
    36 Sent when a finger (or stylus) is lifted from the touch device.
       
    37 Fields:
       
    38 Same as SDL_FINGERDOWN.
       
    39 
       
    40 
       
    41 ===========================================================================
       
    42 Functions
       
    43 ===========================================================================
       
    44 SDL provides the ability to access the underlying Finger structures.
       
    45 These structures should _never_ be modified.
       
    46 
       
    47 The following functions are included from SDL_touch.h
       
    48 
       
    49 To get a SDL_TouchID call SDL_GetTouchDevice(index).
       
    50 This returns a SDL_TouchID.
       
    51 IMPORTANT: If the touch has been removed, or there is no touch with the given ID, SDL_GetTouchID will return 0. Be sure to check for this!
       
    52 
       
    53 The number of touch devices can be queried with SDL_GetNumTouchDevices().
       
    54 
       
    55 A SDL_TouchID may be used to get pointers to SDL_Finger.
       
    56 
       
    57 SDL_GetNumTouchFingers(touchID) may be used to get the number of fingers currently down on the device.
       
    58 
       
    59 The most common reason to access SDL_Finger is to query the fingers outside the event. In most cases accessing the fingers is using the event. This would be accomplished by code like the following:
       
    60 
       
    61       float x = event.tfinger.x;
       
    62       float y = event.tfinger.y;
       
    63 
       
    64 
       
    65 
       
    66 To get a SDL_Finger, call SDL_GetTouchFinger(touchID,index), where touchID is a SDL_TouchID, and index is the requested finger.
       
    67 This returns a SDL_Finger*, or NULL if the finger does not exist, or has been removed.
       
    68 A SDL_Finger is guaranteed to be persistent for the duration of a touch, but it will be de-allocated as soon as the finger is removed. This occurs when the SDL_FINGERUP event is _added_ to the event queue, and thus _before_ the SDL_FINGERUP event is polled.
       
    69 As a result, be very careful to check for NULL return values.
       
    70 
       
    71 A SDL_Finger has the following fields:
       
    72 >x,y,pressure:
       
    73 	The current coordinates of the touch.
       
    74 >pressure:
       
    75 	The pressure of the touch.
       
    76 
       
    77 ===========================================================================
       
    78 Notes
       
    79 ===========================================================================
       
    80 For a complete example see test/testgesture.c
       
    81 
       
    82 Please direct questions/comments to:
       
    83    jim.tla+sdl_touch@gmail.com
       
    84    (original author, API was changed since)