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Diffstat (limited to 'build/lib/SDL2-2.0.5/docs/README-touch.md')
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diff --git a/build/lib/SDL2-2.0.5/docs/README-touch.md b/build/lib/SDL2-2.0.5/docs/README-touch.md new file mode 100644 index 0000000..b6745ac --- /dev/null +++ b/build/lib/SDL2-2.0.5/docs/README-touch.md @@ -0,0 +1,86 @@ +Touch +=========================================================================== +System Specific Notes +=========================================================================== +Linux: +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. + +Mac: +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. + +iPhone: +Works out of box. + +Windows: +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 + +=========================================================================== +Events +=========================================================================== +SDL_FINGERDOWN: +Sent when a finger (or stylus) is placed on a touch device. +Fields: +* event.tfinger.touchId - the Id of the touch device. +* event.tfinger.fingerId - the Id of the finger which just went down. +* event.tfinger.x - the x coordinate of the touch (0..1) +* event.tfinger.y - the y coordinate of the touch (0..1) +* event.tfinger.pressure - the pressure of the touch (0..1) + +SDL_FINGERMOTION: +Sent when a finger (or stylus) is moved on the touch device. +Fields: +Same as SDL_FINGERDOWN but with additional: +* event.tfinger.dx - change in x coordinate during this motion event. +* event.tfinger.dy - change in y coordinate during this motion event. + +SDL_FINGERUP: +Sent when a finger (or stylus) is lifted from the touch device. +Fields: +Same as SDL_FINGERDOWN. + + +=========================================================================== +Functions +=========================================================================== +SDL provides the ability to access the underlying SDL_Finger structures. +These structures should _never_ be modified. + +The following functions are included from SDL_touch.h + +To get a SDL_TouchID call SDL_GetTouchDevice(int index). +This returns a SDL_TouchID. +IMPORTANT: If the touch has been removed, or there is no touch with the given index, SDL_GetTouchDevice() will return 0. Be sure to check for this! + +The number of touch devices can be queried with SDL_GetNumTouchDevices(). + +A SDL_TouchID may be used to get pointers to SDL_Finger. + +SDL_GetNumTouchFingers(touchID) may be used to get the number of fingers currently down on the device. + +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: + + float x = event.tfinger.x; + float y = event.tfinger.y; + + + +To get a SDL_Finger, call SDL_GetTouchFinger(SDL_TouchID touchID, int index), where touchID is a SDL_TouchID, and index is the requested finger. +This returns a SDL_Finger *, or NULL if the finger does not exist, or has been removed. +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. +As a result, be very careful to check for NULL return values. + +A SDL_Finger has the following fields: +* x, y: + The current coordinates of the touch. +* pressure: + The pressure of the touch. + + +=========================================================================== +Notes +=========================================================================== +For a complete example see test/testgesture.c + +Please direct questions/comments to: + jim.tla+sdl_touch@gmail.com + (original author, API was changed since) |