README.touch
changeset 6987 7084af936d82
parent 4693 2ede56a19f2f
child 7127 5011ddf43295
--- a/README.touch	Sat Mar 09 10:35:12 2013 -0800
+++ b/README.touch	Sun Mar 10 09:03:38 2013 -0700
@@ -5,7 +5,7 @@
 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 API's 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.
+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.
@@ -21,18 +21,18 @@
 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..touch.xres)
-event.tfinger.y        - the y coordinate of the touch (0..touch.yres)
-event.tfinger.pressure - the pressure of the touch (0..touch.pressureres)
+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 FINGERDOWN but with additional:
-event.tfginer.dx       - change in x coordinate during this motion event.
-event.tfginer.dy       - change in y coordinate during this motion event.
+event.tfinger.dx       - change in x coordinate during this motion event.
+event.tfinger.dy       - change in y coordinate during this motion event.
 
-SDL_FINGERMOTION:
+SDL_FINGERUP:
 Sent when a finger (or stylus) is lifted from the touch device.
 Fields:
 Same as FINGERDOWN.
@@ -41,56 +41,38 @@
 ===========================================================================
 Functions
 ===========================================================================
-SDL provides the ability to access the underlying Touch and Finger structures.
+SDL provides the ability to access the underlying Finger structures.
 These structures should _never_ be modified.
 
-The following functions are included from SDL_Touch.h
-
-To get a SDL_Touch device call SDL_GetTouch(touchId). 
-This returns an SDL_Touch*. 
-IMPORTANT: If the touch has been removed, or there is no touch with the given ID, SDL_GetTouch will return null. Be sure to check for this!
+The following functions are included from SDL_touch.h
 
-An SDL_Touch has the following fields:
->xres,yres,pressures:
-	The resolution at which x,y, and pressure values are reported. Currently these will always be equal to 2^15, but this may not always be the case. 
+To get a SDL_TouchID call SDL_GetTouchDevice(index).
+This returns a SDL_TouchID.
+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!
 
->pressure_max, pressure_min, x_max, x_min, y_max, y_min
-	Which give, respectively, the maximum and minumum values that the touch digitizer can return for pressure, x coordiniate, and y coordinate AS REPORTED BY THE OPERATING SYSTEM.
-On Mac/iPhone systems _max will always be 0, and _min will always be 1. 
+The number of touch devices can be queried with SDL_GetNumTouchDevices().
 
->native_xres,native_yres,native_pressureres:
-	The native resolution of the touch device AS REPORTED BY THE OPERATING SYSTEM.
-On Mac/iPhone systems these will always be 1.
+A SDL_Touch may be used to get pointers to SDL_Finger.
 
->num_fingers:
-	The number of fingers currently down on the device.
+SDL_GetNumTouchFingers(touchID) may be used to get the number of fingers currently down on the device.
 
->fingers:
-	An array of pointers to the fingers which are on the device.
-
-
-The most common reason to access a touch device is to normalize inputs. This would be accomplished by code like the following:
+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:
 
-      SDL_Touch* inTouch = SDL_GetTouch(event.tfinger.touchId);
-      if(inTouch == NULL) continue; //The touch has been removed
-
-      float x = ((float)event.tfinger.x)/inTouch->xres;
-      float y = ((float)event.tfinger.y)/inTouch->yres;
+      float x = event.tfinger.x;
+      float y = event.tfinger.y;
 
 
 
-To get an SDL_Finger, call SDL_GetFinger(touch,fingerId), where touch is a pointer to an SDL_Touch device, and fingerId is the id of the requested finger.
-This returns an SDL_Finger*, or null if the finger does not exist, or has been removed.
-An 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 FINGERUP event is polled. 
-As a result, be very careful to check for null return values.
+To get a SDL_Finger, call SDL_GetTouchFinger(touchID,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 FINGERUP event is polled.
+As a result, be very careful to check for NULL return values.
 
-An SDL_Finger has the following fields:
+A SDL_Finger has the following fields:
 >x,y,pressure:
 	The current coordinates of the touch.
->xdelta,ydelta: 
-	The change in position resulting from the last finger motion.
->last_x, last_y, last_pressure:
-	 The previous coordinates of the touch.
+>pressure:
+	The pressure of the touch.
 
 ===========================================================================
 Notes
@@ -99,3 +81,4 @@
 
 Please direct questions/comments to:
    jim.tla+sdl_touch@gmail.com
+   (original author, API was changed since)