Merge pull request #89 from akdor1154/tabletInputFix

Make networktablet act as a Tablet, not a Touchscreen

Author: rfc2822

app-android/app/src/main/java/at/bitfire/gfxtablet/CanvasView.java

@@ -17,10 +17,17 @@
 public class CanvasView extends View implements SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = "GfxTablet.CanvasView";
 
+	private enum InRangeStatus {
+		OutOfRange,
+		InRange,
+		FakeInRange
+	}
+
     final SharedPreferences settings;
     NetworkClient netClient;
 	boolean acceptStylusOnly;
 	int maxX, maxY;
+	InRangeStatus inRangeStatus;
 
 
     // setup
@@ -35,6 +42,7 @@ public CanvasView(Context context, AttributeSet attributeSet) {
         settings.registerOnSharedPreferenceChangeListener(this);
         setBackground();
         setInputMethods();
+		inRangeStatus = InRangeStatus.OutOfRange;
     }
 
     public void setNetworkClient(NetworkClient networkClient) {
@@ -83,13 +91,23 @@ public boolean onGenericMotionEvent(MotionEvent event) {
 		if (isEnabled()) {
 			for (int ptr = 0; ptr < event.getPointerCount(); ptr++)
 				if (!acceptStylusOnly || (event.getToolType(ptr) == MotionEvent.TOOL_TYPE_STYLUS)) {
+					short nx = normalizeX(event.getX(ptr)),
+							ny = normalizeY(event.getY(ptr)),
+							npressure = normalizePressure(event.getPressure(ptr));
 					Log.v(TAG, String.format("Generic motion event logged: %f|%f, pressure %f", event.getX(ptr), event.getY(ptr), event.getPressure(ptr)));
-					if (event.getActionMasked() == MotionEvent.ACTION_HOVER_MOVE)
-						netClient.getQueue().add(new NetEvent(Type.TYPE_MOTION,
-							normalizeX(event.getX(ptr)),
-							normalizeY(event.getY(ptr)),
-							normalizePressure(event.getPressure(ptr))
-						));
+					switch (event.getActionMasked()) {
+					case MotionEvent.ACTION_HOVER_MOVE:
+						netClient.getQueue().add(new NetEvent(Type.TYPE_MOTION, nx, ny, npressure));
+						break;
+					case MotionEvent.ACTION_HOVER_ENTER:
+						inRangeStatus = InRangeStatus.InRange;
+						netClient.getQueue().add(new NetEvent(Type.TYPE_BUTTON, nx, ny, npressure, -1, true));
+						break;
+					case MotionEvent.ACTION_HOVER_EXIT:
+						inRangeStatus = InRangeStatus.OutOfRange;
+						netClient.getQueue().add(new NetEvent(Type.TYPE_BUTTON, nx, ny, npressure, -1, false));
+						break;
+					}
 				}
 			return true;
 		}
@@ -110,11 +128,19 @@ public boolean onTouchEvent(@NonNull MotionEvent event) {
 						netClient.getQueue().add(new NetEvent(Type.TYPE_MOTION, nx, ny, npressure));
 						break;
 					case MotionEvent.ACTION_DOWN:
+						if (inRangeStatus == inRangeStatus.OutOfRange) {
+							inRangeStatus = inRangeStatus.FakeInRange;
+							netClient.getQueue().add(new NetEvent(Type.TYPE_BUTTON, nx, ny, (short)0, -1, true));
+						}
 						netClient.getQueue().add(new NetEvent(Type.TYPE_BUTTON, nx, ny, npressure, 0, true));
 						break;
 					case MotionEvent.ACTION_UP:
 					case MotionEvent.ACTION_CANCEL:
 						netClient.getQueue().add(new NetEvent(Type.TYPE_BUTTON, nx, ny, npressure, 0, false));
+						if (inRangeStatus == inRangeStatus.FakeInRange) {
+							inRangeStatus = inRangeStatus.OutOfRange;
+							netClient.getQueue().add(new NetEvent(Type.TYPE_BUTTON, nx, ny, (short)0, -1, false));
+						}
 						break;
 					}
 

doc/protocol.txt

@@ -20,8 +20,21 @@ Packet structure, uses network byte order (big endian):
   1  unsigned int16     pressure (accepting full range 0..65535, but will clip to 32768 == pressure 1.0f on Android device)
 
   when type == button event:
-  1  signed int8        number of button, starting with 0
+  1  signed int8     button id:
+                       -1: stylus in range pseudo-button
+                        0: left click / stylus in contact / button 0
+                        1: extra button 1
+                        2: extra button 2
   1  byte             button status:
                         0 button is released ("up")
                         1 button is pressed ("down")
 
+XInput will ignore BTN_TOUCH events if they are not preceeded by
+a BTN_TOOL_PEN event -- this would never happen for a real stylus,
+because it would imply the stylus is touching the pad, yet too far
+away from the pad to be detected.
+
+A GfxTablet client must therefore be careful to send a "Button -1
+down" event before a "Button 0 down" event, to emulate this
+behaviour. If they are faking these events, they'll probably want
+to likewise send a "Button -1 up" event after a "Button 0 up" event.

driver-uinput/networktablet.c

@@ -35,6 +35,12 @@ void init_device(int fd)
 		die("error: ioctl UI_SET_EVBIT EV_KEY");
 	if (ioctl(fd, UI_SET_KEYBIT, BTN_TOUCH) < 0)
 		die("error: ioctl UI_SET_KEYBIT");
+	if (ioctl(fd, UI_SET_KEYBIT, BTN_TOOL_PEN) < 0)
+		die("error: ioctl UI_SET_KEYBIT");
+	if (ioctl(fd, UI_SET_KEYBIT, BTN_STYLUS) < 0)
+		die("error: ioctl UI_SET_KEYBIT");
+	if (ioctl(fd, UI_SET_KEYBIT, BTN_STYLUS2) < 0)
+		die("error: ioctl UI_SET_KEYBIT");
 
 	// enable 2 main axes + pressure (absolute positioning)
 	if (ioctl(fd, UI_SET_EVBIT, EV_ABS) < 0)
@@ -144,8 +150,19 @@ int main(void)
 				send_event(device, EV_SYN, SYN_REPORT, 1);
 				break;
 			case EVENT_TYPE_BUTTON:
+				// stylus hovering
+				if (ev_pkt.button == -1)
+					send_event(device, EV_KEY, BTN_TOOL_PEN, ev_pkt.down);
+				// stylus touching
 				if (ev_pkt.button == 0)
 					send_event(device, EV_KEY, BTN_TOUCH, ev_pkt.down);
+				// button 1
+				if (ev_pkt.button == 1)
+					send_event(device, EV_KEY, BTN_STYLUS, ev_pkt.down);
+				// button 2
+				if (ev_pkt.button == 2)
+					send_event(device, EV_KEY, BTN_STYLUS2, ev_pkt.down);
+				printf("sent button: %hhi, %hhu\n", ev_pkt.button, ev_pkt.down);
 				send_event(device, EV_SYN, SYN_REPORT, 1);
 				break;
 

driver-uinput/protocol.h

@@ -20,7 +20,11 @@ struct event_packet
 	};
 
 	struct {	/* only required for EVENT_TYPE_BUTTON */
-		int8_t button;		/* number of button, beginning with 1 */
+		int8_t button;		/* button id:
+								-1 = stylus in range,
+								 0 = tap/left click/button 0,
+								 1 = button 1,
+								 2 = button 2 */
 		int8_t down;		/* 1 = button down, 0 = button up */
 	};
 };