Merge pull request #88 from akdor1154/uint16_t

Use unsigned shorts as for value range

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

@@ -124,17 +124,18 @@ public class CanvasView extends View implements SharedPreferences.OnSharedPrefer
 		return false;
 	}
 	
-	
+	// these overflow and wrap around to negative short values, but thankfully Java will continue
+	// on regardless, so we can just ignore Java's interpretation of them and send them anyway.
 	short normalizeX(float x) {
-		return (short)(Math.min(Math.max(0, x), maxX) * Short.MAX_VALUE/maxX);
+		return (short)(Math.min(Math.max(0, x), maxX) * 2*Short.MAX_VALUE/maxX);
 	}
 	
 	short normalizeY(float x) {
-		return (short)(Math.min(Math.max(0, x), maxY) * Short.MAX_VALUE/maxY);
+		return (short)(Math.min(Math.max(0, x), maxY) * 2*Short.MAX_VALUE/maxY);
 	}
 	
 	short normalizePressure(float x) {
-		return (short)(Math.min(Math.max(0, x), 2.0) * Short.MAX_VALUE/2.0);
+		return (short)(Math.min(Math.max(0, x), 2.0) * Short.MAX_VALUE);
 	}
 
 }

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

@@ -15,7 +15,7 @@ public class NetEvent {
 		TYPE_DISCONNECT
 	}
 	static final String signature = "GfxTablet";
-	static final short protocol_version = 1;
+	static final short protocol_version = 2;
 	
 	final Type type;
 	short x, y, pressure;

doc/protocol.txt

@@ -2,26 +2,26 @@ Network protocol used by GfxTablet
 
 
 
-Version 1
+Version 2
 ---------
 
 GfxTablet app sends UDP packets to port 40118 of the destination host.
 
 Packet structure, uses network byte order (big endian):
 
-  9  bytes    "GfxTablet"
-  1  word     version number
-  1  byte     type:
-                0 motion event (hovering)
-                1 button event (finger, pen etc. touches surface)
+  9  bytes             "GfxTablet"
+  1  unsigned int16     version number
+  1  byte             event type:
+                        0: motion event (hovering)
+                        1: button event (finger, pen etc. touches surface)
 
-  1  word     x (using full range: 0..65535)
-  1  word     y (using full range: 0..65535)
-  1  word     pressure (using full range 0..65535, 32768 == pressure 1.0f on Android device)
+  1  unsigned int16     x (using full range: 0..65535)
+  1  unsigned int16     y (using full range: 0..65535)
+  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  byte     number of button, starting with 0
-  1  byte     button status:
-                0 button is released ("up")
-                1 button is pressed ("down")
+  1  signed int8        number of button, starting with 0
+  1  byte             button status:
+                        0 button is released ("up")
+                        1 button is pressed ("down")
 

driver-uinput/Makefile

@@ -2,7 +2,7 @@ TARGET = networktablet
 PREFIX = /usr/local
 BINDIR = $(PREFIX)/bin
 
-networktablet : networktablet.c protocol.h
+networktablet : networktablet.c
 
 clean :
 	rm -f networktablet

driver-uinput/networktablet.c

@@ -10,6 +10,7 @@
 #include <arpa/inet.h>
 #include <linux/input.h>
 #include <linux/uinput.h>
+#include <stdint.h>
 #include "protocol.h"
 
 #define die(str, args...) { \
@@ -52,11 +53,11 @@ void init_device(int fd)
 	uidev.id.product = 0x1;
 	uidev.id.version = 1;
 	uidev.absmin[ABS_X] = 0;
-	uidev.absmax[ABS_X] = SHRT_MAX;
+	uidev.absmax[ABS_X] = UINT16_MAX;
 	uidev.absmin[ABS_Y] = 0;
-	uidev.absmax[ABS_Y] = SHRT_MAX;
+	uidev.absmax[ABS_Y] = UINT16_MAX;
 	uidev.absmin[ABS_PRESSURE] = 0;
-	uidev.absmax[ABS_PRESSURE] = SHRT_MAX/2;
+	uidev.absmax[ABS_PRESSURE] = INT16_MAX;
 	if (write(fd, &uidev, sizeof(uidev)) < 0)
 		die("error: write");
 
@@ -132,7 +133,7 @@ int main(void)
 		ev_pkt.x = ntohs(ev_pkt.x);
 		ev_pkt.y = ntohs(ev_pkt.y);
 		ev_pkt.pressure = ntohs(ev_pkt.pressure);
-		printf("x: %hi, y: %hi, pressure: %hi\n", ev_pkt.x, ev_pkt.y, ev_pkt.pressure);
+		printf("x: %hu, y: %hu, pressure: %hu\n", ev_pkt.x, ev_pkt.y, ev_pkt.pressure);
 
 		send_event(device, EV_ABS, ABS_X, ev_pkt.x);
 		send_event(device, EV_ABS, ABS_Y, ev_pkt.y);

driver-uinput/protocol.h

@@ -1,7 +1,6 @@
-
 #define GFXTABLET_PORT 40118
 
-#define PROTOCOL_VERSION 1
+#define PROTOCOL_VERSION 2
 
 
 #pragma pack(push)
@@ -13,16 +12,16 @@
 struct event_packet
 {
 	char signature[9];
-	unsigned short version;
-	char type;	/* EVENT_TYPE_... */
+	uint16_t version;
+	uint8_t type;	/* EVENT_TYPE_... */
 	struct {	/* required */
-		short x, y;
-		short pressure;
+		uint16_t x, y;
+		uint16_t pressure;
 	};
 
 	struct {	/* only required for EVENT_TYPE_BUTTON */
-		char button;		/* number of button, beginning with 1 */
-		char down;		/* 1 = button down, 0 = button up */
+		int8_t button;		/* number of button, beginning with 1 */
+		int8_t down;		/* 1 = button down, 0 = button up */
 	};
 };