Add support for high-resolution scroll events

src/InputStream.c

@@ -599,8 +599,8 @@ int LiSendMultiControllerEvent(short controllerNumber, short activeGamepadMask,
         leftStickX, leftStickY, rightStickX, rightStickY);
 }
 
-// Send a scroll event to the streaming machine
+// Send a high resolution scroll event to the streaming machine
-int LiSendScrollEvent(signed char scrollClicks) {
+int LiSendHighResScrollEvent(short scrollAmount) {
     PPACKET_HOLDER holder;
     int err;
 
@@ -622,7 +622,7 @@ int LiSendScrollEvent(signed char scrollClicks) {
     }
     holder->packet.scroll.zero1 = 0;
     holder->packet.scroll.zero2 = 0;
-    holder->packet.scroll.scrollAmt1 = htons(scrollClicks * 120);
+    holder->packet.scroll.scrollAmt1 = htons(scrollAmount);
     holder->packet.scroll.scrollAmt2 = holder->packet.scroll.scrollAmt1;
     holder->packet.scroll.zero3 = 0;
 
@@ -633,3 +633,8 @@ int LiSendScrollEvent(signed char scrollClicks) {
 
     return err;
 }
+
+// Send a scroll event to the streaming machine
+int LiSendScrollEvent(signed char scrollClicks) {
+    return LiSendHighResScrollEvent(scrollClicks * 120);
+}

src/Limelight.h

@@ -416,8 +416,16 @@ int LiSendMultiControllerEvent(short controllerNumber, short activeGamepadMask,
     short leftStickX, short leftStickY, short rightStickX, short rightStickY);
 
 // This function queues a vertical scroll event to the remote server.
+// The number of "clicks" is multiplied by WHEEL_DELTA (120) before
+// being sent to the PC.
 int LiSendScrollEvent(signed char scrollClicks);
 
+// This function queues a vertical scroll event to the remote server.
+// Unlike LiSendScrollEvent(), this function can send wheel events
+// smaller than 120 units for devices that support "high resolution"
+// scrolling (Apple Trackpads, Microsoft Precision Touchpads, etc.).
+int LiSendHighResScrollEvent(short scrollAmount);
+
 // This function returns a time in milliseconds with an implementation-defined epoch.
 // NOTE: This will be populated from gettimeofday() if !HAVE_CLOCK_GETTIME and
 // populated from clock_gettime(CLOCK_MONOTONIC) if HAVE_CLOCK_GETTIME.