Make vertical sliders slower

Make vertical sliders slower. The intention is to make the up/down
slider slower, as we have less visibility and do smaller movements in
that direction.

srcs/juloo.keyboard2/Pointers.java

@@ -608,6 +608,10 @@ public final class Pointers implements Handler.Callback
     static final float SPEED_SMOOTHING = 0.7f;
     /** Avoid absurdly large values. */
     static final float SPEED_MAX = 4.f;
+    /** Make vertical sliders slower. The intention is to make the up/down
+        slider slower, as we have less visibility and do smaller movements in
+        that direction. */
+    static final float SPEED_VERTICAL_MULT = 0.5f;
 
     public void onTouchMove(Pointer ptr, float x, float y)
     {
@@ -621,8 +625,9 @@ public final class Pointers implements Handler.Callback
           return;
         last_move_ms = System.currentTimeMillis();
       }
-      d += ((x - last_x) * direction_x + (y - last_y) * direction_y)
+      d += ((x - last_x) * speed * direction_x
-        * speed / _config.slide_step_px;
+          + (y - last_y) * speed * SPEED_VERTICAL_MULT * direction_y)
+        / _config.slide_step_px;
       update_speed(travelled, x, y);
       // Send an event when [abs(d)] exceeds [1].
       int d_ = (int)d;