Ticket #4731: wacom_filter.patch

src/add-ons/input_server/devices/wacom/TabletDevice.h

@@ -14 +14 @@
 
 #include "PointingDevice.h"
 
+#define MAX_FILTER_SAMPLES 4
+
 class TabletDevice : public PointingDevice {
  public:
                                 TabletDevice(MasterServerDevice* parent,
@@ -108 +110 @@
 
             float               fJitterX;
             float               fJitterY;
+
+            float               fFilterX[MAX_FILTER_SAMPLES];
+            float               fFilterY[MAX_FILTER_SAMPLES];
 };
 
 #endif  // WACOM_TABLET_H

src/add-ons/input_server/devices/wacom/TabletDevice.cpp

@@ -230 +230 @@
     fMaxY = maxY;
     fJitterX = JITTER_X;
     fJitterY = JITTER_Y;
+    for (int i = 0; i < MAX_FILTER_SAMPLES; i++) {
+        fFilterX[i] = 0.0;
+        fFilterY[i] = 0.0;
+    }
 }
 
 // ReadData
@@ -427 +431 @@
         float unfilteredY = y;
 
         if (fHasContact) {
+            // apply a bit of filtering
+            for (int i = 0; i < MAX_FILTER_SAMPLES - 1; i++) {
+                fFilterX[i] = fFilterX[i + 1];
+                fFilterY[i] = fFilterY[i + 1];
+                x += fFilterX[i];
+                y += fFilterY[i];
+            }
+            fFilterX[MAX_FILTER_SAMPLES - 1] = unfilteredX;
+            fFilterY[MAX_FILTER_SAMPLES - 1] = unfilteredY;
+            x /= MAX_FILTER_SAMPLES;
+            y /= MAX_FILTER_SAMPLES;
+
             deltaX = x - fPosX;
             deltaY = y - fPosY;
 
             absDeltaX = fabsf(deltaX);
             absDeltaY = fabsf(deltaY);
-
-#if 0 //DEBUG
-fParent->LogString() << "x: " << x << ", y: " << y << ", pressure: " << pressure << "\n";
-fParent->LogString() << "tilt x: " << tiltX << ", tilt y: " << tiltY << "\n\n";
-#endif
-            // apply a bit of filtering
-            if (absDeltaX < fJitterX)
-                x = fPosX;
-            if (absDeltaY < fJitterY)
-                y = fPosY;
+        } else {
+            for (int i = 0; i < MAX_FILTER_SAMPLES; i++) {
+                fFilterX[i] = x;
+                fFilterY[i] = y;
+            }
         }
     
         // only do send message if something changed
@@ -468 +479 @@
                 // adjust mouse coordinates as well
                 // to have the mouse appear at the pens
                 // last position when switching
-                fFakeMouseX = unfilteredX;
-                fFakeMouseY = unfilteredY;
+                fFakeMouseX = x;
+                fFakeMouseY = y;
             } else if (mode == MODE_MOUSE) {
                 // apply acceleration
                 float accelerationX = fJitterX * ACCELERATION_KICK_IN;