Ticket #4847: 0001-fix-for-older-Wacom-tablet.patch

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

@@ -386 +386 @@
                     pressure = 0.0;
                     eraser = 0;
                 } else {
-//                  eraser = (data[1] & 0x20); // eraser is een tool-id
-//                  firstButton = (pressureData > 0) && data[9] <= 0x68;// > 180);
-//                  firstButton = (pressureData > 180);
-                    firstButton = (data[6] > 0);
+                    firstButton = (data[6] > 2);
+                        // For Intuos it MUST be >1,
+                        // but '>1' still gets false actuations (shaking)
                     secondButton = (data[1] & 0x02);
                     thirdButton = (data[1] & 0x04);
                     hasContact = (data[1] & 0x40);
-                    // convert tilt (-128 ... 127)
-//                  int8 tiltDataX = ((data[7] & 0x3f) << 2) | ((data[8] & 0x80) >> 6);
+                        // TODO: is this meaningful? (always true on Intuos)
+                    if (fDeviceMode == DEVICE_INTUOS) { // TODO: test perhaps superfluous?
+                        // Original Intuos protocol:
+                        //  data[6] is used to signal use of the eraser,
+                        //  as well as being the high bits of pressure.
+                        //  While not in contact:
+                        //   If the pen end is lowermost data[6] = 1;
+                        //   If the eraser end is down data[6] = 0, and pressure is strictly 0
+                        //   data[9] (top 5 bits: 0x70..0xd0) indicates height above the tablet.
+                        eraser = fEraser;
+                            // keep established value unless not touching pad
+                        // Eraser state only valid when away from surface
+                        if (data[6] <= 1 && data[9] > 0x80) {   // not touching tablet
+                            if (pressureData == 0) eraser = 1;  // strictly 0 means eraser
+                            else if (pressureData > 6) eraser = 0;  // avoid slop
+                        }
+                    }
+                    // Get raw tilt values (0..54..127)
                     int8 tiltDataX = ((data[7] & 0x3f) << 1) | ((data[8] & 0x80) >> 7);
                     int8 tiltDataY = data[8] & 0x7f;
-//                  int8 tiltDataY = 0;
                     // convert to floats
                     tiltX = (float)(tiltDataX - 64) / 64.0;
                     tiltY = (float)(tiltDataY - 64) / 64.0;