Index: ui/events/ozone/evdev/touch_noise/far_apart_taps_touch_noise_filter.cc |
diff --git a/ui/events/ozone/evdev/touch_noise/far_apart_taps_touch_noise_filter.cc b/ui/events/ozone/evdev/touch_noise/far_apart_taps_touch_noise_filter.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..a1f997f57caa48aad79fe6eb1d88fd985c940356 |
--- /dev/null |
+++ b/ui/events/ozone/evdev/touch_noise/far_apart_taps_touch_noise_filter.cc |
@@ -0,0 +1,91 @@ |
+// Copyright 2015 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#include "ui/events/ozone/evdev/touch_noise/far_apart_taps_touch_noise_filter.h" |
+ |
+#include <cmath> |
+ |
+#include "base/logging.h" |
+#include "base/strings/stringprintf.h" |
+ |
+namespace ui { |
+ |
+namespace { |
+ |
+// Minimum squared distance between taps to be considered far apart. |
+const int kMinDistance2 = 1500 * 1500; |
+ |
+// Max time between taps considered. |
+const int kMaxTapDeltaMs = 30; |
+ |
+// Maximum squared movement of a touch to still be considered a tap. |
+const int kMaxTapMovement2 = 20 * 20; |
+ |
+// Returns the squared distance between (|x1|, |y1|) and (|x2|, |y2|). |
+int Distance2(int x1, int y1, int x2, int y2) { |
+ int offset_x = x2 - x1; |
+ int offset_y = y2 - y1; |
+ return offset_x * offset_x + offset_y * offset_y; |
+} |
+ |
+} // namespace |
+ |
+void FarApartTapsTouchNoiseFilter::Filter( |
+ const std::vector<InProgressTouchEvdev>& touches, |
+ base::TimeDelta time, |
+ std::bitset<kNumTouchEvdevSlots>* slots_with_noise) { |
+ // Remove old taps. |
+ base::TimeDelta tap_cutoff = |
+ time - base::TimeDelta::FromMilliseconds(kMaxTapDeltaMs); |
+ for (size_t i = 0; i < arraysize(tracked_taps_); ++i) { |
+ if (tracked_taps_[i].start < tap_cutoff) |
+ tracked_taps_[i].Invalidate(); |
+ } |
+ |
+ for (const InProgressTouchEvdev& touch : touches) { |
+ // Only look at slots with active touches. |
+ if (!touch.touching && !touch.was_touching) |
+ continue; |
+ |
+ size_t slot = touch.slot; |
+ if (!touch.was_touching) { |
+ // Track new finger info. |
+ tracked_taps_[slot] = Tap(time, touch.x, touch.y); |
+ } else if (tracked_taps_[slot].is_valid()) { |
+ // Check if this finger has moved too far to be considered a tap. |
+ if (kMaxTapMovement2 < Distance2(touch.x, touch.y, tracked_taps_[slot].x, |
+ tracked_taps_[slot].y)) { |
+ tracked_taps_[slot].Invalidate(); |
+ } |
+ } |
+ |
+ if (tracked_taps_[slot].is_valid()) { |
+ // Check distance from other tracked taps. |
+ int min_distance2 = -1; |
+ for (size_t i = 0; i < arraysize(tracked_taps_); ++i) { |
+ if (i == slot || !tracked_taps_[i].is_valid()) |
+ continue; |
+ |
+ int dist2 = |
+ Distance2(tracked_taps_[i].x, tracked_taps_[i].y, touch.x, touch.y); |
+ if (min_distance2 < 0 || dist2 < min_distance2) |
+ min_distance2 = dist2; |
+ } |
+ |
+ if (min_distance2 > kMinDistance2) { |
+ // The other finger should see this one on its next frame and also |
+ // get canceled. |
+ VLOG(2) << base::StringPrintf( |
+ "Cancel tracking id %d %.0fpx from other current taps.", |
+ touch.tracking_id, sqrt(min_distance2)); |
+ slots_with_noise->set(slot); |
+ } |
+ } |
+ |
+ if (!touch.touching) |
+ tracked_taps_[slot].Invalidate(); |
+ } |
+} |
+ |
+} // namespace ui |