Refactor proximity info

Change-Id: I668e6abfe202e1a56d59b6b6e58d1b4f003b720a

8 files changed, 594 insertions, 426 deletions

diff --git a/native/jni/Android.mk b/native/jni/Android.mk
index f2aebd55d..3735ec07b 100644
--- a/native/jni/Android.mk
+++ b/native/jni/Android.mk
@@ -54,7 +54,9 @@ LATIN_IME_CORE_SRC_FILES := \
     dictionary.cpp \
     dic_traverse_wrapper.cpp \
     proximity_info.cpp \
+    proximity_info_params.cpp \
     proximity_info_state.cpp \
+    proximity_info_state_utils.cpp \
     unigram_dictionary.cpp \
     words_priority_queue.cpp \
     suggest/gesture_suggest.cpp \
diff --git a/native/jni/src/defines.h b/native/jni/src/defines.h
index f5f527831..1f432b431 100644
--- a/native/jni/src/defines.h
+++ b/native/jni/src/defines.h
@@ -248,6 +248,9 @@ static inline void prof_out(void) {
 // GCC warns about this.
 #define S_INT_MIN (-2147483647 - 1) // -(1 << 31)
 #endif
+
+#define MAX_PERCENTILE 100
+
 // Number of base-10 digits in the largest integer + 1 to leave room for a zero terminator.
 // As such, this is the maximum number of characters will be needed to represent an int as a
 // string, including the terminator; this is used as the size of a string buffer large enough to
diff --git a/native/jni/src/proximity_info_params.cpp b/native/jni/src/proximity_info_params.cpp
new file mode 100644
index 000000000..45f8fb529
--- /dev/null
+++ b/native/jni/src/proximity_info_params.cpp
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "proximity_info_params.h"
+
+namespace latinime {
+const int ProximityInfoParams::LOOKUP_RADIUS_PERCENTILE = 50;
+const int ProximityInfoParams::FIRST_POINT_TIME_OFFSET_MILLIS = 150;
+const int ProximityInfoParams::STRONG_DOUBLE_LETTER_TIME_MILLIS = 600;
+const int ProximityInfoParams::MIN_DOUBLE_LETTER_BEELINE_SPEED_PERCENTILE = 5;
+} // namespace latinime
diff --git a/native/jni/src/proximity_info_params.h b/native/jni/src/proximity_info_params.h
new file mode 100644
index 000000000..e54945e6c
--- /dev/null
+++ b/native/jni/src/proximity_info_params.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_PROXIMITY_INFO_PARAMS_H
+#define LATINIME_PROXIMITY_INFO_PARAMS_H
+
+#include "defines.h"
+
+namespace latinime {
+
+class ProximityInfoParams {
+ public:
+    static const int LOOKUP_RADIUS_PERCENTILE;
+    static const int FIRST_POINT_TIME_OFFSET_MILLIS;
+    static const int STRONG_DOUBLE_LETTER_TIME_MILLIS;
+    static const int MIN_DOUBLE_LETTER_BEELINE_SPEED_PERCENTILE;
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(ProximityInfoParams);
+};
+} // namespace latinime
+#endif // LATINIME_PROXIMITY_INFO_PARAMS_H
diff --git a/native/jni/src/proximity_info_state.cpp b/native/jni/src/proximity_info_state.cpp
index 31b6e4baf..5f3b26662 100644
--- a/native/jni/src/proximity_info_state.cpp
+++ b/native/jni/src/proximity_info_state.cpp
@@ -32,10 +32,6 @@ const int ProximityInfoState::NORMALIZED_SQUARED_DISTANCE_SCALING_FACTOR =
         1 << NORMALIZED_SQUARED_DISTANCE_SCALING_FACTOR_LOG_2;
 const float ProximityInfoState::NOT_A_DISTANCE_FLOAT = -1.0f;
 const int ProximityInfoState::NOT_A_CODE = -1;
-const int ProximityInfoState::LOOKUP_RADIUS_PERCENTILE = 50;
-const int ProximityInfoState::FIRST_POINT_TIME_OFFSET_MILLIS = 150;
-const int ProximityInfoState::STRONG_DOUBLE_LETTER_TIME_MILLIS = 600;
-const int ProximityInfoState::MIN_DOUBLE_LETTER_BEELINE_SPEED_PERCENTILE = 5;
 
 void ProximityInfoState::initInputParams(const int pointerId, const float maxPointToKeyLength,
         const ProximityInfo *proximityInfo, const int *const inputCodes, const int inputSize,
@@ -102,8 +98,14 @@ void ProximityInfoState::initInputParams(const int pointerId, const float maxPoi
     }
 
     if (mSampledInputSize > 0 && isGeometric) {
-        refreshSpeedRates(inputSize, xCoordinates, yCoordinates, times, lastSavedInputSize);
-        refreshBeelineSpeedRates(inputSize, xCoordinates, yCoordinates, times);
+        mAverageSpeed = ProximityInfoStateUtils::refreshSpeedRates(
+                inputSize, xCoordinates, yCoordinates, times, lastSavedInputSize,
+                mSampledInputSize, &mSampledInputXs, &mSampledInputYs, &mTimes, &mLengthCache,
+                &mInputIndice, &mSpeedRates, &mDirections);
+        ProximityInfoStateUtils::refreshBeelineSpeedRates(
+                mProximityInfo->getMostCommonKeyWidth(), mAverageSpeed, inputSize,
+                xCoordinates, yCoordinates, times, mSampledInputSize, &mSampledInputXs,
+                &mSampledInputYs, &mInputIndice, &mBeelineSpeedPercentiles);
     }
 
     if (DEBUG_GEO_FULL) {
@@ -233,151 +235,6 @@ void ProximityInfoState::initInputParams(const int pointerId, const float maxPoi
     }
 }
 
-void ProximityInfoState::refreshSpeedRates(const int inputSize, const int *const xCoordinates,
-        const int *const yCoordinates, const int *const times, const int lastSavedInputSize) {
-    // Relative speed calculation.
-    const int sumDuration = mTimes.back() - mTimes.front();
-    const int sumLength = mLengthCache.back() - mLengthCache.front();
-    mAverageSpeed = static_cast<float>(sumLength) / static_cast<float>(sumDuration);
-    mSpeedRates.resize(mSampledInputSize);
-    for (int i = lastSavedInputSize; i < mSampledInputSize; ++i) {
-        const int index = mInputIndice[i];
-        int length = 0;
-        int duration = 0;
-
-        // Calculate velocity by using distances and durations of
-        // NUM_POINTS_FOR_SPEED_CALCULATION points for both forward and backward.
-        static const int NUM_POINTS_FOR_SPEED_CALCULATION = 2;
-        for (int j = index; j < min(inputSize - 1, index + NUM_POINTS_FOR_SPEED_CALCULATION);
-                ++j) {
-            if (i < mSampledInputSize - 1 && j >= mInputIndice[i + 1]) {
-                break;
-            }
-            length += getDistanceInt(xCoordinates[j], yCoordinates[j],
-                    xCoordinates[j + 1], yCoordinates[j + 1]);
-            duration += times[j + 1] - times[j];
-        }
-        for (int j = index - 1; j >= max(0, index - NUM_POINTS_FOR_SPEED_CALCULATION); --j) {
-            if (i > 0 && j < mInputIndice[i - 1]) {
-                break;
-            }
-            // TODO: use mLengthCache instead?
-            length += getDistanceInt(xCoordinates[j], yCoordinates[j],
-                    xCoordinates[j + 1], yCoordinates[j + 1]);
-            duration += times[j + 1] - times[j];
-        }
-        if (duration == 0 || sumDuration == 0) {
-            // Cannot calculate speed; thus, it gives an average value (1.0);
-            mSpeedRates[i] = 1.0f;
-        } else {
-            const float speed = static_cast<float>(length) / static_cast<float>(duration);
-            mSpeedRates[i] = speed / mAverageSpeed;
-        }
-    }
-
-    // Direction calculation.
-    mDirections.resize(mSampledInputSize - 1);
-    for (int i = max(0, lastSavedInputSize - 1); i < mSampledInputSize - 1; ++i) {
-        mDirections[i] = getDirection(i, i + 1);
-    }
-}
-
-static const int MAX_PERCENTILE = 100;
-void ProximityInfoState::refreshBeelineSpeedRates(const int inputSize,
-        const int *const xCoordinates, const int *const yCoordinates, const int * times) {
-    if (DEBUG_SAMPLING_POINTS){
-        AKLOGI("--- refresh beeline speed rates");
-    }
-    mBeelineSpeedPercentiles.resize(mSampledInputSize);
-    for (int i = 0; i < mSampledInputSize; ++i) {
-        mBeelineSpeedPercentiles[i] = static_cast<int>(calculateBeelineSpeedRate(
-                i, inputSize, xCoordinates, yCoordinates, times) * MAX_PERCENTILE);
-    }
-}
-
-float ProximityInfoState::calculateBeelineSpeedRate(
-        const int id, const int inputSize, const int *const xCoordinates,
-        const int *const yCoordinates, const int * times) const {
-    if (mSampledInputSize <= 0 || mAverageSpeed < 0.001f) {
-        if (DEBUG_SAMPLING_POINTS){
-            AKLOGI("--- invalid state: cancel. size = %d, ave = %f",
-                    mSampledInputSize, mAverageSpeed);
-        }
-        return 1.0f;
-    }
-    const int lookupRadius =
-            mProximityInfo->getMostCommonKeyWidth() * LOOKUP_RADIUS_PERCENTILE / MAX_PERCENTILE;
-    const int x0 = mSampledInputXs[id];
-    const int y0 = mSampledInputYs[id];
-    const int actualInputIndex = mInputIndice[id];
-    int tempTime = 0;
-    int tempBeelineDistance = 0;
-    int start = actualInputIndex;
-    // lookup forward
-    while (start > 0 && tempBeelineDistance < lookupRadius) {
-        tempTime += times[start] - times[start - 1];
-        --start;
-        tempBeelineDistance = getDistanceInt(x0, y0, xCoordinates[start], yCoordinates[start]);
-    }
-    // Exclusive unless this is an edge point
-    if (start > 0 && start < actualInputIndex) {
-        ++start;
-    }
-    tempTime= 0;
-    tempBeelineDistance = 0;
-    int end = actualInputIndex;
-    // lookup backward
-    while (end < (inputSize - 1) && tempBeelineDistance < lookupRadius) {
-        tempTime += times[end + 1] - times[end];
-        ++end;
-        tempBeelineDistance = getDistanceInt(x0, y0, xCoordinates[end], yCoordinates[end]);
-    }
-    // Exclusive unless this is an edge point
-    if (end > actualInputIndex && end < (inputSize - 1)) {
-        --end;
-    }
-
-    if (start >= end) {
-        if (DEBUG_DOUBLE_LETTER) {
-            AKLOGI("--- double letter: start == end %d", start);
-        }
-        return 1.0f;
-    }
-
-    const int x2 = xCoordinates[start];
-    const int y2 = yCoordinates[start];
-    const int x3 = xCoordinates[end];
-    const int y3 = yCoordinates[end];
-    const int beelineDistance = getDistanceInt(x2, y2, x3, y3);
-    int adjustedStartTime = times[start];
-    if (start == 0 && actualInputIndex == 0 && inputSize > 1) {
-        adjustedStartTime += FIRST_POINT_TIME_OFFSET_MILLIS;
-    }
-    int adjustedEndTime = times[end];
-    if (end == (inputSize - 1) && inputSize > 1) {
-        adjustedEndTime -= FIRST_POINT_TIME_OFFSET_MILLIS;
-    }
-    const int time = adjustedEndTime - adjustedStartTime;
-    if (time <= 0) {
-        return 1.0f;
-    }
-
-    if (time >= STRONG_DOUBLE_LETTER_TIME_MILLIS){
-        return 0.0f;
-    }
-    if (DEBUG_DOUBLE_LETTER) {
-        AKLOGI("--- (%d, %d) double letter: start = %d, end = %d, dist = %d, time = %d, speed = %f,"
-                " ave = %f, val = %f, start time = %d, end time = %d",
-                id, mInputIndice[id], start, end, beelineDistance, time,
-                (static_cast<float>(beelineDistance) / static_cast<float>(time)), mAverageSpeed,
-                ((static_cast<float>(beelineDistance) / static_cast<float>(time)) / mAverageSpeed),
-                adjustedStartTime, adjustedEndTime);
-    }
-    // Offset 1%
-    // TODO: Detect double letter more smartly
-    return 0.01f + static_cast<float>(beelineDistance) / static_cast<float>(time) / mAverageSpeed;
-}
-
 bool ProximityInfoState::checkAndReturnIsContinuationPossible(const int inputSize,
         const int *const xCoordinates, const int *const yCoordinates, const int *const times,
         const bool isGeometric) const {
@@ -581,17 +438,8 @@ void ProximityInfoState::popInputData() {
 }
 
 float ProximityInfoState::getDirection(const int index0, const int index1) const {
-    if (index0 < 0 || index0 > mSampledInputSize - 1) {
-        return 0.0f;
-    }
-    if (index1 < 0 || index1 > mSampledInputSize - 1) {
-        return 0.0f;
-    }
-    const int x1 = mSampledInputXs[index0];
-    const int y1 = mSampledInputYs[index0];
-    const int x2 = mSampledInputXs[index1];
-    const int y2 = mSampledInputYs[index1];
-    return getAngle(x1, y1, x2, y2);
+    return ProximityInfoStateUtils::getDirection(
+            &mSampledInputXs, &mSampledInputYs, index0, index1);
 }
 
 float ProximityInfoState::getPointAngle(const int index) const {
diff --git a/native/jni/src/proximity_info_state.h b/native/jni/src/proximity_info_state.h
index 0f0eb7d39..d31447ead 100644
--- a/native/jni/src/proximity_info_state.h
+++ b/native/jni/src/proximity_info_state.h
@@ -24,6 +24,7 @@
 #include "char_utils.h"
 #include "defines.h"
 #include "hash_map_compat.h"
+#include "proximity_info_params.h"
 #include "proximity_info_state_utils.h"
 
 namespace latinime {
@@ -37,10 +38,6 @@ class ProximityInfoState {
     static const int NORMALIZED_SQUARED_DISTANCE_SCALING_FACTOR;
     static const float NOT_A_DISTANCE_FLOAT;
     static const int NOT_A_CODE;
-    static const int LOOKUP_RADIUS_PERCENTILE;
-    static const int FIRST_POINT_TIME_OFFSET_MILLIS;
-    static const int STRONG_DOUBLE_LETTER_TIME_MILLIS;
-    static const int MIN_DOUBLE_LETTER_BEELINE_SPEED_PERCENTILE;
 
     /////////////////////////////////////////
     // Defined in proximity_info_state.cpp //
@@ -180,7 +177,8 @@ class ProximityInfoState {
         const int beelineSpeedRate = getBeelineSpeedPercentile(id);
         if (beelineSpeedRate == 0) {
             return A_STRONG_DOUBLE_LETTER;
-        } else if (beelineSpeedRate < MIN_DOUBLE_LETTER_BEELINE_SPEED_PERCENTILE) {
+        } else if (beelineSpeedRate
+                < ProximityInfoParams::MIN_DOUBLE_LETTER_BEELINE_SPEED_PERCENTILE) {
             return A_DOUBLE_LETTER;
         } else {
             return NOT_A_DOUBLE_LETTER;
@@ -249,10 +247,6 @@ class ProximityInfoState {
     void popInputData();
     void updateAlignPointProbabilities(const int start);
     bool suppressCharProbabilities(const int index1, const int index2);
-    void refreshSpeedRates(const int inputSize, const int *const xCoordinates,
-            const int *const yCoordinates, const int *const times, const int lastSavedInputSize);
-    void refreshBeelineSpeedRates(const int inputSize,
-            const int *const xCoordinates, const int *const yCoordinates, const int * times);
     float calculateBeelineSpeedRate(const int id, const int inputSize,
             const int *const xCoordinates, const int *const yCoordinates, const int * times) const;
 
diff --git a/native/jni/src/proximity_info_state_utils.cpp b/native/jni/src/proximity_info_state_utils.cpp
new file mode 100644
index 000000000..146ce0545
--- /dev/null
+++ b/native/jni/src/proximity_info_state_utils.cpp
@@ -0,0 +1,484 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vector>
+
+#include "geometry_utils.h"
+#include "proximity_info.h"
+#include "proximity_info_params.h"
+#include "proximity_info_state_utils.h"
+
+namespace latinime {
+/* static */ int ProximityInfoStateUtils::updateTouchPoints(const int mostCommonKeyWidth,
+        const ProximityInfo *const proximityInfo, const int maxPointToKeyLength,
+        const int *const inputProximities,
+        const int *const inputXCoordinates, const int *const inputYCoordinates,
+        const int *const times, const int *const pointerIds, const int inputSize,
+        const bool isGeometric, const int pointerId, const int pushTouchPointStartIndex,
+        std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs,
+        std::vector<int> *sampledInputTimes, std::vector<int> *sampledLengthCache,
+        std::vector<int> *sampledInputIndice) {
+    if (DEBUG_SAMPLING_POINTS) {
+        if (times) {
+            for (int i = 0; i < inputSize; ++i) {
+                AKLOGI("(%d) x %d, y %d, time %d",
+                        i, xCoordinates[i], yCoordinates[i], times[i]);
+            }
+        }
+    }
+#ifdef DO_ASSERT_TEST
+    if (times) {
+        for (int i = 0; i < inputSize; ++i) {
+            if (i > 0) {
+                ASSERT(times[i] >= times[i - 1]);
+            }
+        }
+    }
+#endif
+    const bool proximityOnly = !isGeometric
+            && (inputXCoordinates[0] < 0 || inputYCoordinates[0] < 0);
+    int lastInputIndex = pushTouchPointStartIndex;
+    for (int i = lastInputIndex; i < inputSize; ++i) {
+        const int pid = pointerIds ? pointerIds[i] : 0;
+        if (pointerId == pid) {
+            lastInputIndex = i;
+        }
+    }
+    if (DEBUG_GEO_FULL) {
+        AKLOGI("Init ProximityInfoState: last input index = %d", lastInputIndex);
+    }
+    // Working space to save near keys distances for current, prev and prevprev input point.
+    NearKeysDistanceMap nearKeysDistances[3];
+    // These pointers are swapped for each inputs points.
+    NearKeysDistanceMap *currentNearKeysDistances = &nearKeysDistances[0];
+    NearKeysDistanceMap *prevNearKeysDistances = &nearKeysDistances[1];
+    NearKeysDistanceMap *prevPrevNearKeysDistances = &nearKeysDistances[2];
+    // "sumAngle" is accumulated by each angle of input points. And when "sumAngle" exceeds
+    // the threshold we save that point, reset sumAngle. This aims to keep the figure of
+    // the curve.
+    float sumAngle = 0.0f;
+
+    for (int i = pushTouchPointStartIndex; i <= lastInputIndex; ++i) {
+        // Assuming pointerId == 0 if pointerIds is null.
+        const int pid = pointerIds ? pointerIds[i] : 0;
+        if (DEBUG_GEO_FULL) {
+            AKLOGI("Init ProximityInfoState: (%d)PID = %d", i, pid);
+        }
+        if (pointerId == pid) {
+            const int c = isGeometric ?
+                    NOT_A_COORDINATE : getPrimaryCodePointAt(inputProximities, i);
+            const int x = proximityOnly ? NOT_A_COORDINATE : inputXCoordinates[i];
+            const int y = proximityOnly ? NOT_A_COORDINATE : inputYCoordinates[i];
+            const int time = times ? times[i] : -1;
+
+            if (i > 1) {
+                const float prevAngle = getAngle(
+                        inputXCoordinates[i - 2], inputYCoordinates[i - 2],
+                        inputXCoordinates[i - 1], inputYCoordinates[i - 1]);
+                const float currentAngle =
+                        getAngle(inputXCoordinates[i - 1], inputYCoordinates[i - 1], x, y);
+                sumAngle += getAngleDiff(prevAngle, currentAngle);
+            }
+
+            if (pushTouchPoint(mostCommonKeyWidth, proximityInfo, maxPointToKeyLength,
+                    i, c, x, y, time, isGeometric /* do sampling */,
+                    i == lastInputIndex, sumAngle, currentNearKeysDistances,
+                    prevNearKeysDistances, prevPrevNearKeysDistances,
+                    sampledInputXs, sampledInputYs, sampledInputTimes, sampledLengthCache,
+                    sampledInputIndice)) {
+                // Previous point information was popped.
+                NearKeysDistanceMap *tmp = prevNearKeysDistances;
+                prevNearKeysDistances = currentNearKeysDistances;
+                currentNearKeysDistances = tmp;
+            } else {
+                NearKeysDistanceMap *tmp = prevPrevNearKeysDistances;
+                prevPrevNearKeysDistances = prevNearKeysDistances;
+                prevNearKeysDistances = currentNearKeysDistances;
+                currentNearKeysDistances = tmp;
+                sumAngle = 0.0f;
+            }
+        }
+    }
+    return sampledInputXs->size();
+}
+
+/* static */ const int *ProximityInfoStateUtils::getProximityCodePointsAt(
+        const int *const inputProximities, const int index) {
+    return inputProximities + (index * MAX_PROXIMITY_CHARS_SIZE_INTERNAL);
+}
+
+/* static */ int ProximityInfoStateUtils::getPrimaryCodePointAt(
+        const int *const inputProximities, const int index) {
+    return getProximityCodePointsAt(inputProximities, index)[0];
+}
+
+/* static */ void ProximityInfoStateUtils::popInputData(std::vector<int> *sampledInputXs,
+        std::vector<int> *sampledInputYs, std::vector<int> *sampledInputTimes,
+        std::vector<int> *sampledLengthCache, std::vector<int> *sampledInputIndice) {
+    sampledInputXs->pop_back();
+    sampledInputYs->pop_back();
+    sampledInputTimes->pop_back();
+    sampledLengthCache->pop_back();
+    sampledInputIndice->pop_back();
+}
+
+/* static */ float ProximityInfoStateUtils::refreshSpeedRates(const int inputSize,
+        const int *const xCoordinates, const int *const yCoordinates, const int *const times,
+        const int lastSavedInputSize, const int sampledInputSize,
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs,
+        const std::vector<int> *const sampledInputTimes,
+        const std::vector<int> *const sampledLengthCache,
+        const std::vector<int> *const sampledInputIndice, std::vector<float> *sampledSpeedRates,
+        std::vector<float> *sampledDirections) {
+    // Relative speed calculation.
+    const int sumDuration = sampledInputTimes->back() - sampledInputTimes->front();
+    const int sumLength = sampledLengthCache->back() - sampledLengthCache->front();
+    const float averageSpeed = static_cast<float>(sumLength) / static_cast<float>(sumDuration);
+    sampledSpeedRates->resize(sampledInputSize);
+    for (int i = lastSavedInputSize; i < sampledInputSize; ++i) {
+        const int index = (*sampledInputIndice)[i];
+        int length = 0;
+        int duration = 0;
+
+        // Calculate velocity by using distances and durations of
+        // NUM_POINTS_FOR_SPEED_CALCULATION points for both forward and backward.
+        static const int NUM_POINTS_FOR_SPEED_CALCULATION = 2;
+        for (int j = index; j < min(inputSize - 1, index + NUM_POINTS_FOR_SPEED_CALCULATION);
+                ++j) {
+            if (i < sampledInputSize - 1 && j >= (*sampledInputIndice)[i + 1]) {
+                break;
+            }
+            length += getDistanceInt(xCoordinates[j], yCoordinates[j],
+                    xCoordinates[j + 1], yCoordinates[j + 1]);
+            duration += times[j + 1] - times[j];
+        }
+        for (int j = index - 1; j >= max(0, index - NUM_POINTS_FOR_SPEED_CALCULATION); --j) {
+            if (i > 0 && j < (*sampledInputIndice)[i - 1]) {
+                break;
+            }
+            // TODO: use mLengthCache instead?
+            length += getDistanceInt(xCoordinates[j], yCoordinates[j],
+                    xCoordinates[j + 1], yCoordinates[j + 1]);
+            duration += times[j + 1] - times[j];
+        }
+        if (duration == 0 || sumDuration == 0) {
+            // Cannot calculate speed; thus, it gives an average value (1.0);
+            (*sampledSpeedRates)[i] = 1.0f;
+        } else {
+            const float speed = static_cast<float>(length) / static_cast<float>(duration);
+            (*sampledSpeedRates)[i] = speed / averageSpeed;
+        }
+    }
+
+    // Direction calculation.
+    sampledDirections->resize(sampledInputSize - 1);
+    for (int i = max(0, lastSavedInputSize - 1); i < sampledInputSize - 1; ++i) {
+        (*sampledDirections)[i] = getDirection(sampledInputXs, sampledInputYs, i, i + 1);
+    }
+    return averageSpeed;
+}
+
+/* static */ void ProximityInfoStateUtils::refreshBeelineSpeedRates(const int mostCommonKeyWidth,
+        const float averageSpeed, const int inputSize, const int *const xCoordinates,
+        const int *const yCoordinates, const int *times, const int sampledInputSize,
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs, const std::vector<int> *const inputIndice,
+        std::vector<int> *beelineSpeedPercentiles) {
+    if (DEBUG_SAMPLING_POINTS) {
+        AKLOGI("--- refresh beeline speed rates");
+    }
+    beelineSpeedPercentiles->resize(sampledInputSize);
+    for (int i = 0; i < sampledInputSize; ++i) {
+        (*beelineSpeedPercentiles)[i] = static_cast<int>(calculateBeelineSpeedRate(
+                mostCommonKeyWidth, averageSpeed, i, inputSize, xCoordinates, yCoordinates, times,
+                sampledInputSize, sampledInputXs, sampledInputYs, inputIndice) * MAX_PERCENTILE);
+    }
+}
+
+/* static */float ProximityInfoStateUtils::getDirection(
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs, const int index0, const int index1) {
+    ASSERT(sampledInputXs && sampledInputYs);
+    const int sampledInputSize =sampledInputXs->size();
+    if (index0 < 0 || index0 > sampledInputSize - 1) {
+        return 0.0f;
+    }
+    if (index1 < 0 || index1 > sampledInputSize - 1) {
+        return 0.0f;
+    }
+    const int x1 = (*sampledInputXs)[index0];
+    const int y1 = (*sampledInputYs)[index0];
+    const int x2 = (*sampledInputXs)[index1];
+    const int y2 = (*sampledInputYs)[index1];
+    return getAngle(x1, y1, x2, y2);
+}
+
+// Calculating point to key distance for all near keys and returning the distance between
+// the given point and the nearest key position.
+/* static */ float ProximityInfoStateUtils::updateNearKeysDistances(
+        const ProximityInfo *const proximityInfo, const float maxPointToKeyLength, const int x,
+        const int y, NearKeysDistanceMap *const currentNearKeysDistances) {
+    static const float NEAR_KEY_THRESHOLD = 2.0f;
+
+    currentNearKeysDistances->clear();
+    const int keyCount = proximityInfo->getKeyCount();
+    float nearestKeyDistance = maxPointToKeyLength;
+    for (int k = 0; k < keyCount; ++k) {
+        const float dist = proximityInfo->getNormalizedSquaredDistanceFromCenterFloatG(k, x, y);
+        if (dist < NEAR_KEY_THRESHOLD) {
+            currentNearKeysDistances->insert(std::pair<int, float>(k, dist));
+        }
+        if (nearestKeyDistance > dist) {
+            nearestKeyDistance = dist;
+        }
+    }
+    return nearestKeyDistance;
+}
+
+// Check if previous point is at local minimum position to near keys.
+/* static */ bool ProximityInfoStateUtils::isPrevLocalMin(
+        const NearKeysDistanceMap *const currentNearKeysDistances,
+        const NearKeysDistanceMap *const prevNearKeysDistances,
+        const NearKeysDistanceMap *const prevPrevNearKeysDistances) {
+    static const float MARGIN = 0.01f;
+
+    for (NearKeysDistanceMap::const_iterator it = prevNearKeysDistances->begin();
+            it != prevNearKeysDistances->end(); ++it) {
+        NearKeysDistanceMap::const_iterator itPP = prevPrevNearKeysDistances->find(it->first);
+        NearKeysDistanceMap::const_iterator itC = currentNearKeysDistances->find(it->first);
+        if ((itPP == prevPrevNearKeysDistances->end() || itPP->second > it->second + MARGIN)
+                && (itC == currentNearKeysDistances->end() || itC->second > it->second + MARGIN)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+// Calculating a point score that indicates usefulness of the point.
+/* static */ float ProximityInfoStateUtils::getPointScore(const int mostCommonKeyWidth,
+        const int x, const int y, const int time, const bool lastPoint, const float nearest,
+        const float sumAngle, const NearKeysDistanceMap *const currentNearKeysDistances,
+        const NearKeysDistanceMap *const prevNearKeysDistances,
+        const NearKeysDistanceMap *const prevPrevNearKeysDistances,
+        std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs) {
+    static const int DISTANCE_BASE_SCALE = 100;
+    static const float NEAR_KEY_THRESHOLD = 0.6f;
+    static const int CORNER_CHECK_DISTANCE_THRESHOLD_SCALE = 25;
+    static const float NOT_LOCALMIN_DISTANCE_SCORE = -1.0f;
+    static const float LOCALMIN_DISTANCE_AND_NEAR_TO_KEY_SCORE = 1.0f;
+    static const float CORNER_ANGLE_THRESHOLD = M_PI_F * 2.0f / 3.0f;
+    static const float CORNER_SUM_ANGLE_THRESHOLD = M_PI_F / 4.0f;
+    static const float CORNER_SCORE = 1.0f;
+
+    const size_t size = sampledInputXs->size();
+    // If there is only one point, add this point. Besides, if the previous point's distance map
+    // is empty, we re-compute nearby keys distances from the current point.
+    // Note that the current point is the first point in the incremental input that needs to
+    // be re-computed.
+    if (size <= 1 || prevNearKeysDistances->empty()) {
+        return 0.0f;
+    }
+
+    const int baseSampleRate = mostCommonKeyWidth;
+    const int distPrev = getDistanceInt(sampledInputXs->back(), sampledInputYs->back(),
+            (*sampledInputXs)[size - 2], (*sampledInputYs)[size - 2]) * DISTANCE_BASE_SCALE;
+    float score = 0.0f;
+
+    // Location
+    if (!isPrevLocalMin(currentNearKeysDistances, prevNearKeysDistances,
+        prevPrevNearKeysDistances)) {
+        score += NOT_LOCALMIN_DISTANCE_SCORE;
+    } else if (nearest < NEAR_KEY_THRESHOLD) {
+        // Promote points nearby keys
+        score += LOCALMIN_DISTANCE_AND_NEAR_TO_KEY_SCORE;
+    }
+    // Angle
+    const float angle1 = getAngle(x, y, sampledInputXs->back(), sampledInputYs->back());
+    const float angle2 = getAngle(sampledInputXs->back(), sampledInputYs->back(),
+            (*sampledInputXs)[size - 2], (*sampledInputYs)[size - 2]);
+    const float angleDiff = getAngleDiff(angle1, angle2);
+
+    // Save corner
+    if (distPrev > baseSampleRate * CORNER_CHECK_DISTANCE_THRESHOLD_SCALE
+            && (sumAngle > CORNER_SUM_ANGLE_THRESHOLD || angleDiff > CORNER_ANGLE_THRESHOLD)) {
+        score += CORNER_SCORE;
+    }
+    return score;
+}
+
+// Sampling touch point and pushing information to vectors.
+// Returning if previous point is popped or not.
+/* static */ bool ProximityInfoStateUtils::pushTouchPoint(const int mostCommonKeyWidth,
+        const ProximityInfo *const proximityInfo, const int maxPointToKeyLength,
+        const int inputIndex, const int nodeCodePoint, int x, int y,
+        const int time, const bool sample, const bool isLastPoint, const float sumAngle,
+        NearKeysDistanceMap *const currentNearKeysDistances,
+        const NearKeysDistanceMap *const prevNearKeysDistances,
+        const NearKeysDistanceMap *const prevPrevNearKeysDistances,
+        std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs,
+        std::vector<int> *sampledInputTimes, std::vector<int> *sampledLengthCache,
+        std::vector<int> *sampledInputIndice) {
+    static const int LAST_POINT_SKIP_DISTANCE_SCALE = 4;
+
+    size_t size = sampledInputXs->size();
+    bool popped = false;
+    if (nodeCodePoint < 0 && sample) {
+        const float nearest = updateNearKeysDistances(
+                proximityInfo, maxPointToKeyLength, x, y, currentNearKeysDistances);
+        const float score = getPointScore(mostCommonKeyWidth, x, y, time, isLastPoint, nearest,
+                sumAngle, currentNearKeysDistances, prevNearKeysDistances,
+                prevPrevNearKeysDistances, sampledInputXs, sampledInputYs);
+        if (score < 0) {
+            // Pop previous point because it would be useless.
+            popInputData(sampledInputXs, sampledInputYs, sampledInputTimes, sampledLengthCache,
+                    sampledInputIndice);
+            size = sampledInputXs->size();
+            popped = true;
+        } else {
+            popped = false;
+        }
+        // Check if the last point should be skipped.
+        if (isLastPoint && size > 0) {
+            if (getDistanceInt(x, y, sampledInputXs->back(),
+                    sampledInputYs->back()) * LAST_POINT_SKIP_DISTANCE_SCALE
+                            < mostCommonKeyWidth) {
+                // This point is not used because it's too close to the previous point.
+                if (DEBUG_GEO_FULL) {
+                    AKLOGI("p0: size = %zd, x = %d, y = %d, lx = %d, ly = %d, dist = %d, "
+                           "width = %d", size, x, y, mSampledInputXs.back(),
+                           mSampledInputYs.back(), ProximityInfoUtils::getDistanceInt(
+                                   x, y, mSampledInputXs.back(), mSampledInputYs.back()),
+                           mProximityInfo->getMostCommonKeyWidth()
+                                   / LAST_POINT_SKIP_DISTANCE_SCALE);
+                }
+                return popped;
+            }
+        }
+    }
+
+    if (nodeCodePoint >= 0 && (x < 0 || y < 0)) {
+        const int keyId = proximityInfo->getKeyIndexOf(nodeCodePoint);
+        if (keyId >= 0) {
+            x = proximityInfo->getKeyCenterXOfKeyIdG(keyId);
+            y = proximityInfo->getKeyCenterYOfKeyIdG(keyId);
+        }
+    }
+
+    // Pushing point information.
+    if (size > 0) {
+        sampledLengthCache->push_back(
+                sampledLengthCache->back() + getDistanceInt(
+                        x, y, sampledInputXs->back(), sampledInputYs->back()));
+    } else {
+        sampledLengthCache->push_back(0);
+    }
+    sampledInputXs->push_back(x);
+    sampledInputYs->push_back(y);
+    sampledInputTimes->push_back(time);
+    sampledInputIndice->push_back(inputIndex);
+    if (DEBUG_GEO_FULL) {
+        AKLOGI("pushTouchPoint: x = %03d, y = %03d, time = %d, index = %d, popped ? %01d",
+                x, y, time, inputIndex, popped);
+    }
+    return popped;
+}
+
+/* static */ float ProximityInfoStateUtils::calculateBeelineSpeedRate(const int mostCommonKeyWidth,
+        const float averageSpeed, const int id, const int inputSize, const int *const xCoordinates,
+        const int *const yCoordinates, const int *times, const int sampledInputSize,
+        const std::vector<int> *const sampledInputXs,
+        const std::vector<int> *const sampledInputYs, const std::vector<int> *const inputIndice) {
+    if (sampledInputSize <= 0 || averageSpeed < 0.001f) {
+        if (DEBUG_SAMPLING_POINTS) {
+            AKLOGI("--- invalid state: cancel. size = %d, ave = %f",
+                    mSampledInputSize, mAverageSpeed);
+        }
+        return 1.0f;
+    }
+    const int lookupRadius = mostCommonKeyWidth
+            * ProximityInfoParams::LOOKUP_RADIUS_PERCENTILE / MAX_PERCENTILE;
+    const int x0 = (*sampledInputXs)[id];
+    const int y0 = (*sampledInputYs)[id];
+    const int actualInputIndex = (*inputIndice)[id];
+    int tempTime = 0;
+    int tempBeelineDistance = 0;
+    int start = actualInputIndex;
+    // lookup forward
+    while (start > 0 && tempBeelineDistance < lookupRadius) {
+        tempTime += times[start] - times[start - 1];
+        --start;
+        tempBeelineDistance = getDistanceInt(x0, y0, xCoordinates[start], yCoordinates[start]);
+    }
+    // Exclusive unless this is an edge point
+    if (start > 0 && start < actualInputIndex) {
+        ++start;
+    }
+    tempTime= 0;
+    tempBeelineDistance = 0;
+    int end = actualInputIndex;
+    // lookup backward
+    while (end < (inputSize - 1) && tempBeelineDistance < lookupRadius) {
+        tempTime += times[end + 1] - times[end];
+        ++end;
+        tempBeelineDistance = getDistanceInt(x0, y0, xCoordinates[end], yCoordinates[end]);
+    }
+    // Exclusive unless this is an edge point
+    if (end > actualInputIndex && end < (inputSize - 1)) {
+        --end;
+    }
+
+    if (start >= end) {
+        if (DEBUG_DOUBLE_LETTER) {
+            AKLOGI("--- double letter: start == end %d", start);
+        }
+        return 1.0f;
+    }
+
+    const int x2 = xCoordinates[start];
+    const int y2 = yCoordinates[start];
+    const int x3 = xCoordinates[end];
+    const int y3 = yCoordinates[end];
+    const int beelineDistance = getDistanceInt(x2, y2, x3, y3);
+    int adjustedStartTime = times[start];
+    if (start == 0 && actualInputIndex == 0 && inputSize > 1) {
+        adjustedStartTime += ProximityInfoParams::FIRST_POINT_TIME_OFFSET_MILLIS;
+    }
+    int adjustedEndTime = times[end];
+    if (end == (inputSize - 1) && inputSize > 1) {
+        adjustedEndTime -= ProximityInfoParams::FIRST_POINT_TIME_OFFSET_MILLIS;
+    }
+    const int time = adjustedEndTime - adjustedStartTime;
+    if (time <= 0) {
+        return 1.0f;
+    }
+
+    if (time >= ProximityInfoParams::STRONG_DOUBLE_LETTER_TIME_MILLIS){
+        return 0.0f;
+    }
+    if (DEBUG_DOUBLE_LETTER) {
+        AKLOGI("--- (%d, %d) double letter: start = %d, end = %d, dist = %d, time = %d,"
+                " speed = %f, ave = %f, val = %f, start time = %d, end time = %d",
+                id, mInputIndice[id], start, end, beelineDistance, time,
+                (static_cast<float>(beelineDistance) / static_cast<float>(time)), mAverageSpeed,
+                ((static_cast<float>(beelineDistance) / static_cast<float>(time))
+                        / mAverageSpeed), adjustedStartTime, adjustedEndTime);
+    }
+    // Offset 1%
+    // TODO: Detect double letter more smartly
+    return 0.01f + static_cast<float>(beelineDistance) / static_cast<float>(time) / averageSpeed;
+}
+} // namespace latinime
diff --git a/native/jni/src/proximity_info_state_utils.h b/native/jni/src/proximity_info_state_utils.h
index 53b992a2a..90a98ef8d 100644
--- a/native/jni/src/proximity_info_state_utils.h
+++ b/native/jni/src/proximity_info_state_utils.h
@@ -20,11 +20,11 @@
 #include <vector>
 
 #include "defines.h"
-#include "geometry_utils.h"
-#include "hash_map_compat.h"
-#include "proximity_info.h"
 
 namespace latinime {
+class ProximityInfo;
+class ProximityInfoParams;
+
 class ProximityInfoStateUtils {
  public:
     static int updateTouchPoints(const int mostCommonKeyWidth,
@@ -35,211 +35,48 @@ class ProximityInfoStateUtils {
             const bool isGeometric, const int pointerId, const int pushTouchPointStartIndex,
             std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs,
             std::vector<int> *sampledInputTimes, std::vector<int> *sampledLengthCache,
-            std::vector<int> *sampledInputIndice) {
-        if (DEBUG_SAMPLING_POINTS) {
-            if (times) {
-                for (int i = 0; i < inputSize; ++i) {
-                    AKLOGI("(%d) x %d, y %d, time %d",
-                            i, xCoordinates[i], yCoordinates[i], times[i]);
-                }
-            }
-        }
-#ifdef DO_ASSERT_TEST
-        if (times) {
-            for (int i = 0; i < inputSize; ++i) {
-                if (i > 0) {
-                    ASSERT(times[i] >= times[i - 1]);
-                }
-            }
-        }
-#endif
-        const bool proximityOnly = !isGeometric
-                && (inputXCoordinates[0] < 0 || inputYCoordinates[0] < 0);
-        int lastInputIndex = pushTouchPointStartIndex;
-        for (int i = lastInputIndex; i < inputSize; ++i) {
-            const int pid = pointerIds ? pointerIds[i] : 0;
-            if (pointerId == pid) {
-                lastInputIndex = i;
-            }
-        }
-        if (DEBUG_GEO_FULL) {
-            AKLOGI("Init ProximityInfoState: last input index = %d", lastInputIndex);
-        }
-        // Working space to save near keys distances for current, prev and prevprev input point.
-        NearKeysDistanceMap nearKeysDistances[3];
-        // These pointers are swapped for each inputs points.
-        NearKeysDistanceMap *currentNearKeysDistances = &nearKeysDistances[0];
-        NearKeysDistanceMap *prevNearKeysDistances = &nearKeysDistances[1];
-        NearKeysDistanceMap *prevPrevNearKeysDistances = &nearKeysDistances[2];
-        // "sumAngle" is accumulated by each angle of input points. And when "sumAngle" exceeds
-        // the threshold we save that point, reset sumAngle. This aims to keep the figure of
-        // the curve.
-        float sumAngle = 0.0f;
-
-        for (int i = pushTouchPointStartIndex; i <= lastInputIndex; ++i) {
-            // Assuming pointerId == 0 if pointerIds is null.
-            const int pid = pointerIds ? pointerIds[i] : 0;
-            if (DEBUG_GEO_FULL) {
-                AKLOGI("Init ProximityInfoState: (%d)PID = %d", i, pid);
-            }
-            if (pointerId == pid) {
-                const int c = isGeometric ?
-                        NOT_A_COORDINATE : getPrimaryCodePointAt(inputProximities, i);
-                const int x = proximityOnly ? NOT_A_COORDINATE : inputXCoordinates[i];
-                const int y = proximityOnly ? NOT_A_COORDINATE : inputYCoordinates[i];
-                const int time = times ? times[i] : -1;
-
-                if (i > 1) {
-                    const float prevAngle = getAngle(
-                            inputXCoordinates[i - 2], inputYCoordinates[i - 2],
-                            inputXCoordinates[i - 1], inputYCoordinates[i - 1]);
-                    const float currentAngle =
-                            getAngle(inputXCoordinates[i - 1], inputYCoordinates[i - 1], x, y);
-                    sumAngle += getAngleDiff(prevAngle, currentAngle);
-                }
-
-                if (pushTouchPoint(mostCommonKeyWidth, proximityInfo, maxPointToKeyLength,
-                        i, c, x, y, time, isGeometric /* do sampling */,
-                        i == lastInputIndex, sumAngle, currentNearKeysDistances,
-                        prevNearKeysDistances, prevPrevNearKeysDistances,
-                        sampledInputXs, sampledInputYs, sampledInputTimes, sampledLengthCache,
-                        sampledInputIndice)) {
-                    // Previous point information was popped.
-                    NearKeysDistanceMap *tmp = prevNearKeysDistances;
-                    prevNearKeysDistances = currentNearKeysDistances;
-                    currentNearKeysDistances = tmp;
-                } else {
-                    NearKeysDistanceMap *tmp = prevPrevNearKeysDistances;
-                    prevPrevNearKeysDistances = prevNearKeysDistances;
-                    prevNearKeysDistances = currentNearKeysDistances;
-                    currentNearKeysDistances = tmp;
-                    sumAngle = 0.0f;
-                }
-            }
-        }
-        return sampledInputXs->size();
-    }
-
+            std::vector<int> *sampledInputIndice);
     static const int *getProximityCodePointsAt(
-            const int *const inputProximities, const int index) {
-        return inputProximities + (index * MAX_PROXIMITY_CHARS_SIZE_INTERNAL);
-    }
-
-    static int getPrimaryCodePointAt(const int *const inputProximities, const int index) {
-        return getProximityCodePointsAt(inputProximities, index)[0];
-    }
-
+            const int *const inputProximities, const int index);
+    static int getPrimaryCodePointAt(const int *const inputProximities, const int index);
     static void popInputData(std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs,
             std::vector<int> *sampledInputTimes, std::vector<int> *sampledLengthCache,
-            std::vector<int> *sampledInputIndice) {
-        sampledInputXs->pop_back();
-        sampledInputYs->pop_back();
-        sampledInputTimes->pop_back();
-        sampledLengthCache->pop_back();
-        sampledInputIndice->pop_back();
-    }
+            std::vector<int> *sampledInputIndice);
+    static float refreshSpeedRates(const int inputSize, const int *const xCoordinates,
+            const int *const yCoordinates, const int *const times, const int lastSavedInputSize,
+            const int sampledInputSize, const std::vector<int> *const sampledInputXs,
+            const std::vector<int> *const sampledInputYs,
+            const std::vector<int> *const sampledInputTimes,
+            const std::vector<int> *const sampledLengthCache,
+            const std::vector<int> *const sampledInputIndice,
+            std::vector<float> *sampledSpeedRates, std::vector<float> *sampledDirections);
+    static void refreshBeelineSpeedRates(const int mostCommonKeyWidth,  const float averageSpeed,
+            const int inputSize, const int *const xCoordinates, const int *const yCoordinates,
+            const int *times, const int sampledInputSize,
+            const std::vector<int> *const sampledInputXs,
+            const std::vector<int> *const sampledInputYs, const std::vector<int> *const inputIndice,
+            std::vector<int> *beelineSpeedPercentiles);
+    static float getDirection(const std::vector<int> *const sampledInputXs,
+            const std::vector<int> *const sampledInputYs,
+            const int index0, const int index1);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(ProximityInfoStateUtils);
 
     typedef hash_map_compat<int, float> NearKeysDistanceMap;
 
-    // Calculating point to key distance for all near keys and returning the distance between
-    // the given point and the nearest key position.
     static float updateNearKeysDistances(const ProximityInfo *const proximityInfo,
             const float maxPointToKeyLength, const int x, const int y,
-            NearKeysDistanceMap *const currentNearKeysDistances) {
-        static const float NEAR_KEY_THRESHOLD = 2.0f;
-
-        currentNearKeysDistances->clear();
-        const int keyCount = proximityInfo->getKeyCount();
-        float nearestKeyDistance = maxPointToKeyLength;
-        for (int k = 0; k < keyCount; ++k) {
-            const float dist = proximityInfo->getNormalizedSquaredDistanceFromCenterFloatG(k, x, y);
-            if (dist < NEAR_KEY_THRESHOLD) {
-                currentNearKeysDistances->insert(std::pair<int, float>(k, dist));
-            }
-            if (nearestKeyDistance > dist) {
-                nearestKeyDistance = dist;
-            }
-        }
-        return nearestKeyDistance;
-    }
-
-    // Check if previous point is at local minimum position to near keys.
+            NearKeysDistanceMap *const currentNearKeysDistances);
     static bool isPrevLocalMin(const NearKeysDistanceMap *const currentNearKeysDistances,
             const NearKeysDistanceMap *const prevNearKeysDistances,
-            const NearKeysDistanceMap *const prevPrevNearKeysDistances) {
-        static const float MARGIN = 0.01f;
-
-        for (NearKeysDistanceMap::const_iterator it = prevNearKeysDistances->begin();
-            it != prevNearKeysDistances->end(); ++it) {
-            NearKeysDistanceMap::const_iterator itPP = prevPrevNearKeysDistances->find(it->first);
-            NearKeysDistanceMap::const_iterator itC = currentNearKeysDistances->find(it->first);
-            if ((itPP == prevPrevNearKeysDistances->end() || itPP->second > it->second + MARGIN)
-                    && (itC == currentNearKeysDistances->end()
-                            || itC->second > it->second + MARGIN)) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    // Calculating a point score that indicates usefulness of the point.
+            const NearKeysDistanceMap *const prevPrevNearKeysDistances);
     static float getPointScore(const int mostCommonKeyWidth,
             const int x, const int y, const int time, const bool lastPoint, const float nearest,
             const float sumAngle, const NearKeysDistanceMap *const currentNearKeysDistances,
             const NearKeysDistanceMap *const prevNearKeysDistances,
             const NearKeysDistanceMap *const prevPrevNearKeysDistances,
-            std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs) {
-        static const int DISTANCE_BASE_SCALE = 100;
-        static const float NEAR_KEY_THRESHOLD = 0.6f;
-        static const int CORNER_CHECK_DISTANCE_THRESHOLD_SCALE = 25;
-        static const float NOT_LOCALMIN_DISTANCE_SCORE = -1.0f;
-        static const float LOCALMIN_DISTANCE_AND_NEAR_TO_KEY_SCORE = 1.0f;
-        static const float CORNER_ANGLE_THRESHOLD = M_PI_F * 2.0f / 3.0f;
-        static const float CORNER_SUM_ANGLE_THRESHOLD = M_PI_F / 4.0f;
-        static const float CORNER_SCORE = 1.0f;
-
-        const size_t size = sampledInputXs->size();
-        // If there is only one point, add this point. Besides, if the previous point's distance map
-        // is empty, we re-compute nearby keys distances from the current point.
-        // Note that the current point is the first point in the incremental input that needs to
-        // be re-computed.
-        if (size <= 1 || prevNearKeysDistances->empty()) {
-            return 0.0f;
-        }
-
-        const int baseSampleRate = mostCommonKeyWidth;
-        const int distPrev = getDistanceInt(
-                sampledInputXs->back(), sampledInputYs->back(),
-                (*sampledInputXs)[size - 2], (*sampledInputYs)[size - 2]) * DISTANCE_BASE_SCALE;
-        float score = 0.0f;
-
-        // Location
-        if (!isPrevLocalMin(currentNearKeysDistances, prevNearKeysDistances,
-            prevPrevNearKeysDistances)) {
-            score += NOT_LOCALMIN_DISTANCE_SCORE;
-        } else if (nearest < NEAR_KEY_THRESHOLD) {
-            // Promote points nearby keys
-            score += LOCALMIN_DISTANCE_AND_NEAR_TO_KEY_SCORE;
-        }
-        // Angle
-        const float angle1 = getAngle(x, y, sampledInputXs->back(), sampledInputYs->back());
-        const float angle2 = getAngle(sampledInputXs->back(), sampledInputYs->back(),
-                (*sampledInputXs)[size - 2], (*sampledInputYs)[size - 2]);
-        const float angleDiff = getAngleDiff(angle1, angle2);
-
-        // Save corner
-        if (distPrev > baseSampleRate * CORNER_CHECK_DISTANCE_THRESHOLD_SCALE
-                && (sumAngle > CORNER_SUM_ANGLE_THRESHOLD || angleDiff > CORNER_ANGLE_THRESHOLD)) {
-            score += CORNER_SCORE;
-        }
-        return score;
-    }
-
-    // Sampling touch point and pushing information to vectors.
-    // Returning if previous point is popped or not.
+            std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs);
     static bool pushTouchPoint(const int mostCommonKeyWidth,
             const ProximityInfo *const proximityInfo, const int maxPointToKeyLength,
             const int inputIndex, const int nodeCodePoint, int x, int y,
@@ -249,71 +86,13 @@ class ProximityInfoStateUtils {
             const NearKeysDistanceMap *const prevPrevNearKeysDistances,
             std::vector<int> *sampledInputXs, std::vector<int> *sampledInputYs,
             std::vector<int> *sampledInputTimes, std::vector<int> *sampledLengthCache,
-            std::vector<int> *sampledInputIndice) {
-        static const int LAST_POINT_SKIP_DISTANCE_SCALE = 4;
-
-        size_t size = sampledInputXs->size();
-        bool popped = false;
-        if (nodeCodePoint < 0 && sample) {
-            const float nearest = updateNearKeysDistances(
-                    proximityInfo, maxPointToKeyLength, x, y, currentNearKeysDistances);
-            const float score = getPointScore(mostCommonKeyWidth, x, y, time, isLastPoint, nearest,
-                    sumAngle, currentNearKeysDistances, prevNearKeysDistances,
-                    prevPrevNearKeysDistances, sampledInputXs, sampledInputYs);
-            if (score < 0) {
-                // Pop previous point because it would be useless.
-                popInputData(sampledInputXs, sampledInputYs, sampledInputTimes, sampledLengthCache,
-                        sampledInputIndice);
-                size = sampledInputXs->size();
-                popped = true;
-            } else {
-                popped = false;
-            }
-            // Check if the last point should be skipped.
-            if (isLastPoint && size > 0) {
-                if (getDistanceInt(x, y, sampledInputXs->back(),
-                        sampledInputYs->back()) * LAST_POINT_SKIP_DISTANCE_SCALE
-                                < mostCommonKeyWidth) {
-                    // This point is not used because it's too close to the previous point.
-                    if (DEBUG_GEO_FULL) {
-                        AKLOGI("p0: size = %zd, x = %d, y = %d, lx = %d, ly = %d, dist = %d, "
-                               "width = %d", size, x, y, mSampledInputXs.back(),
-                               mSampledInputYs.back(), ProximityInfoUtils::getDistanceInt(
-                                       x, y, mSampledInputXs.back(), mSampledInputYs.back()),
-                               mProximityInfo->getMostCommonKeyWidth()
-                                       / LAST_POINT_SKIP_DISTANCE_SCALE);
-                    }
-                    return popped;
-                }
-            }
-        }
-
-        if (nodeCodePoint >= 0 && (x < 0 || y < 0)) {
-            const int keyId = proximityInfo->getKeyIndexOf(nodeCodePoint);
-            if (keyId >= 0) {
-                x = proximityInfo->getKeyCenterXOfKeyIdG(keyId);
-                y = proximityInfo->getKeyCenterYOfKeyIdG(keyId);
-            }
-        }
-
-        // Pushing point information.
-        if (size > 0) {
-            sampledLengthCache->push_back(
-                    sampledLengthCache->back() + getDistanceInt(
-                            x, y, sampledInputXs->back(), sampledInputYs->back()));
-        } else {
-            sampledLengthCache->push_back(0);
-        }
-        sampledInputXs->push_back(x);
-        sampledInputYs->push_back(y);
-        sampledInputTimes->push_back(time);
-        sampledInputIndice->push_back(inputIndex);
-        if (DEBUG_GEO_FULL) {
-            AKLOGI("pushTouchPoint: x = %03d, y = %03d, time = %d, index = %d, popped ? %01d",
-                    x, y, time, inputIndex, popped);
-        }
-        return popped;
-    }
+            std::vector<int> *sampledInputIndice);
+    static float calculateBeelineSpeedRate(const int mostCommonKeyWidth, const float averageSpeed,
+            const int id, const int inputSize, const int *const xCoordinates,
+            const int *const yCoordinates, const int *times, const int sampledInputSize,
+            const std::vector<int> *const sampledInputXs,
+            const std::vector<int> *const sampledInputYs,
+            const std::vector<int> *const inputIndice);
 };
 } // namespace latinime
 #endif // LATINIME_PROXIMITY_INFO_STATE_UTILS_H