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LatinIME/native/jni/src/proximity_info_state.cpp
Ken Wakasa 1e61493c50 Use 32-bit code points for suggestions output 
This is a multi-project commit with Ic43dd666

bug: 6526418
Change-Id: I39c1acb4e91d04cd8a4ec5a943c8cf575da75ebc
2012-11-01 00:09:51 +09:00

1003 lines
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/*
* Copyright (C) 2012 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 <cstring> // for memset()
#include <sstream> // for debug prints
#include <stdint.h>
#define LOG_TAG "LatinIME: proximity_info_state.cpp"
#include "defines.h"
#include "geometry_utils.h"
#include "proximity_info.h"
#include "proximity_info_state.h"
namespace latinime {
const int ProximityInfoState::NORMALIZED_SQUARED_DISTANCE_SCALING_FACTOR_LOG_2 = 10;
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;
void ProximityInfoState::initInputParams(const int pointerId, const float maxPointToKeyLength,
const ProximityInfo *proximityInfo, const int *const inputCodes, const int inputSize,
const int *const xCoordinates, const int *const yCoordinates, const int *const times,
const int *const pointerIds, const bool isGeometric) {
if (isGeometric) {
mIsContinuationPossible = checkAndReturnIsContinuationPossible(
inputSize, xCoordinates, yCoordinates, times);
} else {
mIsContinuationPossible = false;
}
mProximityInfo = proximityInfo;
mHasTouchPositionCorrectionData = proximityInfo->hasTouchPositionCorrectionData();
mMostCommonKeyWidthSquare = proximityInfo->getMostCommonKeyWidthSquare();
mLocaleStr = proximityInfo->getLocaleStr();
mKeyCount = proximityInfo->getKeyCount();
mCellHeight = proximityInfo->getCellHeight();
mCellWidth = proximityInfo->getCellWidth();
mGridHeight = proximityInfo->getGridWidth();
mGridWidth = proximityInfo->getGridHeight();
memset(mInputCodes, 0, sizeof(mInputCodes));
if (!isGeometric && pointerId == 0) {
// Initialize
// - mInputCodes
// - mNormalizedSquaredDistances
// TODO: Merge
for (int i = 0; i < inputSize; ++i) {
const int primaryKey = inputCodes[i];
const int x = xCoordinates[i];
const int y = yCoordinates[i];
int *proximities = &mInputCodes[i * MAX_PROXIMITY_CHARS_SIZE_INTERNAL];
mProximityInfo->calculateNearbyKeyCodes(x, y, primaryKey, proximities);
}
if (DEBUG_PROXIMITY_CHARS) {
for (int i = 0; i < inputSize; ++i) {
AKLOGI("---");
for (int j = 0; j < MAX_PROXIMITY_CHARS_SIZE_INTERNAL; ++j) {
int icc = mInputCodes[i * MAX_PROXIMITY_CHARS_SIZE_INTERNAL + j];
int icfjc = inputCodes[i * MAX_PROXIMITY_CHARS_SIZE_INTERNAL + j];
icc += 0;
icfjc += 0;
AKLOGI("--- (%d)%c,%c", i, icc, icfjc); AKLOGI("--- A<%d>,B<%d>", icc, icfjc);
}
}
}
}
///////////////////////
// Setup touch points
int pushTouchPointStartIndex = 0;
int lastSavedInputSize = 0;
mMaxPointToKeyLength = maxPointToKeyLength;
if (mIsContinuationPossible && mInputIndice.size() > 1) {
// Just update difference.
// Two points prior is never skipped. Thus, we pop 2 input point data here.
pushTouchPointStartIndex = mInputIndice[mInputIndice.size() - 2];
popInputData();
popInputData();
lastSavedInputSize = mInputXs.size();
} else {
// Clear all data.
mInputXs.clear();
mInputYs.clear();
mTimes.clear();
mInputIndice.clear();
mLengthCache.clear();
mDistanceCache.clear();
mNearKeysVector.clear();
mSearchKeysVector.clear();
mRelativeSpeeds.clear();
mCharProbabilities.clear();
mDirections.clear();
}
if (DEBUG_GEO_FULL) {
AKLOGI("Init ProximityInfoState: reused points = %d, last input size = %d",
pushTouchPointStartIndex, lastSavedInputSize);
}
mInputSize = 0;
if (xCoordinates && yCoordinates) {
const bool proximityOnly = !isGeometric && (xCoordinates[0] < 0 || yCoordinates[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(i);
const int x = proximityOnly ? NOT_A_COORDINATE : xCoordinates[i];
const int y = proximityOnly ? NOT_A_COORDINATE : yCoordinates[i];
const int time = times ? times[i] : -1;
if (i > 1) {
const float prevAngle = getAngle(xCoordinates[i - 2], yCoordinates[i - 2],
xCoordinates[i - 1], yCoordinates[i - 1]);
const float currentAngle =
getAngle(xCoordinates[i - 1], yCoordinates[i - 1], x, y);
sumAngle += getAngleDiff(prevAngle, currentAngle);
}
if (pushTouchPoint(i, c, x, y, time, isGeometric /* do sampling */,
i == lastInputIndex, sumAngle, currentNearKeysDistances,
prevNearKeysDistances, prevPrevNearKeysDistances)) {
// 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;
}
}
}
mInputSize = mInputXs.size();
}
if (mInputSize > 0 && isGeometric) {
// Relative speed calculation.
const int sumDuration = mTimes.back() - mTimes.front();
const int sumLength = mLengthCache.back() - mLengthCache.front();
const float averageSpeed = static_cast<float>(sumLength) / static_cast<float>(sumDuration);
mRelativeSpeeds.resize(mInputSize);
for (int i = lastSavedInputSize; i < mInputSize; ++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 < mInputSize - 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;
}
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);
mRelativeSpeeds[i] = 1.0f;
} else {
const float speed = static_cast<float>(length) / static_cast<float>(duration);
mRelativeSpeeds[i] = speed / averageSpeed;
}
}
// Direction calculation.
mDirections.resize(mInputSize - 1);
for (int i = max(0, lastSavedInputSize - 1); i < mInputSize - 1; ++i) {
mDirections[i] = getDirection(i, i + 1);
}
}
if (DEBUG_GEO_FULL) {
for (int i = 0; i < mInputSize; ++i) {
AKLOGI("Sampled(%d): x = %d, y = %d, time = %d", i, mInputXs[i], mInputYs[i],
mTimes[i]);
}
}
if (mInputSize > 0) {
const int keyCount = mProximityInfo->getKeyCount();
mNearKeysVector.resize(mInputSize);
mSearchKeysVector.resize(mInputSize);
mDistanceCache.resize(mInputSize * keyCount);
for (int i = lastSavedInputSize; i < mInputSize; ++i) {
mNearKeysVector[i].reset();
mSearchKeysVector[i].reset();
static const float NEAR_KEY_NORMALIZED_SQUARED_THRESHOLD = 4.0f;
for (int k = 0; k < keyCount; ++k) {
const int index = i * keyCount + k;
const int x = mInputXs[i];
const int y = mInputYs[i];
const float normalizedSquaredDistance =
mProximityInfo->getNormalizedSquaredDistanceFromCenterFloatG(k, x, y);
mDistanceCache[index] = normalizedSquaredDistance;
if (normalizedSquaredDistance < NEAR_KEY_NORMALIZED_SQUARED_THRESHOLD) {
mNearKeysVector[i][k] = true;
}
}
}
if (isGeometric) {
// updates probabilities of skipping or mapping each key for all points.
updateAlignPointProbabilities(lastSavedInputSize);
static const float READ_FORWORD_LENGTH_SCALE = 0.95f;
const int readForwordLength = static_cast<int>(
hypotf(mProximityInfo->getKeyboardWidth(), mProximityInfo->getKeyboardHeight())
* READ_FORWORD_LENGTH_SCALE);
for (int i = 0; i < mInputSize; ++i) {
if (i >= lastSavedInputSize) {
mSearchKeysVector[i].reset();
}
for (int j = max(i, lastSavedInputSize); j < mInputSize; ++j) {
if (mLengthCache[j] - mLengthCache[i] >= readForwordLength) {
break;
}
mSearchKeysVector[i] |= mNearKeysVector[j];
}
}
}
}
if (DEBUG_SAMPLING_POINTS) {
std::stringstream originalX, originalY, sampledX, sampledY;
for (int i = 0; i < inputSize; ++i) {
originalX << xCoordinates[i];
originalY << yCoordinates[i];
if (i != inputSize - 1) {
originalX << ";";
originalY << ";";
}
}
for (int i = 0; i < mInputSize; ++i) {
sampledX << mInputXs[i];
sampledY << mInputYs[i];
if (i != mInputSize - 1) {
sampledX << ";";
sampledY << ";";
}
}
AKLOGI("\n%s, %s,\n%s, %s,\n", originalX.str().c_str(), originalY.str().c_str(),
sampledX.str().c_str(), sampledY.str().c_str());
}
// end
///////////////////////
memset(mNormalizedSquaredDistances, NOT_A_DISTANCE, sizeof(mNormalizedSquaredDistances));
memset(mPrimaryInputWord, 0, sizeof(mPrimaryInputWord));
mTouchPositionCorrectionEnabled = mInputSize > 0 && mHasTouchPositionCorrectionData
&& xCoordinates && yCoordinates;
if (!isGeometric && pointerId == 0) {
for (int i = 0; i < inputSize; ++i) {
mPrimaryInputWord[i] = getPrimaryCodePointAt(i);
}
for (int i = 0; i < mInputSize && mTouchPositionCorrectionEnabled; ++i) {
const int *proximityCodePoints = getProximityCodePointsAt(i);
const int primaryKey = proximityCodePoints[0];
const int x = xCoordinates[i];
const int y = yCoordinates[i];
if (DEBUG_PROXIMITY_CHARS) {
int a = x + y + primaryKey;
a += 0;
AKLOGI("--- Primary = %c, x = %d, y = %d", primaryKey, x, y);
}
for (int j = 0; j < MAX_PROXIMITY_CHARS_SIZE_INTERNAL && proximityCodePoints[j] > 0;
++j) {
const int currentCodePoint = proximityCodePoints[j];
const float squaredDistance =
hasInputCoordinates() ? calculateNormalizedSquaredDistance(
mProximityInfo->getKeyIndexOf(currentCodePoint), i) :
NOT_A_DISTANCE_FLOAT;
if (squaredDistance >= 0.0f) {
mNormalizedSquaredDistances[i * MAX_PROXIMITY_CHARS_SIZE_INTERNAL + j] =
(int) (squaredDistance * NORMALIZED_SQUARED_DISTANCE_SCALING_FACTOR);
} else {
mNormalizedSquaredDistances[i * MAX_PROXIMITY_CHARS_SIZE_INTERNAL + j] =
(j == 0) ? EQUIVALENT_CHAR_WITHOUT_DISTANCE_INFO :
PROXIMITY_CHAR_WITHOUT_DISTANCE_INFO;
}
if (DEBUG_PROXIMITY_CHARS) {
AKLOGI("--- Proximity (%d) = %c", j, currentCodePoint);
}
}
}
}
if (DEBUG_GEO_FULL) {
AKLOGI("ProximityState init finished: %d points out of %d", mInputSize, inputSize);
}
}
bool ProximityInfoState::checkAndReturnIsContinuationPossible(const int inputSize,
const int *const xCoordinates, const int *const yCoordinates, const int *const times) {
for (int i = 0; i < mInputSize; ++i) {
const int index = mInputIndice[i];
if (index > inputSize || xCoordinates[index] != mInputXs[i] ||
yCoordinates[index] != mInputYs[i] || times[index] != mTimes[i]) {
return false;
}
}
return true;
}
// Calculating point to key distance for all near keys and returning the distance between
// the given point and the nearest key position.
float ProximityInfoState::updateNearKeysDistances(const int x, const int y,
NearKeysDistanceMap *const currentNearKeysDistances) {
static const float NEAR_KEY_THRESHOLD = 2.0f;
currentNearKeysDistances->clear();
const int keyCount = mProximityInfo->getKeyCount();
float nearestKeyDistance = mMaxPointToKeyLength;
for (int k = 0; k < keyCount; ++k) {
const float dist = mProximityInfo->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.
bool ProximityInfoState::isPrevLocalMin(const NearKeysDistanceMap *const currentNearKeysDistances,
const NearKeysDistanceMap *const prevNearKeysDistances,
const NearKeysDistanceMap *const prevPrevNearKeysDistances) const {
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.
float ProximityInfoState::getPointScore(
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) const {
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 = mInputXs.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 = mProximityInfo->getMostCommonKeyWidth();
const int distPrev = getDistanceInt(mInputXs.back(), mInputYs.back(),
mInputXs[size - 2], mInputYs[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, mInputXs.back(), mInputYs.back());
const float angle2 = getAngle(mInputXs.back(), mInputYs.back(),
mInputXs[size - 2], mInputYs[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.
bool ProximityInfoState::pushTouchPoint(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) {
static const int LAST_POINT_SKIP_DISTANCE_SCALE = 4;
size_t size = mInputXs.size();
bool popped = false;
if (nodeCodePoint < 0 && sample) {
const float nearest = updateNearKeysDistances(x, y, currentNearKeysDistances);
const float score = getPointScore(x, y, time, isLastPoint, nearest, sumAngle,
currentNearKeysDistances, prevNearKeysDistances, prevPrevNearKeysDistances);
if (score < 0) {
// Pop previous point because it would be useless.
popInputData();
size = mInputXs.size();
popped = true;
} else {
popped = false;
}
// Check if the last point should be skipped.
if (isLastPoint && size > 0) {
if (getDistanceInt(x, y, mInputXs.back(), mInputYs.back())
* LAST_POINT_SKIP_DISTANCE_SCALE < mProximityInfo->getMostCommonKeyWidth()) {
// 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, mInputXs.back(), mInputYs.back(),
getDistanceInt(x, y, mInputXs.back(), mInputYs.back()),
mProximityInfo->getMostCommonKeyWidth()
/ LAST_POINT_SKIP_DISTANCE_SCALE);
}
return popped;
}
}
}
if (nodeCodePoint >= 0 && (x < 0 || y < 0)) {
const int keyId = mProximityInfo->getKeyIndexOf(nodeCodePoint);
if (keyId >= 0) {
x = mProximityInfo->getKeyCenterXOfKeyIdG(keyId);
y = mProximityInfo->getKeyCenterYOfKeyIdG(keyId);
}
}
// Pushing point information.
if (size > 0) {
mLengthCache.push_back(
mLengthCache.back() + getDistanceInt(x, y, mInputXs.back(), mInputYs.back()));
} else {
mLengthCache.push_back(0);
}
mInputXs.push_back(x);
mInputYs.push_back(y);
mTimes.push_back(time);
mInputIndice.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;
}
float ProximityInfoState::calculateNormalizedSquaredDistance(
const int keyIndex, const int inputIndex) const {
if (keyIndex == NOT_AN_INDEX) {
return NOT_A_DISTANCE_FLOAT;
}
if (!mProximityInfo->hasSweetSpotData(keyIndex)) {
return NOT_A_DISTANCE_FLOAT;
}
if (NOT_A_COORDINATE == mInputXs[inputIndex]) {
return NOT_A_DISTANCE_FLOAT;
}
const float squaredDistance = calculateSquaredDistanceFromSweetSpotCenter(
keyIndex, inputIndex);
const float squaredRadius = square(mProximityInfo->getSweetSpotRadiiAt(keyIndex));
return squaredDistance / squaredRadius;
}
int ProximityInfoState::getDuration(const int index) const {
if (index >= 0 && index < mInputSize - 1) {
return mTimes[index + 1] - mTimes[index];
}
return 0;
}
float ProximityInfoState::getPointToKeyLength(const int inputIndex, const int codePoint) const {
const int keyId = mProximityInfo->getKeyIndexOf(codePoint);
if (keyId != NOT_AN_INDEX) {
const int index = inputIndex * mProximityInfo->getKeyCount() + keyId;
return min(mDistanceCache[index], mMaxPointToKeyLength);
}
if (isSkippableCodePoint(codePoint)) {
return 0.0f;
}
// If the char is not a key on the keyboard then return the max length.
return MAX_POINT_TO_KEY_LENGTH;
}
float ProximityInfoState::getPointToKeyByIdLength(const int inputIndex, const int keyId) const {
if (keyId != NOT_AN_INDEX) {
const int index = inputIndex * mProximityInfo->getKeyCount() + keyId;
return min(mDistanceCache[index], mMaxPointToKeyLength);
}
// If the char is not a key on the keyboard then return the max length.
return static_cast<float>(MAX_POINT_TO_KEY_LENGTH);
}
int ProximityInfoState::getSpaceY() const {
const int keyId = mProximityInfo->getKeyIndexOf(KEYCODE_SPACE);
return mProximityInfo->getKeyCenterYOfKeyIdG(keyId);
}
float ProximityInfoState::calculateSquaredDistanceFromSweetSpotCenter(
const int keyIndex, const int inputIndex) const {
const float sweetSpotCenterX = mProximityInfo->getSweetSpotCenterXAt(keyIndex);
const float sweetSpotCenterY = mProximityInfo->getSweetSpotCenterYAt(keyIndex);
const float inputX = static_cast<float>(mInputXs[inputIndex]);
const float inputY = static_cast<float>(mInputYs[inputIndex]);
return square(inputX - sweetSpotCenterX) + square(inputY - sweetSpotCenterY);
}
// Puts possible characters into filter and returns new filter size.
int32_t ProximityInfoState::getAllPossibleChars(
const size_t index, int32_t *const filter, const int32_t filterSize) const {
if (index >= mInputXs.size()) {
return filterSize;
}
int newFilterSize = filterSize;
const int keyCount = mProximityInfo->getKeyCount();
for (int j = 0; j < keyCount; ++j) {
if (mSearchKeysVector[index].test(j)) {
const int32_t keyCodePoint = mProximityInfo->getCodePointOf(j);
bool insert = true;
// TODO: Avoid linear search
for (int k = 0; k < filterSize; ++k) {
if (filter[k] == keyCodePoint) {
insert = false;
break;
}
}
if (insert) {
filter[newFilterSize++] = keyCodePoint;
}
}
}
return newFilterSize;
}
bool ProximityInfoState::isKeyInSerchKeysAfterIndex(const int index, const int keyId) const {
ASSERT(keyId >= 0);
ASSERT(index >= 0 && index < mInputSize);
return mSearchKeysVector[index].test(keyId);
}
void ProximityInfoState::popInputData() {
mInputXs.pop_back();
mInputYs.pop_back();
mTimes.pop_back();
mLengthCache.pop_back();
mInputIndice.pop_back();
}
float ProximityInfoState::getDirection(const int index0, const int index1) const {
if (index0 < 0 || index0 > mInputSize - 1) {
return 0.0f;
}
if (index1 < 0 || index1 > mInputSize - 1) {
return 0.0f;
}
const int x1 = mInputXs[index0];
const int y1 = mInputYs[index0];
const int x2 = mInputXs[index1];
const int y2 = mInputYs[index1];
return getAngle(x1, y1, x2, y2);
}
float ProximityInfoState::getPointAngle(const int index) const {
if (index <= 0 || index >= mInputSize - 1) {
return 0.0f;
}
const float previousDirection = getDirection(index - 1, index);
const float nextDirection = getDirection(index, index + 1);
const float directionDiff = getAngleDiff(previousDirection, nextDirection);
return directionDiff;
}
float ProximityInfoState::getPointsAngle(
const int index0, const int index1, const int index2) const {
if (index0 < 0 || index0 > mInputSize - 1) {
return 0.0f;
}
if (index1 < 0 || index1 > mInputSize - 1) {
return 0.0f;
}
if (index2 < 0 || index2 > mInputSize - 1) {
return 0.0f;
}
const float previousDirection = getDirection(index0, index1);
const float nextDirection = getDirection(index1, index2);
return getAngleDiff(previousDirection, nextDirection);
}
float ProximityInfoState::getLineToKeyDistance(
const int from, const int to, const int keyId, const bool extend) const {
if (from < 0 || from > mInputSize - 1) {
return 0.0f;
}
if (to < 0 || to > mInputSize - 1) {
return 0.0f;
}
const int x0 = mInputXs[from];
const int y0 = mInputYs[from];
const int x1 = mInputXs[to];
const int y1 = mInputYs[to];
const int keyX = mProximityInfo->getKeyCenterXOfKeyIdG(keyId);
const int keyY = mProximityInfo->getKeyCenterYOfKeyIdG(keyId);
return pointToLineSegSquaredDistanceFloat(keyX, keyY, x0, y0, x1, y1, extend);
}
// Updates probabilities of aligning to some keys and skipping.
// Word suggestion should be based on this probabilities.
void ProximityInfoState::updateAlignPointProbabilities(const int start) {
static const float MIN_PROBABILITY = 0.000001f;
static const float MAX_SKIP_PROBABILITY = 0.95f;
static const float SKIP_FIRST_POINT_PROBABILITY = 0.01f;
static const float SKIP_LAST_POINT_PROBABILITY = 0.1f;
static const float MIN_SPEED_RATE_FOR_SKIP_PROBABILITY = 0.15f;
static const float SPEED_WEIGHT_FOR_SKIP_PROBABILITY = 0.9f;
static const float SLOW_STRAIGHT_WEIGHT_FOR_SKIP_PROBABILITY = 0.6f;
static const float NEAREST_DISTANCE_WEIGHT = 0.5f;
static const float NEAREST_DISTANCE_BIAS = 0.5f;
static const float NEAREST_DISTANCE_WEIGHT_FOR_LAST = 0.6f;
static const float NEAREST_DISTANCE_BIAS_FOR_LAST = 0.4f;
static const float ANGLE_WEIGHT = 0.90f;
static const float DEEP_CORNER_ANGLE_THRESHOLD = M_PI_F * 60.0f / 180.0f;
static const float SKIP_DEEP_CORNER_PROBABILITY = 0.1f;
static const float CORNER_ANGLE_THRESHOLD = M_PI_F * 30.0f / 180.0f;
static const float STRAIGHT_ANGLE_THRESHOLD = M_PI_F * 15.0f / 180.0f;
static const float SKIP_CORNER_PROBABILITY = 0.4f;
static const float SPEED_MARGIN = 0.1f;
static const float CENTER_VALUE_OF_NORMALIZED_DISTRIBUTION = 0.0f;
const int keyCount = mProximityInfo->getKeyCount();
mCharProbabilities.resize(mInputSize);
// Calculates probabilities of using a point as a correlated point with the character
// for each point.
for (int i = start; i < mInputSize; ++i) {
mCharProbabilities[i].clear();
// First, calculates skip probability. Starts form MIN_SKIP_PROBABILITY.
// Note that all values that are multiplied to this probability should be in [0.0, 1.0];
float skipProbability = MAX_SKIP_PROBABILITY;
const float currentAngle = getPointAngle(i);
const float relativeSpeed = getRelativeSpeed(i);
float nearestKeyDistance = static_cast<float>(MAX_POINT_TO_KEY_LENGTH);
for (int j = 0; j < keyCount; ++j) {
if (mNearKeysVector[i].test(j)) {
const float distance = getPointToKeyByIdLength(i, j);
if (distance < nearestKeyDistance) {
nearestKeyDistance = distance;
}
}
}
if (i == 0) {
skipProbability *= min(1.0f, nearestKeyDistance * NEAREST_DISTANCE_WEIGHT
+ NEAREST_DISTANCE_BIAS);
// Promote the first point
skipProbability *= SKIP_FIRST_POINT_PROBABILITY;
} else if (i == mInputSize - 1) {
skipProbability *= min(1.0f, nearestKeyDistance * NEAREST_DISTANCE_WEIGHT_FOR_LAST
+ NEAREST_DISTANCE_BIAS_FOR_LAST);
// Promote the last point
skipProbability *= SKIP_LAST_POINT_PROBABILITY;
} else {
// If the current speed is relatively slower than adjacent keys, we promote this point.
if (getRelativeSpeed(i - 1) - SPEED_MARGIN > relativeSpeed
&& relativeSpeed < getRelativeSpeed(i + 1) - SPEED_MARGIN) {
if (currentAngle < CORNER_ANGLE_THRESHOLD) {
skipProbability *= min(1.0f, relativeSpeed
* SLOW_STRAIGHT_WEIGHT_FOR_SKIP_PROBABILITY);
} else {
// If the angle is small enough, we promote this point more. (e.g. pit vs put)
skipProbability *= min(1.0f, relativeSpeed * SPEED_WEIGHT_FOR_SKIP_PROBABILITY
+ MIN_SPEED_RATE_FOR_SKIP_PROBABILITY);
}
}
skipProbability *= min(1.0f, relativeSpeed * nearestKeyDistance *
NEAREST_DISTANCE_WEIGHT + NEAREST_DISTANCE_BIAS);
// Adjusts skip probability by a rate depending on angle.
// ANGLE_RATE of skipProbability is adjusted by current angle.
skipProbability *= (M_PI_F - currentAngle) / M_PI_F * ANGLE_WEIGHT
+ (1.0f - ANGLE_WEIGHT);
if (currentAngle > DEEP_CORNER_ANGLE_THRESHOLD) {
skipProbability *= SKIP_DEEP_CORNER_PROBABILITY;
}
// We assume the angle of this point is the angle for point[i], point[i - 2]
// and point[i - 3]. The reason why we don't use the angle for point[i], point[i - 1]
// and point[i - 2] is this angle can be more affected by the noise.
const float prevAngle = getPointsAngle(i, i - 2, i - 3);
if (i >= 3 && prevAngle < STRAIGHT_ANGLE_THRESHOLD
&& currentAngle > CORNER_ANGLE_THRESHOLD) {
skipProbability *= SKIP_CORNER_PROBABILITY;
}
}
// probabilities must be in [0.0, MAX_SKIP_PROBABILITY];
ASSERT(skipProbability >= 0.0f);
ASSERT(skipProbability <= MAX_SKIP_PROBABILITY);
mCharProbabilities[i][NOT_AN_INDEX] = skipProbability;
// Second, calculates key probabilities by dividing the rest probability
// (1.0f - skipProbability).
const float inputCharProbability = 1.0f - skipProbability;
// TODO: The variance is critical for accuracy; thus, adjusting these parameter by machine
// learning or something would be efficient.
static const float SPEEDxANGLE_WEIGHT_FOR_STANDARD_DIVIATION = 0.3f;
static const float MAX_SPEEDxANGLE_RATE_FOR_STANDERD_DIVIATION = 0.25f;
static const float SPEEDxNEAREST_WEIGHT_FOR_STANDARD_DIVIATION = 0.5f;
static const float MAX_SPEEDxNEAREST_RATE_FOR_STANDERD_DIVIATION = 0.15f;
static const float MIN_STANDERD_DIVIATION = 0.37f;
const float speedxAngleRate = min(relativeSpeed * currentAngle / M_PI_F
* SPEEDxANGLE_WEIGHT_FOR_STANDARD_DIVIATION,
MAX_SPEEDxANGLE_RATE_FOR_STANDERD_DIVIATION);
const float speedxNearestKeyDistanceRate = min(relativeSpeed * nearestKeyDistance
* SPEEDxNEAREST_WEIGHT_FOR_STANDARD_DIVIATION,
MAX_SPEEDxNEAREST_RATE_FOR_STANDERD_DIVIATION);
const float sigma = speedxAngleRate + speedxNearestKeyDistanceRate + MIN_STANDERD_DIVIATION;
NormalDistribution distribution(CENTER_VALUE_OF_NORMALIZED_DISTRIBUTION, sigma);
static const float PREV_DISTANCE_WEIGHT = 0.5f;
static const float NEXT_DISTANCE_WEIGHT = 0.6f;
// Summing up probability densities of all near keys.
float sumOfProbabilityDensities = 0.0f;
for (int j = 0; j < keyCount; ++j) {
if (mNearKeysVector[i].test(j)) {
float distance = sqrtf(getPointToKeyByIdLength(i, j));
if (i == 0 && i != mInputSize - 1) {
// For the first point, weighted average of distances from first point and the
// next point to the key is used as a point to key distance.
const float nextDistance = sqrtf(getPointToKeyByIdLength(i + 1, j));
if (nextDistance < distance) {
// The distance of the first point tends to bigger than continuing
// points because the first touch by the user can be sloppy.
// So we promote the first point if the distance of that point is larger
// than the distance of the next point.
distance = (distance + nextDistance * NEXT_DISTANCE_WEIGHT)
/ (1.0f + NEXT_DISTANCE_WEIGHT);
}
} else if (i != 0 && i == mInputSize - 1) {
// For the first point, weighted average of distances from last point and
// the previous point to the key is used as a point to key distance.
const float previousDistance = sqrtf(getPointToKeyByIdLength(i - 1, j));
if (previousDistance < distance) {
// The distance of the last point tends to bigger than continuing points
// because the last touch by the user can be sloppy. So we promote the
// last point if the distance of that point is larger than the distance of
// the previous point.
distance = (distance + previousDistance * PREV_DISTANCE_WEIGHT)
/ (1.0f + PREV_DISTANCE_WEIGHT);
}
}
// TODO: Promote the first point when the extended line from the next input is near
// from a key. Also, promote the last point as well.
sumOfProbabilityDensities += distribution.getProbabilityDensity(distance);
}
}
// Split the probability of an input point to keys that are close to the input point.
for (int j = 0; j < keyCount; ++j) {
if (mNearKeysVector[i].test(j)) {
float distance = sqrtf(getPointToKeyByIdLength(i, j));
if (i == 0 && i != mInputSize - 1) {
// For the first point, weighted average of distances from the first point and
// the next point to the key is used as a point to key distance.
const float prevDistance = sqrtf(getPointToKeyByIdLength(i + 1, j));
if (prevDistance < distance) {
distance = (distance + prevDistance * NEXT_DISTANCE_WEIGHT)
/ (1.0f + NEXT_DISTANCE_WEIGHT);
}
} else if (i != 0 && i == mInputSize - 1) {
// For the first point, weighted average of distances from last point and
// the previous point to the key is used as a point to key distance.
const float prevDistance = sqrtf(getPointToKeyByIdLength(i - 1, j));
if (prevDistance < distance) {
distance = (distance + prevDistance * PREV_DISTANCE_WEIGHT)
/ (1.0f + PREV_DISTANCE_WEIGHT);
}
}
const float probabilityDensity = distribution.getProbabilityDensity(distance);
const float probability = inputCharProbability * probabilityDensity
/ sumOfProbabilityDensities;
mCharProbabilities[i][j] = probability;
}
}
}
if (DEBUG_POINTS_PROBABILITY) {
for (int i = 0; i < mInputSize; ++i) {
std::stringstream sstream;
sstream << i << ", ";
sstream << "("<< mInputXs[i] << ", ";
sstream << ", "<< mInputYs[i] << "), ";
sstream << "Speed: "<< getRelativeSpeed(i) << ", ";
sstream << "Angle: "<< getPointAngle(i) << ", \n";
for (hash_map_compat<int, float>::iterator it = mCharProbabilities[i].begin();
it != mCharProbabilities[i].end(); ++it) {
if (it->first == NOT_AN_INDEX) {
sstream << it->first
<< "(skip):"
<< it->second
<< "\n";
} else {
sstream << it->first
<< "("
<< static_cast<char>(mProximityInfo->getCodePointOf(it->first))
<< "):"
<< it->second
<< "\n";
}
}
AKLOGI("%s", sstream.str().c_str());
}
}
// Decrease key probabilities of points which don't have the highest probability of that key
// among nearby points. Probabilities of the first point and the last point are not suppressed.
for (int i = max(start, 1); i < mInputSize; ++i) {
for (int j = i + 1; j < mInputSize; ++j) {
if (!suppressCharProbabilities(i, j)) {
break;
}
}
for (int j = i - 1; j >= max(start, 0); --j) {
if (!suppressCharProbabilities(i, j)) {
break;
}
}
}
// Converting from raw probabilities to log probabilities to calculate spatial distance.
for (int i = start; i < mInputSize; ++i) {
for (int j = 0; j < keyCount; ++j) {
hash_map_compat<int, float>::iterator it = mCharProbabilities[i].find(j);
if (it == mCharProbabilities[i].end()){
mNearKeysVector[i].reset(j);
} else if(it->second < MIN_PROBABILITY) {
// Erases from near keys vector because it has very low probability.
mNearKeysVector[i].reset(j);
mCharProbabilities[i].erase(j);
} else {
it->second = -logf(it->second);
}
}
mCharProbabilities[i][NOT_AN_INDEX] = -logf(mCharProbabilities[i][NOT_AN_INDEX]);
}
}
// Decreases char probabilities of index0 by checking probabilities of a near point (index1) and
// increases char probabilities of index1 by checking probabilities of index0.
bool ProximityInfoState::suppressCharProbabilities(const int index0, const int index1) {
ASSERT(0 <= index0 && index0 < mInputSize);
ASSERT(0 <= index1 && index1 < mInputSize);
static const float SUPPRESSION_LENGTH_WEIGHT = 1.5f;
static const float MIN_SUPPRESSION_RATE = 0.1f;
static const float SUPPRESSION_WEIGHT = 0.5f;
static const float SUPPRESSION_WEIGHT_FOR_PROBABILITY_GAIN = 0.1f;
static const float SKIP_PROBABALITY_WEIGHT_FOR_PROBABILITY_GAIN = 0.3f;
const float keyWidthFloat = static_cast<float>(mProximityInfo->getMostCommonKeyWidth());
const float diff = fabsf(static_cast<float>(mLengthCache[index0] - mLengthCache[index1]));
if (diff > keyWidthFloat * SUPPRESSION_LENGTH_WEIGHT) {
return false;
}
const float suppressionRate = MIN_SUPPRESSION_RATE
+ diff / keyWidthFloat / SUPPRESSION_LENGTH_WEIGHT * SUPPRESSION_WEIGHT;
for (hash_map_compat<int, float>::iterator it = mCharProbabilities[index0].begin();
it != mCharProbabilities[index0].end(); ++it) {
hash_map_compat<int, float>::iterator it2 = mCharProbabilities[index1].find(it->first);
if (it2 != mCharProbabilities[index1].end() && it->second < it2->second) {
const float newProbability = it->second * suppressionRate;
const float suppression = it->second - newProbability;
it->second = newProbability;
// mCharProbabilities[index0][NOT_AN_INDEX] is the probability of skipping this point.
mCharProbabilities[index0][NOT_AN_INDEX] += suppression;
// Add the probability of the same key nearby index1
const float probabilityGain = min(suppression * SUPPRESSION_WEIGHT_FOR_PROBABILITY_GAIN,
mCharProbabilities[index1][NOT_AN_INDEX]
* SKIP_PROBABALITY_WEIGHT_FOR_PROBABILITY_GAIN);
it2->second += probabilityGain;
mCharProbabilities[index1][NOT_AN_INDEX] -= probabilityGain;
}
}
return true;
}
// Get a word that is detected by tracing highest probability sequence into codePointBuf and
// returns probability of generating the word.
float ProximityInfoState::getHighestProbabilitySequence(int *const codePointBuf) const {
static const float DEMOTION_LOG_PROBABILITY = 0.3f;
int index = 0;
float sumLogProbability = 0.0f;
// TODO: Current implementation is greedy algorithm. DP would be efficient for many cases.
for (int i = 0; i < mInputSize && index < MAX_WORD_LENGTH_INTERNAL - 1; ++i) {
float minLogProbability = static_cast<float>(MAX_POINT_TO_KEY_LENGTH);
int character = NOT_AN_INDEX;
for (hash_map_compat<int, float>::const_iterator it = mCharProbabilities[i].begin();
it != mCharProbabilities[i].end(); ++it) {
const float logProbability = (it->first != NOT_AN_INDEX)
? it->second + DEMOTION_LOG_PROBABILITY : it->second;
if (logProbability < minLogProbability) {
minLogProbability = logProbability;
character = it->first;
}
}
if (character != NOT_AN_INDEX) {
codePointBuf[index] = mProximityInfo->getCodePointOf(character);
index++;
}
sumLogProbability += minLogProbability;
}
codePointBuf[index] = '\0';
return sumLogProbability;
}
// Returns a probability of mapping index to keyIndex.
float ProximityInfoState::getProbability(const int index, const int keyIndex) const {
ASSERT(0 <= index && index < mInputSize);
hash_map_compat<int, float>::const_iterator it = mCharProbabilities[index].find(keyIndex);
if (it != mCharProbabilities[index].end()) {
return it->second;
}
return static_cast<float>(MAX_POINT_TO_KEY_LENGTH);
}
} // namespace latinime
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