117 lines
4.1 KiB
Java
117 lines
4.1 KiB
Java
/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.inputmethod.keyboard;
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/**
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* This class handles key detection.
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*/
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public class KeyDetector {
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private final int mKeyHysteresisDistanceSquared;
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private final int mKeyHysteresisDistanceForSlidingModifierSquared;
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private Keyboard mKeyboard;
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private int mCorrectionX;
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private int mCorrectionY;
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public KeyDetector() {
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this(0.0f /* keyHysteresisDistance */, 0.0f /* keyHysteresisDistanceForSlidingModifier */);
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}
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/**
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* Key detection object constructor with key hysteresis distances.
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*
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* @param keyHysteresisDistance if the pointer movement distance is smaller than this, the
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* movement will not be handled as meaningful movement. The unit is pixel.
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* @param keyHysteresisDistanceForSlidingModifier the same parameter for sliding input that
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* starts from a modifier key such as shift and symbols key.
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*/
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public KeyDetector(final float keyHysteresisDistance,
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final float keyHysteresisDistanceForSlidingModifier) {
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mKeyHysteresisDistanceSquared = (int)(keyHysteresisDistance * keyHysteresisDistance);
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mKeyHysteresisDistanceForSlidingModifierSquared = (int)(
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keyHysteresisDistanceForSlidingModifier * keyHysteresisDistanceForSlidingModifier);
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}
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public void setKeyboard(final Keyboard keyboard, final float correctionX,
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final float correctionY) {
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if (keyboard == null) {
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throw new NullPointerException();
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}
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mCorrectionX = (int)correctionX;
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mCorrectionY = (int)correctionY;
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mKeyboard = keyboard;
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}
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public int getKeyHysteresisDistanceSquared(final boolean isSlidingFromModifier) {
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return isSlidingFromModifier
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? mKeyHysteresisDistanceForSlidingModifierSquared : mKeyHysteresisDistanceSquared;
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}
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public int getTouchX(final int x) {
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return x + mCorrectionX;
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}
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// TODO: Remove vertical correction.
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public int getTouchY(final int y) {
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return y + mCorrectionY;
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}
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public Keyboard getKeyboard() {
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return mKeyboard;
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}
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public boolean alwaysAllowsKeySelectionByDraggingFinger() {
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return false;
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}
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/**
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* Detect the key whose hitbox the touch point is in.
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*
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* @param x The x-coordinate of a touch point
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* @param y The y-coordinate of a touch point
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* @return the key that the touch point hits.
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*/
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public Key detectHitKey(final int x, final int y) {
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if (mKeyboard == null) {
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return null;
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}
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final int touchX = getTouchX(x);
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final int touchY = getTouchY(y);
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int minDistance = Integer.MAX_VALUE;
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Key primaryKey = null;
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for (final Key key: mKeyboard.getNearestKeys(touchX, touchY)) {
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// An edge key always has its enlarged hitbox to respond to an event that occurred in
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// the empty area around the key. (@see Key#markAsLeftEdge(KeyboardParams)} etc.)
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if (!key.isOnKey(touchX, touchY)) {
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continue;
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}
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final int distance = key.squaredDistanceToEdge(touchX, touchY);
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if (distance > minDistance) {
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continue;
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}
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// To take care of hitbox overlaps, we compare key's code here too.
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if (primaryKey == null || distance < minDistance
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|| key.getCode() > primaryKey.getCode()) {
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minDistance = distance;
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primaryKey = key;
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}
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}
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return primaryKey;
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}
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}
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