LatinIME/java/src/com/android/inputmethod/keyboard/internal/GestureTrail.java

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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.
*/
package com.android.inputmethod.keyboard.internal;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Rect;
import android.os.SystemClock;
import com.android.inputmethod.latin.Constants;
import com.android.inputmethod.latin.R;
import com.android.inputmethod.latin.utils.ResizableIntArray;
/*
* @attr ref R.styleable#MainKeyboardView_gestureTrailFadeoutStartDelay
* @attr ref R.styleable#MainKeyboardView_gestureTrailFadeoutDuration
* @attr ref R.styleable#MainKeyboardView_gestureTrailUpdateInterval
* @attr ref R.styleable#MainKeyboardView_gestureTrailColor
* @attr ref R.styleable#MainKeyboardView_gestureTrailWidth
*/
final class GestureTrail {
public static final boolean DEBUG_SHOW_POINTS = false;
public static final int POINT_TYPE_SAMPLED = 1;
public static final int POINT_TYPE_INTERPOLATED = 2;
private static final int FADEOUT_START_DELAY_FOR_DEBUG = 2000; // millisecond
private static final int FADEOUT_DURATION_FOR_DEBUG = 200; // millisecond
private static final int DEFAULT_CAPACITY = GestureStrokeWithPreviewPoints.PREVIEW_CAPACITY;
// These three {@link ResizableIntArray}s should be synchronized by {@link #mEventTimes}.
private final ResizableIntArray mXCoordinates = new ResizableIntArray(DEFAULT_CAPACITY);
private final ResizableIntArray mYCoordinates = new ResizableIntArray(DEFAULT_CAPACITY);
private final ResizableIntArray mEventTimes = new ResizableIntArray(DEFAULT_CAPACITY);
private final ResizableIntArray mPointTypes = new ResizableIntArray(
DEBUG_SHOW_POINTS ? DEFAULT_CAPACITY : 0);
private int mCurrentStrokeId = -1;
// The wall time of the zero value in {@link #mEventTimes}
private long mCurrentTimeBase;
private int mTrailStartIndex;
private int mLastInterpolatedDrawIndex;
static final class Params {
public final int mTrailColor;
public final float mTrailStartWidth;
public final float mTrailEndWidth;
public final float mTrailBodyRatio;
public boolean mTrailShadowEnabled;
public final float mTrailShadowRatio;
public final int mFadeoutStartDelay;
public final int mFadeoutDuration;
public final int mUpdateInterval;
public final int mTrailLingerDuration;
public Params(final TypedArray mainKeyboardViewAttr) {
mTrailColor = mainKeyboardViewAttr.getColor(
R.styleable.MainKeyboardView_gestureTrailColor, 0);
mTrailStartWidth = mainKeyboardViewAttr.getDimension(
R.styleable.MainKeyboardView_gestureTrailStartWidth, 0.0f);
mTrailEndWidth = mainKeyboardViewAttr.getDimension(
R.styleable.MainKeyboardView_gestureTrailEndWidth, 0.0f);
final int PERCENTAGE_INT = 100;
mTrailBodyRatio = (float)mainKeyboardViewAttr.getInt(
R.styleable.MainKeyboardView_gestureTrailBodyRatio, PERCENTAGE_INT)
/ (float)PERCENTAGE_INT;
final int trailShadowRatioInt = mainKeyboardViewAttr.getInt(
R.styleable.MainKeyboardView_gestureTrailShadowRatio, 0);
mTrailShadowEnabled = (trailShadowRatioInt > 0);
mTrailShadowRatio = (float)trailShadowRatioInt / (float)PERCENTAGE_INT;
mFadeoutStartDelay = DEBUG_SHOW_POINTS ? FADEOUT_START_DELAY_FOR_DEBUG
: mainKeyboardViewAttr.getInt(
R.styleable.MainKeyboardView_gestureTrailFadeoutStartDelay, 0);
mFadeoutDuration = DEBUG_SHOW_POINTS ? FADEOUT_DURATION_FOR_DEBUG
: mainKeyboardViewAttr.getInt(
R.styleable.MainKeyboardView_gestureTrailFadeoutDuration, 0);
mTrailLingerDuration = mFadeoutStartDelay + mFadeoutDuration;
mUpdateInterval = mainKeyboardViewAttr.getInt(
R.styleable.MainKeyboardView_gestureTrailUpdateInterval, 0);
}
}
// Use this value as imaginary zero because x-coordinates may be zero.
private static final int DOWN_EVENT_MARKER = -128;
private static int markAsDownEvent(final int xCoord) {
return DOWN_EVENT_MARKER - xCoord;
}
private static boolean isDownEventXCoord(final int xCoordOrMark) {
return xCoordOrMark <= DOWN_EVENT_MARKER;
}
private static int getXCoordValue(final int xCoordOrMark) {
return isDownEventXCoord(xCoordOrMark)
? DOWN_EVENT_MARKER - xCoordOrMark : xCoordOrMark;
}
public void addStroke(final GestureStrokeWithPreviewPoints stroke, final long downTime) {
synchronized (mEventTimes) {
addStrokeLocked(stroke, downTime);
}
}
private void addStrokeLocked(final GestureStrokeWithPreviewPoints stroke, final long downTime) {
final int trailSize = mEventTimes.getLength();
stroke.appendPreviewStroke(mEventTimes, mXCoordinates, mYCoordinates, mPointTypes);
if (mEventTimes.getLength() == trailSize) {
return;
}
final int[] eventTimes = mEventTimes.getPrimitiveArray();
final int strokeId = stroke.getGestureStrokeId();
// Because interpolation algorithm in {@link GestureStrokeWithPreviewPoints} can't determine
// the interpolated points in the last segment of gesture stroke, it may need recalculation
// of interpolation when new segments are added to the stroke.
// {@link #mLastInterpolatedDrawIndex} holds the start index of the last segment. It may
// be updated by the interpolation
// {@link GestureStrokeWithPreviewPoints#interpolatePreviewStroke}
// or by animation {@link #drawGestureTrail(Canvas,Paint,Rect,Params)} below.
final int lastInterpolatedIndex = (strokeId == mCurrentStrokeId)
? mLastInterpolatedDrawIndex : trailSize;
mLastInterpolatedDrawIndex = stroke.interpolateStrokeAndReturnStartIndexOfLastSegment(
lastInterpolatedIndex, mEventTimes, mXCoordinates, mYCoordinates, mPointTypes);
if (strokeId != mCurrentStrokeId) {
final int elapsedTime = (int)(downTime - mCurrentTimeBase);
for (int i = mTrailStartIndex; i < trailSize; i++) {
// Decay the previous strokes' event times.
eventTimes[i] -= elapsedTime;
}
final int[] xCoords = mXCoordinates.getPrimitiveArray();
final int downIndex = trailSize;
xCoords[downIndex] = markAsDownEvent(xCoords[downIndex]);
mCurrentTimeBase = downTime - eventTimes[downIndex];
mCurrentStrokeId = strokeId;
}
}
/**
* Calculate the alpha of a gesture trail.
* A gesture trail starts from fully opaque. After mFadeStartDelay has been passed, the alpha
* of a trail reduces in proportion to the elapsed time. Then after mFadeDuration has been
* passed, a trail becomes fully transparent.
*
* @param elapsedTime the elapsed time since a trail has been made.
* @param params gesture trail display parameters
* @return the width of a gesture trail
*/
private static int getAlpha(final int elapsedTime, final Params params) {
if (elapsedTime < params.mFadeoutStartDelay) {
return Constants.Color.ALPHA_OPAQUE;
}
final int decreasingAlpha = Constants.Color.ALPHA_OPAQUE
* (elapsedTime - params.mFadeoutStartDelay)
/ params.mFadeoutDuration;
return Constants.Color.ALPHA_OPAQUE - decreasingAlpha;
}
/**
* Calculate the width of a gesture trail.
* A gesture trail starts from the width of mTrailStartWidth and reduces its width in proportion
* to the elapsed time. After mTrailEndWidth has been passed, the width becomes mTraiLEndWidth.
*
* @param elapsedTime the elapsed time since a trail has been made.
* @param params gesture trail display parameters
* @return the width of a gesture trail
*/
private static float getWidth(final int elapsedTime, final Params params) {
final float deltaWidth = params.mTrailStartWidth - params.mTrailEndWidth;
return params.mTrailStartWidth - (deltaWidth * elapsedTime) / params.mTrailLingerDuration;
}
private final RoundedLine mRoundedLine = new RoundedLine();
private final Rect mRoundedLineBounds = new Rect();
/**
* Draw gesture trail
* @param canvas The canvas to draw the gesture trail
* @param paint The paint object to be used to draw the gesture trail
* @param outBoundsRect the bounding box of this gesture trail drawing
* @param params The drawing parameters of gesture trail
* @return true if some gesture trails remain to be drawn
*/
public boolean drawGestureTrail(final Canvas canvas, final Paint paint,
final Rect outBoundsRect, final Params params) {
synchronized (mEventTimes) {
return drawGestureTrailLocked(canvas, paint, outBoundsRect, params);
}
}
private boolean drawGestureTrailLocked(final Canvas canvas, final Paint paint,
final Rect outBoundsRect, final Params params) {
// Initialize bounds rectangle.
outBoundsRect.setEmpty();
final int trailSize = mEventTimes.getLength();
if (trailSize == 0) {
return false;
}
final int[] eventTimes = mEventTimes.getPrimitiveArray();
final int[] xCoords = mXCoordinates.getPrimitiveArray();
final int[] yCoords = mYCoordinates.getPrimitiveArray();
final int[] pointTypes = mPointTypes.getPrimitiveArray();
final int sinceDown = (int)(SystemClock.uptimeMillis() - mCurrentTimeBase);
int startIndex;
for (startIndex = mTrailStartIndex; startIndex < trailSize; startIndex++) {
final int elapsedTime = sinceDown - eventTimes[startIndex];
// Skip too old trail points.
if (elapsedTime < params.mTrailLingerDuration) {
break;
}
}
mTrailStartIndex = startIndex;
if (startIndex < trailSize) {
paint.setColor(params.mTrailColor);
paint.setStyle(Paint.Style.FILL);
final RoundedLine roundedLine = mRoundedLine;
int p1x = getXCoordValue(xCoords[startIndex]);
int p1y = yCoords[startIndex];
final int lastTime = sinceDown - eventTimes[startIndex];
float r1 = getWidth(lastTime, params) / 2.0f;
for (int i = startIndex + 1; i < trailSize; i++) {
final int elapsedTime = sinceDown - eventTimes[i];
final int p2x = getXCoordValue(xCoords[i]);
final int p2y = yCoords[i];
final float r2 = getWidth(elapsedTime, params) / 2.0f;
// Draw trail line only when the current point isn't a down point.
if (!isDownEventXCoord(xCoords[i])) {
final float body1 = r1 * params.mTrailBodyRatio;
final float body2 = r2 * params.mTrailBodyRatio;
final Path path = roundedLine.makePath(p1x, p1y, body1, p2x, p2y, body2);
if (!path.isEmpty()) {
roundedLine.getBounds(mRoundedLineBounds);
if (params.mTrailShadowEnabled) {
final float shadow2 = r2 * params.mTrailShadowRatio;
paint.setShadowLayer(shadow2, 0.0f, 0.0f, params.mTrailColor);
final int shadowInset = -(int)Math.ceil(shadow2);
mRoundedLineBounds.inset(shadowInset, shadowInset);
}
// Take union for the bounds.
outBoundsRect.union(mRoundedLineBounds);
final int alpha = getAlpha(elapsedTime, params);
paint.setAlpha(alpha);
canvas.drawPath(path, paint);
}
}
p1x = p2x;
p1y = p2y;
r1 = r2;
}
if (DEBUG_SHOW_POINTS) {
debugDrawPoints(canvas, startIndex, trailSize, paint);
}
}
final int newSize = trailSize - startIndex;
if (newSize < startIndex) {
mTrailStartIndex = 0;
if (newSize > 0) {
System.arraycopy(eventTimes, startIndex, eventTimes, 0, newSize);
System.arraycopy(xCoords, startIndex, xCoords, 0, newSize);
System.arraycopy(yCoords, startIndex, yCoords, 0, newSize);
if (DEBUG_SHOW_POINTS) {
System.arraycopy(pointTypes, startIndex, pointTypes, 0, newSize);
}
}
mEventTimes.setLength(newSize);
mXCoordinates.setLength(newSize);
mYCoordinates.setLength(newSize);
if (DEBUG_SHOW_POINTS) {
mPointTypes.setLength(newSize);
}
// The start index of the last segment of the stroke
// {@link mLastInterpolatedDrawIndex} should also be updated because all array
// elements have just been shifted for compaction or been zeroed.
mLastInterpolatedDrawIndex = Math.max(mLastInterpolatedDrawIndex - startIndex, 0);
}
return newSize > 0;
}
private void debugDrawPoints(final Canvas canvas, final int startIndex, final int endIndex,
final Paint paint) {
final int[] xCoords = mXCoordinates.getPrimitiveArray();
final int[] yCoords = mYCoordinates.getPrimitiveArray();
final int[] pointTypes = mPointTypes.getPrimitiveArray();
// {@link Paint} that is zero width stroke and anti alias off draws exactly 1 pixel.
paint.setAntiAlias(false);
paint.setStrokeWidth(0);
for (int i = startIndex; i < endIndex; i++) {
final int pointType = pointTypes[i];
if (pointType == POINT_TYPE_INTERPOLATED) {
paint.setColor(Color.RED);
} else if (pointType == POINT_TYPE_SAMPLED) {
paint.setColor(0xFFA000FF);
} else {
paint.setColor(Color.GREEN);
}
canvas.drawPoint(getXCoordValue(xCoords[i]), yCoords[i], paint);
}
paint.setAntiAlias(true);
}
}