| /* |
| * Copyright (C) 2014 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 android.animation; |
| |
| import android.graphics.Path; |
| import android.graphics.PointF; |
| |
| import java.util.ArrayList; |
| |
| /** |
| * PathKeyframes relies on approximating the Path as a series of line segments. |
| * The line segments are recursively divided until there is less than 1/2 pixel error |
| * between the lines and the curve. Each point of the line segment is converted |
| * to a Keyframe and a linear interpolation between Keyframes creates a good approximation |
| * of the curve. |
| * <p> |
| * PathKeyframes is optimized to reduce the number of objects created when there are |
| * many keyframes for a curve. |
| * </p> |
| * <p> |
| * Typically, the returned type is a PointF, but the individual components can be extracted |
| * as either an IntKeyframes or FloatKeyframes. |
| * </p> |
| */ |
| class PathKeyframes implements Keyframes { |
| private static final int FRACTION_OFFSET = 0; |
| private static final int X_OFFSET = 1; |
| private static final int Y_OFFSET = 2; |
| private static final int NUM_COMPONENTS = 3; |
| private static final ArrayList<Keyframe> EMPTY_KEYFRAMES = new ArrayList<Keyframe>(); |
| |
| private PointF mTempPointF = new PointF(); |
| private float[] mKeyframeData; |
| |
| public PathKeyframes(Path path) { |
| this(path, 0.5f); |
| } |
| |
| public PathKeyframes(Path path, float error) { |
| if (path == null || path.isEmpty()) { |
| throw new IllegalArgumentException("The path must not be null or empty"); |
| } |
| mKeyframeData = path.approximate(error); |
| } |
| |
| @Override |
| public ArrayList<Keyframe> getKeyframes() { |
| return EMPTY_KEYFRAMES; |
| } |
| |
| @Override |
| public Object getValue(float fraction) { |
| int numPoints = mKeyframeData.length / 3; |
| if (fraction < 0) { |
| return interpolateInRange(fraction, 0, 1); |
| } else if (fraction > 1) { |
| return interpolateInRange(fraction, numPoints - 2, numPoints - 1); |
| } else if (fraction == 0) { |
| return pointForIndex(0); |
| } else if (fraction == 1) { |
| return pointForIndex(numPoints - 1); |
| } else { |
| // Binary search for the correct section |
| int low = 0; |
| int high = numPoints - 1; |
| |
| while (low <= high) { |
| int mid = (low + high) / 2; |
| float midFraction = mKeyframeData[(mid * NUM_COMPONENTS) + FRACTION_OFFSET]; |
| |
| if (fraction < midFraction) { |
| high = mid - 1; |
| } else if (fraction > midFraction) { |
| low = mid + 1; |
| } else { |
| return pointForIndex(mid); |
| } |
| } |
| |
| // now high is below the fraction and low is above the fraction |
| return interpolateInRange(fraction, high, low); |
| } |
| } |
| |
| private PointF interpolateInRange(float fraction, int startIndex, int endIndex) { |
| int startBase = (startIndex * NUM_COMPONENTS); |
| int endBase = (endIndex * NUM_COMPONENTS); |
| |
| float startFraction = mKeyframeData[startBase + FRACTION_OFFSET]; |
| float endFraction = mKeyframeData[endBase + FRACTION_OFFSET]; |
| |
| float intervalFraction = (fraction - startFraction)/(endFraction - startFraction); |
| |
| float startX = mKeyframeData[startBase + X_OFFSET]; |
| float endX = mKeyframeData[endBase + X_OFFSET]; |
| float startY = mKeyframeData[startBase + Y_OFFSET]; |
| float endY = mKeyframeData[endBase + Y_OFFSET]; |
| |
| float x = interpolate(intervalFraction, startX, endX); |
| float y = interpolate(intervalFraction, startY, endY); |
| |
| mTempPointF.set(x, y); |
| return mTempPointF; |
| } |
| |
| @Override |
| public void invalidateCache() { |
| } |
| |
| @Override |
| public void setEvaluator(TypeEvaluator evaluator) { |
| } |
| |
| @Override |
| public Class getType() { |
| return PointF.class; |
| } |
| |
| @Override |
| public Keyframes clone() { |
| Keyframes clone = null; |
| try { |
| clone = (Keyframes) super.clone(); |
| } catch (CloneNotSupportedException e) {} |
| return clone; |
| } |
| |
| private PointF pointForIndex(int index) { |
| int base = (index * NUM_COMPONENTS); |
| int xOffset = base + X_OFFSET; |
| int yOffset = base + Y_OFFSET; |
| mTempPointF.set(mKeyframeData[xOffset], mKeyframeData[yOffset]); |
| return mTempPointF; |
| } |
| |
| private static float interpolate(float fraction, float startValue, float endValue) { |
| float diff = endValue - startValue; |
| return startValue + (diff * fraction); |
| } |
| |
| /** |
| * Returns a FloatKeyframes for the X component of the Path. |
| * @return a FloatKeyframes for the X component of the Path. |
| */ |
| public FloatKeyframes createXFloatKeyframes() { |
| return new FloatKeyframesBase() { |
| @Override |
| public float getFloatValue(float fraction) { |
| PointF pointF = (PointF) PathKeyframes.this.getValue(fraction); |
| return pointF.x; |
| } |
| }; |
| } |
| |
| /** |
| * Returns a FloatKeyframes for the Y component of the Path. |
| * @return a FloatKeyframes for the Y component of the Path. |
| */ |
| public FloatKeyframes createYFloatKeyframes() { |
| return new FloatKeyframesBase() { |
| @Override |
| public float getFloatValue(float fraction) { |
| PointF pointF = (PointF) PathKeyframes.this.getValue(fraction); |
| return pointF.y; |
| } |
| }; |
| } |
| |
| /** |
| * Returns an IntKeyframes for the X component of the Path. |
| * @return an IntKeyframes for the X component of the Path. |
| */ |
| public IntKeyframes createXIntKeyframes() { |
| return new IntKeyframesBase() { |
| @Override |
| public int getIntValue(float fraction) { |
| PointF pointF = (PointF) PathKeyframes.this.getValue(fraction); |
| return Math.round(pointF.x); |
| } |
| }; |
| } |
| |
| /** |
| * Returns an IntKeyframeSet for the Y component of the Path. |
| * @return an IntKeyframeSet for the Y component of the Path. |
| */ |
| public IntKeyframes createYIntKeyframes() { |
| return new IntKeyframesBase() { |
| @Override |
| public int getIntValue(float fraction) { |
| PointF pointF = (PointF) PathKeyframes.this.getValue(fraction); |
| return Math.round(pointF.y); |
| } |
| }; |
| } |
| |
| private abstract static class SimpleKeyframes implements Keyframes { |
| @Override |
| public void setEvaluator(TypeEvaluator evaluator) { |
| } |
| |
| @Override |
| public void invalidateCache() { |
| } |
| |
| @Override |
| public ArrayList<Keyframe> getKeyframes() { |
| return EMPTY_KEYFRAMES; |
| } |
| |
| @Override |
| public Keyframes clone() { |
| Keyframes clone = null; |
| try { |
| clone = (Keyframes) super.clone(); |
| } catch (CloneNotSupportedException e) {} |
| return clone; |
| } |
| } |
| |
| private abstract static class IntKeyframesBase extends SimpleKeyframes implements IntKeyframes { |
| @Override |
| public Class getType() { |
| return Integer.class; |
| } |
| |
| @Override |
| public Object getValue(float fraction) { |
| return getIntValue(fraction); |
| } |
| } |
| |
| private abstract static class FloatKeyframesBase extends SimpleKeyframes |
| implements FloatKeyframes { |
| @Override |
| public Class getType() { |
| return Float.class; |
| } |
| |
| @Override |
| public Object getValue(float fraction) { |
| return getFloatValue(fraction); |
| } |
| } |
| } |