| /* |
| * 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.transition; |
| |
| import com.android.internal.R; |
| |
| import android.content.Context; |
| import android.content.res.TypedArray; |
| import android.graphics.Matrix; |
| import android.graphics.Path; |
| import android.graphics.PathMeasure; |
| import android.util.AttributeSet; |
| import android.util.FloatMath; |
| import android.util.PathParser; |
| |
| /** |
| * A PathMotion that takes a Path pattern and applies it to the separation between two points. |
| * The starting point of the Path will be moved to the origin and the end point will be scaled |
| * and rotated so that it matches with the target end point. |
| * <p>This may be used in XML as an element inside a transition.</p> |
| * <pre> |
| * {@code |
| * <changeBounds> |
| * <patternMotion android:pathData="M0 0 L0 100 L100 100"/> |
| * </changeBounds> |
| * } |
| * </pre> |
| */ |
| public class PatternMotion extends PathMotion { |
| |
| private Path mOriginalPattern; |
| |
| private final Path mPattern = new Path(); |
| |
| private final Matrix mTempMatrix = new Matrix(); |
| |
| /** |
| * Constructs a PatternMotion with a straight-line pattern. |
| */ |
| public PatternMotion() { |
| mPattern.lineTo(1, 0); |
| mOriginalPattern = mPattern; |
| } |
| |
| public PatternMotion(Context context, AttributeSet attrs) { |
| TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PatternMotion); |
| try { |
| String pathData = a.getString(R.styleable.PatternMotion_pathData); |
| if (pathData == null) { |
| throw new RuntimeException("pathData must be supplied for patternMotion"); |
| } |
| Path pattern = PathParser.createPathFromPathData(pathData); |
| setPattern(pattern); |
| } finally { |
| a.recycle(); |
| } |
| |
| } |
| |
| /** |
| * Creates a PatternMotion with the Path defining a pattern of motion between two coordinates. |
| * The pattern will be translated, rotated, and scaled to fit between the start and end points. |
| * The pattern must not be empty and must have the end point differ from the start point. |
| * |
| * @param pattern A Path to be used as a pattern for two-dimensional motion. |
| */ |
| public PatternMotion(Path pattern) { |
| setPattern(pattern); |
| } |
| |
| /** |
| * Returns the Path defining a pattern of motion between two coordinates. |
| * The pattern will be translated, rotated, and scaled to fit between the start and end points. |
| * The pattern must not be empty and must have the end point differ from the start point. |
| * |
| * @return the Path defining a pattern of motion between two coordinates. |
| * @attr ref android.R.styleable#PatternMotion_pathData |
| */ |
| public Path getPattern() { |
| return mOriginalPattern; |
| } |
| |
| /** |
| * Sets the Path defining a pattern of motion between two coordinates. |
| * The pattern will be translated, rotated, and scaled to fit between the start and end points. |
| * The pattern must not be empty and must have the end point differ from the start point. |
| * |
| * @param pattern A Path to be used as a pattern for two-dimensional motion. |
| * @attr ref android.R.styleable#PatternMotion_pathData |
| */ |
| public void setPattern(Path pattern) { |
| PathMeasure pathMeasure = new PathMeasure(pattern, false); |
| float length = pathMeasure.getLength(); |
| float[] pos = new float[2]; |
| pathMeasure.getPosTan(length, pos, null); |
| float endX = pos[0]; |
| float endY = pos[1]; |
| pathMeasure.getPosTan(0, pos, null); |
| float startX = pos[0]; |
| float startY = pos[1]; |
| |
| if (startX == endX && startY == endY) { |
| throw new IllegalArgumentException("pattern must not end at the starting point"); |
| } |
| |
| mTempMatrix.setTranslate(-startX, -startY); |
| float dx = endX - startX; |
| float dy = endY - startY; |
| float distance = distance(dx, dy); |
| float scale = 1 / distance; |
| mTempMatrix.postScale(scale, scale); |
| double angle = Math.atan2(dy, dx); |
| mTempMatrix.postRotate((float) Math.toDegrees(-angle)); |
| pattern.transform(mTempMatrix, mPattern); |
| mOriginalPattern = pattern; |
| } |
| |
| @Override |
| public Path getPath(float startX, float startY, float endX, float endY) { |
| float dx = endX - startX; |
| float dy = endY - startY; |
| float length = distance(dx, dy); |
| double angle = Math.atan2(dy, dx); |
| |
| mTempMatrix.setScale(length, length); |
| mTempMatrix.postRotate((float) Math.toDegrees(angle)); |
| mTempMatrix.postTranslate(startX, startY); |
| Path path = new Path(); |
| mPattern.transform(mTempMatrix, path); |
| return path; |
| } |
| |
| private static float distance(float x, float y) { |
| return FloatMath.sqrt((x * x) + (y * y)); |
| } |
| } |