/* * Copyright (C) 2017 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.support.transition; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Matrix; import android.graphics.Path; import android.graphics.PathMeasure; import android.support.v4.content.res.TypedArrayUtils; import android.support.v4.graphics.PathParser; import android.util.AttributeSet; import org.xmlpull.v1.XmlPullParser; /** * 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. *

This may be used in XML as an element inside a transition.

*
{@code
 * 
 *     
 * }
 * 
*/ public class PatternPathMotion extends PathMotion { private Path mOriginalPatternPath; private final Path mPatternPath = new Path(); private final Matrix mTempMatrix = new Matrix(); /** * Constructs a PatternPathMotion with a straight-line pattern. */ public PatternPathMotion() { mPatternPath.lineTo(1, 0); mOriginalPatternPath = mPatternPath; } public PatternPathMotion(Context context, AttributeSet attrs) { TypedArray a = context.obtainStyledAttributes(attrs, Styleable.PATTERN_PATH_MOTION); try { String pathData = TypedArrayUtils.getNamedString(a, (XmlPullParser) attrs, "patternPathData", Styleable.PatternPathMotion.PATTERN_PATH_DATA); if (pathData == null) { throw new RuntimeException("pathData must be supplied for patternPathMotion"); } Path pattern = PathParser.createPathFromPathData(pathData); setPatternPath(pattern); } finally { a.recycle(); } } /** * Creates a PatternPathMotion 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 patternPath A Path to be used as a pattern for two-dimensional motion. */ public PatternPathMotion(Path patternPath) { setPatternPath(patternPath); } /** * 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. */ public Path getPatternPath() { return mOriginalPatternPath; } /** * 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 patternPath A Path to be used as a pattern for two-dimensional motion. */ public void setPatternPath(Path patternPath) { PathMeasure pathMeasure = new PathMeasure(patternPath, 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)); patternPath.transform(mTempMatrix, mPatternPath); mOriginalPatternPath = patternPath; } @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(); mPatternPath.transform(mTempMatrix, path); return path; } private static float distance(float x, float y) { return (float) Math.sqrt((x * x) + (y * y)); } }