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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package androidx.transition;
     18 
     19 import android.animation.Animator;
     20 import android.animation.ObjectAnimator;
     21 import android.animation.TypeEvaluator;
     22 import android.content.Context;
     23 import android.graphics.Matrix;
     24 import android.graphics.Rect;
     25 import android.graphics.drawable.Drawable;
     26 import android.util.AttributeSet;
     27 import android.util.Property;
     28 import android.view.View;
     29 import android.view.ViewGroup;
     30 import android.widget.ImageView;
     31 
     32 import androidx.annotation.NonNull;
     33 
     34 import java.util.Map;
     35 
     36 /**
     37  * This Transition captures an ImageView's matrix before and after the
     38  * scene change and animates it during the transition.
     39  *
     40  * <p>In combination with ChangeBounds, ChangeImageTransform allows ImageViews
     41  * that change size, shape, or {@link android.widget.ImageView.ScaleType} to animate contents
     42  * smoothly.</p>
     43  */
     44 public class ChangeImageTransform extends Transition {
     45 
     46     private static final String PROPNAME_MATRIX = "android:changeImageTransform:matrix";
     47     private static final String PROPNAME_BOUNDS = "android:changeImageTransform:bounds";
     48 
     49     private static final String[] sTransitionProperties = {
     50             PROPNAME_MATRIX,
     51             PROPNAME_BOUNDS,
     52     };
     53 
     54     private static final TypeEvaluator<Matrix> NULL_MATRIX_EVALUATOR = new TypeEvaluator<Matrix>() {
     55         @Override
     56         public Matrix evaluate(float fraction, Matrix startValue, Matrix endValue) {
     57             return null;
     58         }
     59     };
     60 
     61     private static final Property<ImageView, Matrix> ANIMATED_TRANSFORM_PROPERTY =
     62             new Property<ImageView, Matrix>(Matrix.class, "animatedTransform") {
     63                 @Override
     64                 public void set(ImageView view, Matrix matrix) {
     65                     ImageViewUtils.animateTransform(view, matrix);
     66                 }
     67 
     68                 @Override
     69                 public Matrix get(ImageView object) {
     70                     return null;
     71                 }
     72             };
     73 
     74     public ChangeImageTransform() {
     75     }
     76 
     77     public ChangeImageTransform(Context context, AttributeSet attrs) {
     78         super(context, attrs);
     79     }
     80 
     81     private void captureValues(TransitionValues transitionValues) {
     82         View view = transitionValues.view;
     83         if (!(view instanceof ImageView) || view.getVisibility() != View.VISIBLE) {
     84             return;
     85         }
     86         ImageView imageView = (ImageView) view;
     87         Drawable drawable = imageView.getDrawable();
     88         if (drawable == null) {
     89             return;
     90         }
     91         Map<String, Object> values = transitionValues.values;
     92 
     93         int left = view.getLeft();
     94         int top = view.getTop();
     95         int right = view.getRight();
     96         int bottom = view.getBottom();
     97 
     98         Rect bounds = new Rect(left, top, right, bottom);
     99         values.put(PROPNAME_BOUNDS, bounds);
    100         values.put(PROPNAME_MATRIX, copyImageMatrix(imageView));
    101     }
    102 
    103     @Override
    104     public void captureStartValues(@NonNull TransitionValues transitionValues) {
    105         captureValues(transitionValues);
    106     }
    107 
    108     @Override
    109     public void captureEndValues(@NonNull TransitionValues transitionValues) {
    110         captureValues(transitionValues);
    111     }
    112 
    113     @Override
    114     public String[] getTransitionProperties() {
    115         return sTransitionProperties;
    116     }
    117 
    118     /**
    119      * Creates an Animator for ImageViews moving, changing dimensions, and/or changing
    120      * {@link android.widget.ImageView.ScaleType}.
    121      *
    122      * @param sceneRoot   The root of the transition hierarchy.
    123      * @param startValues The values for a specific target in the start scene.
    124      * @param endValues   The values for the target in the end scene.
    125      * @return An Animator to move an ImageView or null if the View is not an ImageView,
    126      * the Drawable changed, the View is not VISIBLE, or there was no change.
    127      */
    128     @Override
    129     public Animator createAnimator(@NonNull ViewGroup sceneRoot, TransitionValues startValues,
    130             final TransitionValues endValues) {
    131         if (startValues == null || endValues == null) {
    132             return null;
    133         }
    134         Rect startBounds = (Rect) startValues.values.get(PROPNAME_BOUNDS);
    135         Rect endBounds = (Rect) endValues.values.get(PROPNAME_BOUNDS);
    136         if (startBounds == null || endBounds == null) {
    137             return null;
    138         }
    139 
    140         Matrix startMatrix = (Matrix) startValues.values.get(PROPNAME_MATRIX);
    141         Matrix endMatrix = (Matrix) endValues.values.get(PROPNAME_MATRIX);
    142 
    143         boolean matricesEqual = (startMatrix == null && endMatrix == null)
    144                 || (startMatrix != null && startMatrix.equals(endMatrix));
    145 
    146         if (startBounds.equals(endBounds) && matricesEqual) {
    147             return null;
    148         }
    149 
    150         final ImageView imageView = (ImageView) endValues.view;
    151         Drawable drawable = imageView.getDrawable();
    152         int drawableWidth = drawable.getIntrinsicWidth();
    153         int drawableHeight = drawable.getIntrinsicHeight();
    154 
    155         ImageViewUtils.startAnimateTransform(imageView);
    156 
    157         ObjectAnimator animator;
    158         if (drawableWidth == 0 || drawableHeight == 0) {
    159             animator = createNullAnimator(imageView);
    160         } else {
    161             if (startMatrix == null) {
    162                 startMatrix = MatrixUtils.IDENTITY_MATRIX;
    163             }
    164             if (endMatrix == null) {
    165                 endMatrix = MatrixUtils.IDENTITY_MATRIX;
    166             }
    167             ANIMATED_TRANSFORM_PROPERTY.set(imageView, startMatrix);
    168             animator = createMatrixAnimator(imageView, startMatrix, endMatrix);
    169         }
    170 
    171         ImageViewUtils.reserveEndAnimateTransform(imageView, animator);
    172 
    173         return animator;
    174     }
    175 
    176     private ObjectAnimator createNullAnimator(ImageView imageView) {
    177         return ObjectAnimator.ofObject(imageView, ANIMATED_TRANSFORM_PROPERTY,
    178                 NULL_MATRIX_EVALUATOR, null, null);
    179     }
    180 
    181     private ObjectAnimator createMatrixAnimator(final ImageView imageView, Matrix startMatrix,
    182             final Matrix endMatrix) {
    183         return ObjectAnimator.ofObject(imageView, ANIMATED_TRANSFORM_PROPERTY,
    184                 new TransitionUtils.MatrixEvaluator(), startMatrix, endMatrix);
    185     }
    186 
    187     private static Matrix copyImageMatrix(ImageView view) {
    188         switch (view.getScaleType()) {
    189             case FIT_XY:
    190                 return fitXYMatrix(view);
    191             case CENTER_CROP:
    192                 return centerCropMatrix(view);
    193             default:
    194                 return new Matrix(view.getImageMatrix());
    195         }
    196     }
    197 
    198     /**
    199      * Calculates the image transformation matrix for an ImageView with ScaleType FIT_XY. This
    200      * needs to be manually calculated as the platform does not give us the value for this case.
    201      */
    202     private static Matrix fitXYMatrix(ImageView view) {
    203         final Drawable image = view.getDrawable();
    204         final Matrix matrix = new Matrix();
    205         matrix.postScale(
    206                 ((float) view.getWidth()) / image.getIntrinsicWidth(),
    207                 ((float) view.getHeight()) / image.getIntrinsicHeight());
    208         return matrix;
    209     }
    210 
    211     /**
    212      * Calculates the image transformation matrix for an ImageView with ScaleType CENTER_CROP. This
    213      * needs to be manually calculated for consistent behavior across all the API levels.
    214      */
    215     private static Matrix centerCropMatrix(ImageView view) {
    216         final Drawable image = view.getDrawable();
    217         final int imageWidth = image.getIntrinsicWidth();
    218         final int imageViewWidth = view.getWidth();
    219         final float scaleX = ((float) imageViewWidth) / imageWidth;
    220 
    221         final int imageHeight = image.getIntrinsicHeight();
    222         final int imageViewHeight = view.getHeight();
    223         final float scaleY = ((float) imageViewHeight) / imageHeight;
    224 
    225         final float maxScale = Math.max(scaleX, scaleY);
    226 
    227         final float width = imageWidth * maxScale;
    228         final float height = imageHeight * maxScale;
    229         final int tx = Math.round((imageViewWidth - width) / 2f);
    230         final int ty = Math.round((imageViewHeight - height) / 2f);
    231 
    232         final Matrix matrix = new Matrix();
    233         matrix.postScale(maxScale, maxScale);
    234         matrix.postTranslate(tx, ty);
    235         return matrix;
    236     }
    237 
    238 }
    239