android/support/transition/ViewUtilsApi14.java

/*
 * Copyright (C) 2016 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.graphics.Matrix;
import android.support.annotation.NonNull;
import android.support.annotation.RequiresApi;
import android.view.View;
import android.view.ViewParent;

@RequiresApi(14)
class ViewUtilsApi14 implements ViewUtilsImpl {

    private float[] mMatrixValues;

    @Override
    public ViewOverlayImpl getOverlay(@NonNull View view) {
        return ViewOverlayApi14.createFrom(view);
    }

    @Override
    public WindowIdImpl getWindowId(@NonNull View view) {
        return new WindowIdApi14(view.getWindowToken());
    }

    @Override
    public void setTransitionAlpha(@NonNull View view, float alpha) {
        Float savedAlpha = (Float) view.getTag(R.id.save_non_transition_alpha);
        if (savedAlpha != null) {
            view.setAlpha(savedAlpha * alpha);
        } else {
            view.setAlpha(alpha);
        }
    }

    @Override
    public float getTransitionAlpha(@NonNull View view) {
        Float savedAlpha = (Float) view.getTag(R.id.save_non_transition_alpha);
        if (savedAlpha != null) {
            return view.getAlpha() / savedAlpha;
        } else {
            return view.getAlpha();
        }
    }

    @Override
    public void saveNonTransitionAlpha(@NonNull View view) {
        if (view.getTag(R.id.save_non_transition_alpha) == null) {
            view.setTag(R.id.save_non_transition_alpha, view.getAlpha());
        }
    }

    @Override
    public void clearNonTransitionAlpha(@NonNull View view) {
        // We don't clear the saved value when the view is hidden; that's the situation we are
        // saving this value for.
        if (view.getVisibility() == View.VISIBLE) {
            view.setTag(R.id.save_non_transition_alpha, null);
        }
    }

    @Override
    public void transformMatrixToGlobal(@NonNull View view, @NonNull Matrix matrix) {
        final ViewParent parent = view.getParent();
        if (parent instanceof View) {
            final View vp = (View) parent;
            transformMatrixToGlobal(vp, matrix);
            matrix.preTranslate(-vp.getScrollX(), -vp.getScrollY());
        }
        matrix.preTranslate(view.getLeft(), view.getTop());
        final Matrix vm = view.getMatrix();
        if (!vm.isIdentity()) {
            matrix.preConcat(vm);
        }
    }

    @Override
    public void transformMatrixToLocal(@NonNull View view, @NonNull Matrix matrix) {
        final ViewParent parent = view.getParent();
        if (parent instanceof View) {
            final View vp = (View) parent;
            transformMatrixToLocal(vp, matrix);
            matrix.postTranslate(vp.getScrollX(), vp.getScrollY());
        }
        matrix.postTranslate(view.getLeft(), view.getTop());
        final Matrix vm = view.getMatrix();
        if (!vm.isIdentity()) {
            final Matrix inverted = new Matrix();
            if (vm.invert(inverted)) {
                matrix.postConcat(inverted);
            }
        }
    }

    @Override
    public void setAnimationMatrix(@NonNull View view, Matrix matrix) {
        if (matrix == null || matrix.isIdentity()) {
            view.setPivotX(view.getWidth() / 2);
            view.setPivotY(view.getHeight() / 2);
            view.setTranslationX(0);
            view.setTranslationY(0);
            view.setScaleX(1);
            view.setScaleY(1);
            view.setRotation(0);
        } else {
            float[] values = mMatrixValues;
            if (values == null) {
                mMatrixValues = values = new float[9];
            }
            matrix.getValues(values);
            final float sin = values[Matrix.MSKEW_Y];
            final float cos = (float) Math.sqrt(1 - sin * sin)
                    * (values[Matrix.MSCALE_X] < 0 ? -1 : 1);
            final float rotation = (float) Math.toDegrees(Math.atan2(sin, cos));
            final float scaleX = values[Matrix.MSCALE_X] / cos;
            final float scaleY = values[Matrix.MSCALE_Y] / cos;
            final float dx = values[Matrix.MTRANS_X];
            final float dy = values[Matrix.MTRANS_Y];
            view.setPivotX(0);
            view.setPivotY(0);
            view.setTranslationX(dx);
            view.setTranslationY(dy);
            view.setRotation(rotation);
            view.setScaleX(scaleX);
            view.setScaleY(scaleY);
        }
    }

    @Override
    public void setLeftTopRightBottom(View v, int left, int top, int right, int bottom) {
        v.setLeft(left);
        v.setTop(top);
        v.setRight(right);
        v.setBottom(bottom);
    }

}