AnimatedCoverView.java

/*****************************************************************************
 * AnimatedCoverImageView.java
 *****************************************************************************
 * Copyright © 2011-2013 VLC authors and VideoLAN
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/
package org.videolan.vlc.widget;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.AnimationUtils;
import android.view.animation.Transformation;
import android.view.animation.TranslateAnimation;


public class AnimatedCoverView extends View {

    private Bitmap mImage;

    private TranslateAnimation mCurrentAnim = null;
    private final static int ANIMATION_MOVE_1 = 0;
    private final static int ANIMATION_MOVE_2 = 1;
    private int mCurrentMove = ANIMATION_MOVE_2;

    public AnimatedCoverView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public AnimatedCoverView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public AnimatedCoverView(Context context) {
        super(context);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);

        // Reinitialize the current animation.
        mCurrentAnim = null;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (mImage != null) {
            // Determine the animation parameters.
            Rect rect = new Rect();
            canvas.getClipBounds(rect);

            float ARview = (float)rect.width() / rect.height();
            float ARimage = (float)mImage.getWidth() / mImage.getHeight();

            int scaledImageWidth;
            int scaledImageHeight;

            if (ARimage > ARview) {
                scaledImageWidth = (int)((float)mImage.getWidth() * rect.bottom / mImage.getHeight());
                scaledImageHeight = rect.bottom;
            }
            else {
                scaledImageWidth = rect.right;
                scaledImageHeight = (int)((float)mImage.getHeight() * rect.right / mImage.getWidth());
            }

            // Switch the current animation if needed.
            if (mCurrentAnim == null || mCurrentAnim.hasEnded())
            {
                mCurrentMove = mCurrentMove == ANIMATION_MOVE_1 ? ANIMATION_MOVE_2 : ANIMATION_MOVE_1;

                mCurrentAnim = new TranslateAnimation(
                        mCurrentMove == ANIMATION_MOVE_1 ? 0 : rect.right - scaledImageWidth,
                        mCurrentMove == ANIMATION_MOVE_1 ? rect.right - scaledImageWidth : 0,
                        mCurrentMove == ANIMATION_MOVE_1 ? 0 : rect.bottom - scaledImageHeight,
                        mCurrentMove == ANIMATION_MOVE_1 ? rect.bottom - scaledImageHeight : 0);

                int animationDuration = scaledImageHeight == rect.bottom ?
                        (scaledImageWidth - rect.right) * 15 : (scaledImageHeight - rect.bottom) * 15;
                mCurrentAnim.setDuration(animationDuration);
                mCurrentAnim.setInterpolator(new AccelerateDecelerateInterpolator());
                mCurrentAnim.initialize(mImage.getWidth(), mImage.getHeight(), rect.right, rect.bottom);
            }

            // Animate and draw
            Transformation trans = new Transformation();
            mCurrentAnim.getTransformation(AnimationUtils.currentAnimationTimeMillis(), trans);
            float[] pt = new float[2];
            trans.getMatrix().mapPoints(pt);

            Rect src = new Rect(0, 0, mImage.getWidth(), mImage.getHeight());
            Rect dst = new Rect((int)pt[0], (int)pt[1], (int)pt[0] + scaledImageWidth, (int)pt[1] + scaledImageHeight);
            Paint paint = new Paint();
            paint.setFilterBitmap(true);
            canvas.drawBitmap(mImage, src, dst, paint);
            super.onDraw(canvas);

            // Request another draw operation until time is up.
            invalidate();
        }
    }

    public void setImageBitmap(Bitmap b) {
        mImage = b;
        invalidate();
    }
}