new3d/src/com/android/gallery3d/app/ViewImage.java

package com.android.gallery3d.app;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Bitmap.Config;
import android.os.Bundle;

import com.android.gallery3d.R;
import com.android.gallery3d.data.DataManager;
import com.android.gallery3d.data.ImageService;
import com.android.gallery3d.ui.GLRootView;
import com.android.gallery3d.ui.ImageViewer;
import com.android.gallery3d.ui.StateManager;
import com.android.gallery3d.ui.ImageViewer.ImageData;

import java.util.ArrayList;

public class ViewImage extends Activity implements GalleryContext {

    private static final int BACKUP_SIZE = 512;
    private static final String FILE_NAME = "/sdcard/image.jpg";

    private GLRootView mGLRootView;
    private Bitmap mScaledBitmaps[];
    private Bitmap mBackupBitmap;
    private ImageViewer mImageViewer;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mGLRootView = (GLRootView) findViewById(R.id.gl_root_view);

        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inPreferredConfig = Config.RGB_565;
        Bitmap bitmap = BitmapFactory.decodeFile(FILE_NAME, options);

        mScaledBitmaps = getMipmaps(bitmap);
        mBackupBitmap = getBackupBitmap(bitmap);

        mImageViewer = new ImageViewer(this);
        mImageViewer.setModel(new MyModel(mBackupBitmap, mScaledBitmaps));

        mGLRootView.setContentPane(mImageViewer);
    }


    private static class MyModel implements ImageViewer.Model {
        private static final int SIZE = 3;

        private final Bitmap[] mMipmap;
        private final Bitmap mBackupImage;
        private int mIndex = 0;

        public MyModel(Bitmap backup, Bitmap mipmap[]) {
            mMipmap = mipmap;
            mBackupImage = backup;
        }

        public Bitmap[] getMipmaps() {
            return mMipmap;
        }

        public void next() {
            ++mIndex;
        }

        public void previous() {
            --mIndex;
        }

        public ImageData getImageData(int which) {
            int index = mIndex + which - INDEX_CURRENT;
            if (index < 0 || index >= SIZE) return null;
            return new ImageData(mMipmap[0].getWidth(),
                    mMipmap[0].getHeight(), mBackupImage);
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        mGLRootView.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        synchronized (mGLRootView) {
            mImageViewer.close();
        }
        mGLRootView.onPause();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        for(Bitmap bitmap : mScaledBitmaps) {
            bitmap.recycle();
        }
        mBackupBitmap.recycle();
    }

    static private Bitmap getBackupBitmap(Bitmap bitmap) {
        Config config = bitmap.hasAlpha() ? Config.ARGB_8888 : Config.RGB_565;

        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        float scale = (float) BACKUP_SIZE / (width > height ? width : height);
        width = (int) (width * scale + 0.5f);
        height = (int) (height * scale + 0.5f);
        Bitmap result = Bitmap.createBitmap(width, height, config);
        Canvas canvas = new Canvas(result);
        canvas.scale(scale, scale);
        canvas.drawBitmap(bitmap, 0, 0, null);
        return result;
    }

    static private Bitmap[] getMipmaps(Bitmap bitmap) {
        Config config = bitmap.hasAlpha() ? Config.ARGB_8888 : Config.RGB_565;

        int width = bitmap.getWidth() / 2;
        int height = bitmap.getHeight() / 2;

        ArrayList<Bitmap> list = new ArrayList<Bitmap>();
        list.add(bitmap);
        while (width > BACKUP_SIZE || height > BACKUP_SIZE) {
            Bitmap half = Bitmap.createBitmap(width, height, config);
            Canvas canvas = new Canvas(half);
            canvas.scale(0.5f, 0.5f);
            canvas.drawBitmap(bitmap, 0, 0, null);
            width /= 2;
            height /= 2;
            bitmap = half;
            list.add(bitmap);
        }
        return list.toArray(new Bitmap[list.size()]);
    }

    public Context getAndroidContext() {
        return this;
    }

    public DataManager getDataManager() {
        throw new UnsupportedOperationException();
    }

    public ImageService getImageService() {
        throw new UnsupportedOperationException();
    }

    public StateManager getStateManager() {
        throw new UnsupportedOperationException();
    }

    public Object getUiMonitor() {
        return mGLRootView;
    }

}