photo/util/ImageUtils.java

/*
 * Copyright (C) 2011 Google Inc.
 * Licensed to 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 com.android.ex.photo.util;

import android.content.ContentResolver;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Point;
import android.graphics.Rect;
import android.net.Uri;
import android.os.Build;
import android.util.Log;

import com.android.ex.photo.PhotoViewActivity;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Image utilities
 */
public class ImageUtils {
    // Logging
    private static final String TAG = "ImageUtils";

    /** Minimum class memory class to use full-res photos */
    private final static long MIN_NORMAL_CLASS = 32;
    /** Minimum class memory class to use small photos */
    private final static long MIN_SMALL_CLASS = 24;

    public static enum ImageSize {
        EXTRA_SMALL,
        SMALL,
        NORMAL,
    }

    public static final ImageSize sUseImageSize;
    static {
        // On HC and beyond, assume devices are more capable
        if (Build.VERSION.SDK_INT >= 11) {
            sUseImageSize = ImageSize.NORMAL;
        } else {
            if (PhotoViewActivity.sMemoryClass >= MIN_NORMAL_CLASS) {
                // We have plenty of memory; use full sized photos
                sUseImageSize = ImageSize.NORMAL;
            } else if (PhotoViewActivity.sMemoryClass >= MIN_SMALL_CLASS) {
                // We have slight less memory; use smaller sized photos
                sUseImageSize = ImageSize.SMALL;
            } else {
                // We have little memory; use very small sized photos
                sUseImageSize = ImageSize.EXTRA_SMALL;
            }
        }
    }

    /**
     * @return true if the MimeType type is image
     */
    public static boolean isImageMimeType(String mimeType) {
        return mimeType != null && mimeType.startsWith("image/");
    }

    /**
     * Create a bitmap from a local URI
     *
     * @param resolver The ContentResolver
     * @param uri The local URI
     * @param maxSize The maximum size (either width or height)
     *
     * @return The new bitmap
     */
    public static Bitmap createLocalBitmap(ContentResolver resolver, Uri uri, int maxSize) {
        InputStream inputStream = null;
        try {
            final BitmapFactory.Options opts = new BitmapFactory.Options();
            final Point bounds = getImageBounds(resolver, uri);

            inputStream = resolver.openInputStream(uri);
            opts.inSampleSize = Math.max(bounds.x / maxSize, bounds.y / maxSize);

            final Bitmap decodedBitmap = decodeStream(inputStream, null, opts);

            // Correct thumbnail orientation as necessary
            // TODO: Fix rotation if it's actually a problem
            //return rotateBitmap(resolver, uri, decodedBitmap);
            return decodedBitmap;

        } catch (FileNotFoundException exception) {
            // Do nothing - the photo will appear to be missing
        } catch (IOException exception) {
            // Do nothing - the photo will appear to be missing
        } finally {
            try {
                if (inputStream != null) {
                    inputStream.close();
                }
            } catch (IOException ignore) {
            }
        }
        return null;
    }

    /**
     * Wrapper around {@link BitmapFactory#decodeStream(InputStream, Rect,
     * BitmapFactory.Options)} that returns {@code null} on {@link
     * OutOfMemoryError}.
     *
     * @param is The input stream that holds the raw data to be decoded into a
     *           bitmap.
     * @param outPadding If not null, return the padding rect for the bitmap if
     *                   it exists, otherwise set padding to [-1,-1,-1,-1]. If
     *                   no bitmap is returned (null) then padding is
     *                   unchanged.
     * @param opts null-ok; Options that control downsampling and whether the
     *             image should be completely decoded, or just is size returned.
     * @return The decoded bitmap, or null if the image data could not be
     *         decoded, or, if opts is non-null, if opts requested only the
     *         size be returned (in opts.outWidth and opts.outHeight)
     */
    public static Bitmap decodeStream(InputStream is, Rect outPadding, BitmapFactory.Options opts) {
        try {
            return BitmapFactory.decodeStream(is, outPadding, opts);
        } catch (OutOfMemoryError oome) {
            Log.e(TAG, "ImageUtils#decodeStream(InputStream, Rect, Options) threw an OOME", oome);
            return null;
        }
    }

    /**
     * Gets the image bounds
     *
     * @param resolver The ContentResolver
     * @param uri The uri
     *
     * @return The image bounds
     */
    private static Point getImageBounds(ContentResolver resolver, Uri uri)
            throws IOException {
        final BitmapFactory.Options opts = new BitmapFactory.Options();
        InputStream inputStream = null;

        try {
            opts.inJustDecodeBounds = true;
            inputStream = resolver.openInputStream(uri);
            decodeStream(inputStream, null, opts);

            return new Point(opts.outWidth, opts.outHeight);
        } finally {
            try {
                if (inputStream != null) {
                    inputStream.close();
                }
            } catch (IOException ignore) {
            }
        }
    }
}