ca.ualberta.cmput301w14t08.geochan.json.BitmapJsonConverter.java Source code

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Here is the source code for ca.ualberta.cmput301w14t08.geochan.json.BitmapJsonConverter.java

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/*
 * Copyright 2014 Artem Chikin
 * Copyright 2014 Artem Herasymchuk
 * Copyright 2014 Tom Krywitsky
 * Copyright 2014 Henry Pabst
 * Copyright 2014 Bradley Simons
 * 
 * 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 ca.ualberta.cmput301w14t08.geochan.json;

import java.io.ByteArrayOutputStream;
import java.lang.reflect.Type;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Base64;

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;

/**
 * Handles the serialization and deserialization of Bitmap objects
 * to and from base64 JSON strings.
 * 
 * @author Artem Chikin
 * @author Artem Herasymchuk
 * 
 */
public class BitmapJsonConverter implements JsonSerializer<Bitmap>, JsonDeserializer<Bitmap> {

    /**
     * Deserializes a Bitmap from a base64 JSON string.
     * 
     * @param jsonElement
     *            the JSON element to deserialize
     * @param type
     *            the Type
     * @param jsc
     *            the JSON deserialization context
     * @return The deserialized Bitmap.
     * 
     * @throws JsonParseException
     */
    @Override
    public Bitmap deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsc)
            throws JsonParseException {
        Bitmap image = null;
        JsonObject object = jsonElement.getAsJsonObject();
        String encodedImage = object.get("image").getAsString();
        byte[] byteArray = Base64.decode(encodedImage, Base64.NO_WRAP);

        /*
         * http://stackoverflow.com/a/5878773
         * Sando's workaround for running out of memory on decoding bitmaps.
         */
        BitmapFactory.Options opts = new BitmapFactory.Options();
        opts.inDither = false;
        opts.inPurgeable = true;
        opts.inInputShareable = true;
        opts.inTempStorage = new byte[32 * 1024];
        image = BitmapFactory.decodeByteArray(byteArray, 0, byteArray.length, opts);

        return image;
    }

    /**
     * Serializes a Bitmap to a base64 JSON string.
     * 
     * @param bitmap
     *            the Bitmap to serialize
     * @param type
     *            the type
     * @param jsc
     *            the JSON serialization context
     *            
     * @return a JsonElement representing the serialized Bitmap.
     */
    @Override
    public JsonElement serialize(Bitmap bitmap, Type type, JsonSerializationContext jsc) {
        JsonObject object = new JsonObject();

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG, 90, byteArrayOutputStream);
        byte[] byteArray = byteArrayOutputStream.toByteArray();
        String encoded = Base64.encodeToString(byteArray, Base64.NO_WRAP);
        object.addProperty("image", encoded);

        return object;
    }
}