ProjectAndSceneScreenshotLoader.java

/*
 * Catroid: An on-device visual programming system for Android devices
 * Copyright (C) 2010-2016 The Catrobat Team
 * (<http://developer.catrobat.org/credits>)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * An additional term exception under section 7 of the GNU Affero
 * General Public License, version 3, is available at
 * http://developer.catrobat.org/license_additional_term
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.catrobat.catroid.io;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.widget.ImageView;

import org.catrobat.catroid.R;
import org.catrobat.catroid.stage.StageListener;
import org.catrobat.catroid.utils.ImageEditing;
import org.catrobat.catroid.utils.Utils;

import java.io.File;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ProjectAndSceneScreenshotLoader {

	private class ScreenshotData {
		public String projectName;
		public String sceneName;
		public boolean isBackpackScene;
		public ImageView imageView;

		public ScreenshotData(String projectName, String sceneName, boolean isBackpackScene, ImageView imageView) {
			this.projectName = projectName;
			this.sceneName = sceneName;
			this.isBackpackScene = isBackpackScene;
			this.imageView = imageView;
		}
	}

	private static final int POOL_SIZE = 5;
	private static final int CACHE_MAX_SIZE = 25;
	private static final float LOAD_FACTOR = .75f;
	private static final int INITIAL_VALUE = 13; // (N / LOAD_FACTOR) + 1

	private Map<ImageView, String> imageViews = Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
	private ExecutorService executorService;
	private Context context;

	private Map<String, Bitmap> imageCache = Collections.synchronizedMap(new LinkedHashMap<String, Bitmap>(
			INITIAL_VALUE, LOAD_FACTOR, true) {

		private static final long serialVersionUID = 1L;

		@Override
		protected boolean removeEldestEntry(Map.Entry<String, Bitmap> eldest) {
			return size() > CACHE_MAX_SIZE;
		}
	});

	public ProjectAndSceneScreenshotLoader(Context context) {
		executorService = Executors.newFixedThreadPool(POOL_SIZE);
		this.context = context;
	}

	public void loadAndShowScreenshot(String projectName, String sceneName, boolean isBackpackScene, ImageView
			imageView) {

		String screenShotName = "";
		if (projectName != null) {
			screenShotName = projectName;
		}
		if (sceneName != null) {
			screenShotName = screenShotName.concat(sceneName);
		}

		imageViews.put(imageView, screenShotName);
		Bitmap bitmap = imageCache.get(screenShotName);
		if (bitmap != null) {
			imageView.setImageBitmap(bitmap);
		} else {
			//set a dummy or null in the meantime
			imageView.setImageBitmap(null);
			//queue the loading and showing process
			ScreenshotData screenshotData = new ScreenshotData(projectName, sceneName, isBackpackScene, imageView);
			executorService.submit(new ScreenshotLoader(screenshotData));
		}
	}

	class ScreenshotLoader implements Runnable {
		ScreenshotData projectAndSceneScreenshotData;

		ScreenshotLoader(ScreenshotData screenshotData) {
			this.projectAndSceneScreenshotData = screenshotData;
		}

		@Override
		public void run() {
			if (imageViewReused(projectAndSceneScreenshotData)) {
				return;
			}

			Activity uiActivity = (Activity) projectAndSceneScreenshotData.imageView.getContext();
			String pathOfScreenshot;
			if (projectAndSceneScreenshotData.sceneName != null) {
				if (projectAndSceneScreenshotData.isBackpackScene) {
					pathOfScreenshot = Utils.buildPath(Utils.buildBackpackScenePath(projectAndSceneScreenshotData.sceneName),
							StageListener.SCREENSHOT_MANUAL_FILE_NAME);
				} else {
					pathOfScreenshot = Utils.buildPath(Utils.buildScenePath(projectAndSceneScreenshotData
									.projectName, projectAndSceneScreenshotData.sceneName),
							StageListener.SCREENSHOT_MANUAL_FILE_NAME);
				}
			} else {
				pathOfScreenshot = Utils.buildPath(Utils.buildProjectPath(projectAndSceneScreenshotData.projectName),
						StageListener.SCREENSHOT_MANUAL_FILE_NAME);
			}

			File projectAndSceneImageFile = new File(pathOfScreenshot);

			if (!(projectAndSceneImageFile.exists() && projectAndSceneImageFile.length() > 0)) {
				projectAndSceneImageFile.delete();
				if (projectAndSceneScreenshotData.sceneName != null) {
					if (projectAndSceneScreenshotData.isBackpackScene) {
						pathOfScreenshot = Utils.buildPath(Utils.buildBackpackScenePath(projectAndSceneScreenshotData.sceneName),
								StageListener.SCREENSHOT_AUTOMATIC_FILE_NAME);
					} else {
						pathOfScreenshot = Utils.buildPath(Utils.buildScenePath(projectAndSceneScreenshotData
										.projectName, projectAndSceneScreenshotData.sceneName),
								StageListener.SCREENSHOT_AUTOMATIC_FILE_NAME);
					}
				} else {
					pathOfScreenshot = Utils.buildPath(Utils.buildProjectPath(projectAndSceneScreenshotData.projectName),
							StageListener.SCREENSHOT_AUTOMATIC_FILE_NAME);
				}
				projectAndSceneImageFile = new File(pathOfScreenshot);
			}

			final Bitmap projectAndSceneImage;
			if (!projectAndSceneImageFile.exists() || ImageEditing.getImageDimensions(pathOfScreenshot)[0] < 0) {
				projectAndSceneImage = null;
			} else {
				int width = context.getResources().getDimensionPixelSize(R.dimen.project_thumbnail_width);
				int height = context.getResources().getDimensionPixelSize(R.dimen.project_thumbnail_height);
				projectAndSceneImage = ImageEditing.getScaledBitmapFromPath(pathOfScreenshot, width, height,
						ImageEditing.ResizeType.STAY_IN_RECTANGLE_WITH_SAME_ASPECT_RATIO, true);
			}

			String screenshotName = "";
			if (projectAndSceneScreenshotData.projectName != null) {
				screenshotName = projectAndSceneScreenshotData
						.projectName;
			}
			if (projectAndSceneScreenshotData.sceneName != null) {
				screenshotName = screenshotName.concat(projectAndSceneScreenshotData.sceneName);
			}

			imageCache.put(screenshotName, projectAndSceneImage);
			if (imageViewReused(projectAndSceneScreenshotData)) {
				return;
			}

			uiActivity.runOnUiThread(new Runnable() {
				@Override
				public void run() {
					if (imageViewReused(projectAndSceneScreenshotData)) {
						return;
					}
					if (projectAndSceneImage != null) {
						projectAndSceneScreenshotData.imageView.setImageBitmap(projectAndSceneImage);
					} else {
						projectAndSceneScreenshotData.imageView.setImageBitmap(null);
					}
				}
			});
		}
	}

	boolean imageViewReused(ScreenshotData projectScreenshotData) {
		String tag = imageViews.get(projectScreenshotData.imageView);
		String screenshotName = "";
		if (projectScreenshotData.projectName != null) {
			screenshotName = projectScreenshotData.projectName;
		}
		if (projectScreenshotData.sceneName != null) {
			screenshotName = screenshotName.concat(projectScreenshotData.sceneName);
		}

		if (tag == null || !tag.equals(screenshotName)) {
			return true;
		}
		return false;
	}
}