BitmapTileSourceBase.java

package org.osmdroid.tileprovider.tilesource;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.util.Log;

import org.osmdroid.api.IMapView;
import org.osmdroid.tileprovider.BitmapPool;
import org.osmdroid.tileprovider.MapTile;
import org.osmdroid.tileprovider.ReusableBitmapDrawable;
import org.osmdroid.tileprovider.util.Counters;

import java.io.File;
import java.io.InputStream;
import java.util.Random;

public abstract class BitmapTileSourceBase implements ITileSource {

	private static int globalOrdinal = 0;

	private final int mMinimumZoomLevel;
	private final int mMaximumZoomLevel;

	private final int mOrdinal;
	protected String mName;
	protected String mCopyright;
	protected final String mImageFilenameEnding;
	protected final Random random = new Random();

	private final int mTileSizePixels;

	//private final string mResourceId;

	/**
	 * Constructor
	 * @param aName a human-friendly name for this tile source. this name is also used on the file system, to keep the characters linux file system friendly
	 * @param aZoomMinLevel the minimum zoom level this tile source can provide
	 * @param aZoomMaxLevel the maximum zoom level this tile source can provide
	 * @param aTileSizePixels the tile size in pixels this tile source provides
	 * @param aImageFilenameEnding the file name extension used when constructing the filename
	 */
	public BitmapTileSourceBase(final String aName,
			final int aZoomMinLevel, final int aZoomMaxLevel, final int aTileSizePixels,
			final String aImageFilenameEnding) {
		this(aName, aZoomMinLevel, aZoomMaxLevel, aTileSizePixels, aImageFilenameEnding, null);
	}

	/**
	 * Constructor
	 * @param aName a human-friendly name for this tile source. this name is also used on the file system, to keep the characters linux file system friendly
	 * @param aZoomMinLevel the minimum zoom level this tile source can provide
	 * @param aZoomMaxLevel the maximum zoom level this tile source can provide
	 * @param aTileSizePixels the tile size in pixels this tile source provides
	 * @param aImageFilenameEnding the file name extension used when constructing the filename
	 */
	public BitmapTileSourceBase(final String aName,
								final int aZoomMinLevel, final int aZoomMaxLevel, final int aTileSizePixels,
								final String aImageFilenameEnding, final String aCopyrightNotice) {
		mOrdinal = globalOrdinal++;
		mName = aName;
		mMinimumZoomLevel = aZoomMinLevel;
		mMaximumZoomLevel = aZoomMaxLevel;
		mTileSizePixels = aTileSizePixels;
		mImageFilenameEnding = aImageFilenameEnding;
		mCopyright = aCopyrightNotice;
	}


	@Override
	public int ordinal() {
		return mOrdinal;
	}

	@Override
	public String name() {
		return mName;
	}

	public String pathBase() {
		return mName;
	}

	public String imageFilenameEnding() {
		return mImageFilenameEnding;
	}

	@Override
	public int getMinimumZoomLevel() {
		return mMinimumZoomLevel;
	}

	@Override
	public int getMaximumZoomLevel() {
		return mMaximumZoomLevel;
	}

	@Override
	public int getTileSizePixels() {
		return mTileSizePixels;
	}


	@Override
	public Drawable getDrawable(final String aFilePath) throws LowMemoryException {
		//Log.d(IMapView.LOGTAG, aFilePath + " attempting to load bitmap");
		try {
			// default implementation will load the file as a bitmap and create
			// a BitmapDrawable from it
			BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
			BitmapPool.getInstance().applyReusableOptions(bitmapOptions);
			final Bitmap bitmap;
			//fix for API 15 see https://github.com/osmdroid/osmdroid/issues/227
			if (Build.VERSION.SDK_INT == Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)
				bitmap=BitmapFactory.decodeFile(aFilePath);
			else
				bitmap = BitmapFactory.decodeFile(aFilePath, bitmapOptions);
			if (bitmap != null) {
				return new ReusableBitmapDrawable(bitmap);
			} else {
				File bmp = new File(aFilePath);
				if (bmp.exists()) {
					// if we couldn't load it then it's invalid - delete it
					Log.d(IMapView.LOGTAG, aFilePath + " is an invalid image file, deleting...");
					try {
						new File(aFilePath).delete();
					} catch (final Throwable e) {
						Log.e(IMapView.LOGTAG, "Error deleting invalid file: " + aFilePath, e);
					}
				} else
					Log.d(IMapView.LOGTAG, "Request tile: " + aFilePath + " does not exist");
			}
		} catch (final OutOfMemoryError e) {
			Log.e(IMapView.LOGTAG,"OutOfMemoryError loading bitmap: " + aFilePath);
			System.gc();
			throw new LowMemoryException(e);
		} catch (final Exception e){
			Log.e(IMapView.LOGTAG,"Unexpected error loading bitmap: " + aFilePath,e);
			Counters.tileDownloadErrors++;
			System.gc();
		}
		return null;
	}

	@Override
	public String getTileRelativeFilenameString(final MapTile tile) {
		final StringBuilder sb = new StringBuilder();
		sb.append(pathBase());
		sb.append('/');
		sb.append(tile.getZoomLevel());
		sb.append('/');
		sb.append(tile.getX());
		sb.append('/');
		sb.append(tile.getY());
		sb.append(imageFilenameEnding());
		return sb.toString();
	}

	@Override
	public Drawable getDrawable(final InputStream aFileInputStream) throws LowMemoryException {
		try {
			// default implementation will load the file as a bitmap and create
			// a BitmapDrawable from it
			BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
			BitmapPool.getInstance().applyReusableOptions(bitmapOptions);
			final Bitmap bitmap = BitmapFactory.decodeStream(aFileInputStream, null, bitmapOptions);
			if (bitmap != null) {
				return new ReusableBitmapDrawable(bitmap);
			}
		} catch (final OutOfMemoryError e) {
			Log.e(IMapView.LOGTAG,"OutOfMemoryError loading bitmap");
			System.gc();
			throw new LowMemoryException(e);
		} catch (Exception ex) {
			Log.w(IMapView.LOGTAG,"#547 Error loading bitmap" + pathBase(), ex);
		}
		return null;
	}

	public static final class LowMemoryException extends Exception {
		private static final long serialVersionUID = 146526524087765134L;

		public LowMemoryException(final String pDetailMessage) {
			super(pDetailMessage);
		}

		public LowMemoryException(final Throwable pThrowable) {
			super(pThrowable);
		}
	}

	@Override
	public String getCopyrightNotice(){
		return mCopyright;
	}
}