MBTiles vector tile source (#740)

Support offline vector maps (MBTiles, MVT, gzipped pbf)

vtm-android-mvt/AndroidManifest.xml

@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<manifest package="org.oscim.android.mvt" />

vtm-android-mvt/build.gradle

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+apply plugin: 'com.android.library'
+apply plugin: 'com.github.dcendents.android-maven'
+
+dependencies {
+    api project(':vtm-android')
+    api project(':vtm-mvt')
+}
+
+android {
+    compileSdkVersion androidCompileSdk()
+    buildToolsVersion "$androidBuildVersionTools"
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_7
+        targetCompatibility JavaVersion.VERSION_1_7
+    }
+
+    defaultConfig {
+        versionCode project.versionCode()
+        versionName project.versionName()
+        minSdkVersion androidMinSdk()
+        targetSdkVersion androidTargetSdk()
+    }
+
+    sourceSets {
+        main {
+            manifest.srcFile 'AndroidManifest.xml'
+            java.srcDirs = ['src']
+        }
+        debug.setRoot('build-types/debug')
+        release.setRoot('build-types/release')
+    }
+
+    lintOptions { abortOnError false }
+}
+
+android.libraryVariants.all { variant ->
+    def name = variant.buildType.name
+    if (name == "debug")
+        return
+
+    def jar = project.tasks.create "jar${name.capitalize()}", Jar
+    jar.dependsOn variant.javaCompileProvider
+    jar.exclude '**/BuildConfig.class'
+    jar.exclude '**/R.class'
+    jar.exclude '**/R$*.class'
+    jar.from variant.javaCompileProvider.get().destinationDir
+    artifacts.add('archives', jar)
+}
+
+if (project.hasProperty("SONATYPE_USERNAME")) {
+    afterEvaluate {
+        project.apply from: "${rootProject.projectDir}/deploy.gradle"
+    }
+}

vtm-android-mvt/src/org/oscim/android/mvt/tiling/source/mbtiles/MBTilesMvtTileDataSource.java

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+/*
+ * Copyright 2019 Kostas Tzounopoulos
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.oscim.android.mvt.tiling.source.mbtiles;
+
+import android.database.Cursor;
+import org.oscim.android.tiling.source.mbtiles.MBTilesTileDataSource;
+import org.oscim.android.tiling.source.mbtiles.MBTilesUnsupportedException;
+import org.oscim.core.MercatorProjection;
+import org.oscim.layers.tile.MapTile;
+import org.oscim.tiling.ITileDataSink;
+import org.oscim.tiling.OverzoomDataSink;
+import org.oscim.tiling.QueryResult;
+import org.oscim.tiling.source.mvt.MvtTileDecoder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.zip.GZIPInputStream;
+
+/**
+ * A tile data source for MBTiles vector databases.
+ */
+public class MBTilesMvtTileDataSource extends MBTilesTileDataSource {
+
+    private static final Logger log = LoggerFactory.getLogger(MBTilesMvtTileDataSource.class);
+
+    private static final List<String> SUPPORTED_FORMATS = Collections.singletonList("pbf");
+    private static final String WHERE_FORMAT = "zoom_level=%d AND tile_column=%d AND tile_row=%d";
+
+    private final String mLanguage;
+
+    private final ThreadLocal<MvtTileDecoder> mThreadLocalDecoders = new ThreadLocal<MvtTileDecoder>() {
+        @Override
+        protected MvtTileDecoder initialValue() {
+            return new MvtTileDecoder(mLanguage);
+        }
+    };
+
+    /**
+     * Create a tile data source for MBTiles vector databases.
+     *
+     * @param path     the path to the MBTiles database.
+     * @param language the language to use when rendering the MBTiles.
+     */
+    public MBTilesMvtTileDataSource(String path, String language) {
+        super(path);
+        mLanguage = language != null ? language : "en";
+
+        try {
+            assertDatabaseFormat();
+        } catch (MBTilesUnsupportedException e) {
+            log.error("Invalid MBTiles database", e);
+        }
+    }
+
+    @Override
+    public void cancel() {
+        // do nothing
+    }
+
+    @Override
+    public void dispose() {
+        if (mDatabase != null && mDatabase.isOpen())
+            mDatabase.close();
+    }
+
+    @Override
+    public List<String> getSupportedFormats() {
+        return SUPPORTED_FORMATS;
+    }
+
+    private MapTile mapTile(Cursor cursor) {
+        int tileX = cursor.getInt(cursor.getColumnIndexOrThrow("tile_column"));
+        int tileY = cursor.getInt(cursor.getColumnIndexOrThrow("tile_row"));
+        int zoomLevel = cursor.getInt(cursor.getColumnIndexOrThrow("zoom_level"));
+        long tmsTileY = MercatorProjection.tileYToTMS(tileY, (byte) zoomLevel);
+        return new MapTile(tileX, (int) tmsTileY, zoomLevel);
+    }
+
+    /**
+     * Overzoom on the DB layer: generate a query for all tiles with lower zoomLevel than the one requested.
+     */
+    private String overzoomQuery(MapTile tile) {
+        long tmsTileY = MercatorProjection.tileYToTMS(tile.tileY, tile.zoomLevel);
+        StringBuilder sb = new StringBuilder();
+        sb.append("(");
+        for (int zoomLevel = tile.zoomLevel - 1; zoomLevel > 0; zoomLevel--) {
+            int diff = tile.zoomLevel - zoomLevel;
+            sb.append(String.format(Locale.US, WHERE_FORMAT, zoomLevel, tile.tileX >> diff, tmsTileY >> diff));
+            if (zoomLevel > 1) // Not the last iteration
+                sb.append(") OR (");
+        }
+        sb.append(")");
+        return String.format(SELECT_TILES_FORMAT, sb.toString());
+    }
+
+    @Override
+    public void query(MapTile requestTile, ITileDataSink requestDataSink) {
+        Cursor cursor = null;
+        ITileDataSink responseDataSink = requestDataSink;
+        try {
+            long tmsTileY = MercatorProjection.tileYToTMS(requestTile.tileY, requestTile.zoomLevel);
+            cursor = mDatabase.rawQuery(String.format(SELECT_TILES_FORMAT, String.format(Locale.US, WHERE_FORMAT, requestTile.zoomLevel, requestTile.tileX, tmsTileY)), null);
+
+            if (cursor.getCount() == 0) {
+                cursor.close();
+                cursor = mDatabase.rawQuery(overzoomQuery(requestTile), null);
+            }
+
+            if (cursor.moveToFirst()) {
+                byte[] bytes = cursor.getBlob(cursor.getColumnIndexOrThrow("tile_data"));
+
+                MapTile responseTile = mapTile(cursor);
+                if (requestTile.zoomLevel != responseTile.zoomLevel)
+                    responseDataSink = new OverzoomDataSink(requestDataSink, responseTile, requestTile);
+
+                boolean success = mThreadLocalDecoders.get().decode(responseTile, responseDataSink, new GZIPInputStream(new ByteArrayInputStream(bytes)));
+                responseDataSink.completed(success ? QueryResult.SUCCESS : QueryResult.FAILED);
+            } else
+                responseDataSink.completed(QueryResult.TILE_NOT_FOUND);
+        } catch (IOException e) {
+            responseDataSink.completed(QueryResult.FAILED);
+        } finally {
+            if (cursor != null)
+                cursor.close();
+        }
+    }
+}

vtm-android-mvt/src/org/oscim/android/mvt/tiling/source/mbtiles/MBTilesMvtTileSource.java

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+/*
+ * Copyright 2019 Kostas Tzounopoulos
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.oscim.android.mvt.tiling.source.mbtiles;
+
+import org.oscim.android.tiling.source.mbtiles.MBTilesTileSource;
+
+/**
+ * A tile source for MBTiles vector databases.
+ */
+public class MBTilesMvtTileSource extends MBTilesTileSource {
+
+    /**
+     * Create a tile source for MBTiles vector databases.
+     *
+     * @param path the path to the MBTiles database.
+     */
+    public MBTilesMvtTileSource(String path) {
+        this(path, null);
+    }
+
+    /**
+     * Create a tile source for MBTiles vector databases.
+     *
+     * @param path     the path to the MBTiles database.
+     * @param language the language to use when rendering the MBTiles.
+     */
+    public MBTilesMvtTileSource(String path, String language) {
+        super(new MBTilesMvtTileDataSource(path, language));
+    }
+}