geopackage-sdk/src/main/java/mil/nga/geopackage/tiles/retriever/TileCreator.java
private Bitmap reprojectTile(Bitmap tile, int requestedTileWidth, int requestedTileHeight, BoundingBox requestBoundingBox, ProjectionTransform transformRequestToTiles, BoundingBox tilesBoundingBox) {

        final double requestedWidthUnitsPerPixel = (requestBoundingBox.getMaxLongitude() - requestBoundingBox.getMinLongitude()) / requestedTileWidth;
        final double requestedHeightUnitsPerPixel = (requestBoundingBox.getMaxLatitude() - requestBoundingBox.getMinLatitude()) / requestedTileHeight;

        final double tilesDistanceWidth = tilesBoundingBox.getMaxLongitude() - tilesBoundingBox.getMinLongitude();
        final double tilesDistanceHeight = tilesBoundingBox.getMaxLatitude() - tilesBoundingBox.getMinLatitude();

        final int width = tile.getWidth();
        final int height = tile.getHeight();

        // Tile pixels of the tile matrix tiles
        int[] pixels = new int[width * height];
        tile.getPixels(pixels, 0, width, 0, 0, width, height);

        // Projected tile pixels to draw the reprojected tile
        int[] projectedPixels = new int[requestedTileWidth * requestedTileHeight];

        // Retrieve each pixel in the new tile from the unprojected tile
        for (int y = 0; y < requestedTileHeight; y++) {
            for (int x = 0; x < requestedTileWidth; x++) {

                double longitude = requestBoundingBox.getMinLongitude() + (x * requestedWidthUnitsPerPixel);
                double latitude = requestBoundingBox.getMaxLatitude() - (y * requestedHeightUnitsPerPixel);
                ProjCoordinate fromCoord = new ProjCoordinate(longitude, latitude);
                ProjCoordinate toCoord = transformRequestToTiles.transform(fromCoord);
                double projectedLongitude = toCoord.x;
                double projectedLatitude = toCoord.y;

                int xPixel = (int) Math.round(((projectedLongitude - tilesBoundingBox.getMinLongitude()) / tilesDistanceWidth) * width);
                int yPixel = (int) Math.round(((tilesBoundingBox.getMaxLatitude() - projectedLatitude) / tilesDistanceHeight) * height);

                xPixel = Math.max(0, xPixel);
                xPixel = Math.min(width - 1, xPixel);

                yPixel = Math.max(0, yPixel);
                yPixel = Math.min(height - 1, yPixel);

                int color = pixels[(yPixel * width) + xPixel];
                projectedPixels[(y * requestedTileWidth) + x] = color;
            }
        }

        // Draw the new tile bitmap
        Bitmap projectedTileBitmap = Bitmap.createBitmap(requestedTileWidth,
                requestedTileHeight, tile.getConfig());
        projectedTileBitmap.setPixels(projectedPixels, 0, requestedTileWidth, 0, 0, requestedTileWidth, requestedTileHeight);

        return projectedTileBitmap;
    }
private Bitmap reprojectTile(Bitmap tile, int requestedTileWidth, int requestedTileHeight, BoundingBox requestBoundingBox, ProjectionTransform transformRequestToTiles, BoundingBox tilesBoundingBox) {

        final double requestedWidthUnitsPerPixel = (requestBoundingBox.getMaxLongitude() - requestBoundingBox.getMinLongitude()) / requestedTileWidth;
        final double requestedHeightUnitsPerPixel = (requestBoundingBox.getMaxLatitude() - requestBoundingBox.getMinLatitude()) / requestedTileHeight;

        final double tilesDistanceWidth = tilesBoundingBox.getMaxLongitude() - tilesBoundingBox.getMinLongitude();
        final double tilesDistanceHeight = tilesBoundingBox.getMaxLatitude() - tilesBoundingBox.getMinLatitude();

        final int width = tile.getWidth();
        final int height = tile.getHeight();

        // Tile pixels of the tile matrix tiles
        int[] pixels = new int[width * height];
        tile.getPixels(pixels, 0, width, 0, 0, width, height);

        // Projected tile pixels to draw the reprojected tile
        int[] projectedPixels = new int[requestedTileWidth * requestedTileHeight];

        // Retrieve each pixel in the new tile from the unprojected tile
        for (int y = 0; y < requestedTileHeight; y++) {
            for (int x = 0; x < requestedTileWidth; x++) {

                double longitude = requestBoundingBox.getMinLongitude() + (x * requestedWidthUnitsPerPixel);
                double latitude = requestBoundingBox.getMaxLatitude() - (y * requestedHeightUnitsPerPixel);
                ProjCoordinate fromCoord = new ProjCoordinate(longitude, latitude);
                ProjCoordinate toCoord = transformRequestToTiles.transform(fromCoord);
                double projectedLongitude = toCoord.x;
                double projectedLatitude = toCoord.y;

                int xPixel = (int) Math.round(((projectedLongitude - tilesBoundingBox.getMinLongitude()) / tilesDistanceWidth) * width);
                int yPixel = (int) Math.round(((tilesBoundingBox.getMaxLatitude() - projectedLatitude) / tilesDistanceHeight) * height);

                xPixel = Math.max(0, xPixel);
                xPixel = Math.min(width - 1, xPixel);

                yPixel = Math.max(0, yPixel);
                yPixel = Math.min(height - 1, yPixel);

                int color = pixels[(yPixel * width) + xPixel];
                projectedPixels[(y * requestedTileWidth) + x] = color;
            }
        }

        // Draw the new tile bitmap
        Bitmap projectedTileBitmap = Bitmap.createBitmap(requestedTileWidth,
                requestedTileHeight, tile.getConfig());
        projectedTileBitmap.setPixels(projectedPixels, 0, requestedTileWidth, 0, 0, requestedTileWidth, requestedTileHeight);

        return projectedTileBitmap;
    }
private Bitmap reprojectTile ( Bitmap tile , int requestedTileWidth , int requestedTileHeight , BoundingBox requestBoundingBox , ProjectionTransform transformRequestToTiles , BoundingBox tilesBoundingBox ) { final double requestedWidthUnitsPerPixel = ( requestBoundingBox . getMaxLongitude ( ) - requestBoundingBox . getMinLongitude ( ) ) / requestedTileWidth ; final double requestedHeightUnitsPerPixel = ( requestBoundingBox . getMaxLatitude ( ) - requestBoundingBox . getMinLatitude ( ) ) / requestedTileHeight ; final double tilesDistanceWidth = tilesBoundingBox . getMaxLongitude ( ) - tilesBoundingBox . getMinLongitude ( ) ; final double tilesDistanceHeight = tilesBoundingBox . getMaxLatitude ( ) - tilesBoundingBox . getMinLatitude ( ) ; final int width = tile . getWidth ( ) ; final int height = tile . getHeight ( ) ; // Tile pixels of the tile matrix tiles int [ ] pixels = new int [ width * height ] ; tile . getPixels ( pixels , 0 , width , 0 , 0 , width , height ) ; // Projected tile pixels to draw the reprojected tile int [ ] projectedPixels = new int [ requestedTileWidth * requestedTileHeight ] ; // Retrieve each pixel in the new tile from the unprojected tile for ( int y = 0 ; y < requestedTileHeight ; y ++ ) { for ( int x = 0 ; x < requestedTileWidth ; x ++ ) { double longitude = requestBoundingBox . getMinLongitude ( ) + ( x * requestedWidthUnitsPerPixel ) ; double latitude = requestBoundingBox . getMaxLatitude ( ) - ( y * requestedHeightUnitsPerPixel ) ; ProjCoordinate fromCoord = new ProjCoordinate ( longitude , latitude ) ; ProjCoordinate toCoord = transformRequestToTiles . transform ( fromCoord ) ; double projectedLongitude = toCoord . x ; double projectedLatitude = toCoord . y ; int xPixel = ( int ) Math . round ( ( ( projectedLongitude - tilesBoundingBox . getMinLongitude ( ) ) / tilesDistanceWidth ) * width ) ; int yPixel = ( int ) Math . round ( ( ( tilesBoundingBox . getMaxLatitude ( ) - projectedLatitude ) / tilesDistanceHeight ) * height ) ; xPixel = Math . max ( 0 , xPixel ) ; xPixel = Math . min ( width - 1 , xPixel ) ; yPixel = Math . max ( 0 , yPixel ) ; yPixel = Math . min ( height - 1 , yPixel ) ; int color = pixels [ ( yPixel * width ) + xPixel ] ; projectedPixels [ ( y * requestedTileWidth ) + x ] = color ; } } // Draw the new tile bitmap Bitmap projectedTileBitmap = Bitmap . createBitmap ( requestedTileWidth , requestedTileHeight , tile . getConfig ( ) ) ; projectedTileBitmap . setPixels ( projectedPixels , 0 , requestedTileWidth , 0 , 0 , requestedTileWidth , requestedTileHeight ) ; return projectedTileBitmap ; }
Reproject the tile to the requested projection

@param tile                    tile in the tile matrix projection
@param requestedTileWidth      requested tile width
@param requestedTileHeight     requested tile height
@param requestBoundingBox      request bounding box in the request projection
@param transformRequestToTiles transformation from request to tiles
@param tilesBoundingBox        request bounding box in the tile matrix projection
@return projected tile
Reproject the tile to the requested projection