/// <summary> /// Gets a tile at a higher zoom level and scales part of it for the requested tile /// </summary> /// <param name="topLeftTile">The top left tile coordinates</param> /// <param name="zoomLevel">The requested zoom level</param> /// <param name="path">The file path</param> /// <param name="generatedName">The name of the DXF file (for design and alignment files it is generated)</param> /// <param name="filespaceId">The filespace ID</param> /// <param name="maxZoomLevel">The maximum zoom level for which tiles have been generated</param> /// <param name="numTiles">The number of tiles for the requested zoom level</param> /// <returns>A scaled tile</returns> private async Task <byte[]> GetTileAtHigherZoom(Point topLeftTile, int zoomLevel, string path, string generatedName, string filespaceId, int maxZoomLevel, int numTiles) { int zoomLevelFound = maxZoomLevel; // Calculate the tile coords of the higher zoom level tile that covers the requested tile Point ptRequestedTile = new Point(topLeftTile.y, topLeftTile.x); Point ptRequestedPixel = WebMercatorProjection.TileToPixel(ptRequestedTile); int numTilesAtRequestedZoomLevel = numTiles; Point ptRequestedWorld = WebMercatorProjection.PixelToWorld(ptRequestedPixel, numTilesAtRequestedZoomLevel); int numTilesAtFoundZoomLevel = TileServiceUtils.NumberOfTiles(maxZoomLevel); Point ptHigherPixel = WebMercatorProjection.WorldToPixel(ptRequestedWorld, numTilesAtFoundZoomLevel); Point ptHigherTile = WebMercatorProjection.PixelToTile(ptHigherPixel); //Note PixelToTile uses Math.Floor so this tile coordinate will be the top left of the tile // With the new tile coords of the higher zoom level tile, see if it exists on TCC string fullHigherTileName = $"{FileUtils.ZoomPath(FileUtils.TilePath(path, generatedName), zoomLevelFound)}/{ptHigherTile.y}/{ptHigherTile.x}.png"; log.LogDebug("DxfTileExecutor: looking for higher tile {0}", fullHigherTileName); byte[] tileData = await DownloadTile(filespaceId, fullHigherTileName, "higher"); if (tileData != null) { tileData = ScaleTile(tileData, zoomLevel - zoomLevelFound, ptHigherTile, ptRequestedWorld, numTilesAtFoundZoomLevel); } return(tileData); }
/// <summary> /// Scales a tile /// </summary> /// <param name="tileData">The tile to scale</param> /// <param name="zoomLevelDifference">The difference between the downloaded tile and the rqeuested tile zoom levels</param> /// <param name="ptHigherTile"></param> /// <param name="ptRequestedWorld"></param> /// <param name="numTilesAtFoundZoomLevel">The number of tiles for the higher zoom level</param> /// <returns>A scaled tile</returns> private byte[] ScaleTile(byte[] tileData, int zoomLevelDifference, Point ptHigherTile, Point ptRequestedWorld, int numTilesAtFoundZoomLevel) { // Calculate the tile coords of the BR corner of the higher zoom level tile // so that we can identify which sub-part of it to crop and scale Point ptHigherTileTopLeft = ptHigherTile; Point ptHigherTileBotRight = new Point(ptHigherTile.y + 1, ptHigherTile.x + 1); // Calculate the sub-tile rectangle that we need to crop out of the higher tile // using a simple proportion calculation based on which part of the higher tile // covers the original requested tile in world coordinates Point ptHigherWorldTopLeft = WebMercatorProjection.PixelToWorld(WebMercatorProjection.TileToPixel(ptHigherTileTopLeft), numTilesAtFoundZoomLevel); Point ptHigherWorldBotRight = WebMercatorProjection.PixelToWorld(WebMercatorProjection.TileToPixel(ptHigherTileBotRight), numTilesAtFoundZoomLevel); double ratioX = (ptRequestedWorld.x - ptHigherWorldTopLeft.x) / (ptHigherWorldBotRight.x - ptHigherWorldTopLeft.x); double ratioY = (ptRequestedWorld.y - ptHigherWorldTopLeft.y) / (ptHigherWorldBotRight.y - ptHigherWorldTopLeft.y); int startX = (int)Math.Floor(WebMercatorProjection.TILE_SIZE * ratioX); int startY = (int)Math.Floor(WebMercatorProjection.TILE_SIZE * ratioY); // Calculate how much up-scaling of higher level zoom tile we need to do // based on the difference between the requested and higher zoom levels int croppedTileSize = WebMercatorProjection.TILE_SIZE / (1 << zoomLevelDifference); // Set the crop rectangle and draw it into a new bitmap, scaling it up to the standard tile size Rectangle cropRect = new Rectangle(startX, startY, croppedTileSize, croppedTileSize); log.LogDebug("DxfTileExecutor: crop rectangle x = {0}, y = {1}, size = {2}", startX, startY, croppedTileSize); //source bitmap using (var tileStream = new MemoryStream(tileData)) using (Bitmap higherBitmap = new Bitmap(tileStream)) //destination bitmap using (Bitmap target = new Bitmap(WebMercatorProjection.TILE_SIZE, WebMercatorProjection.TILE_SIZE)) using (Graphics g = Graphics.FromImage(target)) { g.CompositingMode = CompositingMode.SourceCopy; g.CompositingQuality = CompositingQuality.HighQuality; g.InterpolationMode = InterpolationMode.HighQualityBicubic; g.SmoothingMode = SmoothingMode.HighQuality; g.PixelOffsetMode = PixelOffsetMode.HighQuality; g.DrawImage(higherBitmap, new Rectangle(0, 0, target.Width, target.Height), cropRect, GraphicsUnit.Pixel); g.Flush(); return(target.BitmapToByteArray()); } }
protected override async Task <ContractExecutionResult> ProcessAsyncEx <T>(T item) { var request = item as DxfTileRequest; if (request == null) { ThrowRequestTypeCastException <DxfTileRequest>(); } string filespaceId = FileDescriptorExtensions.GetFileSpaceId(configStore, log); //Calculate zoom level int zoomLevel = TileServiceUtils.CalculateZoomLevel(request.bbox.TopRightLat - request.bbox.BottomLeftLat, request.bbox.TopRightLon - request.bbox.BottomLeftLon); log.LogDebug("DxfTileExecutor: BBOX differences {0} {1} {2}", request.bbox.TopRightLat - request.bbox.BottomLeftLat, request.bbox.TopRightLon - request.bbox.BottomLeftLon, zoomLevel); int numTiles = TileServiceUtils.NumberOfTiles(zoomLevel); Point topLeftLatLng = new Point(request.bbox.TopRightLat.LatRadiansToDegrees(), request.bbox.BottomLeftLon.LonRadiansToDegrees()); Point topLeftTile = WebMercatorProjection.LatLngToTile(topLeftLatLng, numTiles); log.LogDebug("DxfTileExecutor: zoomLevel={0}, numTiles={1}, xtile={2}, ytile={3}", zoomLevel, numTiles, topLeftTile.x, topLeftTile.y); log.LogDebug("DxfTileExecutor: {0} files", request.files.Count()); //Short circuit overlaying if there no files to overlay as ForAll is an expensive operation if (!request.files.Any()) { byte[] emptyOverlayData = null; using (Bitmap bitmap = new Bitmap(WebMercatorProjection.TILE_SIZE, WebMercatorProjection.TILE_SIZE)) { emptyOverlayData = bitmap.BitmapToByteArray(); } return(new TileResult(emptyOverlayData)); } log.LogDebug(string.Join(",", request.files.Select(f => f.Name).ToList())); List <byte[]> tileList = new List <byte[]>(); var fileTasks = request.files.Select(async file => { //foreach (var file in request.files) //Check file type to see if it has tiles if (file.ImportedFileType == ImportedFileType.Alignment || file.ImportedFileType == ImportedFileType.DesignSurface || file.ImportedFileType == ImportedFileType.Linework) { if (zoomLevel >= file.MinZoomLevel) { var suffix = FileUtils.GeneratedFileSuffix(file.ImportedFileType); string generatedName = FileUtils.GeneratedFileName(file.Name, suffix, FileUtils.DXF_FILE_EXTENSION); byte[] tileData = null; if (zoomLevel <= file.MaxZoomLevel || file.MaxZoomLevel == 0) //0 means not calculated { tileData = await GetTileAtRequestedZoom(topLeftTile, zoomLevel, file.Path, generatedName, filespaceId); } else if (zoomLevel - file.MaxZoomLevel <= 5) //Don't try to scale if the difference is too excessive { tileData = await GetTileAtHigherZoom(topLeftTile, zoomLevel, file.Path, generatedName, filespaceId, file.MaxZoomLevel, numTiles); } else { log.LogDebug( "DxfTileExecutor: difference between requested and maximum zooms too large; not even going to try to scale tile"); } if (tileData != null) { tileList.Add(tileData); } } } }); await Task.WhenAll(fileTasks); //Overlay the tiles. Return an empty tile if none to overlay. log.LogDebug("DxfTileExecutor: Overlaying {0} tiles", tileList.Count); byte[] overlayData = null; System.Drawing.Point origin = new System.Drawing.Point(0, 0); using (Bitmap bitmap = new Bitmap(WebMercatorProjection.TILE_SIZE, WebMercatorProjection.TILE_SIZE)) using (Graphics g = Graphics.FromImage(bitmap)) { foreach (byte[] tileData in tileList) { using (var tileStream = new MemoryStream(tileData)) { Image image = Image.FromStream(tileStream); g.DrawImage(image, origin); } } overlayData = bitmap.BitmapToByteArray(); } return(new TileResult(overlayData)); }