tile creator tile sizes when tile width and/or height are null

ngageoint · Dec 15, 2021 · c435a79 · c435a79
1 parent 14973f2
commit c435a79
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -8,6 +8,7 @@ Adheres to [Semantic Versioning](http://semver.org/).
 
 * UrlTileGenerator HTTP Method and Header field values support
 * FeatureTiles FeatureIndexManager and FeatureIndexResults support
+* TileCreator improved tile sizes when tile width and/or height are not specified
 * Bounding Box world bounds shortcuts for WGS84 and Web Mercator
 
 ## [6.1.1](https://github.com/ngageoint/geopackage-java/releases/tag/6.1.1) (11-10-2021)

diff --git a/src/main/java/mil/nga/geopackage/tiles/TileCreator.java b/src/main/java/mil/nga/geopackage/tiles/TileCreator.java
@@ -406,38 +406,31 @@ private GeoPackageTile getTile(BoundingBox requestBoundingBox,
 
 					if (tileResults.getCount() > 0) {
 
-						BoundingBox requestProjectedBoundingBox = requestBoundingBox
-								.transform(transformRequestToTiles);
-
-						// Determine the requested tile dimensions, or use the
-						// dimensions of a single tile matrix tile
-						int requestedTileWidth = width != null ? width
-								: (int) tileMatrix.getTileWidth();
-						int requestedTileHeight = height != null ? height
-								: (int) tileMatrix.getTileHeight();
+						// Determine the tile dimensions
+						int[] tileDimensions = tileDimensions(
+								requestBoundingBox, tilesBoundingBox,
+								tileMatrix);
+						int requestedTileWidth = tileDimensions[0];
+						int requestedTileHeight = tileDimensions[1];
 
 						// Determine the size of the tile to initially draw
 						int tileWidth = requestedTileWidth;
 						int tileHeight = requestedTileHeight;
 						if (!sameUnit) {
-							tileWidth = (int) Math
-									.round((requestProjectedBoundingBox
-											.getMaxLongitude()
-											- requestProjectedBoundingBox
-													.getMinLongitude())
-											/ tileMatrix.getPixelXSize());
+							tileWidth = (int) Math.round((tilesBoundingBox
+									.getMaxLongitude()
+									- tilesBoundingBox.getMinLongitude())
+									/ tileMatrix.getPixelXSize());
 							tileHeight = (int) Math
-									.round((requestProjectedBoundingBox
-											.getMaxLatitude()
-											- requestProjectedBoundingBox
-													.getMinLatitude())
+									.round((tilesBoundingBox.getMaxLatitude()
+											- tilesBoundingBox.getMinLatitude())
 											/ tileMatrix.getPixelYSize());
 						}
 
 						// Draw the resulting bitmap with the matching tiles
 						GeoPackageTile geoPackageTile = drawTile(tileMatrix,
-								tileResults, requestProjectedBoundingBox,
-								tileWidth, tileHeight);
+								tileResults, tilesBoundingBox, tileWidth,
+								tileHeight);
 
 						// Create the tile
 						if (geoPackageTile != null) {
@@ -469,6 +462,89 @@ private GeoPackageTile getTile(BoundingBox requestBoundingBox,
 		return tile;
 	}
 
+	/**
+	 * Determine the tile dimensions. Specified width and/or height values are
+	 * used. When only one of width or height is specified, other is determined
+	 * as a request ratio. When neither width or height is specified, determine
+	 * from the tile matrix as a request ratio.
+	 * 
+	 * @param requestBoundingBox
+	 *            request bounding box
+	 * @param tilesBoundingBox
+	 *            tiles bounding box
+	 * @param tileMatrix
+	 *            tile matrix
+	 * @return tile dimensions array of size 2 [width, height]
+	 */
+	private int[] tileDimensions(BoundingBox requestBoundingBox,
+			BoundingBox tilesBoundingBox, TileMatrix tileMatrix) {
+
+		// Determine the tile dimensions
+		int requestedTileWidth;
+		int requestedTileHeight;
+		if (width != null && height != null) {
+
+			// Requested dimensions
+			requestedTileWidth = width;
+			requestedTileHeight = height;
+
+		} else if (width == null && height == null) {
+
+			// Determine dimensions from a single tile matrix
+			// tile as a ratio to the requested bounds
+			double requestLonRange = requestBoundingBox.getLongitudeRange();
+			double requestLatRange = requestBoundingBox.getLatitudeRange();
+			double pixelXSize = tileMatrix.getPixelXSize();
+			double pixelYSize = tileMatrix.getPixelYSize();
+			if (requestProjection.isUnit(tilesProjection.getUnit())) {
+				// Same unit, use the pixel x and y size
+				requestedTileWidth = (int) Math
+						.round(requestLonRange / pixelXSize);
+				requestedTileHeight = (int) Math
+						.round(requestLatRange / pixelYSize);
+			} else {
+				// Use the max tile pixel length and adjust to
+				// the sides to the requested bounds ratio
+				double maxLength = Math.max(
+						tilesBoundingBox.getLongitudeRange() / pixelXSize,
+						tilesBoundingBox.getLatitudeRange() / pixelYSize);
+				if (requestLonRange < requestLatRange) {
+					requestedTileWidth = (int) Math.round(
+							maxLength * (requestLonRange / requestLatRange));
+					requestedTileHeight = (int) Math.round(maxLength);
+				} else if (requestLatRange < requestLonRange) {
+					requestedTileWidth = (int) Math.round(maxLength);
+					requestedTileHeight = (int) Math.round(
+							maxLength * (requestLatRange / requestLonRange));
+				} else {
+					requestedTileWidth = (int) Math.round(maxLength);
+					requestedTileHeight = requestedTileWidth;
+				}
+			}
+
+		} else if (width == null) {
+
+			// Requested height, determine width as a ratio from
+			// the requested bounds
+			requestedTileHeight = height;
+			requestedTileWidth = (int) Math
+					.round(height * (requestBoundingBox.getLongitudeRange()
+							/ requestBoundingBox.getLatitudeRange()));
+
+		} else {
+
+			// Requested width, determine height as a ratio from
+			// the requested bounds
+			requestedTileWidth = width;
+			requestedTileHeight = (int) Math
+					.round(width * (requestBoundingBox.getLatitudeRange()
+							/ requestBoundingBox.getLongitudeRange()));
+
+		}
+
+		return new int[] { requestedTileWidth, requestedTileHeight };
+	}
+
 	/**
 	 * Draw the tile from the tile results
 	 *