Add defines for certain reprojection constants

src/ol/ol.js

@@ -28,6 +28,13 @@ ol.DEFAULT_MAX_ZOOM = 42;
 ol.DEFAULT_MIN_ZOOM = 0;
 
 
+/**
+ * @define {number} Default maximum allowed threshold  (in pixels) for
+ *     reprojection triangulation. Default is `0.5`.
+ */
+ol.DEFAULT_RASTER_REPROJ_ERROR_THRESHOLD = 0.5;
+
+
 /**
  * @define {number} Default high water mark.
  */
@@ -166,6 +173,39 @@ ol.OVERVIEWMAP_MAX_RATIO = 0.75;
 ol.OVERVIEWMAP_MIN_RATIO = 0.1;
 
 
+/**
+ * @define {number} Maximum number of source tiles for raster reprojection.
+ *     If too many source tiles are determined to be loaded to create a single
+ *     reprojected tile the browser can become unresponsive or even crash.
+ *     This can happen if the developer defines projections improperly and/or
+ *     with unlimited extents.
+ *     If too many tiles are required, no tiles are loaded and
+ *     `ol.TileState.ERROR` state is set. Default is `100`.
+ */
+ol.RASTER_REPROJ_MAX_SOURCE_TILES = 100;
+
+
+/**
+ * @define {number} Maximum number of subdivision steps during raster
+ *     reprojection triangulation. Prevents high memory usage and large
+ *     number of proj4 calls when for certain transformations and areas.
+ *     At most `2*(4^this)` triangles are created. Default is `5`.
+ */
+ol.RASTER_REPROJ_MAX_SUBDIVISION = 5;
+
+
+/**
+ * @define {number} Maximum allowed size of triangle relative to world width.
+ *     When transforming corners of world extent between certain projections,
+ *     The resulting triangulation seems to have zero error and no subdivision
+ *     is performed.
+ *     If the triangle width is more than this (relative to world width; 0-1),
+ *     subdivison is forced (respecting `ol.RASTER_REPROJ_MAX_SUBDIVISION`).
+ *     Default is `0.25`.
+ */
+ol.RASTER_REPROJ_MAX_TRIANGLE_WIDTH = 0.25;
+
+
 /**
  * @define {number} Tolerance for geometry simplification in device pixels.
  */