[core] Add setMaxOverscaleFactorForParentTiles

1 files changed, 14 insertions, 0 deletions

diff --git a/include/mbgl/style/source.hpp b/include/mbgl/style/source.hpp
index 622c2e42ff..32b15bdf47 100644
--- a/include/mbgl/style/source.hpp
+++ b/include/mbgl/style/source.hpp
@@ -75,6 +75,20 @@ public:
     virtual void loadDescription(FileSource&) = 0;
     void setPrefetchZoomDelta(optional<uint8_t> delta) noexcept;
     optional<uint8_t> getPrefetchZoomDelta() const noexcept;
+
+    // Sets a limit for how much a parent tile can be overscaled.
+    //
+    // When a set of tiles for a current zoom level is being rendered and some of the
+    // ideal tiles that cover the screen are not yet loaded, parent tile could be
+    // used instead. This might introduce unwanted rendering side-effects, especially
+    // for raster tiles that are overscaled multiple times.
+    //
+    // For example, an overscale factor of 3 would mean that on zoom level 3, the
+    // minimum zoom level of a parent tile that could be used in place of an ideal
+    // tile during rendering would be zoom 0. By default, no limit is set, so any
+    // parent tile may be used.
+    void setMaxOverscaleFactorForParentTiles(optional<uint8_t> overscaleFactor) noexcept;
+    optional<uint8_t> getMaxOverscaleFactorForParentTiles() const noexcept;
     void dumpDebugLogs() const;
 
     virtual bool supportsLayerType(const mbgl::style::LayerTypeInfo*) const = 0;