| AbstractHeatmapOverlay | 
 Ancestor for heatmap image overlays. 
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| AbstractPositionableHeatmapOverlay | 
 Ancestor for overlays that can be positioned on the heatmap panel. 
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| AbstractPositionableHeatmapOverlayWithDimensions | 
 Ancestor for overlays that can be positioned on the heatmap panel and support
 dimensions. 
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| AbstractSingleColorHeatmapOverlay | 
 Ancestor for overlays that just use a single color. 
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| Centroid | 
 Paints the centroid's location over the heatmap image. 
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| HighestTemperature | 
 Overlays the heatmap with the points that have the highest temperature. 
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| LowestTemperature | 
 Overlays the heatmap with the points that have the lowest temperature. 
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| Null | 
 Dummy overlay, does nothing. 
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| TextOverlay | 
 Displays text as overlay, either the fixed text, or if empty, a report value. 
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