I'm using a "Custom Heat Map Source" as described here:
https://docs.telerik.com/devtools/wpf/controls/radheatmap/howto/create-custom-heatmap-source

Upon initialization, I fill in the color of all the cells with a default color.
Later, as data comes in, I update the color of individual cells.

It seems that the only way to refresh the Definition so that it will display the newly set cell color is to do the following:

HeatMapDefinition.SelectedItems = new Collection<object>();

After that, the Definition updates itself by calling method "CustomHeatMapDefinition::GetColor()" on each and every cell (which of course gets delegated to the "CustomHeatMapSource" implementation.

This could lead to performance problems on large Heat-Maps.

So my request is that there is a feature allowing the updating of individual cell-data and a refresh mechanism that would not query each heat-map cell afterwards, but only the updated cells.

I have discussed this in a support request (https://www.telerik.com/account/support-tickets/view-ticket/1464531) with Dinko and he suggested I request this feature.

Best,
Mark

Make the following selection-related methods of the HeatMapDefinition class "protected internal virtual" instead of "internal virtual". 

• IsCellSelected
  
• IsRowSelected
  
• IsColumnSelected
  

This will allow the developer to properly implement also the selection feature in their custom heat map definition code.

Currently, the there are two frames that happen on property changed that cause the blink. On the first frame, the labels are cleared and the cells are drawn. On the next frame, the labels measure/arrange phase catch up with the cells image drawing and the control is rendered again. Because of this when a cell value is changing at a fast rate (in a timer or similar) and redrawing of the cells is required, a blinking of all texts in the control can be observed.

Allow setting different sizes of the cells (row height, cell width) according to the data.

Currently, the colorizator of the heatmap is choosing a color based on the minimum and maximum values in the entire ItemsSource of the CategoricalDefinition. Add modes that change this behavior so that the color is chosen based on the minimum and maximum in the same row (or column).

With the heatmap, it would be a useful option to be able to distinguish the order that columns and rows are presented.  Currently it is one or the other, and seemingly only as per the row or column field is encountered during the rendering of the heatmap