That would be an interesting challenge, and it may be possible. Can you share (attach) your workbook or dataset?
Did you manage to do this? I am trying to do the same thing and am struggling to see how it can be done?
If you have any tips I would appreciate it.
A quick table calculation to give % of total of each row for the colour scale lets you get the heat-map per row.
If the dataset doesn't have any rows for some cells of the heat-map they will be blank automatically. If there are rows with NULL values the only think I can think of is to set the bar length to zero for that cell - which is not great because it leaves a thin line for that cell.
Superstore Sales example attached. Sheet1 shows the missing data case, in sheet2 I've mocked up the case with existing rows with NULLs.
heatmap_colour_range.twbx 1.1 MB