A number of people have asked me whether MATLAB can add text to heatmaps to show the exact values. This is very easy to do, however, making a the text robust to resizing, zooming and other operations is a little trickier.
This example shows how to add text to the heatmap and also includes an M-file that shows how to handle zooming and resizing.
MATLAB 7.4 (R2007a)
This was created with R2007a but should run with version back to R14.