how to fill the region with know boundary directly on the figure

Hi there, I have a image plotted to a figure and by selecting some point with mouse, I outline the coordinates on the boundary. In side the boundary, there are lots of detail, so how can I fill all pixels inside that boundary with some color directly in the plot?

The coordinates obtained is mathematical coordinates instead of pixel coordinates. Thanks.

Answer 1

[Rick Rosson]

>> doc patch