About a month-or-so ago, I promised I would start work on selection tool for the image viewer. I finally got around to it. I ended up doing a pretty significant overhaul, but I think it was worth it. See PR # 390 <https://github.com/scikit-image/scikit-image/pull/390> I'll copy my PR message below, just for completeness: Major overhaul of tools for interacting with the scikit-image viewer. * Add skimage.viewer.canvastools subpackage with line and rectangle selection tools * Refactor line profile plugin to use line tool * Fix viewer canvas * Fix blitting behavior * New plugins (ColorHistogram, Measure, Crop) To get a feel for the changes, see new examples in `viewer_examples/plugins` located in the root directory of package. Cheers, -Tony