Manipulate — create a simple panel containing
Locator objects
Dynamic — set up dynamic variables and a dynamic overall display
DynamicModule — localize and save dynamic variables
LocatorPane — place one or more locators with arbitrary appearances on any image
LocatorAutoCreate — option to allow new locators to be created by clicking
Locator — set up a movable thumb connected to a dynamic variable
ClickPane — respond to the locations of clicks on any image, perhaps dynamic
PlotRange — specify a fixed coordinate system
