NAME: crosshairs PURPOSE: Display crosshairs on the plot window, display the data coordinates of the cursor position on the plot, and return the coordinates of clicked points. Use the mouse buttons to control operation: 1: Record and print a point 2: Delete the previously recorded point 3: Quit. CALLING SEQUENCE: crosshairs,x,y INPUTS: x,y: set to named variables to return the data coordinates of the cursor position where mouse button 1 was pressed. KEYWORD PARAMETERS: COLOR: set to a scalar byte to change the color of the crosshairs. note: you will not get the color you ask for. it's the nature of XOR graphics. could be useful to change colors though. LEGEND: set a position for the legend, in data coords. DOT_CURSOR: change the cursor to a dot. it's smaller and makes seeing the data easier. warning: will reset the cursor to crosshairs after quitting. if you had set your own cursor (changed from the default) it'll be replaced. FIX: if crosshairs crashes (if you Control-C out of it) then you probabaly want to call crosshairs,/fix all it does is calls: device,set_graphics=3,/cursor_cross but do you want to remember that line? FIX repairs the changes to the X device that crosshairs made. SILENT: don't print clicked points NOLEGEND: don't display the legend OUTPUTS: prints clicked data points to the terminal, prints the current cursor position on the graphics window (or last position before leaving the window) SIDE EFFECTS: can mess up your display. use crosshairs,/fix to fix. can leave junk on your plot. not recommended for use if you intend to call tvrd() before reploting. LAST MODIFICATION: @(#)crosshairs.pro 1.5 98/07/31 CREATED BY: Frank V. Marcoline NOTES: Inspired by IDL's box_cursor.pro