Manually tracking an object through stacks#
Now that we have a macro to measure the xy position of the mouse cursor, we can make a simple manual tracking macro. It will record the xy position of an object that is under the mouse when the hotkey g is pressed, and advance to the next frame in the stack for the next measurement. 
Modify the previous macro to advance one timepoint every run
macro "get_mouse_xy [g]" {
    getCursorLoc(x, y, z, modifiers);
    print(x,y);
    if (getSliceNumber + 1 < nSlices) {
        setSlice(getSliceNumber + 1); //(1)!
    }
}
- Why wouldn't we use 
run("Next Slice [>]");here? 
Hint
Remember that when we we make change to our macro, we need to re-install the new version!