Thomas Otterstaetter

Also, if you happen to have very uneven axis ranges (one small, one very big), the behaviour can be somewhat odd with the cursor jumping between points seemingly at random.

Try

h = plot(linspace(1,7000,5),linspace(10,30,5)); pathManipulator(h, 'nocheck')

with one axis at 7000 ticks and the other at 5. As you can see, when you try to move one marker past another left/right, the cursor switches to the other marker even though the distance seems fairly large. This does not happen when passing the marker up/down.

My solution is to take the axis ranges into account and scale the vertical and the horizontal distances accordingly before calculating the pythagoras distance.

So swap out all lines

[~,minDistIndex]=min((XData-currentPoint(1,1)).^2+(YData-currentPoint(1,2)).^2);

with

cAxis=[get(axHandle,'XLim') get(axHandle,'YLim')];
xScale = cAxis(2)-cAxis(1);
yScale = cAxis(4)-cAxis(3);
[~,minDistIndex]=min(((XData-currentPoint(1,1))*yScale).^2+((YData-currentPoint(1,2))*xScale).^2);

and it should do the trick.

Thanks for the feedback :)
I incorporated the turning off feature - admittedly not very beautiful anymore by loading the Userdata of the line....but it works ;)

Beautiful piece!

Would be nice with a feature that allows turning the whole thing on and off and restoring the line properties. E.g LineManipulator(h, 'off') or similar.

Also, I modified your script to check the closest distance for all line objects, not just the most recent one.

%% ClosestPoint
% Find the closest point in all available line objects
function [lineHandle, minDistIndex] = ClosestPoint(currentPoint)
lineHandles = get(axHandle, 'Children');

% Init output etc.
minDist = Inf;
minDistIndex = 0;
lineHandle = 0;

% Iterate through all children of the current axes
for i = 1:length(lineHandles)
objType = get(lineHandles(i), 'Type');
objTag = get(lineHandles(i), 'Tag');

% Only check line objects
if strcmp(objType, 'line') && ~strcmp(objTag, 'Ghost')
XData = get(lineHandles(i), 'XData');
YData = get(lineHandles(i), 'YData');
[dist, distIndex] = min((XData - currentPoint(1,1)).^2 + (YData - currentPoint(1,2)).^2);

if dist < minDist
minDist = dist;
minDistIndex = distIndex;
lineHandle = lineHandles(i);
end
end
end
end

Just comment out all lines
[~,minDistIndex]=min((XData-currentPoint(1,1)).^2+(YData-currentPoint(1,2)).^2);
and insert
[lineHandle, minDistIndex] = ClosestPoint(currentPoint);
before lines
XData=get(lineHandle,'XData');
YData=get(lineHandle,'YData');

I just disabled the ghost lines from plotting, but you can easily modify the script to tag those lines with e.g 'Ghost' to exclude them. Example:
plot(axHandle,get(lineHandle,'XData'),get(lineHandle,'YData'),'Color',get(lineHandle,'Color')...
,'Linewidth',get(lineHandle,'LineWidth')*0.5,'LineStyle',':','Tag','Ghost')