Plot a point in a GUI with mouse click

I would like to draw a point in the UIAxes. To do this, I want to determine the position of the mouse pointer in the callback function and draw a point with it. I have created this class:

classdef PlottingClass < handle

properties

fig;

ax;

points = [];

end

methods

function self = PlottingClass();

self.fig = uifigure("Name","test");

self.ax = uiaxes(self.fig);

grid(self.ax,"on")

xlabel(self.ax,"Time")

ylabel(self.ax,"Value")

self.ax.ButtonDownFcn = @self.plottingfcn;

end

end

methods

function plottingfcn(self,axes,hit)

allPoint = hit.IntersectionPoint;

x= allPoint(1);

y= allPoint(2);

z= allPoint(3);

plot(axes,x,y,"o",MarkerSize=2)

self.points = [self.points , [x;y]]

grid(axes,"on")

xlabel(axes,"Zeit")

ylabel(axes,"Value")

disp("x "+x)

disp("y "+y)

disp("z "+z)

end

end

end

When I create an object and click in the UIAxes, I get this output:

x -0.12607

y 1.2151

z -1

Now I wanted to ask why z = -1.

I hope you can help me.

Thank you very much.

Answer 1

[Voss]

Apparently plot changes the axes' ZLim to [-1 1], which you can check by displaying the ZLim before and after the first click.

You can avoid that by setting the ZLimMode to 'manual' (or just setting ZLim to [0 1] or whatever) initially.

(And while you're doing that, you might also want to set the XLim/XLimMode and YLim/YLimMode in order to avoid having those limits automatically update when plot is called, because after XLim/YLim auto-updating, the plotted point may no longer be at the mouse pointer location.)