Warning message when using Patch in 2015 matlab?

Hello I have a question about patch.

I have this code working fine in Matlab2014

clear;clc;close all;

box=[0 20 20 0; 0 0 20 20];

hold on;
h.box= patch(0,0,'b','erasemode','xor'); 
xlim([-10,1000]); ylim([-10,1000])
axis equal

for i = 1: 1000
    xb=box+i;
    set(h.box, 'xdata', xb(1,:), 'ydata', xb(2,:))
    drawnow;
end

When i started running it on 2015 i am getting this kind of warning

Warning: The EraseMode property is no longer supported and will error in a
future release. Use the ANIMATEDLINE function for animating lines and
points instead of EraseMode 'none'. Removing instances of EraseMode set to
'normal', 'xor', and 'background' has minimal impact. 
> In test (line 9)

So i decided to try and update the code according to the advise given by the warning

here is my new code

clear;clc;close all;

box=[0 20 20 0; 0 0 20 20];

hold on;

h.box = animatedline('MaximumNumPoints',80,'Color','b');
xlim([-10,1000]); ylim([-10,1000])
axis equal

for i = 1: 1000
    xb=box+i;
    addpoints(h.box,xb(1,:),xb(2,:));   
    drawnow;
end

Still not what i wanted it to look like, I wanted it to be functioning exactly as my 2014 code any advise what to do?

Answer 1

[Walter Roberson]

clear; clc; close all;

box=[0 20 20 0; 0 0 20 20];

h.box= patch(0,0,'b'); 
xlim([-10,1000]); ylim([-10,1000]);
axis equal
drawnow();
set(gca, 'xlimmode', 'manual', 'ylimmode', 'manual')
hold on;

for i = 1: 1000
    xb=box+i;
    set(h.box, 'xdata', xb(1,:), 'ydata', xb(2,:))
    drawnow;
end

I made this code bug-for-bug compatible because you asked for it to function exactly the same as your R2014 code. In your code, the "axis equal" overrode the xlim([-10,1000]) and ylim([-10,1000]) giving you limits of -1000 to +1000. The axis equal also set the xlimmode and ylimmode to auto which is why if you just remove the drawmode parameter with your code you would get the unexpected scrolling x axis. The effect of "axis equal" on the xlim and ylim in R2014a can depend upon the commands that follow before the object is rendered and upon the figure position, so I force the object to render before turning off automatic axis limits so that the x axis limits are set to [-640.286298568507, 640.286298568507] in a bug-for-bug compatible way.

I would suggest that you revise the code to do what your code appears to want to do, not what your current code does.

box=[0 20 20 0; 0 0 20 20];

h.box= patch(0,0,'b'); 
xlim([-10,1000]); ylim([-10,1000]);
hold on;

for i = 1: 1000
    xb=box+i;
    set(h.box, 'xdata', xb(1,:), 'ydata', xb(2,:))
    drawnow;
end

Without the "axis equal" after you have already set your xlim and ylim, the limits become exactly what you set and remain that way because xlim() and ylim() set xlimmode and ylimmode to 'manual' (no need to force them back to manual after "axis equal" has reset them if you skip the "axis equal")