Issues with CurrentPoint in R2021b

Question

Matt Butts 2021-12-15

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1611820-issues-with-currentpoint-in-r2021b

评论： Stephane Lagace 2023-7-12

I am trying to track some user clicks within an axes that lives within a uifigure.

I was originally using CurrentPoint from the axes object, but I started to notice that in certain scenarios, the coordinates of CurrentPoint did not seem to be correct for where the mouse event happened. I did as much investigating as I could and found a possible solution in looking at the event IntersectionPoint property.

I can effectively use the IntersectionPoint property of the event for mouse down and up events and I get coordiantes that very closely match where I was trying to click.

I need something like IntersectionPoint that can be used withn mouse motion callbacks because CurrentPoint is off by a significant amount.

Here is what I have in all of my callbacks:

cp = get(obj.Axes,'CurrentPoint');
ip = evt.IntersectionPoint;
fprintf('Current Point: (%g,%g)\nIntersection Point: (%g,%g)\n\n',cp(1,1),cp(1,2),ip(1,1),ip(1,2));

Then when I execute clicks, attempting to click near (11,1200) on the axes, I get the follwing:

Current Point: (10.9365,1376.74)
Intersection Point: (10.9782,1196.9)

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Matt Butts 2021-12-15

在 MATLAB Online 中打开

I tried to create a simple example, but of course the problem doesn't replicate immediately so I need to work more on that. I did add this code to my callback and this is what I am getting.

Callback code:

function axesClick(obj,~,evt)
  set(obj.Figure,'WindowButtonUpFcn','');
  set(obj.Figure,'WindowButtonMotionFcn','');
  cp = get(obj.Axes,'CurrentPoint');
  ip = evt.IntersectionPoint;
  fprintf('Current Point: (%g,%g)\nIntersection Point: (%g,%g)\nError: %g\n\n',cp(1,1),cp(1,2),ip(1,1),ip(1,2),norm(cp(1,1:2)-ip(1,1:2)));
end

With that as the callback and clicking in random spots, I get:

Current Point: (9.83083,1536.08)
Intersection Point: (9.92481,1191.75)
Error: 344.33
Current Point: (10.9211,1486.6)
Intersection Point: (11.015,1134.02)
Error: 352.577
Current Point: (11.7481,1412.37)
Intersection Point: (11.8421,1059.79)
Error: 352.577
Current Point: (12.1992,1173.2)
Intersection Point: (12.2932,820.619)
Error: 352.577
Current Point: (13.9286,1593.81)
Intersection Point: (14.0226,1241.24)
Error: 352.577

When watching where I click, I can say for certain that the InterserctionPoint is very close to where I am actually clicking.

Bruno Luong 2021-12-16

What if you call drawnow on top of your callback function? Also make sure the axes handle is the one you see on the screen, and not some hidden axes.

Matt Butts 2021-12-16

I tried sprinkling drawnows everywhere, including at the beginning of the callback and there were no differences.

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Answer 1

Benjamin Kraus 2021-12-16

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1611820-issues-with-currentpoint-in-r2021b#answer_856505

We've seen issues in the past with CurrentPoint being slightly off, and we are investigating them. Can you provide a little more information about your particular setup and I'll add it to our internal report about this issue? Specifically:

You said "CurrentPoint is off by a significant amount" but your reproduction steps show off by ~1 pixel. Have you experienced errors that are larger than 1 pixel before?
In the code you posted you have an axes directly in a uifigure. Are you using anything else in the figure, like tabs, panels, uigridlayout, etc.? Is the axes always directly in the uifigure, or is it in another container inside the uifigure?
Any reproduction code you have, with as much detail as you can include, will be helpful.
Are you using the "Scrollable" feature of the uifigures?
What platform are you using? Windows? Mac? Linux?
What is the output from rendererinfo run on your axes?
What is your screen resolution and pixel density?

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Bruno Luong 2021-12-16

在 MATLAB Online 中打开

I change my script to be able to display error for figure and uifigure, and obviously the problem lies on uifigure

function checkcperror(uiflag)
% uiflag: true to check uifigure; false old figure
close all
if uiflag
   fig = uifigure('Name','uifigure');
    ax = uiaxes('Parent',fig);
    fprintf('Check for uifigure\n')
else
    fig = figure('Name','figure');
    ax = axes('Parent',fig);
    fprintf('Check for figure\n')
end
set(ax, 'Units','normalize', 'innerposition',[0 0 1 1]);
set(ax,'ButtonDownFcn',@chekerrorcb);
text(ax,0.5,0.5,'click on the axes','HorizontalAlignment','center');
set(ax,'Unit','pixel');
end
function chekerrorcb(ax, event)
p1 = event.IntersectionPoint(1,1:2);
p2 = ax.CurrentPoint(1,1:2);
d = p1-p2;
ax.Units = 'pixel';
pos = get(ax,'Position');
dx = pos(3);
dy = pos(4);
fprintf('error = %g pixel\n',norm(d.*[dx dy]));
end

Results (R2021b, Windows 8 run on Remote Desktop):

>> checkcperror(false)
Check for figure
error = 0.58519 pixel
error = 0.585183 pixel
error = 0.585197 pixel
error = 0.5852 pixel
error = 0.585196 pixel
error = 0.585185 pixel
>> checkcperror(true)
Check for uifigure
error = 14.5491 pixel
error = 15.43 pixel
error = 14.549 pixel
error = 14.5491 pixel
error = 15.43 pixel
error = 16.3111 pixel
error = 15.43 pixel
error = 16.3111 pixel
error = 14.549 pixel
error = 14.5491 pixel

Bruno Luong 2021-12-17

编辑：Bruno Luong 2021-12-17

在 MATLAB Online 中打开

FWIW, I test to plot both coordinates returned by CurrentPoint and IntersectionPoint on the same axes and in all the cases CurrentPoint can correctly follow the mouse and IntersectionPoint cannnot. That is fine with me as I use CurrentPoint currently. I'm in the opposite situation than you Matt.

Here is the function with plot. In my case the difference is 3 pixels for uifigure and 0.7 pixel for figure. CurrentPoint returns correct values as stated ealier.

function checkcperror(uiflag)
% uiflag: true to check uifigure; false old figure
if nargin < 1
    uiflag = true;
end
close all
if uiflag
    name = 'uifigure';
    fig = uifigure('Name', name);
    ax = uiaxes('Parent',fig);
else
    name = 'figure';
    fig = figure('Name', name);
    ax = axes('Parent',fig);
end
fprintf('*** Check for %s ***\n', name)
h = plot(ax,nan(3,2),nan(3,2));
legend(h, 'IntersectionPoint', 'CurrentPoint');
axis(ax,[0 1 0 1]);
set(ax, 'Units','normalize', 'innerposition',[0 0 1 1]);
set(ax,'ButtonDownFcn',@(ax,event) chekerrorcb(ax,event,h));
text(ax,0.5,0.5,sprintf('%s click on the axes', name), ...
    'HorizontalAlignment','center');
end
function chekerrorcb(ax, event, h)
drawnow
ip = event.IntersectionPoint(1,1:2);
cp = ax.CurrentPoint(1,1:2);
d = ip-cp;
ax.Units = 'pixel';
pos = get(ax,'innerposition');
dx = pos(3);
dy = pos(4);
dpxl = d.*[dx dy];
fprintf('error = %g pixel\n',norm(dpxl));
set(h(1),'XData',[get(h(1),'XData') ip(1)]);
set(h(1),'YData',[get(h(1),'YData') ip(2)]);
set(h(2),'XData',[get(h(2),'XData') cp(1)]);
set(h(2),'YData',[get(h(2),'YData') cp(2)]);
set(ax, 'Units','normalize', 'innerposition', [0 0 1 1]);
axis(ax,[0 1 0 1]);
drawnow
end

Stephane Lagace 2023-7-12

Hello I have the same problem only when the uiaxes is in a couple nested gridlayouts

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Issues with CurrentPoint in R2021b

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Issues with CurrentPoint in R2021b

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