dragging a selected point within uiaxes

Question

Alain Barraud 2021-1-25

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/726813-dragging-a-selected-point-within-uiaxes

评论： Adam Danz 2021-2-15

Hello,

wihin standard figure and axes, I can easely move point.

These points are the graphical representation of complex numbers, so when I move a point I must move its conjugate accordingly.

All works fine with classical figure. I currently use gco to obtain the current point handle. What would be the equivalent with uiaxes within an uifigure?

Best Regards

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Adam Danz 2021-1-26

"dragging" a plotted point isn't supported in any type of figure although some objects such as text or a point object are draggable.

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Answer 1

Adam Danz 2021-1-26

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/726813-dragging-a-selected-point-within-uiaxes#answer_606293

编辑：Adam Danz 2021-1-26

在 MATLAB Online 中打开

HandleVisibility is set to off by default with uifigures and this prevents gcf/gca/gco from accessing the figure handle or anything within the figure.

Just before using gco, set the HandleVisibility to "on" and then set it off again at the end of the function.

Example

% uifig is the handle to the figure
uifig.HandleVisibility = 'on'; 
h = gco(); 
uifig.HandleVisibility = 'off';
% You could leave it on but that risks other plotting functions
% having unintended access to the figure.

Alternatively you can set the handle visibility to "callback" so that it's accessible from callback functions.

You may need to make the figure & axes active after doing this; if so, see these instructions to a similar question.

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Alain Barraud 2021-1-27

在 MATLAB Online 中打开

the content of gco is correct, in particular xdata and ydata are OK.

However when the mouse cursor moves the axes CurrentPoint is not good immediatly.

If I click on the point without moving xdata and CurrentPoint(1) are identical however CurrentPoint(3) is bad quite different of ydata.

You can verfy with the following test

function TestDrag(action)
% action ='wt' uifigure and axes within a uitab !! axes current point is bad !!
% action ='w*' uifigure and axes within uifigure OK
% action ='st'  figure and axes within a uitab OK
% action ='s*' figure and axes within figure OK
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
hf=findobj('type','figure','tag','TestDrag');
if lower(action(1))=='w'
    if isempty(hf), hf=uifigure('tag','TestDrag','handlevisibility','on');end
    position=hf.Position;position(1:2)=[1 1];
    clf;
    if lower(action(2))=='t'
        htabbed=uitabgroup(hf,'position',position);
        htab=uitab(htabbed,'title','test');
    else
        htab=hf;
    end
    ax=uiaxes('parent',htab,'XLim',[0 1],'YLim',[0 1]);
else
    if isempty(hf), hf=figure('tag','TestDrag','unit','pixel');end
    position=hf.Position;position(1:2)=[1 1];
    clf;
    if lower(action(2))=='t'
    htabbed=uitabgroup(hf,'unit','pixel','position',position);
    htab=uitab(htabbed,'title','test');
    else
        htab=hf;
    end
    ax=axes('parent',htab,'XLim',[0 1],'YLim',[0 1],'unit','pixel');
end
cla;
line(.5,.5,'marker','o','markersize',5,'ButtonDownFcn',@(s,e) Drag(hf,ax,'start'),'parent',ax);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function Drag(hf,ax,action)
switch action
    case 'start'%
        set(hf,'WindowButtonMotionFcn',@(s,e) Drag(hf,ax,'move'))
        set(hf,'WindowButtonUpFcn',@(s,e) Drag(hf,ax,'stop'))
        Drag(hf,ax,'move')
    case 'move'
        Cpoint=ax.CurrentPoint;
        yf=Cpoint(3);
        xf=Cpoint(1);
        pt=gco;
        pt.XData=xf;pt.YData=yf;
    case 'stop'
        set(hf,'WindowButtonMotionFcn','')
        set(hf,'WindowButtonUpFcn','')
end

Adam Danz 2021-1-27

编辑：Adam Danz 2021-1-27

在 MATLAB Online 中打开

I ran your demo and I understand what you're doing now.

I also updated it to include the uitab and when I drag the object there is a constant y-offset but the x coordinate doesn't seem to have a problem.

After some tinkering, I believe this is an error with the current point calculations from within Matlab code. If you read the documentation on the CurrentPoint property, you'll see that it changes when there is a WindowButtonMotionFcn assigned to the figure which is the case in your code. However, if you remove that and simplify the Drag callback function to merely display the current point, the error remains.

However, if you set the tab group units to normalize using uitg.Units='Normalized' where uitg is the tab group handle, the y error is greatly reduced and almost completely corrected. Unfortunately the position of the uitab group also slightly changes when the units are set to normalized.

For this reason, I believe it's an error in converting position between nested parents (fig>uitab group > uitab > axes).

I suggest you contact tech support if you want to pursue this > Contact Us - MATLAB & Simulink

% My reproduction of the problem
% function TestDrag()
hf=findobj('type','figure','tag','TestDrag');
if isempty(hf), hf=uifigure('tag','TestDrag','handlevisibility','on');end
uitg = uitabgroup(hf);
uit = uitab(uitg);
ax=uiaxes('parent',uit,'XLim',[0 1],'YLim',[0 1]);
ax.Position(3:4)= [150 150];
xlim(ax,[0,1])
ylim(ax,[0,1])
hold on
grid(ax,'on')
h =plot(ax, .5,.5,'marker','o','markersize',5,'ButtonDownFcn',@(s,e) Drag(hf,ax,'start'));
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function Drag(hf,ax,action)
switch action
    case 'start'%
        set(hf,'WindowButtonMotionFcn',@(s,e) Drag(hf,ax,'move'))
        set(hf,'WindowButtonUpFcn',@(s,e) Drag(hf,ax,'stop'))
        Drag(hf,ax,'move')
    case 'move'
        Cpoint=ax.CurrentPoint
        yf=Cpoint(1,2);
        xf=Cpoint(1,1);
        pt=gco(ancestor(ax,'figure'));
        pt.XData=xf;
        pt.YData=yf;
    case 'stop'
        set(hf,'WindowButtonMotionFcn','')
        set(hf,'WindowButtonUpFcn','')
end
end