'CurrentPoint' fails in GUI when function is called by 'ButtonDownFcn'

Question

Jeff 2012-3-7

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/31433-currentpoint-fails-in-gui-when-function-is-called-by-buttondownfcn

评论： KAE 2017-6-15

I have a GUI with an axis. I would like to be able to click and drag on the axis and have the start and end points detected in the units of the axis.

For a blank GUI with axes1 placed:

Code in OpeningFcn

% --- Executes just before currentpointtest is made visible.
function currentpointtest_OpeningFcn(hObject, eventdata, handles, varargin)
% Choose default command line output for currentpointtest
handles.output = hObject;
% Update handles structure
guidata(hObject, handles);
I = imread('cameraman.tif'); 
h = imshow(I, 'Parent', handles.axes1);
set(h, 'ButtonDownFcn', @getClicks)

Code in Callback:

function getClicks(~,~)
point1 = get(gca,'CurrentPoint')    % button down detected
finalRect = rbbox;                  % return figure units
point2 = get(gca,'CurrentPoint')    % button up detected

point1 is correct, but point2 returns the same value as point1. I need the values relative to the axes, so 'PointerLocation' doesn't seem like an option. Also as a side note, if the getClicks function is called from a push button everything works fine.

Does anyone know what is happening here and how I can get both point1 and point2?

Update(2012-03-07): I also tried the following:

function getClicks(~,~)
 point1 = get(gca,'CurrentPoint')    % button down detected
 set(gcf, 'WindowButtonUpFcn', @upCall)
 finalRect = rbbox;                  % return figure units
 set(gcf, 'WindowButtonUpFcn', '')
 point2 = get(gca,'CurrentPoint')    % button up detected
function upCall(~,~)
 upPoint = get(gca,'CurrentPoint')