It looks strange, I'm not using slider for viewing image/graph on axes by sliding it. Code shown below is a part of my m-file.
function slider2_Callback(hObject, eventdata, handles)
% hObject handle to slider2 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
fname = getappdata(0, 'fname');
[a, map] = imread(fname);
x = ind2rgb(a, map);
b = get(handles.slider2,'value');
j = imadjust(x,[],[],b);
axes(handles.axes1);
imshow(j);
b in above code is a variable. The moment I slide the slider image brightness changes but at first when I run the code slider's initial point will be in extreme left. But for above code slider should be at the center as shown below
How can i set values( to increase/decrease brightness) to that slider? How can i go for it?
If you use GUIDE: You could set the value within the OpeningFcn
If you are not using GUIDE: You can set the value when creating the slider
assuming, the name (or Tag) of your slider is "slider1":
mean_slider = get(handles.slider1,'Max')/2;
set(handles.slider1, 'Value', mean_slider )
You can use for example:
set(handles.slider2,'value',50)
This allows you to set the value of the slider (and make it equal to 50). You can also specify the value of the slider when you create it, using the property inspector if I'm not mistaken.
But the previous line of code doesn't trigger the callback of the slider when executed.
Related
using GUIDE I have now a programm whose output is a vector and a plot of its data. Because the plot has many little variations, I used the csaps function to get a smoothier plot. I want now to add a slider to my figure to change the smoothing parameter and I want that the plot to be updated each time the value of the slider changes. How can I do this? I found this on mathworks.com but I coudn't apply it to my case: https://de.mathworks.com/help/control/ref/stepplot.html .
Add callback to your slider. To do so in GUIDE press right mouse button on the slider and select view callbacks -> callback. It will create something like this in .m file of your GUIDE object:
function slider_Callback(hObject, eventdata, handles)
% hObject handle to slider (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Hint: get(hObject,'Value') returns toggle state of slider
Everything you will place under %Hint would be executed every time the slider is changing its state. For example you can re-plot the graph:
% Hint: get(hObject,'Value') returns toggle state of slider
plot(x_value,y_value);
I am attaching a sample GUI codes, which has two axes with 2 images and when I use ginput to select seed point I am able to select on either axes, Is there anyway to limit the ginput to a specific axes
% --- Executes on button press in open.
function open_Callback(hObject, eventdata, handles)
% hObject handle to open (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
global img1;
global img2;
img1 = imread('peppers.png');
img2 = imread('rice.png');
axes(handles.axes1);
imshow(img1,[]);
axes(handles.axes2);
imshow(img2,[]);
% --- Executes on button press in seedpointSelect.
function seedpointSelect_Callback(hObject, eventdata, handles)
% hObject handle to seedpointSelect (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
global img1;
global img2;
global x;
global y;
axes(handles.axes1);
imshow(img1,[]);
[y,x] = ginput(handles.axes1);
y = round(y); x = round(x);
set(handles.xcord,'String',num2str(x));
set(handles.ycord,'String',num2str(y));
Any help on limiting ginput to a specific axes,
Thanks,
Gopi
In older versions of MATLAB you used to be able to change the HitTest property of the axes to ignore the click from ginput
set(handles.axes2, 'Hittest', 'off')
The better approach though is to use ButtonDownFcn as you have much more control over mouse events with an axes object.
From within your OpeningFcn
set(handles.axes1, 'ButtonDownFcn', #mouseCallback)
Then you'll need to create the callback function
function mouseCallback(src, evnt)
handles = guidata(src);
% Get the current point
xyz = get(src, 'CurrentPoint');
x = xyz(1,1);
y = xyz(1,2);
% Store x/y here or whatever you need to do
end
Don't use ginput, create a mouse click callback instead (ButtonDownFcn). You can set the callback to, for example, remove the callback function from the axis. In your main program, which sets the callback, you then waitfor that property to change. As soon as the user clicks, you get control back, and you can then read the location of the last mouse click (CurrentPoint). Note that the position you read out is in axis coordinates, not screen pixels. This is a good thing, it most likely corresponds to a pixel in the image displayed.
i have a GUI based in matlab 2015 to code
when i push/ press the button one of edit box data keeps changing but i want its value to keep on changing according to my call back until i release it
for now i have to keep on clicking my push button again and again which changes my edit box value
Kindly suggest me a workarround
% --- Executes on button press in pushbutton27.
function pushbutton27_Callback(hObject, eventdata, handles)
% hObject handle to pushbutton27 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
Freq = (str2double(get(handles.edit4,'String')))+ 0.001;
if Freq > 20
set(handles.edit4,'String','20');
else
set(handles.edit4,'String',num2str(Freq));
end
uicontrol has only the Callback and ButtonDownFcn properties that respond to mouse clicks. If the property Enable of the uicontrol is set to 'on', only the function specified in Callback reacts to left-clicks. If the property is set to 'off' or 'inactive' it also reacts to right-clicks. Because for inactive uicontrols you cannot change the Value by clicking on it, I don't see a direct solution using uicontrol.
A solution is to use the figure's WindowButtonDownFcn and WindowButtonUpFcn properties. For the button down you could use something like:
function buttondown(hobj,~,hedit)
hobj.UserData = true;
while hobj.UserData
pause(0.2); % put a pause so it doesnt change too fast
hedit.String = datestr(now); % you can set it to anything you want here
end
end
For the button up:
function buttonup(hobj,~)
hObj.UserData = false;
end
Of course, if you have multiple buttons that have to work this way, in the buttondown function you must test where the cursor's position is that by checking the CurrentPoint property.
In Matlab GUI, I need a user mouse input as a rectangle that I have to plot on the axes1.
For this, I have code below:
axes(handles.axes1);
filename = 'A';
img = imread(filename);
imshow(img);
hold on;
rect_cord = getrect(handles.axes1);
rectangle('Curvature', [0 0],'Position', [rect_cord],'EdgeColor',[1 0 0]);
This code runs fine (takes user input and plots the rectangle). However, for some images I don't want to get the user input from mouse (using getrect). In this case, how to skip the getrect function and move on to next image?
I have a pushbutton ("next"), I want to show next image when push button is pressed instead of taking user input.
Thanks,
I will try to rephrase and modify a bit: you want to draw a rectangle only if one clicks on the axes or image.
Therefore:
First of all I would suggest to put the getrect-part into another function. This function should only be triggered if one clicks on the image. The so called "ButtownDownFcn" seems to be suitable for this job. When using GUIDE, you will find it double-clicking on the axes within the property-inspector that is popping up.
Then put the getrect-part into this function:
function axes1_ButtonDownFcn(hObject, eventdata, handles)
% hObject handle to axes1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
rect_cord = getrect(handles.axes1);
rectangle('Curvature', [0 0],'Position', [rect_cord],'EdgeColor',[1 0 0]);
Now I thought that this is all that has to be done. But testing this with a plot or image within the axes prooved me wrong :o
Sadly one has to redirect the children of the axes to this function, because by default, it is only assigned to the background of the axes (=the blank axes).
by searching the net, I found the following solution here:
Matlab in Chemical Engineering: Interacting with your graph through mouse clicks
It works like this:
when plotting the image, you have to add the line
% and we also have to attach the function to the children, in this
% case that is the line in the axes.
set(get(gca,'Children'),'ButtonDownFcn', #mouseclick_callback)
Hope that helps!
I am quite new to MATLAB GUI programming (using GUIDE sorry) and I have the following issue: The GUI displays on an axis an image sequence stored in a cell array. I have a couple of pushbuttons and a slider to scroll through the sequence. In order to get a 'continuous slider' I use a listener, which kind of works but creates some problems:
1) When I press the slider, a figure is created and the first frame of the sequence is displayed in it, but as I move the slider the sequence is displayed in the axis of my GUI (which is what I want) and the figure becomes empty. Can anybody tell me why this figure is created and how can I avoid it?
2) Once I press the slider button and thus use the listener, all handles inside the GUI are not functionnal as Matlab does not recognize them and I'm stuck with a functionnal slider/display but I can't use the pushbuttons.
Any ideas on why this happens? Here is the code I use in the Create Function of the slider:
function slider2_Frame_Video_Callback(hObject, eventdata, handles)
hListener = addlistener(hObject,'ContinuousValueChange',#(a,b) slider2_Frame_Video_Callback(hObject, eventdata, handles)); % a and b are dummy arguments
guidata(hObject,handles)
In the slider callback, the code looks like this (basically imshow in the current axis):
axes(hAxis)
imshow(Movie{frame},'parent',hAxis);
drawnow
% This does not work either as handles.edit_FrameNumber is not recognized by Matlab
set(handles.edit_FrameNumber, 'String', frame);
guidata(hObject,handles);
Any hints are welcome thanks!
I wonder if part of the problem is that a listener is being instantiated each time the user moves the slider since the listener code is within this callback AND that the callback being provided to the listener (seems like some kind of strange back-and-forth there). So every time the user releases the mouse button after a slide, a new listener is created. This may be causing some problems with the other buttons not being responsive.
Rather than instantiating the listener there, I would do this in the Opening_Fcn of your GUI:
% --- Executes just before frameSlider is made visible.
function frameSlider_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject handle to figure
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% varargin command line arguments to frameSlider (see VARARGIN)
% Choose default command line output for frameSlider
handles.output = hObject;
if ~isfield(handles,'hListener')
handles.hListener = ...
addlistener(handles.slider1,'ContinuousValueChange',#respondToContSlideCallback);
end
% Update handles structure
guidata(hObject, handles);
My GUI is named frameSlider; yours will be something else. The above creates one listener with a callback to a function that you will need to define in the same *.m file, respondToContSlideCallback.
A sample body for the callback that is to respond to the continuous slide is
% --- Executes on slider movement.
function respondToContSlideCallback(hObject, eventdata)
% hObject handle to slider1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% Hints: get(hObject,'Value') returns position of slider
% get(hObject,'Min') and get(hObject,'Max') to determine range of slider
% first we need the handles structure which we can get from hObject
handles = guidata(hObject);
% test to display the current value along the slider
disp(['at slider coordinate ' num2str(get(hObject,'Value'))]);
If you run this code, the Command Window will display continuously the slider coordinate as you move the slider from end to end.
Your above code has a Movies cell array. How is that being accessed by your callback? Is it a global variable or ..? Where does hist come from? If Movies is the result of some other function call, then it can be saved to handles too (in whichever location it gets loaded from file). I suppose you will also have to map the slider control coordinates to the number of frames that you have (though maybe you have already done this?).