Adding drag capabilities to a Matlab gui

Here is an example from the newsgroup

but could be probably done neater with nested functions.

function test
 % test gui function

 % create figure
 fig = figure;

 % set the figure's WindowButtonDownFcn
 set(fig,'WindowButtonDownFcn',{@wbd});
end

function wbd(h,evd)

 disp('down')

 % get the values and store them in the figure's appdata
 props.WindowButtonMotionFcn = get(h,'WindowButtonMotionFcn');
 props.WindowButtonUpFcn = get(h,'WindowButtonUpFcn');
 setappdata(h,'TestGuiCallbacks',props);

 % set the new values for the WindowButtonMotionFcn and
 % WindowButtonUpFcn
 set(h,'WindowButtonMotionFcn',{@wbm})
 set(h,'WindowButtonUpFcn',{@wbu})
end

function wbm(h,evd)
 % executes while the mouse moves

 disp('motion')
end

function wbu(h,evd)
 % executes when the mouse button is released

 disp('up')

 % get the properties and restore them
 props = getappdata(h,'TestGuiCallbacks');
 set(h,props);
end

Create a movie with Matlab

If you want to show how your plots change with time, a movie is a good idea. Especially since MATLAB can produce movies that can be embedded in your presentations, or be seen with any good ol' movie player. Here's how:Courtesy of http://www.ecogito.net/matlab/

The idea is to create plot figures and compile them as frames of your movie.

    % Create a new figure, and position it
        fig1 = figure;
        winsize = get(fig1,'Position');
        winsize(1:2) = [0 0];
    % Create movie file with required parameters
        fps= 25;
        outfile = sprintf('%s',outFileName)
        mov = avifile(outfile,'fps',fps,'quality',100);
    % Ensure each frame is of the same size
        set(fig1,'NextPlot','replacechildren');
        for i=1:numframes
            plot(x,y); % generate your plot
    % put this plot in a movieframe
    % In case plot title and axes area are needed
    %     F = getframe(fig1,winsize);
    % For clean plot without title and axes
            F = getframe;
            mov = addframe(mov,F);
        end
    % save movie
        mov = close(mov);

Voila! (Make sure that you do not open any window over your plot window while MATLAB is compiling your movie, else those windows will become part of your movie)

Input data using a mouse

Use ginput function:

 x=0;y=0;
 while ~isempty(x)
    [x1,y1]=ginput(1);
    plot([x x1],[y y1],'b.-');
    hold on
    x=x1;y=y1;
end

Create a multiline title in a GUI

Use char function:

 txt=char('First line','Second line','etc');
 title(txt);

The char function is used here to consolidate strings of different length into a single array. You might wish to play around with the alignment:

 h=title(txt);
 set(h,'HorizontalAlignment','Right');
 set(h,'VerticalAlignment','Middle');

Draw a cube

Simple function to draw a voxel (cube, cuboid) in a specific position of specific dimensions in a 3-D plot. Transparency of the voxel can also be specified.

Many voxels can be aggregated to form a different shapes (a simple 3-D "+" is shown in the screenshot).

Written by Joel Suresh

function voxel(i,d,c,alpha);

%VOXEL function to draw a 3-D voxel in a 3-D plot
%
%Usage
%   voxel(start,size,color,alpha);
%
%   will draw a voxel at 'start' of size 'size' of color 'color' and
%   transparency alpha (1 for opaque, 0 for transparent)
%   Default size is 1
%   Default color is blue
%   Default alpha value is 1
%
%   start is a three element vector [x,y,z]
%   size the a three element vector [dx,dy,dz]
%   color is a character string to specify color
%       (type 'help plot' to see list of valid colors)
%
%
%   voxel([2 3 4],[1 2 3],'r',0.7);
%   axis([0 10 0 10 0 10]);
%

%   Suresh Joel Apr 15,2003
%           Updated Feb 25, 2004

switch(nargin),
case 0
    disp('Too few arguements for voxel');
    return;
case 1
    l=1;    %default length of side of voxel is 1
    c='b';  %default color of voxel is blue
case 2,
    c='b';
case 3,
    alpha=1;
case 4,
    %do nothing
otherwise
    disp('Too many arguements for voxel');
end;

x=[i(1)+[0 0 0 0 d(1) d(1) d(1) d(1)]; ...
        i(2)+[0 0 d(2) d(2) 0 0 d(2) d(2)]; ...
        i(3)+[0 d(3) 0 d(3) 0 d(3) 0 d(3)]]';

for n=1:3
    if n==3,
        x=sortrows(x,[n,1]);
    else
        x=sortrows(x,[n n+1]);
    end;
    temp=x(3,:);
    x(3,:)=x(4,:);
    x(4,:)=temp;
    h=patch(x(1:4,1),x(1:4,2),x(1:4,3),c);
    set(h,'FaceAlpha',alpha);
    temp=x(7,:);
    x(7,:)=x(8,:);
    x(8,:)=temp;
    h=patch(x(5:8,1),x(5:8,2),x(5:8,3),c);
    set(h,'FaceAlpha',alpha);
end

Draw a circle

I track visitors to my site using google analytics and I noticed I had 8 visitors to my site last week looking for how to draw a circle. However I didn't have any circle drawing snippets. So I have borrowed some code from the Mathworks file exchange.

This code is courtesy of Zhenhai Wang.

function H=circle(center,radius,NOP,style)
%-----------------------------------------------------
% H=CIRCLE(CENTER,RADIUS,NOP,STYLE)
% This routine draws a circle with center defined as
% a vector CENTER, radius as a scaler RADIS. NOP is
% the number of points on the circle. As to STYLE,
% use it the same way as you use the rountine PLOT.
% Since the handle of the object is returned, you
% use routine SET to get the best result.
%
%   Usage Examples,
%
%   circle([1,3],3,1000,':');
%   circle([2,4],2,1000,'--');
%
%   Zhenhai Wang <zhenhai@ieee.org>
%   Version 1.00
%   December, 2002
%-----------------------------------------------------

if (nargin <3),
 error('Please see help for INPUT DATA.');
elseif (nargin==3)
    style='b-';
end;
THETA=linspace(0,2*pi,NOP);
RHO=ones(1,NOP)*radius;
[X,Y] = pol2cart(THETA,RHO);
X=X+center(1);
Y=Y+center(2);
H=plot(X,Y,style);
axis square;

GUI layout without GUIDE

Using the layout tool from XTargets you can write code like this

f = figure('units','pixels','position',[10 10 500 500]);
layout = xtargets_borderlayout(f);
layout.add(uicontrol('units','pixels','string','north'),'north');
layout.add(uicontrol('units','pixels','string','south'),'south');
layout.add(uicontrol('units','pixels','string','east'),'east');
layout.add(uicontrol('units','pixels','string','west'),'west');
layout.add(uicontrol('units','pixels','string','centre'),'centre');

And it creates a panel like in this link

See the full tutorial for more information

GUI Tables

Here is a simple way to use java tables in matlab. I've wrapped the standard java table model with a matlab data model. Nested functions are taken advantage of to provide data set and get methods, cell rendering and entry validation.

% XTARGETS_UITABLE
%
% t = xtargets_uitable(table, rows, cols, getfun, setfun, labelfun, editfun)
%
% Arguments
%   table     Any instance or subclass instance of javax.swing.JTable
%   rows      numbers of rows
%   cols      number of cols
%   getfun    function handle for aquiring data to the table.
%             val = getfun(row, col)
%   setfun    function handle for setting data to the table.
%             setfun(row, col, val)
%   labelfun  function handle for generating a label in the table
%             string = labelfun(row, col, val)
%   editfun   function handle for validating string input
%             value = editfun(row, col, string)
%             throw an error if the string is invalid
%             to show a dialog box and reset the old value
%             of the cell
%   table    an instance of javax.swing.JTable or a subclass of
%
% Example
%   See xtargets_uitable_test
%

% Copyright Brad Phelan (C) 2005 under the LGPL license
% http://xtargets.com
function t = xtargets_uitable(table, rows, cols, getfun, setfun, labelfun, editfun)


    import javax.swing.*;
    import javax.swing.table.*;
    import ca.odell.renderpack.*;

    tableModel = javax.swing.table.DefaultTableModel(rows,cols);

    % Initialize the table model
    for r = 1:rows
       for c = 1:cols
           tableModel.setValueAt(labelfun(r,c,getfun(r,c)),r-1,c-1);
       end
    end

    table.setModel(tableModel);


    scroller = JScrollPane(table);
    scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);
    scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);


    [hcom, hg] = javacomponent(scroller);
    hg = handle(hg);
    p = schema.prop(hg,'table','mxArray');
    hg.table = handle(table);
    set(hg,'position',[0 0 200 200]);

    %Fix for JTable focus bug : see http://www.mycgiserver.com/~Kleopatra/swing/table/merlineditfun.html
    table.putClientProperty('terminateEditOnFocusLost', java.lang.Boolean.TRUE);
    table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);


    t = hg;

    % A flag to avoid change handler recursion
    syncchange = false;

    set(tableModel, 'TableChangedCallback', @change_fcn);
    function change_fcn(src, ev)
        if syncchange
            % This change was invoked from this handler
            syncchange = false;
            return
        end
        syncchange = true;

        row = ev.getFirstRow;
        col = ev.getColumn;

        string = tableModel.getValueAt(row,col);

        row = row + 1;
        col = col + 1;
        % Perform validation on the string and convert it to a value
        try
            val = editfun(row, col, string);
            setfun(row,col,val);
            tableModel.setValueAt(labelfun(row,col,val), row-1,col-1);
        catch
            errordlg(lasterr,'Invalid Edit');
            % The value was not valid so reset the cell
            tableModel.setValueAt(labelfun(row,col,getfun(row,col)), row-1,col-1);
        end

    end
end

A test function demonstrates the behaviour of the table with a simple data model and validation.

% xtargets_uitable_test
%
% A simple example of using the table model to modify data in
% a nested function workspace. The data is in double format
% so we use the '%g' sscanf pattern to render and read the
% data from the table cells.

% Copyright Brad Phelan (C) 2005 under the LGPL license
% http://xtargets.com
function xtargets_uitable_test
    close all;

    data = rand(5);

    table = javax.swing.JTable;

    % Create a uitable with a simple matlab data model. Specify
    % that the conversion class will be %g.
    t = xtargets_uitable(table, 5,5, @getfun, @setfun, @labelfun, @editfun);

    function val = getfun( row, col)
       val = data(row,col);
    end

    function setfun( row, col, val)
       data(row,col) = val;
    end

    function val = editfun(row, col, string)
        val = sscanf(string, '%g');
        if isempty(val)
            error([ '''' string ''' is not a valid entry' ]);
        end
    end

    function label = labelfun(row, col, val)
         label = sprintf('%g',val);
    end

    % uicontrol to display the data model on the command line
    uicontrol('string','push me','position',[300 0 100 50], ...
        'callback',@disp_data);

    function disp_data(src,ev)
        disp(data);
    end
end

Adding Callbacks to uitable

The basic uitable object in matlab is just a peer for the true table. To expose all the possible callbacks do the following

>> t = uitable;
>> tj = t.getTable;
>> set(tj)

gives you

ComponentHiddenCallback: string -or- function handle -or- cell array
ComponentMovedCallback: string -or- function handle -or- cell array
ComponentResizedCallback: string -or- function handle -or- cell array
ComponentShownCallback: string -or- function handle -or- cell array
MouseDraggedCallback: string -or- function handle -or- cell array
MouseMovedCallback: string -or- function handle -or- cell array
PropertyChangeCallback: string -or- function handle -or- cell array
FocusGainedCallback: string -or- function handle -or- cell array
FocusLostCallback: string -or- function handle -or- cell array
CaretPositionChangedCallback: string -or- function handle -or- cell array
InputMethodTextChangedCallback: string -or- function handle -or- cell array
KeyPressedCallback: string -or- function handle -or- cell array
KeyReleasedCallback: string -or- function handle -or- cell array
KeyTypedCallback: string -or- function handle -or- cell array
MouseClickedCallback: string -or- function handle -or- cell array
MouseEnteredCallback: string -or- function handle -or- cell array
MouseExitedCallback: string -or- function handle -or- cell array
MousePressedCallback: string -or- function handle -or- cell array
MouseReleasedCallback: string -or- function handle -or- cell array
HierarchyChangedCallback: string -or- function handle -or- cell array
VetoableChangeCallback: string -or- function handle -or- cell array
ComponentAddedCallback: string -or- function handle -or- cell array
ComponentRemovedCallback: string -or- function handle -or- cell array
AncestorMovedCallback: string -or- function handle -or- cell array
AncestorResizedCallback: string -or- function handle -or- cell array
AncestorMovedCallback_: string -or- function handle -or- cell array
AncestorAddedCallback: string -or- function handle -or- cell array
AncestorRemovedCallback: string -or- function handle -or- cell array
MouseWheelMovedCallback: string -or- function handle -or- cell array
ButtonDownFcn: string -or- function handle -or- cell array

You add the callback like

set(tj,'MouseClickedCallback',@(handle,event)disp('hello world'));

The handle is argument to the callback is the handle to the uitable and the event is a subclass of java.awt.event.