% pltsq.m -----------------------------------------------------------
% pltsq shows how a square wave can be approximated by adding up the
% first five odd harmonics of a sine wave. To make the GUI interface
% more challenging and interesting, the amplitude is continually
% varied (periodically between plus and minus 1). If you can fully
% understand this 50 line routine, you are well on your was to
% creating your own plt based GUI applications.
% -- Demonstrates how you can add additional GUI controls to the plt
% window. Typically this is something you will want to do when
% creating an application based on plt.
% -- 10 uicontrols are added to the figure using 'uicontrol'
% (4 popups, 2 buttons, and 6 text labels).
% -- The uicontrol units are changed to normalized so that they
% reposition properly when you resize the plt figure window.
% -- The cursor callback and the plt('rename') call are used to provide
% simultaneous cursor readouts in the TraceID box for all 5 traces.
% (Click the stop button first to make it easier to cursor, and then
% click anywhere in the plot area to see all 5 cursor values update.)
% -- The 'AxisPos' argument makes room for the uicontrols added above
% the plot area and to make room for the wider TraceIDs
% -- The 'Options' argument is used to turn off grid lines (initially)
% and to remove the y-axis Log selector from the menu box.
% -- With the Erasemode popup, you can explore the effect of the
% erasemode property on drawing speed.
% ----- Author: ----- Paul Mennen
% ----- Email: ----- paul@mennen.org
function pltsq()
S.tr = plt(0,[0 0 0 0 0],'AxisPos',[1.4 1 .94 .94 1.9],...
'FigName','pltsq: Square wave speed test','Options','Ticks/-Ylog',...
'Xlim',[0 4*pi],'Ylim',[-1.05,1.05],'LabelX','Cycles','LabelY','' );
S.era = uicontrol('string',{'normal' 'background' 'xor' 'none'});
S.pts = uicontrol('string','25|50|100|200|400|800|1600');
S.spd = uicontrol('string','1|2|4|8|16|32|64|128|256|512|1024');
S.cyc = uicontrol('string','1|2|4|8|16|32');
S.stp = uicontrol('string','Stop','User',1);
S.go = uicontrol('string','Start');
S.cid = getappdata(gcf,'cid'); % get cursor ID
plt('cursor',S.cid,'set','moveCB',{@curCB,S}); % set cursor callback
ui = [S.era S.pts S.spd S.cyc S.stp S.go];
set(ui,{'Position'},{[242 498 110 18]; [457 498 60 18]; [602 498 65 18];
[ 20 200 57 20]; [ 20 355 50 22]; [ 20 385 50 22]},...
'Units','Norm','CallBack',{@uiCB,S});
set(ui(1:4),'Style','Popup','BackGround',[0 1 1],{'Value'},{1;3;5;1});
set(S.stp,'CallBack','set(gcbo,''User'',0);');
% create a label to identify each popup menu
set([uicontrol; uicontrol; uicontrol; uicontrol],'Style','Text',...
{'String'},{'EraseMode';'Points/cycle';'Speed';'Cycles'},...
{'Position'},{[150 495 90 18]; [370 495 85 18];
[540 495 60 18]; [ 21 220 55 20]},'Units','Norm');
curCB(S); uiCB(0,0,S); % start it moving
% end function pltsq
function curCB(S) % cursor callback
t = {'Fund' '+ 3rd' '+ 5th' '+ 7th' '+ 9th'}; % Trace IDs
[xy m] = plt('cursor',S.cid,'get','position'); % get cursor index (m)
for k=1:5
y = get(S.tr(k),'y'); % get y data for each trace
t{k} = sprintf('%s: %4.4f',t{k},y(m)); % append cursor value to TraceID
end;
plt('rename',t);
%end function curCB
function uiCB(h,arg2,S) % uicontrol callbacks
Ncyc = 2^get(S.cyc,'Value')/2; % Number of cycles
Pts = 12.5*2^get(S.pts,'Value'); % Points per cycle
Speed = 2^get(S.spd,'Value'); % Amplitude step size
x = [0: 1/Pts : Ncyc]; % initialize x axis values
plt('cursor',S.cid,'set','xlim',[0 Ncyc]);
y = zeros(5,length(x)); v = y(1,:);
m=1; for k=1:5 v=v+sin(2*pi*m*x)/m; m=m+2; y(k,:)=v; end;
emode = get(S.era,'string');
set(S.tr,'x',x,'y',x,'EraseMode',emode{get(S.era,'Value')});
m = 0; set(S.stp,'User',1);
while ishandle(S.stp) & get(S.stp,'User') % loop until stop is clicked
m = m+1; a = sin(Speed*m/6000); % update amplitude based on Speed
for k=1:5 set(S.tr(k),'y',a*y(k,:)); end; % update trace values
drawnow;
end;
%end function pltsq
