# How to plot graph using ginput?

10 views (last 30 days)
VALARMATHY K on 30 Oct 2017
Commented: VALARMATHY K on 6 Nov 2017
Hi friends i want to plot a graph between two graphic input, i did it but i want to make it as my input should be visible before plotting.
This is my code..
axis([0 100 0 100]);
hold on
nodes = 2;
PauseTime = 0.05;
[x,y] = ginput(nodes);
plot(x,y,'--ys','LineWidth',2,'MarkerEdgeColor','b','MarkerFaceColor','b', 'MarkerSize',4);

OCDER on 30 Oct 2017
To do what you want would require using callback functions. See this video here to understand how it works: https://blogs.mathworks.com/videos/2008/05/27/advanced-matlab-capture-mouse-movement/
To summon this function, do:
plotLines(5) %for 5 points, 4 lines
The function is below. You have to modify this based on what you want to accomplish with drawing lines. Play around with the callback functions: startLine, stopLine, dragLine.
function plotLines(nodes)
axis([0 100 0 100]);
set(gca, 'xlim', [0 100], 'ylim', [0 100]);
hold on;
%nodes = 2; %It's now the function input
PauseTime = 0.05; %You can use drawnow instead of pause to refresh plots.
set(gcf, 'WindowButtonDownFcn', @startLine);
set(gcf, 'WindowButtonUpFcn', @stopLine);
function startLine(varargin)
pt = get(gca, 'currentpoint');
if isempty(findobj(gca, 'type', 'line'))
plot(gca, [pt(1,1), pt(1,1)], [pt(1,2), pt(1,2)], '--ys', 'LineWidth',2, 'MarkerEdgeColor','b', 'MarkerFaceColor','b', 'MarkerSize',4);
else
Lx = findobj(gca, 'type', 'line');
Xdata = get(Lx, 'Xdata');
Ydata = get(Lx, 'Ydata');
if length(Xdata) > nodes-1; return; end %Edit this depending on your definition of "node".
Xdata(end+1) = pt(1,1);
Ydata(end+1) = pt(1,2);
set(Lx, 'Xdata', Xdata, 'Ydata', Ydata);
end
set(gcf, 'WindowButtonMotion', @dragLine)
end
function dragLine(varargin)
pt = get(gca, 'currentpoint');
Lx = findobj(gca, 'type', 'line');
Xdata = get(Lx, 'Xdata');
Ydata = get(Lx, 'Ydata');
Xdata(end) = pt(1,1);
Ydata(end) = pt(1,2);
set(Lx, 'Xdata', Xdata, 'Ydata', Ydata);
end
function stopLine(varargin)
set(gcf, 'WindowButtonMotion', '');
end
end
VALARMATHY K on 1 Nov 2017
Thank you sir its working

Walter Roberson on 31 Oct 2017
Consider using imline()
VALARMATHY K on 6 Nov 2017
Thank you sir