put length "ginput" above the line

Hello... I want to illustrate my question by a picture like this http://www.flickr.com/photos/rye_ni/7095315251/. I make the line using "ginput", and i get length of the line by this code..

% Initially, the list of points is empty.
xy = [];
n = 0;
% disp('Left mouse button picks points.')
% disp('Right mouse button picks last point.')
but = 1;
while but == 1
    [xi,yi,but] = ginput(1);
    plot(xi,yi,'rx','LineWidth',2)
    n = n+1;
    xy(:,n) = [xi;yi];
end

% Plot the interpolated curve.
plot(xy(1,:),xy(2,:),'m-','LineWidth',2);
% ---------------------------
pjgAsli = sum(sqrt(diff(xy(1,:)).^2 + diff(xy(2,:)).^2));

the length of the line is "pjgAsli".. How i can put this value above the line..?? Thank you.. ^^

Answer 1

[Jakob Sørensen]

% Aquire locations
dX         = -10; % Text horizontal offset, change to adjust
dY         = 10;  % Text height offset, change to adjust
xLocation  = mean([xy(1,1) xy(1,2)]);
yLocation  = mean([xy(2,1) xy(2,2)])+dY;

% Make a text string, change unit, to desired unit
textString = sprintf('%2.2f units',pjgAsli);

% Write text to figure*
th = text(xLocation, yLocation, textString);

• The 'th' part is to easily acces the text later. It's not strictly needed.

[Rahma Yeni]

Thank you Jakob..

I can implement it to my project.. ^^

[Rahma Yeni]

once more again Jakob.. ^^

is possible to change the color and size of the font..??

Answer 2

[Jakob Sørensen]

You can adjust the properties either at creation...

text(xLocation, yLocation, 'textString', 'Color', 'Red', ...
     'FontSize',20);

Or at an existing text...

set(th, 'Color', 'Red', ...
        'FontSize',20);

There is also one for font style, but I can't really remember that. You should be able to find that with Google though.