www.gusucode.com > graphics 案例源码程序 matlab代码 > graphics/AddTextArrowsToDataPointsOnGraphExample.m

    %% Add Text to Three Data Points on Graph
% This example shows how to add text descriptions with arrows that point to   
% three data points on a graph. 
% 
% Use the |linspace| function to create |t| as a vector of 50 values between   
% 0 and $2\pi$. Create |y| as  sine values. Plot the data. 

t = linspace(0,2*pi,50);
y = sin(t);
plot(t,y)
%% 
% Use the |text| function to add a text description to the graph at the   
% point $(\pi,\sin(\pi))$. The first two input arguments to this function   
% specify the text position. The third argument specifies the text. Display   
% an arrow pointing to the left by including the TeX markup |\leftarrow| in the   
% text. Use the TeX markup |\pi| for the Greek  letter  $\pi$.


x1 = pi;
y1 = sin(pi);
txt1 = '\leftarrow sin(\pi) = 0';
text(x1,y1,txt1)

%% 
% Add text descriptions to two more data points on the graph. By default,
% the data point is to the left of the text. To show the data point to the
% right of the text, specify the |HorizontalAlignment| property as
% |'right'|. Use the TeX markup |\rightarrow| to diplay an arrow pointing
% to the right.

x2 = 3*pi/4;
y2 = sin(3*pi/4);
txt2 = '\leftarrow sin(3\pi/4) = 0.71';
text(x2,y2,txt2)

x3 = 5*pi/4;
y3 = sin(5*pi/4);
txt3 = 'sin(5\pi/4) = -0.71 \rightarrow';
text(x3,y3,txt3,'HorizontalAlignment','right')