大家会吗？Matlab中的图形对象的选择

森之张卫东

            图形对象的选择

在本例中的程序可以探测图形对象的属性，并显示如何用函数waitforbuttonpress和gco选择对象。程序允许用户可以多次重复选择对象。

% Script file: select_object.m

%

% Purpose:

% This program illustrates the use of waitforbuttonpress

% and gco to select graphics objects. It creates a plot

% of sin(x) and cos(x), and then allows a user to select

% any object and examine its properties. The program

% terminates when a key press occurs.

%

% Record of revisions:

% Date Programmer Description of change

% ==== ========== =====================

% 11/23/97 S. J. Chapman Originalcode

%

% Define variables:

% details -- Object details

% H1 -- Handle of sine line

% H2 -- Handle of cosine line

% Handle -- Handle of current object

% k -- Result of waitforbuttonpress

% type -- Object type

% x -- Independent variable

% y1 -- sin(x)

% y2 -- cos(x)

% yn -- Yes/No

% Calculate sin(x) and cos(x)

x = -3*pi:pi/10:3*pi;

y1 = sin(x);

y2 = cos(x);

% Plot the functions.

H1 = plot(x,y1);

set(H1,'LineWidth',2);

hold on;

H2 = plot(x,y2);

set(H2,'LineWidth',2,'LineStyle',':','Color','r');

title('\bfPlot of sin \itx \rm\bf and cos \itx');

xlabel('\bf\itx');

ylabel('\bfsin \itx \rm\bf and cos \itx');

legend('sine','cosine');

hold off;

% Now set up a loop and wait for a mouse click.

k = waitforbuttonpress;

while k == 0

    % Get the handle of theobject

    Handle = gco;

    % Get the type of thisobject.

    type = get(Handle,'Type');

    % Display object type

    disp (['Object type = 'type '.']);

    % Do we display thedetails?

    yn = input('Do you want todisplay details? (y/n) ','s');

    if yn == 'y'

        details = get(Handle);

        disp(details);

    end

    % Check for another mouseclick

    k = waitforbuttonpress;

end

森之张卫东

1. % Script file: select_object.m
   
2. %
   
3. % Purpose:
   
4. % This program illustrates the use of waitforbuttonpress
   
5. % and gco to select graphics objects. It creates a plot
   
6. % of sin(x) and cos(x), and then allows a user to select
   
7. % any object and examine its properties. The program
   
8. % terminates when a key press occurs.
   
9. %
   
10. % Record of revisions:
    
11. % Date Programmer Description of change
    
12. % ==== ========== =====================
    
13. % 11/23/97 S. J. Chapman Original code
    
14. %
    
15. % Define variables:
    
16. % details -- Object details
    
17. % H1 -- Handle of sine line
    
18. % H2 -- Handle of cosine line
    
19. % Handle -- Handle of current object
    
20. % k -- Result of waitforbuttonpress
    
21. % type -- Object type
    
22. % x -- Independent variable
    
23. % y1 -- sin(x)
    
24. % y2 -- cos(x)
    
25. % yn -- Yes/No
    
26. % Calculate sin(x) and cos(x)
    
27. x = -3*pi:pi/10:3*pi;
    
28. y1 = sin(x);
    
29. y2 = cos(x);
    
30. % Plot the functions.
    
31. H1 = plot(x,y1);
    
32. set(H1,'LineWidth',2);
    
33. hold on;
    
34. H2 = plot(x,y2);
    
35. set(H2,'LineWidth',2,'LineStyle',':','Color','r');
    
36. title('\bfPlot of sin \itx \rm\bf and cos \itx');
    
37. xlabel('\bf\itx');
    
38. ylabel('\bfsin \itx \rm\bf and cos \itx');
    
39. legend('sine','cosine');
    
40. hold off;
    
41. % Now set up a loop and wait for a mouse click.
    
42. k = waitforbuttonpress;
    
43. while k == 0
    
44.     % Get the handle of the object
    
45.     Handle = gco;
    
46.     % Get the type of this object.
    
47.     type = get(Handle,'Type');
    
48.     % Display object type
    
49.     disp (['Object type = ' type '.']);
    
50.     % Do we display the details?
    
51.     yn = input('Do you want to display details? (y/n) ','s');
    
52.     if yn == 'y'
    
53.         details = get(Handle);
    
54.         disp(details);
    
55.     end
    
56.     % Check for another mouse click
    
57.     k = waitforbuttonpress;
    
58. end
    

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