draggable.m

医学图像处理matlab工具箱

function draggable(h,varargin)
% DRAGGABLE - Make it so that a graphics object can be dragged in a figure.
%   This function makes an object interactive by allowing it to be dragged
%   accross a set of axes, following or not certain constraints. This
%   allows for intuitive control elements which are not buttons or other
%   standard GUI objects, and which reside inside an axis. Typical use
%   involve markers on an axis, whose position alters the output of a
%   computation or display
% 
%   >> draggable(h);
%   
%   makes the object with handle "h" draggable. Use the "Position" property
%   of the object to retrieve its position, by issuing a get(h,'Position')
%   command.
%
%   >> draggable(h,...,motionfcn)
%
%   where "motionfcn" is a function handle, executes the given function
%   while the object is dragged. Handle h is passed to motionfcn as an
%   argument. Argument "motionfcn" can be put anywhere after handle "h".
%
%   >> draggable(h,...,constraint,p);
%
%   enables the object with handle "h" to be dragged, with a constraint.
%   Arguments "constraint" (a string) and "p" (a vector) can be put
%   anywhere after handle "h".
%
%   The argument "constraint" may be one of the following strings:
%
%       'n' or 'none':          The object is unconstrained (default).
%       'h' or 'horizontal':    The object can only be moved horizontally.
%       'v' or 'vertical':      The object can only be moved vertically.
%
%   The argument "p" is an optional parameter which depends upon the
%   constraint type:
%
%   Constraint      p                   Description
%   -----------------------------------------------------------------------
%
%   'none'          [x1 x2 y1 y2]       Drag range (for the object's outer
%                                       limits, from x1 to x2 on the x-axis
%                                       and from y1 to y2 on the y-axis).
%                                       Default is the current axes range.
%                                       Use "inf" if no limit is desired.
%
%   'horizontal'    [xmin xmax]         Drag range (for the object's outer
%                                       limits). Default is the x-axis
%                                       range. Use "inf" if no limit is
%                                       desired.
%
%   'vertical'      [ymin ymax]         Drag range (for the object's outer
%                                       limits). Default is the y-axis
%                                       range. Use "inf" if no limit is
%                                       desired.
%
%   -----------------------------------------------------------------------
%
%   >> draggable(h,...,renderer);
%
%   where renderer is one of 'painters', 'zbuffer' or 'opengl', uses the
%   corresponding renderer for the figure while the graphical object whose
%   handle is h is being dragged. By default, zbuffer is used since it is
%   the only renderer that offers both acceptable performance and a
%   guaranteed correct behavior with draggable. The 'painters' renderer is
%   too slow, while the 'opengl' renderer's behavior with draggable depends
%   ont the graphics driver used and may differ from what is expected. 
%
%   >> draggable(h,'off')
%
%   returns object h to its original, non-draggable state.
%
%   See the source code (e.g. by issuing "type draggable" at the Matlab 
%   prompt) for implementation notes and the copyright notice.

% VERSION INFORMATION:
% 2003-11-20:   Initially submitted to MatlabCentral.Com
% 2004-01-06:   Addition of the renderer option, as proposed by Ohad Gal
%               as a feedback on MatlabCentral.Com.
% 2004-02-18:   Bugfix: now works with 1-element plots and line objects
% 2004-03-04:   Bugfix: sanitized the way the object's new position is
%               computed; it now always follow the mouse even after the
%               mouse pointer was out of the axes.
% 2004-03-05:   Bugfix: movement when mouse is out of the axes is now
%               definitely correct ;)

% IMPLEMENTATION NOTES:
%
% This function uses the dragged object's "ButtonDownFcn" function and set it
% so that the objec becomes draggable. Any previous "ButtonDownFcn" is thus
% lost during operation, but is retrieved after issuing the draggable(h,'off')
% command.
%
% Information about the object's behavior is also stored in the object's
% 'UserData' property, using setappdata() and getappdata(). The original
% 'UserData' property is restored after issuing the draggable(h,'off')
% command.
%
% The corresponding figure's "WindowButtonDownFcn", "WindowButtonUpFcn" and
% "WindowButtonMotionFcn" functions.  During operation, those functions are
% set by DRAGGABLE; however, the original ones are restored after the user
% stops dragging the object.
%
% By default, DRAGGABLE also switches the figure's renderer to 'zbuffer'
% during operation: 'painters' is not fast enough and 'opengl' sometimes
% produce curious results. However there may be a need to switch to another
% renderer, so the user can now specify a specific figure renderer during
% object drag (thanks to Ohad Gal for the suggestion).
%
% The "motionfcn" function handle is called at each displacement, after the
% object's position is updated, using "feval(motionfcn,h)", where h is the
% object's handle.
%
% TO DO:
%
% 1 - For now, DRAGGABLE allows only one object at a time to be draggable. In
% the future, draggable(h), where h is a vector of handles, will create a
% group of objects that will all be dragged when one of them is selected.

% ==============================================================================
% Copyright (C) 2003, 2004
% Francois Bouffard
% [e-mail]
% Universit