function MainFig = mouse_figure(MainFig)
%MOUSE_FIGURE mouse-friendly figure
%
% MOUSE_FIGURE() creates a figure (or modifies an existing one) that allows
% zooming with the scroll wheel and panning with mouse clicks, *without*
% first selecting the ZOOM or PAN tools from the toolbar. Moreover, zooming
% occurs to and from the point the mouse currently hovers over, instead of
% to and from the less intuitive "CameraPosition".
%
% Scroll: zoom in/out
% Left click: pan
% Double click: reset view to default view
% Right click: set new default view
%
% LIMITATIONS: This function (re-)efines several functions in the figure
% (WindowScrollWheelFcn, WindowButtonDownFcn, WindowButtonUpFcn and
% WindowButtonMotionFcn), so if you have any of these functions already
% defined they will get overwritten. Also, MOUSE_FIGURE() only works
% properly for 2-D plots. As such, it should only be used for simple,
% first-order plots intended for "quick-n-dirty" data exploration.
%
% EXAMPLE:
%
% mouse_figure;
% x = linspace(-1, 1, 10000);
% y = sin(1./x);
% plot(x, y)
%
% See also figure, axes, zoom, pan.
% Author : Rody P.S. Oldenhuis
% Affiliation : Delft University of Technology
% Faculty of Aerospace Engineering
% Dep. of Astrodynamics & Satellite Systems
% Contact : oldenhuis@dds.nl
% Licensing/
% (C) info : Frankly I don't care what you do with it,
% as long as I get some credit when you copy
% practically the exact code ^_^
% initialize
status = ''; previous_point = [];
% initialize axes
if (nargin == 0) || ~ishandle(MainFig)
MainFig = figure; axs = gca;
else
axs = get(MainFig, 'currentaxes');
end
% only works properly for 2D plots
if ~is2D(axs) % is2D might disappear in a future release...
error('mouse_figure:plot3D_not_supported', ...
'MOUSE_FIGURE() only works for 2-D plots.');
end
% get original limits
original_xlim = get(axs, 'xlim');
original_ylim = get(axs, 'ylim');
% define zooming with scrollwheel, and panning with mouseclicks
set(MainFig, ...
'WindowScrollWheelFcn' , @scroll_zoom,...
'WindowButtonDownFcn' , @pan_click,...
'WindowButtonUpFcn' , @pan_release,...
'WindowButtonMotionFcn', @pan_motion);
% zoom in to the current point with the mouse wheel
function scroll_zoom(varargin)
% double check if these axes are indeed the current axes
if get(MainFig, 'currentaxes') ~= axs, return, end
% get the amount of scolls
scrolls = varargin{2}.VerticalScrollCount;
% get the axes' x- and y-limits
xlim = get(axs, 'xlim'); ylim = get(axs, 'ylim');
% get the current camera position, and save the [z]-value
cam_pos_Z = get(axs, 'cameraposition'); cam_pos_Z = cam_pos_Z(3);
% get the current point
old_position = get(axs, 'CurrentPoint'); old_position(1,3) = cam_pos_Z;
% calculate zoom factor
zoomfactor = 1 - scrolls/50;
% adjust camera position
set(axs, 'cameratarget', [old_position(1, 1:2), 0],...
'cameraposition', old_position(1, 1:3));
% adjust the camera view angle (equal to zooming in)
camzoom(zoomfactor);
% zooming with the camera has the side-effect of
% NOT adjusting the axes limits. We have to correct for this:
x_lim1 = (old_position(1,1) - min(xlim))/zoomfactor;
x_lim2 = (max(xlim) - old_position(1,1))/zoomfactor;
xlim = [old_position(1,1) - x_lim1, old_position(1,1) + x_lim2];
y_lim1 = (old_position(1,2) - min(ylim))/zoomfactor;
y_lim2 = (max(ylim) - old_position(1,2))/zoomfactor;
ylim = [old_position(1,2) - y_lim1, old_position(1,2) + y_lim2];
set(axs, 'xlim', xlim), set(axs, 'ylim', ylim)
% set new camera position
new_position = get(axs, 'CurrentPoint');
old_camera_target = get(axs, 'CameraTarget');
old_camera_target(3) = cam_pos_Z;
new_camera_position = old_camera_target - ...
(new_position(1,1:3) - old_camera_target(1,1:3));
% adjust camera target and position
set(axs, 'cameraposition', new_camera_position(1, 1:3),...
'cameratarget', [new_camera_position(1, 1:2), 0]);
% we also have to re-set the axes to stretch-to-fill mode
set(axs, 'cameraviewanglemode', 'auto',...
'camerapositionmode', 'auto',...
'cameratargetmode', 'auto');
end % scroll_zoom
% pan upon mouse click
function pan_click(varargin)
% double check if these axes are indeed the current axes
if get(MainFig, 'currentaxes') ~= axs, return, end
% perform appropriate action
switch lower(get(MainFig, 'selectiontype'))
% start panning on left click
case 'normal'
status = 'down';
previous_point = get(axs, 'CurrentPoint');
% reset view on double click
case 'open' % double click (left or right)
set(axs, 'Xlim', original_xlim,...
'Ylim', original_ylim);
% right click - set new reset state
case 'alt'
original_xlim = get(axs, 'xlim');
original_ylim = get(axs, 'ylim');
end
end
% release mouse button
function pan_release(varargin)
% double check if these axes are indeed the current axes
if get(MainFig, 'currentaxes') ~= axs, return, end
% just reset status
status = '';
end
% move the mouse (with button clicked)
function pan_motion(varargin)
% double check if these axes are indeed the current axes
if get(MainFig, 'currentaxes') ~= axs, return, end
% return if there isn't a previous point
if isempty(previous_point), return, end
% return if mouse hasn't been clicked
if isempty(status), return, end
% get current location (in pixels)
current_point = get(axs, 'CurrentPoint');
% get current XY-limits
xlim = get(axs, 'xlim'); ylim = get(axs, 'ylim');
% find change in position
delta_points = current_point - previous_point;
% adjust limits
new_xlim = xlim - delta_points(1);
new_ylim = ylim - delta_points(3);
% set new limits
set(axs, 'Xlim', new_xlim); set(axs, 'Ylim', new_ylim);
% save new position
previous_point = get(axs, 'CurrentPoint');
end
end
