zoom_wheel(hfig,opt​ions)

% ZOOM IN AND OUT USING THE MOUSE WHEEL
This codes implements the zoom in figures using the wheel.
This is done by modifying the WindowScrollWheelFcn callback function.

% SYNTAX:

*) zoom_wheel: will add the zoom functionality in the current figure.
*) zoom_wheel(hfig): will add the zoom functionality in the figure
identified with the figure handle hfig.
*) zoom_wheel(options): will add the zoom functionality in the current
figure with customization given by options.
*) zoom_wheel(hfig, options): will add the zoom functionality in the figure
identified with the figure handle hfig with customization given by options.

% INPUT ARGUMENTS

*) hfig: Figure handle. If none is provided, current figure will be
employed.
*) options: Structure with the following fields for customizing the behaviour of the zoom functionality
*) Magnify: General magnitication factor. Unity or greater (by default 1.1).
*) XMagnify: Magnification factor of X axis (unity by default).
*) YMagnify: Magnification factor of Y axis (unity by default).
*) ChangeMagnify: Relative increase of the magnification factor. Unity or greater (by default 1.1).
*) IncreaseChange: Relative increase in the ChangeMagnify factor. Unity or greater (by default 1.1).
*) MinValue: Sets the minimum value that Magnify, ChangeMagnify and
IncreaseChange can take.
*) Pause: Number of seconds that information about the value of
Magnify and ChangeMagnify will be displayed everytime their value if
changed.

% BEHAVIOUR:

The magnification along the X axis is given by the formula

options.Magnify * options.XMagnify

and analogously for the Y axis. Whether zooming in (incrementing the
distance between data points) or zooming out (decrementing the distance
between data points) depends on the direction of rotation of the mouse wheel.

When *shift* is pressed, the rotation of the mouse wheel changes the
value of options.Magnify according to the following:

options.Magnify <- options.Magnify * options.ChangeMagnify

and if *Ctrl* is pressed, the rotation of the mouse wheel changes the
value of options.ChangeMagnify according to the following:

options.ChangeMagnify <- options.ChangeMagnify * options.IncreaseChange

When pressing *Alt* while moving the wheel, the zoom returns to the
original state, but not the values of options.

Notice that, in order to add this functionality, zoom_wheel modifies
the WindowScrollWheelFcn callback function in your figure, loosing
nay previous functionality this callback function may have provided
for the particular figure zoom_wheel is applied on.

% EXAMPLES:

h=figure(1);
plot(rand(100,1),rand(100,1));

options.Magnify = 1.05;
options.ChangeMagnify = 1.2;
zoom_wheel(h,options);

% Please, report any bugs to Hugo.Eyherabide@cs.helsinki.fi

% Copyright (c) 2015, Hugo Gabriel Eyherabide, University of Helsinki, Finland.
All rights reserved.

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modification, are permitted provided that the following conditions
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