How do I let a user select an area to zoom in an axis in my GUI?

How do I let a user select an area to zoom in an axis in my GUI?

I have a plot in a GUI window. I want the user to be able to push a button, select a rectangular area, and bring up a zoomed-in view of that area in another figure window. I wanted to use the RBBOX command, but it doesn't return the information about the boundary of the box in the right form, plus I will need to get the data to plot in the other figure. How can I do this? Is there a command to do it?

Answer 1

[MathWorks Support Team]

There is no one command which does this. Most of the complexity of this problem relies on converting the output from RBBOX to actual X and Y coordinates. Assuming that your data is in vectors XDATA and YDATA, the code below does this:

% ax is the handle to the axes where the plot is, fg is the handle to the

% figure

if ~exist('ax')

      ax = gca;

end

if ~exist('fg')

      fg = gcf;

end

k=waitforbuttonpress;

BOUND = rbbox;       % Get the boundary of the box

funits = get(fg,'Units');

aunits = get(ax,'Units');  % Store current units for axes and figure in order to restore them at the end of the routine.

set(fg,'Units','pixels'); % Set the figure units to 'pixels' 

set(ax,'Units','pixels');  % Set the axis units to 'pixels' 

P = get(ax, 'Position');  % Retrieve the axes position.

XLimit = get(ax, 'Xlim');  YLimit = get(ax, 'Ylim');

% Get the coordinates of the lower left corner of the box

% Its height and width, and the X-Y coordinates of the 4 corners

DeltaX = XLimit(2)-XLimit(1);  DeltaY = YLimit(2)-YLimit(1);

LeftDist = BOUND(1)-P(1);  UpDist = BOUND(2)-P(2);

% Defining some useful quantities which will be used often

XLow = XLimit(1)+DeltaX*LeftDist/P(3);

XHigh = XLimit(1)+DeltaX*(LeftDist+BOUND(3))/P(3);

YLow = YLimit(1)+DeltaY*UpDist/P(4);

YHigh = YLimit(1)+DeltaY*(UpDist+BOUND(4))/P(4);

% This is the X-Y information about the corners of the RBBOX

XBounds = [XLow, XHigh]; YBounds = [YLow, YHigh];

% ZOOM IN: Set the axes limits according to the zoom box

set(ax,'XLim',XBounds,'YLim',YBounds);

set(fg,'Units',funits);

set(ax,'Units',aunits);  % Reset the figure and axis units to their original settings