CODEWITHSUNDEEP
matlabmatplotlibplotmatlab-figure
Abdulhameed
Abdulhameed

Reputation: 210

How to show a zoomed part of a graph within a MATLAB plot?

I have about four series of data on a Matlab plot, two of them are quite close and can only be differentiated with a zoom. How do I depict the zoomed part within the existing plot for the viewer. I have checked similar posts but the answers seem very unclear.

I look for something like this:

enter image description here

Upvotes: 2

Views: 10954

Answers (1)

EBH
EBH

Reputation: 10440

Here is a suggestion how to do this with MATLAB. It may need some fine tuning, but it will give you the result:

function pan = zoomin(ax,areaToMagnify,panPosition)
% AX is a handle to the axes to magnify
% AREATOMAGNIFY is the area to magnify, given by a 4-element vector that defines the
%      lower-left and upper-right corners of a rectangle [x1 y1 x2 y2]
% PANPOSTION is the position of the magnifying pan in the figure, defined by
%        the normalized units of the figure [x y w h]
%

fig = ax.Parent;
pan = copyobj(ax,fig);
pan.Position = panPosition;
pan.XLim = areaToMagnify([1 3]);
pan.YLim = areaToMagnify([2 4]);
pan.XTick = [];
pan.YTick = [];
rectangle(ax,'Position',...
    [areaToMagnify(1:2) areaToMagnify(3:4)-areaToMagnify(1:2)])
xy = ax2annot(ax,areaToMagnify([1 4;3 2]));
annotation(fig,'line',[xy(1,1) panPosition(1)],...
    [xy(1,2) panPosition(2)+panPosition(4)],'Color','k')
annotation(fig,'line',[xy(2,1) panPosition(1)+panPosition(3)],...
    [xy(2,2) panPosition(2)],'Color','k')
end

function anxy = ax2annot(ax,xy)
% This function converts the axis unites to the figure normalized unites
% AX is a handle to the figure
% XY is a n-by-2 matrix, where the first column is the x values and the
% second is the y values
% ANXY is a matrix in the same size of XY, but with all the values
% converted to normalized units

pos = ax.Position;
%   white area * ((value - axis min) / axis length)   + gray area
normx = pos(3)*((xy(:,1)-ax.XLim(1))./range(ax.XLim))+ pos(1);
normy = pos(4)*((xy(:,2)-ax.YLim(1))./range(ax.YLim))+ pos(2);
anxy = [normx normy];
end

Note that the units of areaToMagnify are like the axis units, while the units of panPosition are between 0 to 1, like the position property in MATLAB.

Here is an example:

x = -5:0.1:5;
subplot(3,3,[4 5 7 8])
plot(x,cos(x-2),x,sin(x),x,-x-0.5,x,0.1.*x+0.1)
ax = gca;
area = [-0.4 -0.4 0.25 0.25];
inlarge = subplot(3,3,3);
panpos = inlarge.Position;
delete(inlarge);
inlarge = zoomin(ax,area,panpos);
title(inlarge,'Zoom in')

zoomin

Upvotes: 6

Related Questions