Graphics

2D graphics

The plot function

Basic usage

>> x = linspace(0, 2 * pi, 20);
>> y = sin(x);
>> plot(x, y);
>> title('Sine');
>> xlabel('x');
>> ylabel('sin(x)');

Sine

>> z = cos(x);
>> plot(x, y, x, z);
>> % or
>> A = [y; z];
>> plot(x, A);

Sine and cosine

Note that the title and axis labels are cleared.

Parametric plots

>> theta = linspace(0, 4 * pi, 30);
>> r = linspace(1, 2, 30);
>> x = r .* cos(theta);
>> y = r .* sin(theta);
>> plot(x, y);

Parametric plot

Line Specification (LineSpec)

Specifier Line style
- Solid (default)
-- dashed
: dotted
-. dash-dot
Specifier Marker type
+ Plus sign
o Circle
* Asterisk
. Point
x Cross
s, d, Square, Diamond
p, h pentagram, hexagram
^, v, >, < Triangles
Specifier Color
r Red
g Green
b Blue
c Cyan
m Magenta
y Yellow
k Black
w White

Black is k.

>> x = linspace(0, 7, 20);
>> plot(x, sin(x), '--or', x, cos(x), 'pm-.', x, -sin(x), 'g:.');

LineSpec

3D graphics

x = linspace(-1, 1, 11);
y = linspace(-2, 2, 15);
[X, Y] = meshgrid(x, y);
Z = exp(-X.^2 - Y.^2);

figure();
surf(X, Y, Z);
xlabel('x'); ylabel('y'); zlabel('z');

figure();
mesh(X, Y, Z);
xlabel('x'); ylabel('y'); zlabel('z');

figure();
waterfall(X, Y, Z);
xlabel('x'); ylabel('y'); zlabel('z');

Surface plot Mesh plot Waterfall plot

Axes options

>> plot(x, sin(x));
>> grid on;
>> box off;
>> axis equal;

>> plot(x, sin(x));
>> xlim([-1 8]);
>> ylim([-0.5 1.5]);

Axes options Axes options

Subplots

>> x = 0:0.5:8;
>> subplot(2, 3, 1);
>> plot(x, sin(x));
>> subplot(2, 3, [2 3]);
>> plot(x, cos(x));
>> subplot(223);
>> plot(x, sin(2 * x));
>> subplot(339);
>> plot(x, cos(x / 2));

Subplot

More plots

Handle graphics

>> x = 0:0.1:1;
>> y = x.^2;
>> hf = figure();
>> hl = plot(x, y);
>> ha = gca();
>> 
>> a = get(hf)
a = 
                 Alphamap: [1x64 double]
             BeingDeleted: 'off'
               BusyAction: 'queue'
            ButtonDownFcn: ''
                 Children: 879
                 Clipping: 'on'
          CloseRequestFcn: 'closereq'
(...)
        WindowButtonUpFcn: ''
        WindowKeyPressFcn: ''
      WindowKeyReleaseFcn: ''
     WindowScrollWheelFcn: ''
              WindowStyle: 'docked'
>> xLim = get(ha, 'XLim')
xLim =
     0     1
>> marker = get(hl, 'Color')
marker =
     0     0     1

x = 1:0.1:2;
y = exp(x);
hf = figure(); % figure handle
hl = plot(x, y); % lineseries handle
ha = gca(); % axes handle

% First image here

set(ha, 'XLim', get(ha, 'XLim') + [-0.1 0.1]);
set(ha, 'XDir', 'reverse');
set(ha, 'YScale', 'log');
set(ha, 'YGrid', 'on');
set(hl, ...
  'Color', [0.4 0.8 0.1], ...
  'Marker', 'd', ...
  'MarkerSize', 12, ...
  'MarkerFace', [0.9 0.1 0.4], ...
  'LineWidth', 3);

% Second image here

Handle graphics Handle graphics

Movies

% From help for getframe
Z = peaks;
figure('Renderer', 'zbuffer');
surf(Z);
axis tight manual;
set(gca, 'NextPlot', 'replaceChildren');
for k = 1:20
    surf(sin(2 * pi * k / 20) * Z, Z)
    F(k) = getframe;
end
movie(F, 5)

Useful libraries