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matlabplotgeometry2doctave

How can I create a rectangle with a hole in MATLAB/OCTAVE?

I would like to plot/draw exactly this shape in MATLAB or OCTAVE. Of course I do know how to plot, and how to create rectangles, using either the plot, the line or the rectangle functions. But I have not yet managed to add this "hole" on the top side of the rectangle. I figure, it's a (half-)circle of radius 0.5 and center point (1.5|2). In OCTAVE, there is a drawCircleArc function, but I don't want to only draw that thing, but also to have the necessary coordinates defining the whole shape for further manipulation.

The desired rectangle with a "hole".

Solution

  • Here is one way (matlab/octave compatible):

    % Specify all polygon points, excluding the semi-circle outline
  X = [1, 0, 0, 3, 3, 2];
  Y = [2, 2, 0, 0, 2, 2];

% Add semi-circle outline to array of polygon points
  t = 0 : -0.01 : -pi;
  X = [X, 1.5 + 0.5 * cos(t)];
  Y = [Y, 2   + 0.5 * sin(t)];

% Use fill to plot the filled polygon, with desired settings
  fill( X, Y, [0.8, 0.8, 0.8], 'linewidth', 1.5 );
  axis( [-2, 4, -2, 4] );   axis equal;