Convert polygonal region to patch faces and vertices
[F,V] = poly2fv(x,y)
[F,V] = poly2fv(x,y) converts
the polygonal region represented by the contours (x,y) into
a faces matrix, F, and a vertices matrix, V,
that can be used with the patch function to display
the region. If the polygon represented by x and y has
multiple parts, either the NaN-separated vector
format or the cell array format may be used. The poly2fv function
creates triangular faces.
Most Mapping Toolbox™ functions adhere to the convention
that individual contours with clockwise-ordered vertices are external
contours and individual contours with counterclockwise-ordered vertices
are internal contours. Although the poly2fv function
ignores vertex order, you should follow the convention when creating
contours to ensure consistency with other functions.
Display a rectangular region with two holes using a single patch object.
% External contour, rectangle.
x1 = [0 0 6 6 0];
y1 = [0 3 3 0 0];
% First hole contour, square.
x2 = [1 2 2 1 1];
y2 = [1 1 2 2 1];
% Second hole contour, triangle.
x3 = [4 5 4 4];
y3 = [1 1 2 1];
% Compute face and vertex matrices.
[f, v] = poly2fv({x1, x2, x3}, {y1, y2, y3});
% Display the patch.
patch('Faces', f, 'Vertices', v, 'FaceColor', 'r', ...
'EdgeColor', 'none');
axis off, axis equal