Basics of MATLAB and Beyond

Simple Two-Dimensional PatchesTo define a simple patch, specify the x and y coordinates and the facecolour:2x = [0 1 1 0];y = [0 0 1 1];patch(x,y,’y’)axis([-2 2 -2 2])10−1−2−2 −1 0 1 2The colour of the edge is black by default. The patch function automaticallycloses the edge if the last vertex is not the same as the first vertex.Patches are usually defined with noncrossing boundaries, but boundariescan cross if required:1x(4) = 2; y(4) = .5;clfpatch(x,y,’y’)0.80.60.40.200 0.5 1 1.5 2(The patch command is a low-level command, which means that it generatesa patch in the current axes without first clearing the axes. Thatis the reason for the clf above.)Between patches whose boundaries cross and those whose boundariesdo not cross are the patches whose boundaries “touch”. These can beused to create patches with holes:x = [0 .5 .5 .4 .5 .6 .5 .5 1 .5];y = [0 0 .1 .2 .3.2 .1 0 0 1];clfh = patch(x,y,’y’);10.80.60.40.200 0.5 1The tell-tale line between the outer boundary and the hole can be deletedby making it either invisible or the same colour as the face:10.8set(h,’edgecolor’,’none’)0.60.400 0.5 1(The command set(h,’edgecolor’,’y’) achieves the same effect.)But it would be nice to leave the edge boundary drawn around theshading; you just have to plot a line with the right points:0.2c○ 2000 by CRC Press LLC