In MATLAB, there are many functions that create regions filled with solid colors (e.g. contourf, area, bar). To do this, a function creates "patch objects" and assigns a single color to each one. Instead of a solid fill, one often wants to fill a patch with a hatch or speckle pattern instead. MATLAB has no built-in way to do this.
The hatchfill function fills patch objects with hatching or speckling. In most cases, adding hatching to a 2D plot requires only three lines of code. For example:
[c,h] = contourf(x,y,z,[0 0]);
hp = findobj(h,'type','patch');
This fills the zero contour with hatching. Hatchfill takes additional parameters if custom patterns are desired. This package incorporates code from Rich Pawlowicz, Iram Weinstein, and Kirill Pankratov.