ol.style.StrokePattern set stroke pattern style to vector features. It uses the cartographic patterns of the ol.style.FillPattern.
Hatching can be defined with a size for the lines, spacing interval and an angle.
Cross, square, tile, dot and circle patterns can be defines with a size and spacing interval. The angle option is a boolean (0|1) for 45° pattern.
You can use font to create a pattern (like FontAwesome patterns in the example ). NB the font must be loaded before pattern creation.