Layer styles are not tools in the common sense, because they don’t modify the content of a layer. Layer styles are more like attributes, which are assigned to a layer in order to modify its appearance. PhotoLine offers many different styles like shadows, glowing, lighting styles and pattern overlay (see chapter 7.8.40).
Here is a small example to demonstrate the advantage of this technique:
Many image-processing applications have a shadow feature. It creates a shadow behind the active layer, so that the layer seems to float over the background. This is achieved by drawing the shadow in the layer itself or by creating an additional layer lying behind the active layer. Both ways work quite well. But it is awkward, if you have to change your layer later, because the shadow is not changed accordingly.
With the shadow being a layer style the situation is different. Every time a layer is changed, the shadow is adjusted automatically.
Of course layer styles can be drawn directly into a layer (see chapter 7.5.26). But then they won’t adjust to the layer content any longer.