The dimensions of a geometric pen are specified in logical units. Therefore, lines drawn with a geometric pen can be scaled — that is, they may appear wider or narrower, depending on the current world transformation. For more information about the world transformation, see Coordinate Spaces and Transformations.
In addition to the three attributes shared with cosmetic pens (width, style, and color), geometric pens possess the following four attributes: pattern, optional hatch, end style, and join style. For more information about these attributes, see Pen Attributes.
To create a geometric pen, an application uses the ExtCreatePen function. As with cosmetic pens, the SelectObject function selects a geometric pen into the application's DC.