KiteStrokePen
class KiteStrokePen
How a canvas strokes a path under a matrix. ISO 32000-1, 8.4.3.2 measures the line width and the dash lengths in user space, so the pen is a circle there. A matrix that scales x and y differently, or skews, turns the circle into an ellipse on the device, and one device width cannot draw it (#108). strokePen picks the space to stroke in.