QuickTime 4 Reference

The Geometric Pen

The contours of framed paths are drawn with the QuickDraw GX geometric pen. You can specify the width of this pen using the pen width property of the style object, and you can specify where to place the pen relative to the contours of a shape using the style attributes, which are described in "Style Attributes" .

Conceptually, the QuickDraw GX geometric pen is a line that QuickDraw GX drags along the contours of the shape being drawn--always keeping it perpendicular to the contours. In effect, the geometric pen turns a framed geometry into a filled one. For example, a line shape, which is always framed, becomes the equivalent of a filled polygon after QuickDraw GX applies the geometric pen.

Figure 19 shows the effect of the geometric pen. This figure shows two geometries-- a line geometry and a curve geometry--and how QuickDraw GX draws them with a pen width of 15.

Figure 19 The QuickDraw GX geometric pen

Notice that the ends of the thick line contour and the thick curve contour in Figure 19 are perpendicular to the direction of the contours themselves.

Figure 20 shows the effect of different pen widths on a semicircular path shape.

Figure 20 Differing pen widths