Legacy Document

Inside Macintosh: Imaging With QuickDraw /

Chapter 3 - QuickDraw Drawing / QuickDraw Drawing Reference

Routines / Managing the Graphics Pen

ShowPen

To change the ink of a graphics pen from invisible (which means that pen drawing doesn't show on the screen) to visible (so that pen drawing does appear on the screen), you can use the ShowPen procedure.

PROCEDURE ShowPen; 

DESCRIPTION

The ShowPen procedure increments the pnVis field of the current graphics port. For 0 or positive values, pen drawing shows on the screen.

For example, if you have used the HidePen procedure to decrement the pnVis field from 0 to -1, you can use the ShowPen procedure to make its value 0 so that QuickDraw resumes drawing on the screen. Subsequent calls to ShowPen increment pnVis beyond 0, so every call to ShowPen should be balanced by a call to HidePen.

ShowPen is called by the procedures CloseRgn (described on page 3-85), ClosePoly (described on page 3-75), and ClosePicture (described in the chapter "Pictures" in this book).