Legacy Document

Important: The information in this document is obsolete and should not be used for new development.

Inside Macintosh: Macintosh Toolbox Essentials /

Chapter 5 - Control Manager / Control Manager Reference

Control Manager Routines / Drawing Controls

ShowControl
To draw a control that is currently invisible, you can use the ShowControl procedure.
PROCEDURE ShowControl (theControl: ControlHandle);
theControl
A handle to the control you want to make visible.

DESCRIPTION
If the specified control is invisible, the ShowControl procedure makes it visible and immediately draws the control within its window without using your window's standard updating mechanism. If the control is already visible, ShowControl has
no effect.
You can make a control invisible in several ways:

You can specify that it's invisible in its control resource.
You can specify that it's invisible in a parameter to the NewControl function.
You can use the HideControl procedure to change a visible control into an invisible one.
You can directly change the contrlVis field of the control's control record.

SPECIAL CONSIDERATIONS
The ShowControl procedure draws the control in its window, but the control can still be completely or partially obscured by overlapping windows or other objects.

SEE ASO
Listing 5-14 on page 5-36 illustrates the use of ShowControl to redisplay scroll bars after moving and resizing them.