Inside Macintosh: Mac OS 8 Toolbox Reference /

Chapter 2 - Control Manager Reference / Control Manager Functions

Manipulating Controls /

ShowControl

CHANGED WITH THE APPEARANCE MANAGER

Makes an invisible control, and any latent embedded controls, visible.

pascal void ShowControl (ControlHandle theControl);

theControl

On input, a handle to the control you want to make visible.

DISCUSSION

If the specified control is invisible, the ShowControl function makes it visible and immediately draws the control within its window without using your window's standard updating mechanism. If the specified control has embedded controls, ShowControl makes the embedded controls visible as well. If the control is already visible, ShowControl has no effect.

If you call ShowControl on a latent embedded control whose embedder is disabled, the embedded control will be invisible until its embedder control is enabled. For a discussion of latency, see "Manipulating Controls".

You can make a control invisible in several ways:

• Specifying its invisibility in the control resource.
• Passing a value of false in the visible parameter of NewControl.
• Calling HideControl.
• Calling SetControlVisibility. The setting takes effect the next time the control is drawn.

SPECIAL CONSIDERATIONS

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

WHEN THE APPEARANCE MANAGER IS NOT AVAILABLE

ShowControl only makes the specified control visible, because embedding hierarchies are not supported.