[Overview][Constants][Types][Procedures and functions][Variables][Index] | Reference for unit 'video' (#rtl)

# UpdateScreen

Update physical screen with internal screen image.

## Declaration

Source position: videoh.inc line 134

`procedure UpdateScreen(`
`Force: Boolean`
`);`

## Description

UpdateScreen synchronizes the actual screen with the contents of the VideoBuf internal buffer. The parameter Force specifies whether the whole screen has to be redrawn (Force=True) or only parts that have changed since the last update of the screen.

The Video unit keeps an internal copy of the screen as it last wrote it to the screen (in the OldVideoBuf array). The current contents of VideoBuf are examined to see what locations on the screen need to be updated. On slow terminals (e.g. a Linux telnet session) this mechanism can speed up the screen redraw considerably.

On platforms where mouse cursor visibility is not guaranteed to be preserved during screen updates this routine has to restore the mouse cursor after the update (usually by calling HideMouse from unit Mouse before the real update and ShowMouse afterwards).

For an example, see most other functions.

## Errors

None.

## See also

ClearScreen |  | Clear the video screen.

Documentation generated on: May 14 2021