Clears the screen in both text modes and graphics modes
Syntax
Usage
Cls mode
Parameters
mode
A optional numeric variable with a value from 0 to 2.
Description
An optional
mode parameter may be given,
If omitted, CLS clears either the text or graphics viewport. If a graphics viewport has been defined using the
View (Graphics) statement, the graphics viewport is cleared. Otherwise, if a text viewport has been defined, it is cleared. Otherwise, the entire screen is cleared.
If 0, clears the entire screen
If 1, clears the graphics viewport if defined. Otherwise, clears the entire screen.
If 2, clears the text viewport
Example
Color , 1
Cls
Locate 12, 35
Print "Hello Universe!"
Using C's
memset instead of CLS might give you a speed boost:
#include "crt.bi"
Const x_res = 640, y_res = 480, bpp = 32
Dim scrbuf As Any Ptr, scrsize As Integer
Dim i As Integer, j As Integer
ScreenRes x_res, y_res, bpp
scrbuf = ScreenPtr
scrsize = x_res * y_res * bpp / 8
Do
ScreenLock
memset scrbuf, 0, scrsize
Circle (320, 240), i
ScreenUnlock
If j = 0 Then
i = i + 1
If i >= 100 Then j = 1
ElseIf j = 1 Then
i = i - 1
If i <= 0 Then j = 0
End If
Sleep 1, 1
Loop While Inkey=""
Differences from QB
See also