Declare Sub ScreenCopy ( ByVal frompage As Integer = -1, ByVal topage As Integer = -1 )

ScreenCopy [ from_page ] [, to_page ]

frompage
topage

from_page is the page to copy from. If this argument is omitted, the current work page is assumed.

to_page is the page to copy to. If this argument is omitted, the currently visible page is assumed.

Page numbers range from 0 to the num_pages specified when setting the graphics mode minus 1

You can use this function to add a double buffer to your graphics. Any graphics screen mode supports this function; you must supply valid page numbers otherwise ScreenCopy will have no effect.

There are two other functons similar to this: Flip and PCopy. Flip is designed to work in OpenGL modes, while PCopy supports console pages on some platforms. Both do the same thing as ScreenCopy in normal graphics modes.

Example:
See ScreenSet example.

'' 320x200x8, with 3 pages
Screen 13,,3

'' image for page #1
ScreenSet 1, 0
Cls
Circle( 160, 100 ), 90, 1 ,,,, f
Circle( 160, 100 ), 90, 15
Print "Press 2 to copy page #2 to visible page"
Print "Press escape to exit"

'' image for page #2
ScreenSet 2, 0
Cls
Line( 50, 50 )-( 270, 150 ), 2, bf
Line( 50, 50 )-( 270, 150 ), 15, b
Print "Press 1 to copy page #1 to visible page"
Print "Press escape to exit"

'' page #0 is the visible page
ScreenSet 0, 0
Cls
Print "Press 1 to copy page #1 to visible page"
Print "Press 2 to copy page #2 to visible page"
Print "Press escape to exit"

Dim k As String

Do
  k = Inkey
  Select Case k
  Case Chr(27)
    Exit Do
  Case "1"
    ScreenCopy 1, 0
  Case "2"
    ScreenCopy 2, 0
  End Select

  Sleep 25
Loop

• Not available in the -lang qb dialect unless referenced with the alias __Screencopy.
  
  

• New to FreeBASIC. QB had PCopy to do the same function.
  
  

• Screen (Graphics)
  
• ScreenRes
  
• ScreenSet