SCREEN (GRAPHICS)

Source: https://www.freebasic.net/wiki/wikka.php?wakka=KeyPgScreengraphics Last revised: 2023-07-12

Initializes a graphics mode using QB-like mode numbers.

Syntax

-lang fb|fblite dialects:

Screen mode [, [depth] [, [num_pages] [, [flags] [, [refresh_rate]]]]]
Screen , [active_page] [, [visible_page]]

-lang qb dialect:

Screen [mode] [, [colormode] [, [active_page] [, [visible_page]]]]

Parameters

• mode — QB-style screen mode number. If 0, closes the graphics mode and returns to console.
• depth — Color depth in bits per pixel for modes 14+: 8, 16, or 32 (15 and 24 are aliases for 16 and 32). Default: 8.
• num_pages — Number of video pages. Default: 1.
• flags — Graphics driver options; constants defined in fbgfx.bi (see Screenres for details).
• refresh_rate — Requested refresh rate.
• active_page — Page where drawing commands take effect.
• visible_page — Page shown to the user.
• colormode — Unused; allowed for QB syntax compatibility.

Description

Screen links the GfxLib and initializes a graphics mode. QB-like graphics and console statements can be used in QB-only and QB-on-GUI modes.

If Screen fails to set the required mode, an "Illegal function call" error is issued. Failures can be detected using On Error or by checking ScreenPtr.

Available Modes

QB compatibility modes:

Mode	Resolution	Emulation	Colors
1	320×200	CGA	16 bg, 4 fg
2	640×200	CGA	2 colors
7	320×200	EGA	16 colors
8	640×200	EGA	16 colors
9	640×350	EGA	16 colors
11	640×480	VGA	2 colors
12	640×480	VGA	16 colors
13	320×200	MCGA	256 colors

FreeBASIC extended modes:

Mode	Resolution
14	320×240
15	400×300
16	512×384
17	640×400
18	640×480
19	800×600
20	1024×768
21	1280×1024

Examples

' Sets screen mode 13 (320×200, 8bpp)
Screen 13
Print "Screen mode 13 set"
Sleep

#include "fbgfx.bi"
#if __FB_LANG__ = "fb"
Using FB
#endif
' Sets 640×480, 32bpp, 4 pages, windowed, switching disabled
Screen 18, 32, 4, (GFX_WINDOWED Or GFX_NO_SWITCH)
If ScreenPtr = 0 Then
    Print "Error setting video mode!"
    End
End If
Print "Successfully set video mode"
Sleep

Platform Differences

• In DOS, windowing and OpenGL options are not available.

Differences from QB

• None in the -lang qb dialect.
• In QB, syntax was Screen mode, colormode, active_page, visible_page; FreeBASIC redefines these parameters.
• Screenset should be used in -lang fb and -lang fblite for page management.

See Also

• Screenres
• Screenset
• ScreenPtr
• ScreenInfo
• ScreenList
• ScreenLock
• ScreenUnlock