.\"	$OpenBSD: rasops.9,v 1.18 2017/08/21 11:49:50 fcambus Exp $
.\"     $NetBSD: rasops.9,v 1.4 2002/02/13 08:18:50 ross Exp $
.\"
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.\" by Gregory McGarry.
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.Dd $Mdocdate: August 21 2017 $
.Dt RASOPS 9
.Os
.Sh NAME
.Nm rasops ,
.Nm rasops_init ,
.Nm rasops_reconfig
.Nd raster display operations
.Sh SYNOPSIS
.In dev/wscons/wsdisplayvar.h
.In dev/rasops/rasops.h
.Ft int
.Fn rasops_init "struct rasops_info *ri" "int wantrows" "int wantcols"
.Ft int
.Fn rasops_reconfig "struct rasops_info *ri" "int wantrows" "int wantcols"
.Sh DESCRIPTION
The
.Nm
subsystem is a set of raster operations for
.Xr wscons 4 .
.Pp
The primary data type for using the raster operations is the
.Em rasops_info
structure in
.Pa dev/rasops/rasops.h :
.Bd -literal
struct rasops_info {

	/*
	 * These must be filled in by the caller
	 */
	int	ri_depth;	/* depth in bits */
	u_char	*ri_bits;	/* ptr to bits */
	int	ri_width;	/* width (pels) */
	int	ri_height;	/* height (pels) */
	int	ri_stride;	/* stride in bytes */

	/*
	 * These can optionally be left zeroed out. If you fill ri_font,
	 * but aren't using wsfont, set ri_wsfcookie to -1.
	 */
	struct	wsdisplay_font *ri_font;
	int	ri_wsfcookie;	/* wsfont cookie */
	void	*ri_hw;		/* driver private data */
	struct wsdisplay_charcell *ri_bs; /* character backing store */
	int	ri_crow;	/* cursor row */
	int	ri_ccol;	/* cursor column */
	int	ri_flg;		/* various operational flags */

	/*
	 * These are optional and will default if zero. Meaningless
	 * on depths other than 15, 16, 24 and 32 bits per pel. On
	 * 24 bit displays, ri_{r,g,b}num must be 8.
	 */
	u_char	ri_rnum;	/* number of bits for red */
	u_char	ri_gnum;	/* number of bits for green */
	u_char	ri_bnum;	/* number of bits for blue */
	u_char	ri_rpos;	/* which bit red starts at */
	u_char	ri_gpos;	/* which bit green starts at */
	u_char	ri_bpos;	/* which bit blue starts at */

	/*
	 * These are filled in by rasops_init()
	 */
	int	ri_emuwidth;	/* width we actually care about */
	int	ri_emuheight;	/* height we actually care about */
	int	ri_emustride;	/* bytes per row we actually care about */
	int	ri_rows;	/* number of rows (characters) */
	int	ri_cols;	/* number of columns (characters) */
	int	ri_delta;	/* row delta in bytes */
	int	ri_pelbytes;	/* bytes per pel (may be zero) */
	int	ri_fontscale;	/* fontheight * fontstride */
	int	ri_xscale;	/* fontwidth * pelbytes */
	int	ri_yscale;	/* fontheight * stride */
	u_char  *ri_origbits;	/* where screen bits actually start */
	int	ri_xorigin;	/* where ri_bits begins (x) */
	int	ri_yorigin;	/* where ri_bits begins (y) */
	int32_t	ri_devcmap[16]; /* color -\*[Gt] framebuffer data */

	/*
	 * The emulops you need to use, and the screen caps for wscons
	 */
	struct	wsdisplay_emulops ri_ops;
	int	ri_caps;

	/*
	 * Callbacks so we can share some code
	 */
	void	(*ri_do_cursor)(struct rasops_info *);
	void	(*ri_updatecursor)(struct rasops_info *);

#if NRASOPS_ROTATION > 0
	/* Used to intercept putchar to permit display rotation */
	struct	wsdisplay_emulops ri_real_ops;
#endif
};
.Ed
.Pp
The value of the
.Em ri_flg
member is formed by OR'ing the following values:
.Pp
.Bl -tag -offset indent -width RI_CLEARMARGINS -compact
.It RI_FULLCLEAR
Force eraserows() to clear the whole screen instead of only text lines,
when invoked with an
.Em nrows
parameter equal to the number of text lines.
.It RI_FORCEMONO
Do not output coloured text, even if the display supports it.
.It RI_BSWAP
Specifies that the frame buffer endianness is different from the CPU's.
.It RI_CURSOR
Set when the text cursor is enabled.
.It RI_CLEAR
Clear the display upon initialization.
.It RI_CLEARMARGINS
Clear display margins upon initialization.
.It RI_CENTER
Center the text area.
.\" Only honoured if option RASOPS_CLIPPING which we don't use.
.\" .It RI_CURSORCLIP
.\" Cursor is currently clipped
.It RI_ROTATE_CW
Rotate the text display quarter clockwise.
.It RI_ROTATE_CCW
Rotate the text display quarter counter-clockwise.
.It RI_CFGDONE
.Fn rasops_reconfig
completed successfully
.It RI_VCONS
Support the use of multiple screens.
.It RI_WRONLY
Do not read back pixels from the frame buffer memory when performing
screen-to-screen copy operations.
This flag is ignored unless
.Dv RI_VCONS
is set or the
.Em ri_bs
member is set.
.El
.Sh FUNCTIONS
.Bl -tag -width compact
.It Fn rasops_init "ri" "wantrows" "wantcols"
Initialise a
.Em rasops_info
descriptor.
The arguments
.Fa wantrows
and
.Fa wantcols
are the number of rows and columns we'd like.
In terms of
optimization, fonts that are a multiple of 8 pixels wide work the
best.
.It Fn rasops_reconfig "ri" "wantrows" "wantcols"
Reconfigure a
.Em rasops_info
descriptor because parameters have changed in some way.
The arguments
.Fa wantrows
and
.Fa wantcols
are the number of rows and columns we'd like.
If calling
.Fn rasops_reconfig
to change the font and ri_wsfcookie \*[Ge] 0, you must call
.Fn wsfont_unlock
on it, and reset it to -1 (or a new, valid cookie).
.El
.Sh CODE REFERENCES
This section describes places within the
.Ox
source tree where actual code implementing or utilising the rasops
subsystem can be found.
All pathnames are relative to
.Pa /usr/src .
.Pp
The rasops subsystem is implemented within the directory
.Pa sys/dev/rasops .
The
.Nm
module itself is implemented within the file
.Pa sys/dev/rasops/rasops.c .
.Sh SEE ALSO
.Xr intro 9
.\" XXX These don't exist yet
.\" .Xr wscons 9 ,
.\" .Xr wsdisplay 9 ,
.\" .Xr wsfont 9
.Sh HISTORY
The
.Nm
subsystem appeared in
.Nx 1.5
and
.Ox
first support appeared in
.Ox 2.9 .
.Sh AUTHORS
.An -nosplit
The
.Nm
subsystem was written by
.An Andrew Doran Aq Mt ad@NetBSD.org .
Display rotation was written by
.An Christopher Pascoe Aq Mt pascoe@openbsd.org .
.Sh CAVEATS
Display rotation only works for 16bpp displays.