video_txt

Defines for character codes to draw single border frames
#define	VERT_BAR   0xB3
#define	HOR_BAR   0xC4
#define	LL_CORNER   0xC0
#define	UL_CORNER   0xDA
#define	LR_CORNER   0xD9
#define	UR_CORNER   0xBF
Module's external functions
char *	vt_init (vt_info_t *vi_p)
	Initializes the video module in text mode.
void	vt_fill (char ch, char attr)
	Fills the screen with the input character, with the specified attribute.
void	vt_blank ()
	Blanks screen.
int	vt_print_char (char ch, char attr, int r, int c)
	Prints a character on the screen.
int	vt_print_string (char *str, char attr, int r, int c)
	Prints a string on the screen.
int	vt_print_int (int n, char attr, int r, int c)
	Prints an integer on the screen.
int	vt_draw_frame (int width, int height, char attr, int r, int c)
	Draws a frame on the screen.

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Detailed Description

Functions for outputing data to screen in text mode

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Define Documentation

#define VERT_BAR   0xB3

CP437 code for vertical bar

#define HOR_BAR   0xC4

CP437 code for horizontal bar

#define LL_CORNER   0xC0

CP437 code for lower-left corner symbol

#define UL_CORNER   0xDA

CP437 code for upper-left corner symbol

#define LR_CORNER   0xD9

CP437 code for lower-right corner symbol

#define UR_CORNER   0xBF

CP437 code for upper-right corner symbol

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Function Documentation

char* vt_init

(

vt_info_t *

vi_p

)

Initializes the video module in text mode.

Maps VRAM to the process' address space and initializes static global variables with the resolution of the screen

Parameters:

vi_p	address of vt_info_t structure with the necessary information

Returns:

Virtual address VRAM was mapped to. NULL, upon failure.

void vt_fill	(	char	ch,
		char	attr
	)

Fills the screen with the input character, with the specified attribute.

Parameters:

ch	character to fill the screen with
attr	attribute of character to fill the screen with

int vt_print_char	(	char	ch,
		char	attr,
		int	r,
		int	c
	)

Prints a character on the screen.

Prints a character, with the specified attribute, at the specified position on the screen in text mode, by writing to the corresponding location in VRAM

Parameters:

ch	character to print
attr	attribute of character to print
r	row where to print (row 0 is the first one)
c	column where to print (column 0 is the first one)

Returns:

0 upon success, non-zero upon failure

int vt_print_string	(	char *	str,
		char	attr,
		int	r,
		int	c
	)

Prints a string on the screen.

Prints a string, with the specified attribute, at the specified position in the screen in text mode, by writing to the corresponding location in VRAM

Parameters:

str	string to print
attr	attribute of character to print
r	row where to print (row 0 is the first one)
c	column where to print (column 0 is the first one)

Returns:

0 upon success, non-zero upon failure

int vt_print_int	(	int	n,
		char	attr,
		int	r,
		int	c
	)

Prints an integer on the screen.

Prints an integer, with the specified attribute, at the specified position in the screen in text mode, by writing to the corresponding location in VRAM

Parameters:

n	integer number to print
attr	attribute of character to print
r	row where to print (row 0 is the first one)
c	column where to print (column 0 is the first one)

Returns:

0 upon success, non-zero upon failure

int vt_draw_frame	(	int	width,
		int	height,
		char	attr,
		int	r,
		int	c
	)

Draws a frame on the screen.

Draws a frame, with the specified dimensions and attribute, at the specified position in the screen in text mode, by writing to the corresponding location in VRAM

Parameters:

width	frame width in number of columns
height	frame heigth in number of lines
attr	attribute of frame to draw
r	row where to print top left corner (row 0 is the first one)
c	column where to print top left corner (column 0 is the first one)

Returns:

0 upon success, non-zero upon failure