TextWindow Class Reference

Virtual windows in text mode. More...

#include <textwindow.h>

Inheritance diagram for TextWindow:

Collaboration diagram for TextWindow:

Public Member Functions
	TextWindow (unsigned from_col, unsigned to_col, unsigned from_row, unsigned to_row, bool use_cursor=false)
	Constructor of a text window.
void	setPos (unsigned rel_x, unsigned rel_y)
	Set the cursor position in the window.
void	getPos (unsigned &rel_x, unsigned &rel_y) const
	Get the current cursor position in the window.
void	print (const char *string, size_t length, Attribute attrib=TextMode::Attribute())
	Display multiple characters in the window.
void	reset (char character=' ', Attribute attrib=TextMode::Attribute())
	Delete all contents in the window and reset the cursor.

Protected Attributes
unsigned	from_col
	Start column position (inclusive) of window.
unsigned	to_col
	End column position (exclusive) of window.
unsigned	from_row
	Start row position (inclusive) of window.
unsigned	to_row
	End row position (exclusive) of window.
bool	use_cursor
	use hardware cursor
unsigned	pos_x
	Software cursor column.
unsigned	pos_y
	Software cursor row.

Private Member Functions
void	scrollUp () const
	Scroll the contents of a window a line up.

Additional Inherited Members
Public Types inherited from TextMode
enum	Color {   BLACK , BLUE , GREEN , CYAN ,   RED , MAGENTA , BROWN , LIGHT_GREY ,   DARK_GREY , LIGHT_BLUE , LIGHT_GREEN , LIGHT_CYAN ,   LIGHT_RED , LIGHT_MAGENTA , YELLOW , WHITE }
	CGA color palette. More...
Static Public Member Functions inherited from TextMode
static void	setCursor (unsigned abs_x, unsigned abs_y)
	Set the keyboard hardware cursor to absolute screen position.
static void	getCursor (unsigned &abs_x, unsigned &abs_y)
	Retrieve the keyboard hardware cursor position on screen.
static void	show (unsigned abs_x, unsigned abs_y, char character, Attribute attrib=Attribute())
	Basic output of a character at a specific position on the screen.
Static Public Attributes inherited from TextMode
static const unsigned	ROWS = 25
	Visible rows in text mode.
static const unsigned	COLUMNS = 80
	Visible columns in text mode.
Protected Member Functions inherited from TextMode
	TextMode ()
	Default constructor.
Static Protected Attributes inherited from TextMode
static Cell *const	TEXT_BUFFER_BASE = reinterpret_cast<TextMode::Cell *>(0xb8000)
	Base address for linear text buffer in video memory.

Detailed Description

Virtual windows in text mode.

Outputs text on a part of the screen in text mode, a window defined in its position and size (with its own cursor).

This allows to separate the output of the application from the debug output on the screen without having to synchronize.

Constructor & Destructor Documentation

TextWindow()

TextWindow::TextWindow	(	unsigned	from_col,
		unsigned	to_col,
		unsigned	from_row,
		unsigned	to_row,
		bool	use_cursor = false )

Constructor of a text window.

Creates a virtual, rectangular text window on the screen. The coordinates to construct the window are absolute positions in the TextMode screen.

Note

Overlapping windows are neither supported nor prevented – better just try to avoid construction windows with overlapping coordinates!

Warning

Don't use the hardware cursor in more than one window!

Parameters

from_col	Text Window starts in column from_col, the first (leftmost) possible column is 0
to_col	Text Window extends to the right to column to_col (exclusive). This column has to be strictly greater than from_col, the maximum allowed value is TextMode::COLUMNS (rightmost)
from_row	Text Window starts in row from_row, the first possible (uppermost) row is 0
to_row	Text Window extends down to row to_row (exclusive). This row has to be strictly greater than from_row, the maximum allowed value is TextMode::ROWS (bottom-most)
use_cursor	Specifies whether the hardware cursor (true) or a software cursor/variable (false) should be used to store the current position

Member Function Documentation

getPos()

void TextWindow::getPos	(	unsigned &	rel_x,
		unsigned &	rel_y ) const

Get the current cursor position in the window.

Depending on the constructor parameter use_cursor either the hardware cursor (and only the hardware cursor!) is used or the position is retrieved from the internally stored object.

Parameters

rel_x	Column in window
rel_y	Row in window

print()

void TextWindow::print	(	const char *	string,
		size_t	length,
		Attribute	attrib = TextMode::Attribute() )

Display multiple characters in the window.

Output a character string, starting at the current cursor position. Since the string does not need to contain a \0 termination (unlike the common C string), a length parameter is required to specify the number of characters in the string. When the output is complete, the cursor is positioned after the last printed character. The same attributes (colors) are used for the entire text.

If there is not enough space left at the end of the line, the output continues on the following line. As soon as the last window line is filled, the entire window area is moved up one line: The first line disappears, the bottom line is cleared.

A line break also occurs whenever the character \n appears in the text.

Parameters

string	Text to be printed
length	Length of text
attrib	Attribute for text

reset()

void TextWindow::reset	(	char	character = ' ',
		Attribute	attrib = TextMode::Attribute() )

Delete all contents in the window and reset the cursor.

Parameters

character	Fill character
attrib	Attribute for fill character

scrollUp()

void TextWindow::scrollUp ( ) const

private

Scroll the contents of a window a line up.

Moves the screen content up one line. The new line at the bottom of the screen is filled with blanks.

setPos()

void TextWindow::setPos	(	unsigned	rel_x,
		unsigned	rel_y )

Set the cursor position in the window.

Depending on the constructor parameter use_cursor either the hardware cursor (and only the hardware cursor!) is used or the position is stored internally in the object.

The coordinates are relative to the upper left starting position of the window.

Parameters

rel_x	Column in window
rel_y	Row in window

Member Data Documentation

use_cursor

bool TextWindow::use_cursor

protected

use hardware cursor

otherwise the position is stored in local variables

---

The documentation for this class was generated from the following files:

• machine/textwindow.h
• machine/textwindow.cc