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// SPDX-License-Identifier: GPL-2.0
#ifndef SCREEN_H
#define SCREEN_H
/**
* \file
*
* Provides the display interface. It provides an 80x25 VGA-compatible text
* display.
*
*//*
* Copyright (C) 2020-2024 Martin Whitaker.
*/
#include <stdint.h>
/**
* Screen size definitions. The screen size cannot be changed.
*/
#define SCREEN_WIDTH 80
#define SCREEN_HEIGHT 25
typedef union {
struct {
uint8_t ch;
uint8_t attr;
};
struct {
uint16_t value;
};
} vga_char_t;
typedef vga_char_t vga_buffer_t[SCREEN_HEIGHT][SCREEN_WIDTH];
/**
* Colours that can be used for the foreground or background.
*/
typedef enum {
BLACK = 0,
BLUE = 1,
GREEN = 2,
CYAN = 3,
RED = 4,
MAUVE = 5,
YELLOW = 6,
WHITE = 7
} screen_colour_t;
/**
* BIOS/UEFI(GOP) agnostic framebuffer copy
*/
extern vga_buffer_t shadow_buffer;
/**
* Modifier that can be added to any foreground colour.
* Has no effect on background colours.
*/
#define BOLD 8
/**
* Initialise the display interface.
*/
void screen_init(void);
/**
* Set the foreground colour used for subsequent drawing operations.
*/
void set_foreground_colour(screen_colour_t colour);
/**
* Set the background colour used for subsequent drawing operations.
*/
void set_background_colour(screen_colour_t colour);
/**
* Clear the whole screen, using the current background colour.
*/
void clear_screen(void);
/**
* Clear the specified region of the screen, using the current background
* colour.
*/
void clear_screen_region(int start_row, int start_col, int end_row, int end_col);
/**
* Move the contents of the specified region of the screen up one row,
* discarding the top row, and clearing the bottom row, using the current
* background colour.
*/
void scroll_screen_region(int start_row, int start_col, int end_row, int end_col);
/**
* Copy the contents of the specified region of the screen into the supplied
* buffer.
*/
void save_screen_region(int start_row, int start_col, int end_row, int end_col, uint16_t buffer[]);
/**
* Restore the specified region of the screen from the supplied buffer.
* This restores both text and colours.
*/
void restore_screen_region(int start_row, int start_col, int end_row, int end_col, const uint16_t buffer[]);
/**
* Write the supplied character to the specified screen location, using the
* current foreground colour. Has no effect if the location is outside the
* screen.
*/
void print_char(int row, int col, char ch);
#endif // SCREEN_H
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