screen.c

#include <stdio.h>
#include <stdarg.h>
#include <sys/ioctl.h>
#include "screen.h"

//this whole file is based on ansi escape codes:
//https://en.wikipedia.org/wiki/ANSI_escape_code

//These two varaibles will hold the terminal size after a call to screenInit
uint16_t screenWidth=0;
uint16_t screenHeight=0;

//Initialize the screen: get terminal size and hide the cursor
void screenInit(void)
{
 struct winsize window;
 //get window attributes
 ioctl(0,TIOCGWINSZ,&window);
 //save terminal width and height
 screenWidth=window.ws_col;
 screenHeight=window.ws_row;
 //hide the cursor
 printf("\033[?25l");
 //reset attributes so we don't have any terminal color affecting our print
 screenReset();
 //clear the screen so we don't have any terminal text left
 screenClear();
 fflush(stdout);
}

//Deinitialize the screen: reset attributes and show the cursor
void screenDeinit(void)
{
 //clear the screen so we don't leave any mess
 screenClear();
 //reset attributes so we don't leave any color
 screenReset();
 //show the cursor
 printf("\033[?25h");
 fflush(stdout);
}

//reset printing attributes
void screenReset(void)
{
 printf("\033[0m");
 fflush(stdout);
}

//clear the screen
void screenClear(void)
{
 printf("\033[H\033[J");
 fflush(stdout);
}

//put a char at x,y using current attributes
void screenPut(int8_t x,int8_t y,uint8_t c)
{
 printf("\033[%d;%dH%c",y+1,x+1,c);
 fflush(stdout);
}

//put a char at x,y changing foreground and background colors
void screenColorPut(int8_t x,int8_t y,int8_t fg,int8_t bg,uint8_t c)
{
 printf("\033[%d;%dH\033[%d;%dm%c",y+1,x+1,bg+10,fg,c);
 //reset the screen attributes since this fg and bg are just for this print
 screenReset();
 fflush(stdout);
}

//print a string at x,y using current attributes
void screenPrint(int8_t x,int8_t y,char* format,...)
{
 va_list argumentList;
 //get the variadic function arguments
 va_start(argumentList,format);
 printf("\033[%d;%dH",y+1,x+1);
 //use vprintf since it takes a va_list while printf takes a ...
 vprintf(format,argumentList);
 fflush(stdout);
 va_end(argumentList);
}

//print a string at x,y changing foreground and background colors
void screenColorPrint(int8_t x,int8_t y,int8_t fg,int8_t bg,char* format,...)
{
 va_list argumentList;
 va_start(argumentList,format);
 printf("\033[%d;%dH\033[%d;%dm",y+1,x+1,bg+10,fg);
 vprintf(format,argumentList);
 //reset the screen attributes since this fg and bg are just for this print
 screenReset();
 fflush(stdout);
 va_end(argumentList);
}

//draw a box from x0,y0 to x1,y1 with fg and bg colors
void screenBox(int8_t x0,int8_t y0,int8_t x1,int8_t y1,int8_t fg,int8_t bg)
{
 //draw all four corner
 screenColorPut(x0,y0,fg,bg,'+');
 screenColorPut(x1,y0,fg,bg,'+');
 screenColorPut(x0,y1,fg,bg,'+');
 screenColorPut(x1,y1,fg,bg,'+');
 //draw 2 horizontal line
 for(int8_t dx=x0+1;dx<x1;dx++)
 {
  screenColorPut(dx,y0,fg,bg,'-');
  screenColorPut(dx,y1,fg,bg,'-');
 }
 //draw two vertical line
 for(int8_t dy=y0+1;dy<y1;dy++)
 {
  screenColorPut(x0,dy,fg,bg,'|');
  screenColorPut(x1,dy,fg,bg,'|');
 }
 //fill the box
 for(int8_t dy=y0+1;dy<y1-1;dy++)
 {
  for(int8_t dx=x0+1;dx<x1-1;dx++)
  {
   screenColorPut(dx,dy,fg,bg,' ');
  }
 }
}

//change foreground and background colors attribute
void screenColor(int8_t fg,int8_t bg)
{
 printf("\033[%d;%dm",bg+10,fg);
 fflush(stdout);
}