Printing color strings uses only printf, without any alternative libraries such as ncurses? Yes, we can do that in any unix based operating system that support ANSI codes, I am not sure whether it works on either windows or mac, have no chance to try at the moment.
By feeding some magic characters to printf, you can manipulate your fore color, background color and even attributes. Lets look at a simple example to print “Hello World” in Bright Red with background black.
#define BRIGHT 1 #define RED 31 #define BG_BLACK 40 printf("%c[%d;%d;%dmHello World", 0x1B, BRIGHT,RED,BG_BLACK);
Okay, the code above print the string with bright red but the color setting will remain, to reset back the color to default, refers the code as bellow:
printf("%c[%dm", 0x1B, 0);
The fore color, background color and attributes codes are shown as bellow
Text attributes 0 All attributes off 1 Bold on 4 Underscore (on monochrome display adapter only) 5 Blink on 7 Reverse video on 8 Concealed on Foreground colors 30 Black 31 Red 32 Green 33 Yellow 34 Blue 35 Magenta 36 Cyan 37 White Background colors 40 Black 41 Red 42 Green 43 Yellow 44 Blue 45 Magenta 46 Cyan 47 White
How’s the color magic works? 0x1B is a special code that used to do all the color settings. 0x1B is hex code equivalent to decimal 27. With character(27) and a open square blacket “[“, initiate the setting. The rest of the values are (attribute);(fore color);(background color) and it ends the setting with ” m “. So entire thing will be look like this:
With that the rest of your print line will be in bright yellow with background color black.
I have transparent background, What if I want my default background instead of any color?
Simple, ignore the background color, How?
The line above will print bright yellow “Hello World” with default bg color.