ColoredText - How to Print Colored Text using Java

• Download demo - 4.6 KB

Introduction

It can be very useful to emphasize some of our text prints with some colors. We can do that using a standard print command, by adding some escape sequences. Since it can be annoying to manually write the appropriate escape sequence every time we need it, I created a helper class for simplifying this task:

package sz;

public class ColoredText {
    private static final String ESC_STR = "\u001B";
    private static final String RESET_ESC_SEQUENCE_STR = "\u001B[0m";

    private String coloredStr;

    private ColoredText(String text, int color) {
        coloredStr = toColoredStr(text, color);
    }

    private ColoredText(String initial, String text, int color) {
        coloredStr = initial + toColoredStr(text, color);
    }

    public static ColoredText with(String text, int color) {
        return new ColoredText(text, color);
    }

    public ColoredText plus(String text, int color) {
        return new ColoredText(coloredStr, text, color);
    }

    public void print() {
        System.out.print(coloredStr);
    }

    public void println() {
        System.out.println(coloredStr);
    }

    @Override
    public String toString() {
        return coloredStr;
    }

    private String toEscSequenceStr(int color) {
        int foreground = 30;
        foreground += color & 0x07;
        color >>= 3;
        foreground += 60 * (color & 0x01);
        color >>= 1;

        int background = 40;
        background += color & 0x07;
        color >>= 3;
        background += 60 * (color & 0x01);

        return String.format("%s[%d;%dm", ESC_STR, foreground, background);
    }

    private String toColoredStr(String text, int color) {
        return String.format("%s%s%s", toEscSequenceStr(color), text, RESET_ESC_SEQUENCE_STR);
    }
}

This class takes a text, and a 8 bits number for the color. Then, it uses the appropriate escape sequences for defining the needed colors for the text. The given 8 bits color is constructed with a foreground color (the lower 4 bits), and a background color (the higher 4 bits).

For demonstrating the usage of this class, I created a simple program that prints a colors table, and a colored smiley:

import sz.ColoredText;

public class Main {
    public static void main(String[] args) {
        ColoredText.with("Colors table (", 0x8c).
                plus("hex values", 0x8a).plus("):", 0x8c).println();

        printColorsTable();

        System.out.println();

        printSmiley();
    }

    private static void printColorsTable() {
        for (int backgroundInx = 0; backgroundInx < 16; backgroundInx++) {
            for (int foregroundInx = 0; foregroundInx < 16; foregroundInx++) {
                ColoredText.with(" " + Integer.toHexString(backgroundInx) + 
                                       Integer.toHexString(foregroundInx),
                        (backgroundInx << 4) + foregroundInx).print();
            }

            System.out.println();
        }
    }

    private static void printSmiley() {
        int[][] colorsMatrix = {
            {0x00, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x00},
            {0x30, 0x30, 0xf0, 0xf0, 0xf0, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0x30, 0x30},
            {0x30, 0x30, 0xf0, 0xc0, 0xf0, 0x30, 0x30, 0xf0, 0xc0, 0xf0, 0x30, 0x30},
            {0x30, 0x30, 0xf0, 0xf0, 0xf0, 0x30, 0x30, 0xf0, 0xf0, 0xf0, 0x30, 0x30},
            {0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30},
            {0x30, 0x30, 0x30, 0x30, 0x30, 0xb0, 0xb0, 0x30, 0x30, 0x30, 0x30, 0x30},
            {0x30, 0x30, 0x30, 0x30, 0x30, 0xb0, 0xb0, 0x30, 0x30, 0x30, 0x30, 0x30},
            {0x30, 0x30, 0x90, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x90, 0x30, 0x30},
            {0x30, 0x30, 0x30, 0x90, 0x30, 0x30, 0x30, 0x30, 0x90, 0x30, 0x30, 0x30},
            {0x30, 0x30, 0x30, 0x30, 0x90, 0x30, 0x30, 0x90, 0x30, 0x30, 0x30, 0x30},
            {0x30, 0x30, 0x30, 0x30, 0x30, 0x90, 0x90, 0x30, 0x30, 0x30, 0x30, 0x30},
            {0x00, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x00}
        };

        for (int j = 0; j < 12; j++) {
            for (int i = 0; i < 12; i++) {
                ColoredText.with("  ", colorsMatrix[j][i]).print();
            }

            System.out.println();;
        }
    }
}

The result is:

History

• 14^th January, 2022: Initial version