Gets color of a block in Fabric 1.20.[1-2-3-4] and prints its RGB, HSL, CMYK, HEX and decimal value.

ColorPicker.java

package io.github.densamisten.color_picker.client;

import net.fabricmc.api.ClientModInitializer;
import net.fabricmc.fabric.api.client.keybinding.v1.KeyBindingHelper;
import net.fabricmc.fabric.api.event.player.UseBlockCallback;
import net.minecraft.block.BlockState;
import net.minecraft.client.option.KeyBinding;
import net.minecraft.client.util.InputUtil;
import net.minecraft.text.ClickEvent;
import net.minecraft.text.Text;
import net.minecraft.util.ActionResult;
import net.minecraft.util.hit.HitResult;
import net.minecraft.util.math.BlockPos;
import org.lwjgl.glfw.GLFW;

public class ColorPickerClient implements ClientModInitializer {

    private boolean useBlockCallbackEnabled = true;

    private static final KeyBinding toggleUseBlockCallback = KeyBindingHelper.registerKeyBinding(new KeyBinding(
            "key.colorpicker.toggle",
            InputUtil.Type.KEYSYM,
            GLFW.GLFW_KEY_UNKNOWN, // Change this to the desired key
            "category.colorpicker"
    ));

    @Override
    public void onInitializeClient() {
// Register UseBlockCallback
        UseBlockCallback.EVENT.register((player, world, hand, hitResult) -> {
            if (hitResult.getType() == HitResult.Type.BLOCK) {
                if (toggleUseBlockCallback.wasPressed()) {
                    useBlockCallbackEnabled = !useBlockCallbackEnabled;
                    if (useBlockCallbackEnabled) {
                        player.sendMessage(Text.of("UseBlockCallback enabled."), false);
                    } else {
                        player.sendMessage(Text.of("UseBlockCallback disabled."), false);
                    }
                }

                if (useBlockCallbackEnabled) {
                    // Check if the player is looking at a block
                    BlockPos blockPos = hitResult.getBlockPos();
                    BlockState blockState = world.getBlockState(blockPos);

                    // Get the color of the block
                    int blockColor = blockState.getBlock().getDefaultMapColor().color;

                    // Convert color to RGB, HSL, and CMYK
                    int red = (blockColor >> 16) & 0xFF;
                    int green = (blockColor >> 8) & 0xFF;
                    int blue = blockColor & 0xFF;

                    // RGB to HEX conversion
                    String hex = String.format("#%02X%02X%02X", red, green, blue);

                    // RGB to HSL conversion
                    double[] hsl = rgbToHsl(red, green, blue);
                    double hue = hsl[0];
                    double saturation = hsl[1];
                    double lightness = hsl[2];

                    // RGB to CMYK conversion
                    double[] cmyk = rgbToCmyk(red, green, blue);
                    double cyan = cmyk[0];
                    double magenta = cmyk[1];
                    double yellow = cmyk[2];
                    double black = cmyk[3];

                    // Print information about the block color to the console
                    String concatenatedString = red + ", " + green + ", " + blue;

                    Text rgbInfo = Text.literal("RGB: " + red + "," + green + "," + blue).styled((style) -> style.withClickEvent(new ClickEvent(ClickEvent.Action.COPY_TO_CLIPBOARD, concatenatedString)));
                    Text hexInfo = Text.literal("HEX: " + hex).styled((style) -> style.withClickEvent(new ClickEvent(ClickEvent.Action.COPY_TO_CLIPBOARD, hex)));
                    Text hslInfo = Text.literal("HSL: Hue: " + hue + ", Saturation: " + saturation + ", Lightness: " + lightness).styled((style) -> style.withClickEvent(new ClickEvent(ClickEvent.Action.COPY_TO_CLIPBOARD, "Hue: " + hue + ", Saturation: " + saturation + ", Lightness: " + lightness)));
                    String concatenatedCmykString = cyan + ", " + magenta + ", " + yellow + ", " + black;
                    Text cmykInfo = Text.literal("CMYK: Cyan: " + cyan + ", Magenta: " + magenta + ", Yellow: " + yellow + ", Black: " + black).styled((style) -> style.withClickEvent(new ClickEvent(ClickEvent.Action.COPY_TO_CLIPBOARD, concatenatedCmykString)));
                    Text decimalInfo = Text.literal("DECIMAL: " + blockColor).styled((style) -> style.withClickEvent(new ClickEvent(ClickEvent.Action.COPY_TO_CLIPBOARD, String.valueOf(blockColor))));
                    player.sendMessage(rgbInfo);
                    player.sendMessage(hexInfo);
                    player.sendMessage(hslInfo);
                    player.sendMessage(cmykInfo);
                    player.sendMessage(decimalInfo);
                    return ActionResult.SUCCESS; // Consume the interaction if UseBlockCallback is enabled
                }
            }
            return ActionResult.PASS; // Allow other mods to handle the interaction
        });
    }   
    // Helper method to convert RGB to HSL
    private static double[] rgbToHsl(int r, int g, int b) {
        double hue, saturation, lightness;

        double red = r / 255.0;
        double green = g / 255.0;
        double blue = b / 255.0;

        double max = Math.max(red, Math.max(green, blue));
        double min = Math.min(red, Math.min(green, blue));

        // Calculating the hue
        if (max == min) {
            hue = 0; // Undefined hue
        } else if (max == red) {
            hue = ((green - blue) / (max - min)) % 6;
        } else if (max == green) {
            hue = (blue - red) / (max - min) + 2;
        } else {
            hue = (red - green) / (max - min) + 4;
        }
        hue *= 60;

        // Adjusting the negative hue
        if (hue < 0) {
            hue += 360;
        }

        // Calculating the lightness
        lightness = (max + min) / 2;

        // Calculating the saturation
        if (max == min) {
            saturation = 0;
        } else if (lightness <= 0.5) {
            saturation = (max - min) / (max + min);
        } else {
            saturation = (max - min) / (2 - (max + min));
        }

        return new double[]{hue, saturation, lightness};
    }

    // Helper method to convert RGB to CMYK
    private static double[] rgbToCmyk(int r, int g, int b) {
        double cyan, magenta, yellow, black;

        double red = r / 255.0;
        double green = g / 255.0;
        double blue = b / 255.0;

        black = 1 - Math.max(red, Math.max(green, blue));

        if (black == 1) {
            cyan = 0;
            magenta = 0;
            yellow = 0;
        } else {
            cyan = (1 - red - black) / (1 - black);
            magenta = (1 - green - black) / (1 - black);
            yellow = (1 - blue - black) / (1 - black);
        }

        return new double[]{cyan, magenta, yellow, black};
    }

}