ColoredBoxGroupAttribute.cs

using Sirenix.OdinInspector;
using Sirenix.Utilities;

#if UNITY_EDITOR
using Sirenix.OdinInspector.Editor;
using Sirenix.Utilities.Editor;
using UnityEditor;
#endif

using UnityEngine;

/// <summary>
///     <para>ColoredBoxGroup is used on any property and organizes the property in a boxed group with a colored header.</para>
///     <para>Use this to cleanly organize relevant values together in the inspector.</para>
/// </summary>
public class ColoredBoxGroupAttribute : PropertyGroupAttribute
{
    private static readonly byte[] GradientColorsLTR =
    {
        163, 163, 163, 254,
        165, 165, 165, 255,
        169, 169, 169, 254,
        171, 171, 171, 255,
        174, 174, 174, 255,
        176, 176, 176, 255,
        180, 180, 180, 255,
        182, 182, 182, 255,
        186, 186, 186, 255,
        189, 189, 189, 254,
        192, 192, 192, 255,
        194, 194, 194, 255,
        198, 198, 198, 254,
        200, 200, 200, 255,
        204, 204, 204, 254,
        206, 206, 206, 255,
        209, 209, 209, 255,
        212, 212, 212, 255,
        215, 215, 215, 255,
        219, 219, 219, 254,
        221, 221, 221, 255,
        224, 224, 224, 255,
        227, 227, 227, 255,
        231, 231, 231, 254,
        233, 233, 233, 255,
        237, 237, 237, 254,
        239, 239, 239, 255,
        242, 242, 242, 255,
        245, 245, 245, 254,
        248, 248, 248, 254,
        251, 251, 251, 255,
        254, 254, 254, 255
    };
    
    private static readonly byte[] GradientColorsRTL =
    {
        253, 253, 253, 254,
        248, 248, 248, 255,
        245, 245, 245, 254,
        241, 241, 241, 255,
        237, 237, 237, 255,
        232, 232, 232, 255,
        229, 229, 229, 255,
        225, 225, 225, 255,
        221, 221, 221, 255,
        218, 218, 218, 254,
        214, 214, 214, 255,
        209, 209, 209, 255,
        206, 206, 206, 254,
        201, 201, 201, 255,
        199, 199, 199, 254,
        193, 193, 193, 255,
        190, 190, 190, 255,
        185, 185, 185, 255,
        182, 182, 182, 255,
        178, 178, 178, 254,
        174, 174, 174, 255,
        170, 170, 170, 255,
        165, 165, 165, 255,
        162, 162, 162, 254,
        157, 157, 157, 255,
        154, 154, 154, 254,
        149, 149, 149, 255,
        145, 145, 145, 255,
        142, 142, 142, 254,
        138, 138, 138, 254,
        134, 134, 134, 255,
        130, 130, 130, 255
    };
    
    private static readonly byte[] GradientColorsCentered =
    {
        132, 132, 132, 254,
        140, 140, 140, 255,
        149, 149, 149, 254,
        156, 156, 156, 255,
        164, 164, 164, 255,
        172, 172, 172, 255,
        180, 180, 180, 255,
        188, 188, 188, 255,
        196, 196, 196, 255,
        204, 204, 204, 254,
        212, 212, 212, 255,
        220, 220, 220, 255,
        229, 229, 229, 254,
        235, 235, 235, 255,
        245, 245, 245, 254,
        251, 251, 251, 255,
        250, 250, 250, 255,
        242, 242, 242, 255,
        235, 235, 235, 255,
        227, 227, 227, 254,
        218, 218, 218, 255,
        211, 211, 211, 255,
        202, 202, 202, 255,
        195, 195, 195, 254,
        187, 187, 187, 255,
        179, 179, 179, 254,
        171, 171, 171, 255,
        163, 163, 163, 255,
        156, 156, 156, 254,
        147, 147, 147, 254,
        139, 139, 139, 255,
        132, 132, 132, 255
    };
    
    public enum Gradient { LeftToRight, RightToLeft, Centered }

    public readonly Gradient GradientType;
    public readonly Color HeaderColor;
    public readonly Color LabelColor;
    public readonly bool ApplyGradient;
    public readonly bool CenterLabel;
    public readonly bool BoldLabel;

    private static Texture2D _headerGradientLTR;
    private static Texture2D _headerGradientRTL;
    private static Texture2D _headerGradientCentered;
    
    public static Texture2D HeaderGradientLTR
    {
        get
        {
            if (_headerGradientLTR == null)
            {
                _headerGradientLTR = new Texture2D(32, 1, TextureFormat.RGBA32, false) {wrapMode = TextureWrapMode.Clamp};
                _headerGradientLTR.LoadRawTextureData(GradientColorsLTR);
                _headerGradientLTR.Apply();
            }

            return _headerGradientLTR;
        }
    }
    
    public static Texture2D HeaderGradientRTL
    {
        get
        {
            if (_headerGradientRTL == null)
            {
                _headerGradientRTL = new Texture2D(32, 1, TextureFormat.RGBA32, false) {wrapMode = TextureWrapMode.Clamp};
                _headerGradientRTL.LoadRawTextureData(GradientColorsRTL);
                _headerGradientRTL.Apply();
            }

            return _headerGradientRTL;
        }
    }
    
    public static Texture2D HeaderGradientCentered
    {
        get
        {
            if (_headerGradientCentered == null)
            {
                _headerGradientCentered = new Texture2D(32, 1, TextureFormat.RGBA32, false) {wrapMode = TextureWrapMode.Clamp};
                _headerGradientCentered.LoadRawTextureData(GradientColorsCentered);
                _headerGradientCentered.Apply();
            }

            return _headerGradientCentered;
        }
    }


    /// <param name="groupName">The box group name.</param>
    /// <param name="headerColor">The color of the header e.g. "#FF0000".</param>
    /// <param name="labelColor">The color of the label e.g. "#FF0000".</param>
    /// <param name="boldLabel">Makes the header label bold if set to true. (default: false)</param>
    /// <param name="applyGradient">Adds a gradient to the header if set to true. (default: true)</param>
    /// <param name="gradientType">Applies the given gradient type. (default: Gradient.LeftToRight)</param>
    /// <param name="centerLabel">Centers the label inside the header if set to true. (default: false)</param>
    public ColoredBoxGroupAttribute(string groupName, string headerColor = null, string labelColor = null, bool boldLabel = false,
                                    bool applyGradient = true, Gradient gradientType = Gradient.LeftToRight, bool centerLabel = false) : base(groupName)
    {
        if (headerColor.IsNullOrWhitespace()) HeaderColor = SirenixGUIStyles.HeaderBoxBackgroundColor;
        else ColorUtility.TryParseHtmlString(headerColor, out HeaderColor);

        if (labelColor.IsNullOrWhitespace()) LabelColor = SirenixGUIStyles.WhiteLabel.normal.textColor;
        else ColorUtility.TryParseHtmlString(labelColor, out LabelColor);

        BoldLabel = boldLabel;
        CenterLabel = centerLabel;
        ApplyGradient = applyGradient;
        GradientType = gradientType;
    }
}

#if UNITY_EDITOR
public class ColoredBoxGroupAttributeDrawer : OdinGroupDrawer<ColoredBoxGroupAttribute>
{
    protected override void DrawPropertyLayout(GUIContent label)
    {
        SirenixEditorGUI.BeginBox();

        BeginColoredBoxHeader(Attribute);
        GUIHelper.PushColor(Attribute.LabelColor);

        GUIStyle labelAlignment = GUI.skin.label;
        labelAlignment.alignment = TextAnchor.MiddleCenter;

        GUIStyle labelStyle = new GUIStyle(GUI.skin.label)
        {
            alignment = Attribute.CenterLabel ? TextAnchor.MiddleCenter : TextAnchor.MiddleLeft,
            fontStyle = Attribute.BoldLabel ? FontStyle.Bold : FontStyle.Normal
        };

        EditorGUILayout.LabelField(Attribute.GroupName, labelStyle);
        GUIHelper.PopColor();
        SirenixEditorGUI.EndBoxHeader();

        GUILayout.Space(1f);

        foreach (InspectorProperty inspectorProperty in Property.Children)
            inspectorProperty.Draw();

        SirenixEditorGUI.EndBox();
    }

    private static void BeginColoredBoxHeader(ColoredBoxGroupAttribute attr)
    {
        GUILayout.Space(-3f);
        
        Rect rect = EditorGUILayout.BeginHorizontal(SirenixGUIStyles.BoxHeaderStyle, GUILayoutOptions.ExpandWidth());

        if (Event.current.type == EventType.Repaint)
        {
            rect = new Rect(rect.x - 3f, rect.y + 1f, rect.width + 6f, rect.height - 1f);

            Texture2D texture = Texture2D.whiteTexture;

            if (attr.ApplyGradient)
            {
                texture = attr.GradientType switch
                {
                    ColoredBoxGroupAttribute.Gradient.LeftToRight => ColoredBoxGroupAttribute.HeaderGradientLTR,
                    ColoredBoxGroupAttribute.Gradient.RightToLeft => ColoredBoxGroupAttribute.HeaderGradientRTL,
                    ColoredBoxGroupAttribute.Gradient.Centered => ColoredBoxGroupAttribute.HeaderGradientCentered,
                    _ => texture
                };
            }
            
            GUI.DrawTexture(rect, texture, ScaleMode.StretchToFill, true, 0f, attr.HeaderColor, 0f, 2f);
            rect.y += 1f;
            SirenixEditorGUI.DrawBorders(rect, 0, 0, 0, 1, new Color(0f, 0f, 0f, 0.4f));
        }

        GUIHelper.PushLabelWidth(GUIHelper.BetterLabelWidth - 4f);
    }
}
#endif