PKHeX/PKHeX.WinForms/Controls/PKM Editor/VerticalTabControl.cs

using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace PKHeX.WinForms.Controls;

public class VerticalTabControl : TabControl
{
    public VerticalTabControl()
    {
        Alignment = TabAlignment.Right;
        DrawMode = TabDrawMode.OwnerDrawFixed;
        SizeMode = TabSizeMode.Fixed;
    }

    protected override void OnDrawItem(DrawItemEventArgs e)
    {
        var index = e.Index;
        var bounds = GetTabRect(index);

        var graphics = e.Graphics;
        if (e.State == DrawItemState.Selected)
        {
            using var brush = new LinearGradientBrush(bounds, Color.White, Color.LightGray, 90f);
            graphics.FillRectangle(brush, bounds);
        }
        else
        {
            e.DrawBackground();
        }

        using var flags = new StringFormat
        {
            Alignment = StringAlignment.Center,
            LineAlignment = StringAlignment.Center,
        };
        using var text = new SolidBrush(ForeColor);
        var tab = TabPages[index];
        graphics.DrawString(tab.Text, Font, text, bounds, flags);
        base.OnDrawItem(e);
    }
}

public sealed class VerticalTabControlEntityEditor : VerticalTabControl
{
    private static readonly Color[] SelectedTags =
    {
        Color.FromArgb(248, 152, 096),
        Color.FromArgb(128, 152, 248),
        Color.FromArgb(248, 168, 208),
        Color.FromArgb(112, 224, 112),
        Color.FromArgb(248, 240, 056),
        Color.RosyBrown,
    };

    protected override void OnDrawItem(DrawItemEventArgs e)
    {
        var index = e.Index;
        var bounds = GetTabRect(index);

        var graphics = e.Graphics;
        if (e.State == DrawItemState.Selected)
        {
            using var brush = new LinearGradientBrush(bounds, Color.White, Color.LightGray, 90f);
            graphics.FillRectangle(brush, bounds);

            using var pipBrush = new SolidBrush(SelectedTags[index]);
            var pip = GetTabRect(index) with { Width = bounds.Width / 8 };
            graphics.FillRectangle(pipBrush, pip);
            bounds = bounds with { Width = bounds.Width - pip.Width, X = bounds.X + pip.Width };
        }
        else
        {
            // no need to shift text
            e.DrawBackground();
        }

        using var flags = new StringFormat
        {
            Alignment = StringAlignment.Center,
            LineAlignment = StringAlignment.Center,
        };
        using var text = new SolidBrush(ForeColor);
        var tab = TabPages[index];
        graphics.DrawString(tab.Text, Font, text, bounds, flags);
    }
}