PanelMessage.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
using Td = Telegram.Td;
using TdApi = Telegram.Td.Api;

namespace TelegramClient {
    public class PanelMessage : Panel {

        public int radiusMessagePanel = 30;

        public PanelMessage() {

            this.BackColor = System.Drawing.Color.Silver;

            this.Width = 200;
            this.Height = 50;

            System.Drawing.Drawing2D.GraphicsPath path1 = new System.Drawing.Drawing2D.GraphicsPath();
            path1.AddLine(radiusMessagePanel, 0, this.Width - radiusMessagePanel, 0);
            path1.AddArc(this.Width - radiusMessagePanel, 0, radiusMessagePanel, radiusMessagePanel, 270, 90);
            path1.AddLine(this.Width, radiusMessagePanel, this.Width, this.Height - radiusMessagePanel);
            path1.AddArc(this.Width - radiusMessagePanel, this.Height - radiusMessagePanel, radiusMessagePanel, radiusMessagePanel, 0, 90);
            path1.AddLine(this.Width - radiusMessagePanel, this.Height, radiusMessagePanel, this.Height);
            path1.AddArc(0, this.Height - radiusMessagePanel, radiusMessagePanel, radiusMessagePanel, 90, 90);
            path1.AddLine(0, this.Height - radiusMessagePanel, 0, radiusMessagePanel);
            path1.AddArc(0, 0, radiusMessagePanel, radiusMessagePanel, 180, 90);
            this.Region = new Region(path1);
        }
    }
}