TextItem.cs :  » Game » SDL » SdlDotNetExamples » SmallDemos » C# / CSharp Open Source

#region LICENSE
/* This file is part of SnowDemo
 * (c) 2003 Sijmen Mulder
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#endregion LICENSE

using System;
using System.Drawing;
using System.Globalization;

using SdlDotNet.Core;
using SdlDotNet.Graphics.Sprites;

namespace SdlDotNetExamples.SmallDemos{
    enum TextFadeState
    {
        BeforeFadeIn,
        FadeIn,
        BeforeFadeOut,
        FadeOut,
        Finished
    }
    /// <summary>
    /// 
    /// </summary>
    public class TextItem : TextSprite
    {
        const float inSpeed = 40;
        const float outSpeed = 40;
        float time;
        float startTime;
        TextFadeState state = TextFadeState.BeforeFadeIn;
        float alpha;

        /// <summary>
        /// 
        /// </summary>
        /// <param name="font"></param>
        /// <param name="positionY"></param>
        /// <param name="phrase"></param>
        /// <param name="startTime"></param>
        public TextItem(string phrase, SdlDotNet.Graphics.Font font, int positionY, float startTime)
            : base(phrase, font, false, new Point(25, positionY))
        {
            base.Surface.Alpha = 0;
            base.Surface.AlphaBlending = true;
            this.startTime = startTime;
        }

        /// <summary>
        /// 
        /// </summary>
        public float StartTime
        {
            get
            {
                return startTime;
            }
            set
            {
                startTime = value;
            }
        }

        /// <summary>
        /// 
        /// </summary>
        public float EndTime
        {
            get
            {
                return startTime + 4.5f;
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="args"></param>
        public override void Update(TickEventArgs args)
        {
            if (args == null)
            {
                throw new ArgumentNullException("args");
            }
            float seconds = args.SecondsElapsed;
            time = Timer.SecondsElapsed;

            switch (state)
            {
                case TextFadeState.BeforeFadeIn:
                    if (time >= startTime)
                    {
                        state = TextFadeState.FadeIn;
                    }
                    break;

                case TextFadeState.FadeIn:
                    if (seconds <= (float.MaxValue / inSpeed) - alpha)
                    {
                        alpha += seconds * inSpeed;
                    }
                    else
                    {
                        alpha = float.MaxValue;
                    }

                    if (alpha >= 255)
                    {
                        alpha = 255;
                        state = TextFadeState.BeforeFadeOut;
                    }
                    this.Surface.Alpha = (byte)alpha;
                    break;

                case TextFadeState.BeforeFadeOut:
                    if (time >= this.EndTime)
                    {
                        state = TextFadeState.FadeOut;
                    }
                    break;

                case TextFadeState.FadeOut:
                    alpha -= seconds * outSpeed;

                    if (alpha <= 0)
                    {
                        alpha = 0;
                        state = TextFadeState.Finished;
                    }
                    this.Surface.Alpha = (byte)alpha;
                    break;
            }
        }
        #region IDisposable
        private bool disposed;

        /// <summary>
        /// Destroys the surface object and frees its memory
        /// </summary>
        /// <param name="disposing">If ture, dispose unmanaged resources</param>
        protected override void Dispose(bool disposing)
        {
            try
            {
                if (!this.disposed)
                {
                    if (disposing)
                    {
                    }
                    this.disposed = true;
                }
            }
            finally
            {
                base.Dispose(disposing);
            }
        }
        #endregion IDisposable
    }
}