clock.cs

清华大学出版社出版的 移动应用开发宝典 张大威（2008）的附书源代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace Chapter15.Windows.Forms
{
    public partial class Clock : Control
    {
        private System.Drawing.Point center;
        //hand lengths
        private int hourHand;
        private int minuteHand;
        //points
        private System.Drawing.Point hour;
        private System.Drawing.Point minute;
        private System.Drawing.Point second;
        //diameter
        private int shortestSide;
        //length of quarter hour notches
        private int hourMarks;

        private Bitmap doubleBuffer;



        public Clock()
        {
            InitializeComponent();
        }

        protected override void OnResize(EventArgs e)
        {
            //since all our logic depends on the control size store key dimensions when the control is resized
            if(Width > Height)
            {
                shortestSide = this.Height;
            }
            else
            {
                shortestSide = this.Width;
            }

            center = new Point(shortestSide / 2, shortestSide / 2);

            //dispose old buffer
            if (doubleBuffer != null)
            {
                doubleBuffer.Dispose();
            }

            doubleBuffer = new Bitmap(shortestSide, shortestSide);
            minuteHand = (shortestSide / 2) - 4;
            hourHand = (shortestSide / 4);
            hourMarks = (shortestSide / 8);

            base.OnResize(e);
        }

        protected override void OnPaint(PaintEventArgs pe)
        {
            // draw the previously created buffer
            pe.Graphics.DrawImage(doubleBuffer, 0, 0);

            // Calling the base class OnPaint
            base.OnPaint(pe);
        }

        private void timerClock_Tick(object sender, EventArgs e)
        {
            //update the hands
            DateTime d = DateTime.Now;
            double angle = d.Second * (Math.PI / 30);
            second = GetHandPoint(center, angle, minuteHand);
            angle = d.Minute * (Math.PI / 30);
            minute = GetHandPoint(center, angle, minuteHand);
            angle = d.Hour * (Math.PI / 6);
            hour = GetHandPoint(center, angle, hourHand);

            Graphics g = Graphics.FromImage(doubleBuffer);
            g.Clear(this.BackColor);

            Pen handPen = new Pen(colorScheme.HandColor, 2);
            Pen borderPen = new Pen(colorScheme.BorderColor);

            g.FillEllipse(new SolidBrush(colorScheme.FaceColor), 0, 0, shortestSide, shortestSide);
            g.DrawEllipse(borderPen, 0, 0, shortestSide, shortestSide);

            //draw quarter marks
            g.DrawLine(borderPen, center.X, 2, center.X, hourMarks);
            g.DrawLine(borderPen, 2, center.Y, hourMarks, center.Y);
            g.DrawLine(borderPen, shortestSide - hourMarks, center.Y, shortestSide - 2, center.Y);
            g.DrawLine(borderPen, center.X, shortestSide - hourMarks, center.X, shortestSide - 2);

            //draw hands
            g.DrawLine(handPen, center.X, center.Y, hour.X, hour.Y);

            g.DrawLine(handPen, center.X, center.Y, minute.X, minute.Y);
            g.DrawLine(borderPen, center.X, center.Y, second.X, second.Y);

            g.FillEllipse(new SolidBrush(colorScheme.HandColor), center.X - 2, center.Y - 2, 4, 4);

            g.Dispose();

            Refresh();
        }

        private static Point GetHandPoint(Point center, double angle, int handlength)
        {
            Point p;

            if (angle > 270)
            {
                angle = angle - 270;
                int height = Convert.ToInt32(Math.Sin(angle) * handlength);
                int width = Convert.ToInt32(Math.Cos(angle) * handlength);
                p = new Point(center.X + width, center.Y + height);
            }
            else if (angle > 180)
            {
                angle = angle - 180;
                int width = Convert.ToInt32(Math.Sin(angle) * handlength);
                int height = Convert.ToInt32(Math.Cos(angle) * handlength);
                p = new Point(center.X - width, center.Y + height);
            }
            else if (angle > 90)
            {
                angle = angle - 90;
                int height = Convert.ToInt32(Math.Sin(angle) * handlength);
                int width = Convert.ToInt32(Math.Cos(angle) * handlength);
                p = new Point(center.X + width, center.Y + height);
            }
            else
            {
                int width = Convert.ToInt32(Math.Sin(angle) * handlength);
                int height = Convert.ToInt32(Math.Cos(angle) * handlength);
                p = new Point(center.X + width, center.Y - height);
            }

            return p;
        }

        #region ColorScheme
        private ColorScheme colorScheme = new ColorScheme();
        public ColorScheme ColorScheme
        {
            get
            {
                return colorScheme;
            }
            set
            {
                colorScheme = value;
            }
        }
        
        #endregion
    }

    public class ColorScheme
    {
        private Color borderColor = Color.Gray;
        public Color BorderColor
        {
            get
            {
                return borderColor;
            }
            set
            {
                borderColor = value;
            }
        }

        private Color faceColor = Color.LightBlue;
        public Color FaceColor
        {
            get
            {
                return faceColor;
            }
            set
            {
                faceColor = value;
            }
        }

        private Color handColor = Color.Black;
        public Color HandColor
        {
            get
            {
                return handColor;
            }
            set
            {
                handColor = value;
            }
        }
    }
}