How to make a loading circle?

Question

Hi there.
I want to do a loading circle in Expression Design (or Blend), but I don't really know how though. So I though I could ask in the expression forum =). What I mean by "loading circle", here's a good code project article showing the different types of loading circle. But I more for the circular gradient (top one) and I think Yahoo Messenger for Vista have that kind of loading circle as well (don't have screenshot of it though).
Hope you understand.
Thanks in advance.
/Joakim.

Answer 1

class LoadingCircle : Control,IDisposable
        private const double NumberOfDegreesInCircle = 360;
        private const double NumberOfDegreesInHalfCircle = NumberOfDegreesInCircle / 2;
        private const int DefaultInnerCircleRadius = 8;
        private const int DefaultOuterCircleRadius = 10;
        private const int DefaultNumberOfSpoke = 10;
        private const int DefaultSpokeThickness = 4;
        private readonly Color DefaultColor = Color.DarkGray;
        private const int IE7InnerCircleRadius = 8;
        private const int IE7OuterCircleRadius = 9;
        private const int IE7NumberOfSpoke = 24;
        private const int IE7SpokeThickness = 4;
        private Timer m_Timer;
        private bool m_IsTimerActive;
        private int m_NumberOfSpoke;
        private int m_SpokeThickness;
        private int m_ProgressValue;
        private int m_OuterCircleRadius;
        private int m_InnerCircleRadius;
        private PointF m_CenterPoint;
        private Color m_Color;
        private Color[] m_Colors;
        private double[] m_Angles;
        [TypeConverter("System.Drawing.ColorConverter"),
      Category("LoadingCircle"),
      Description("Sets the color of spoke.")]
        public Color Color
            get
                return m_Color;
            set
                m_Color = value;
                GenerateColorsPallet();
                Invalidate();
        [System.ComponentModel.Description("Gets or sets the radius of outer circle."),
        System.ComponentModel.Category("LoadingCircle")]
        public int OuterCircleRadius
            get
                if (m_OuterCircleRadius == 0)
                    m_OuterCircleRadius = DefaultOuterCircleRadius;
                return m_OuterCircleRadius;
            set
                m_OuterCircleRadius = value;
                Invalidate();
        [System.ComponentModel.Description("Gets or sets the radius of inner circle."),
        System.ComponentModel.Category("LoadingCircle")]
        public int InnerCircleRadius
            get
                if (m_InnerCircleRadius == 0)
                    m_InnerCircleRadius = DefaultInnerCircleRadius;
                return m_InnerCircleRadius;
            set
                m_InnerCircleRadius = value;
                Invalidate();
        [System.ComponentModel.Description("Gets or sets the number of spoke."),
        System.ComponentModel.Category("LoadingCircle")]
        public int NumberSpoke
            get
                if (m_NumberOfSpoke == 0)
                    m_NumberOfSpoke = DefaultNumberOfSpoke;
                return m_NumberOfSpoke;
            set
                if (m_NumberOfSpoke != value && m_NumberOfSpoke > 0)
                    m_NumberOfSpoke = value;
                    GenerateColorsPallet();
                    GetSpokesAngles();
                    Invalidate();
        private double[] GetSpokesAngles(int _intNumberSpoke)
            double[] Angles = new double[_intNumberSpoke];
            double dblAngle = (double)NumberOfDegreesInCircle / _intNumberSpoke;
            for (int shtCounter = 0; shtCounter < _intNumberSpoke; shtCounter++)
                Angles[shtCounter] = (shtCounter == 0 ? dblAngle : Angles[shtCounter - 1] + dblAngle);
            return Angles;
        private void GetSpokesAngles()
            m_Angles = GetSpokesAngles(NumberSpoke);
        [System.ComponentModel.Description("Gets or sets the number of spoke."),
      System.ComponentModel.Category("LoadingCircle")]
        public bool Active
            get
                return m_IsTimerActive;
            set
                m_IsTimerActive = value;
                ActiveTimer();
        [System.ComponentModel.Description("Gets or sets the thickness of a spoke."),
        System.ComponentModel.Category("LoadingCircle")]
        public int SpokeThickness
            get
                if (m_SpokeThickness <= 0)
                    m_SpokeThickness = DefaultSpokeThickness;
                return m_SpokeThickness;
            set
                m_SpokeThickness = value;
                Invalidate();
        private void ActiveTimer()
            if (m_IsTimerActive)
                m_Timer.Start();
            else
                m_Timer.Stop();
                m_ProgressValue = 0;
            GenerateColorsPallet();
            Invalidate();
        [System.ComponentModel.Description("Gets or sets the rotation speed. Higher the slower."),
        System.ComponentModel.Category("LoadingCircle")]
        public int RotationSpeed
            get
                return m_Timer.Interval;
            set
                if (value > 0)
                    m_Timer.Interval = value;
        private PointF GetCoordinate(PointF _objCircleCenter, int _intRadius, double _dblAngle)
            double dblAngle = Math.PI * _dblAngle / NumberOfDegreesInHalfCircle;
            return new PointF(_objCircleCenter.X + _intRadius * (float)Math.Cos(dblAngle),
                              _objCircleCenter.Y + _intRadius * (float)Math.Sin(dblAngle));
        public LoadingCircle()
            SetCircleAppearance(IE7NumberOfSpoke,
                          IE7SpokeThickness, IE7InnerCircleRadius,
                          IE7OuterCircleRadius);
            SetStyle(ControlStyles.UserPaint, true);
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            //ControlStyles.DoubleBuffer, true);
            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            //   SetStyle(ControlStyles.ResizeRedraw, true);
            //  SetStyle(ControlStyles.SupportsTransparentBackColor, true);
            m_Color = DefaultColor;
            GenerateColorsPallet();
            GetSpokesAngles();
            GetControlCenterPoint();
            m_Timer = new Timer();
            m_Timer.Tick += new EventHandler(aTimer_Tick);
            ActiveTimer();
            this.Resize += new EventHandler(LoadingCircle_Resize);
        private void GetControlCenterPoint()
            m_CenterPoint = GetControlCenterPoint(this);
        private PointF GetControlCenterPoint(Control _objControl)
            return new PointF(_objControl.Width / 2, _objControl.Height / 2 - 1);
        void LoadingCircle_Resize(object sender, EventArgs e)
            GetControlCenterPoint();
        void aTimer_Tick(object sender, EventArgs e)
            m_ProgressValue = ++m_ProgressValue % m_NumberOfSpoke;
            Invalidate();// GC.Collect();
        protected override void OnPaint(PaintEventArgs e)
        //    this.SetStyle(
        //     ControlStyles.AllPaintingInWmPaint |
        //     ControlStyles.DoubleBuffer, true);
            if (m_NumberOfSpoke > 0)
                e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
               e.Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
               e.Graphics.CompositingQuality = CompositingQuality.HighQuality;
                int intPosition = m_ProgressValue;
                for (int intCounter = 0; intCounter < m_NumberOfSpoke; intCounter++)
                    intPosition = intPosition % m_NumberOfSpoke;
                    DrawLine(e.Graphics,
                             GetCoordinate(m_CenterPoint, m_InnerCircleRadius, m_Angles[intPosition]),
                             GetCoordinate(m_CenterPoint, m_OuterCircleRadius, m_Angles[intPosition]),
                             m_Colors[intCounter], m_SpokeThickness);
                    e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
                    e.Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
                    e.Graphics.CompositingQuality = CompositingQuality.HighQuality;
                    DrawLine(e.Graphics,
                               GetCoordinate(m_CenterPoint, m_InnerCircleRadius - 4, m_Angles[intPosition]),
                               GetCoordinate(m_CenterPoint, m_OuterCircleRadius - m_OuterCircleRadius, m_Angles[intPosition]),
                             ColorTranslator.FromHtml("#2a2a2a"), 2); e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
                    intPosition++;
            base.OnPaint(e);
        private void DrawLine(Graphics _objGraphics, PointF _objPointOne, PointF _objPointTwo,
                             Color _objColor, int _intLineThickness)
            using (Pen objPen = new Pen(new SolidBrush(_objColor), _intLineThickness))
                objPen.StartCap = LineCap.Custom;
                objPen.EndCap = LineCap.NoAnchor;
                _objGraphics.DrawLine(objPen, _objPointOne, _objPointTwo);
        public override Size GetPreferredSize(Size proposedSize)
            proposedSize.Width =
                (m_OuterCircleRadius + m_SpokeThickness) * 2;
            return proposedSize;
        private Color Darken(Color _objColor, int _intPercent)
            int intRed = _objColor.R;
            int intGreen = _objColor.G;
            int intBlue = _objColor.B;
            return Color.FromArgb(_intPercent, Math.Min(intRed, byte.MaxValue), Math.Min(intGreen, byte.MaxValue), Math.Min(intBlue, byte.MaxValue));
        private void GenerateColorsPallet()
            m_Colors = GenerateColorsPallet(m_Color, Active, m_NumberOfSpoke);
        private Color[] GenerateColorsPallet(Color _objColor, bool _blnShadeColor, int _intNbSpoke)
            Color[] objColors = new Color[NumberSpoke];
            // Value is used to simulate a gradient feel... For each spoke, the 
            // color will be darken by value in intIncrement.
            byte bytIncrement = (byte)(byte.MaxValue / (NumberSpoke));
            byte PERCENTAGE_OF_DARKEN = 0;
            for (int intCursor = 0; intCursor < NumberSpoke; intCursor++)
                if (_blnShadeColor)
                    if (intCursor == 0 || intCursor < NumberSpoke - _intNbSpoke)
                        objColors[intCursor] = _objColor;
                    else
                        PERCENTAGE_OF_DARKEN += bytIncrement;
                        // Ensure that we don't exceed the maximum alpha
                        // channel value (255)
                        if (PERCENTAGE_OF_DARKEN > byte.MaxValue)
                            PERCENTAGE_OF_DARKEN = byte.MaxValue;
                        objColors[intCursor] = Darken(_objColor, PERCENTAGE_OF_DARKEN);
                else
                    objColors[intCursor] = _objColor;
            return objColors;
        public void SetCircleAppearance(int numberSpoke, int spokeThickness,
                   int innerCircleRadius, int outerCircleRadius)
            NumberSpoke = numberSpoke;
            SpokeThickness = spokeThickness;
            InnerCircleRadius = innerCircleRadius;
            OuterCircleRadius = outerCircleRadius;
            Invalidate();
        protected override void Dispose(bool disposing)
            base.Dispose(disposing);