C# GDI+绘制圆形进度条制作自定义控件

【实例简介】C# GDI 绘制圆形进度条制作自定义控件

【实例截图】

【核心代码】

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

namespace ProgressCircleControl
{
    /// <summary>
    /// 圆形进度条
    /// </summary>
    public class ProgressCircle : Control
    {
        #region variables
        Timer timer;
        Graphics canvasGraphic;
        Image canvas;
        Image icon;
        Rectangle rect;
        int blinkCount = 2;
        int blinkSpeed = 10;
        Pen spokePen = Pens.White;
        int spokeCount = 4;
        Brush pieBrush = Brushes.LawnGreen;
        int value = 0;
        PointF center;
        #endregion
        #region properties
        [DefaultValue(2), Category("Appearance"), Description("Blink count. 0 for disable.")]
        public int BlinkCount
        {
            get { return blinkCount; }
            set
            {
                if (value > -1)
                {
                    blinkCount = value; Refresh();
                }
            }
        }

        [DefaultValue(10), Category("Appearance"), Description("Blink speed.")]
        public int BlinkSpeed
        {
            get { return blinkSpeed; }
            set
            {
                if (value > 0 && value < 256)
                    blinkSpeed = value;
            }
        }

        [DefaultValue(4), Category("Appearance"), Description("Spoke count. Maximum value is 10. 0 for disable.")]
        public int SpokeCount
        {
            get { return spokeCount; }
            set
            {
                spokeCount = value;
                Invalidate();
            }
        }

        [DefaultValue(typeof(Color), "White"), Category("Appearance"), Description("Color of spokes.")]
        public Color SpokeColor
        {
            get { return spokePen.Color; }
            set
            {
                spokePen.Color = value;
                Invalidate();
            }
        }

        [Category("Appearance"), Description("Icon to display. Maximum size is half of the control.")]
        public Image Image
        {
            get { return icon; }
            set
            {
                icon = value;
                Invalidate();
            }
        }

        [DefaultValue(0), Category("Behavior"), Description("Value of percentage.")]
        public int Value
        {
            get { return value; }
            set
            {
                if (value < 0) value = 0;
                if (value > 100) value = 100;
                this.value = value;
                Invalidate();
                if (value == 100 && BlinkCount != 0)
                    timer.Start();
                else
                    if (timer.Enabled)
                    timer.Stop();
            }
        }

        private Color valueTextColor = Color.OrangeRed;
        [Category("Behavior"), Description("进度值的文字颜色，默认是橙红色.")]
        public Color ValueTextColor
        {
            get { return valueTextColor; }
            set { valueTextColor = value; }
        }

        #endregion

        #region initiators
        public ProgressCircle()
        {
            DoubleBuffered = true;
            Width = 64;
            ForeColor = Color.FromArgb(146, 223, 99);
            spokePen = new Pen(BackColor, 1);
            pieBrush = new SolidBrush(ForeColor);
            BackColor = Color.White;
            ForeColor = Color.LawnGreen;
            BlinkCount = 2;
            SpokeColor = Color.White;
            SpokeCount = 4;
            center = new PointF();
            timer = new Timer();
            timer.Interval = 10;
            timer.Tick  = new EventHandler(timer_Tick);
            OnResize(null);
        }
        #endregion

        #region callbacks
        int blink = 0;
        int count = 255;
        void timer_Tick(object sender, EventArgs e)
        {
            if (!timer.Enabled)
                return;

            if (blink == BlinkCount)
            {
                blink = 0;
                count = 255;
                timer.Stop();
                Refresh();
            }
            else
            {
                count -= 5;
                if (count == 0)
                {
                    count = 255;
                    blink  ;
                }
                else
                {
                    Refresh();
                }
            }
        }
        #endregion

        #region painters
        void drawIcon(Graphics g, Image img)
        {
            if (img == null)
                return;
            g.DrawImageUnscaled(img, (this.ClientSize.Width - img.Width) / 2, (this.ClientSize.Height - img.Height) / 2);
        }

        void drawSpokes(Graphics g, int count)
        {
            if (count < 1)
                return;
            if (count > 10)
                count = 10;
            float angleStep = 360f / (count * 2);
            float angle = 0f;
            for (int i = 0; i < count; i  )
            {
                PointF p1 = angleToPoint(angle, rect.Width / 2);
                PointF p2 = angleToPoint(angle   180f, rect.Width / 2);
                g.DrawLine(spokePen, p1, p2);
                angle  = angleStep;
            }
        }

        void drawProgress(Graphics g, float percent)
        {
            if (percent < 0 || percent > 100)
                return;
            g.FillPie(
                pieBrush,
                rect,
                -90,
                (float)(360f * Value / 100f)
                );
        }

        void drawBackground(Graphics g)
        {
            g.Clear(Color.Transparent);
            ((SolidBrush)pieBrush).Color = BackColor;
            g.FillEllipse(pieBrush, rect);
            ((SolidBrush)pieBrush).Color = this.ForeColor;
        }
        #endregion

        #region helpers
        PointF angleToPoint(float angle, float radius)
        {
            return new PointF(
                center.X   radius * (float)Math.Cos(angle * Math.PI / 180),
                center.Y   radius * (float)Math.Sin(angle * Math.PI / 180)
                );
        }
        #endregion

        #region events
        protected override void OnBackColorChanged(EventArgs e)
        {
            base.OnBackColorChanged(e);
        }

        protected override void OnForeColorChanged(EventArgs e)
        {
            base.OnForeColorChanged(e);
            ((SolidBrush)pieBrush).Color = ForeColor;
        }

        protected override void OnResize(EventArgs e)
        {
            this.Height = this.Width;
            rect = ClientRectangle;
            rect.Width -= 1;
            rect.Height -= 1;
            center = new PointF(rect.Width / 2, rect.Height / 2);
            if (!this.ClientSize.IsEmpty)
            {
                if (canvas != null)
                    canvas.Dispose();
                canvas = new Bitmap(rect.Width, rect.Height);
                if (canvasGraphic != null)
                    canvasGraphic.Dispose();
                canvasGraphic = Graphics.FromImage(canvas);
            }
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            e.Graphics.Clear(Parent.BackColor);
            canvasGraphic.SmoothingMode = SmoothingMode.HighQuality;
            drawBackground(canvasGraphic);
            if (!timer.Enabled || blink == BlinkCount)
                drawProgress(canvasGraphic, value);
            else
            {
                ((SolidBrush)pieBrush).Color = Color.FromArgb(count, ForeColor.R, ForeColor.G, ForeColor.B);
                canvasGraphic.FillEllipse(pieBrush, rect);
                ((SolidBrush)pieBrush).Color = ForeColor;
            }
            drawSpokes(canvasGraphic, SpokeCount);
            if (icon != null)
                drawIcon(canvasGraphic, icon);
            e.Graphics.DrawImageUnscaled(canvas, (ClientSize.Width - canvas.Width) / 2, (ClientSize.Height - canvas.Height) / 2);
            if (value != 0)
            {
                var rect = ClientRectangle;
                rect.Inflate(0 - Width / 2, 0 - Height / 2);
                StringFormat sf = new StringFormat();
                sf.LineAlignment = StringAlignment.Center;
                sf.Alignment = StringAlignment.Center;
                e.Graphics.DrawString(value.ToString()   "%", new Font("微软雅黑", 18F, FontStyle.Bold), new SolidBrush(ValueTextColor), rect, sf);
            }
        }
        #endregion
    }
}