NET框架的进展。所见即所得圈（C＃）

 private System.Collections.Generic.Dictionary<Color, SolidBrush> _brushCache = 

            new System.Collections.Generic.Dictionary<Color,SolidBrush>();

 

		private void DrawFilledArc (Graphics grp, Color color, int startAngle)

		{

			grp.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

 

			Rectangle main = this.ClientRectangle;

			

			// If there is no region to be drawn, then this method terminates itself

			if (main.Width - (2*this._ringThickness) < 1 || main.Height -(2*this._ringThickness) <= 1)

				return;

 

			// Calculates the region that will be filled



            using (GraphicsPath outerPath = new GraphicsPath())

            {

                outerPath.AddPie(main, startAngle, this.PieAngle);

 

                Rectangle sub = new Rectangle(main.X + this._ringThickness, main.Y + this._ringThickness, main.Width - (2 * this._ringThickness), main.Height - (2 * this._ringThickness));

 

                using (GraphicsPath innerPath = new GraphicsPath())

                {

                    innerPath.AddPie(sub, startAngle - 1, this.PieAngle + 2);

 

                    using (System.Drawing.Region mainRegion = new Region(outerPath))

                    {

                        using (System.Drawing.Region subRegion = new Region(innerPath))

                        {

 

                            mainRegion.Exclude(subRegion);

                            

                            SolidBrush targetBrush;

                            

                            if (_brushCache.ContainsKey(color))

                            {

                                targetBrush = _brushCache[color];

                            }

                            else

                            {

                                targetBrush = new SolidBrush(color);

                                _brushCache.Add(color,targetBrush);

                            }

                            // Fill that region

                            grp.FillRegion(targetBrush, mainRegion);

                        }

                    }

                }

            }

		}