﻿ Triangle.cs
 File: winforms\Managed\System\WinForms\Triangle.cs Project: ndp\fx\src\System.Windows.Forms.csproj (System.Windows.Forms)
 ```//------------------------------------------------------------------------------ // // Copyright (c) Microsoft Corporation. All rights reserved. // //------------------------------------------------------------------------------ namespace System.Windows.Forms { using System.Diagnostics; using System; using System.Windows.Forms; using System.Drawing; using Microsoft.Win32; /// /// /// This class fully encapsulates the painting logic for a triangle. (Used by DataGrid) /// internal static class Triangle { private const double TRI_HEIGHT_RATIO = 2.5; private const double TRI_WIDTH_RATIO = 0.8; /* Commenting this overload out until someone actually needs it again... public static void Paint(Graphics g, Rectangle bounds, TriangleDirection dir, Brush backBr, Pen backPen) { Paint(g, bounds, dir, backBr, backPen, true); } */ /* Commenting this overload out until someone actually needs it again... public static void Paint(Graphics g, Rectangle bounds, TriangleDirection dir, Brush backBr, Pen backPen, bool opaque) { // build an equilateral triangle centered on the midpoint of the rect. Point[] points = BuildTrianglePoints(dir, bounds); if (opaque) g.FillPolygon(backBr, points); g.DrawPolygon(backPen, points); } */ public static void Paint(Graphics g, Rectangle bounds, TriangleDirection dir, Brush backBr, Pen backPen1, Pen backPen2, Pen backPen3, bool opaque) { // build an equilateral triangle centered on the midpoint of the rect. Point[] points = BuildTrianglePoints(dir, bounds); if (opaque) g.FillPolygon(backBr, points); g.DrawLine(backPen1, points[0], points[1]); g.DrawLine(backPen2, points[1], points[2]); g.DrawLine(backPen3, points[2], points[0]); } private static Point[] BuildTrianglePoints(TriangleDirection dir, Rectangle bounds) { Point[] points = new Point[3]; int updnWidth =(int)(bounds.Width * TRI_WIDTH_RATIO); if (updnWidth % 2 == 1) updnWidth++; int updnHeight =(int)Math.Ceiling((updnWidth/2) * TRI_HEIGHT_RATIO); int lrWidth =(int)(bounds.Height * TRI_WIDTH_RATIO); if (lrWidth % 2 == 0) lrWidth++; int lrHeight =(int)Math.Ceiling((lrWidth/2) * TRI_HEIGHT_RATIO); switch (dir) { case TriangleDirection.Up: { points[0] = new Point(0, updnHeight); points[1] = new Point(updnWidth, updnHeight); points[2] = new Point(updnWidth / 2, 0); } break; case TriangleDirection.Down: { points[0] = new Point(0, 0); points[1] = new Point(updnWidth, 0); points[2] = new Point(updnWidth / 2, updnHeight); } break; case TriangleDirection.Left: { points[0] = new Point(lrWidth, 0); points[1] = new Point(lrWidth, lrHeight); points[2] = new Point(0, lrHeight / 2); } break; case TriangleDirection.Right: { points[0] = new Point(0, 0); points[1] = new Point(0, lrHeight); points[2] = new Point(lrWidth, lrHeight / 2); } break; default: Debug.Fail("Wrong triangle enum"); break; } // we need to center our triangles into the bounds given. // NOTE: On the up/down case, the offsets are different! switch (dir) { case TriangleDirection.Up: case TriangleDirection.Down: OffsetPoints(points, bounds.X +(bounds.Width - updnHeight)/2, bounds.Y +(bounds.Height - updnWidth)/2); break; case TriangleDirection.Left: case TriangleDirection.Right: OffsetPoints(points, bounds.X +(bounds.Width - lrWidth)/2, bounds.Y +(bounds.Height - lrHeight)/2); break; } return points; } private static void OffsetPoints(Point[] points, int xOffset, int yOffset) { for (int i = 0; i < points.Length; i++) { points[i].X += xOffset; points[i].Y += yOffset; } } } /// /// /// /// [To be supplied.] /// internal enum TriangleDirection { /// /// /// /// [To be supplied.] /// Up, /// /// /// /// [To be supplied.] /// Down, /// /// /// /// [To be supplied.] /// Left, /// /// /// /// [To be supplied.] /// Right } } ```