﻿ EllipseGeometry.cs
 File: Core\CSharp\System\Windows\Media\EllipseGeometry.cs Project: wpf\src\PresentationCore.csproj (PresentationCore)
 ```//------------------------------------------------------------------------------ // Microsoft Avalon // Copyright (c) Microsoft Corporation, 2001 // // File: EllipseGeometry.cs //------------------------------------------------------------------------------ using System; using MS.Internal; using System.ComponentModel; using System.ComponentModel.Design.Serialization; using System.Reflection; using System.Collections; using System.Text; using System.Globalization; using System.Windows.Media; using System.Windows.Media.Composition; using System.Windows; using System.Text.RegularExpressions; using System.Windows.Media.Animation; using System.Diagnostics; using System.Runtime.InteropServices; using System.Security; using System.Security.Permissions; using SR=MS.Internal.PresentationCore.SR; using SRID=MS.Internal.PresentationCore.SRID; namespace System.Windows.Media { /// /// This is the Geometry class for Circles and Ellipses /// public sealed partial class EllipseGeometry : Geometry { #region Constructors /// /// /// public EllipseGeometry() { } /// /// Constructor - sets the ellipse to the paramters with the given transformation /// public EllipseGeometry(Rect rect) { if (rect.IsEmpty) { throw new System.ArgumentException(SR.Get(SRID.Rect_Empty, "rect")); } RadiusX = (rect.Right - rect.X) * (1.0 / 2.0); RadiusY = (rect.Bottom - rect.Y) * (1.0 / 2.0); Center = new Point(rect.X + RadiusX, rect.Y + RadiusY); } /// /// Constructor - sets the ellipse to the parameters /// public EllipseGeometry( Point center, double radiusX, double radiusY) { Center = center; RadiusX = radiusX; RadiusY = radiusY; } /// /// Constructor - sets the ellipse to the parameters /// public EllipseGeometry( Point center, double radiusX, double radiusY, Transform transform) : this(center, radiusX, radiusY) { Transform = transform; } #endregion /// /// Gets the bounds of this Geometry as an axis-aligned bounding box /// public override Rect Bounds { get { ReadPreamble(); Rect boundsRect; Transform transform = Transform; if (transform == null || transform.IsIdentity) { Point currentCenter = Center; Double currentRadiusX = RadiusX; Double currentRadiusY = RadiusY; boundsRect = new Rect( currentCenter.X - Math.Abs(currentRadiusX), currentCenter.Y - Math.Abs(currentRadiusY), 2.0 * Math.Abs(currentRadiusX), 2.0 * Math.Abs(currentRadiusY)); } else { // // Matrix geometryMatrix; Transform.GetTransformValue(transform, out geometryMatrix); boundsRect = EllipseGeometry.GetBoundsHelper( null /* no pen */, Matrix.Identity, Center, RadiusX, RadiusY, geometryMatrix, StandardFlatteningTolerance, ToleranceType.Absolute); } return boundsRect; } } /// /// Returns the axis-aligned bounding rectangle when stroked with a pen, after applying /// the supplied transform (if non-null). /// internal override Rect GetBoundsInternal(Pen pen, Matrix matrix, double tolerance, ToleranceType type) { Matrix geometryMatrix; Transform.GetTransformValue(Transform, out geometryMatrix); return EllipseGeometry.GetBoundsHelper( pen, matrix, Center, RadiusX, RadiusY, geometryMatrix, tolerance, type); } /// /// Critical - it calls a critical method, Geometry.GetBoundsHelper and has an unsafe block /// TreatAsSafe - returning an EllipseGeometry's bounds is considered safe /// [SecurityCritical, SecurityTreatAsSafe] internal static Rect GetBoundsHelper(Pen pen, Matrix worldMatrix, Point center, double radiusX, double radiusY, Matrix geometryMatrix, double tolerance, ToleranceType type) { Rect rect; Debug.Assert(worldMatrix != null); Debug.Assert(geometryMatrix != null); if ( (pen == null || pen.DoesNotContainGaps) && worldMatrix.IsIdentity && geometryMatrix.IsIdentity) { double strokeThickness = 0.0; if (Pen.ContributesToBounds(pen)) { strokeThickness = Math.Abs(pen.Thickness); } rect = new Rect( center.X - Math.Abs(radiusX)-0.5*strokeThickness, center.Y - Math.Abs(radiusY)-0.5*strokeThickness, 2.0 * Math.Abs(radiusX)+strokeThickness, 2.0 * Math.Abs(radiusY)+strokeThickness); } else { unsafe { Point * pPoints = stackalloc Point[(int)c_pointCount]; EllipseGeometry.GetPointList(pPoints, c_pointCount, center, radiusX, radiusY); fixed (byte *pTypes = EllipseGeometry.s_roundedPathTypes) { rect = Geometry.GetBoundsHelper( pen, &worldMatrix, pPoints, pTypes, c_pointCount, c_segmentCount, &geometryMatrix, tolerance, type, false); // skip hollows - meaningless here, this is never a hollow } } } return rect; } /// /// Critical - contains unsafe block and calls critical method Geometry.ContainsInternal. /// TreatAsSafe - as this doesn't expose anything sensitive. /// [SecurityCritical, SecurityTreatAsSafe] internal override bool ContainsInternal(Pen pen, Point hitPoint, double tolerance, ToleranceType type) { unsafe { Point *pPoints = stackalloc Point[(int)GetPointCount()]; EllipseGeometry.GetPointList(pPoints, GetPointCount(), Center, RadiusX, RadiusY); fixed (byte* pTypes = GetTypeList()) { return ContainsInternal( pen, hitPoint, tolerance, type, pPoints, GetPointCount(), pTypes, GetSegmentCount()); } } } #region Public Methods /// /// Returns true if this geometry is empty /// public override bool IsEmpty() { return false; } /// /// Returns true if this geometry may have curved segments /// public override bool MayHaveCurves() { return true; } /// /// Gets the area of this geometry /// /// The computational error tolerance /// The way the error tolerance will be interpreted - realtive or absolute public override double GetArea(double tolerance, ToleranceType type) { ReadPreamble(); double area = Math.Abs(RadiusX * RadiusY) * Math.PI; // Adjust to internal transformation Transform transform = Transform; if (transform != null && !transform.IsIdentity) { area *= Math.Abs(transform.Value.Determinant); } return area; } #endregion Public Methods internal override PathFigureCollection GetTransformedFigureCollection(Transform transform) { Point [] points = GetPointList(); // Get the combined transform argument with the internal transform Matrix matrix = GetCombinedMatrix(transform); if (!matrix.IsIdentity) { for (int i=0; i /// GetAsPathGeometry - return a PathGeometry version of this Geometry /// internal override PathGeometry GetAsPathGeometry() { PathStreamGeometryContext ctx = new PathStreamGeometryContext(FillRule.EvenOdd, Transform); PathGeometry.ParsePathGeometryData(GetPathGeometryData(), ctx); return ctx.GetPathGeometry(); } /// /// GetPathGeometryData - returns a byte[] which contains this Geometry represented /// as a path geometry's serialized format. /// internal override PathGeometryData GetPathGeometryData() { if (IsObviouslyEmpty()) { return Geometry.GetEmptyPathGeometryData(); } PathGeometryData data = new PathGeometryData(); data.FillRule = FillRule.EvenOdd; data.Matrix = CompositionResourceManager.TransformToMilMatrix3x2D(Transform); Point[] points = GetPointList(); ByteStreamGeometryContext ctx = new ByteStreamGeometryContext(); ctx.BeginFigure(points[0], true /* is filled */, true /* is closed */); // i == 0, 3, 6, 9 for (int i = 0; i < 12; i += 3) { ctx.BezierTo(points[i + 1], points[i + 2], points[i + 3], true /* is stroked */, true /* is smooth join */); } ctx.Close(); data.SerializedData = ctx.GetData(); return data; } /// /// /// /// /// Critical - Calls critical code /// TreatAsSafe - returning a EllipseGeometry's point list is considered safe /// [SecurityCritical, SecurityTreatAsSafe] private Point[] GetPointList() { Point[] points = new Point[GetPointCount()]; unsafe { fixed(Point *pPoints = points) { EllipseGeometry.GetPointList(pPoints, GetPointCount(), Center, RadiusX, RadiusY); } } return points; } /// /// Critical - Accepts pointer arguments /// [SecurityCritical] private unsafe static void GetPointList(Point * points, uint pointsCount, Point center, double radiusX, double radiusY) { Invariant.Assert(pointsCount >= c_pointCount); radiusX = Math.Abs(radiusX); radiusY = Math.Abs(radiusY); // Set the X coordinates double mid = radiusX * c_arcAsBezier; points[0].X = points[1].X = points[11].X = points[12].X = center.X + radiusX; points[2].X = points[10].X = center.X + mid; points[3].X = points[9].X = center.X; points[4].X = points[8].X = center.X - mid; points[5].X = points[6].X = points[7].X = center.X - radiusX; // Set the Y coordinates mid = radiusY * c_arcAsBezier; points[2].Y = points[3].Y = points[4].Y = center.Y + radiusY; points[1].Y = points[5].Y = center.Y + mid; points[0].Y = points[6].Y = points[12].Y = center.Y; points[7].Y = points[11].Y = center.Y - mid; points[8].Y = points[9].Y = points[10].Y = center.Y - radiusY; } private byte[] GetTypeList() { return s_roundedPathTypes; } private uint GetPointCount() { return c_pointCount; } private uint GetSegmentCount() { return c_segmentCount; } #region Static Data // Approximating a 1/4 circle with a Bezier curve _ internal const double c_arcAsBezier = 0.5522847498307933984; // =( \/2 - 1)*4/3 private const UInt32 c_segmentCount = 4; private const UInt32 c_pointCount = 13; private const byte c_smoothBezier = (byte)MILCoreSegFlags.SegTypeBezier | (byte)MILCoreSegFlags.SegIsCurved | (byte)MILCoreSegFlags.SegSmoothJoin; private static readonly byte[] s_roundedPathTypes = { (byte)MILCoreSegFlags.SegTypeBezier | (byte)MILCoreSegFlags.SegIsCurved | (byte)MILCoreSegFlags.SegSmoothJoin | (byte)MILCoreSegFlags.SegClosed, c_smoothBezier, c_smoothBezier, c_smoothBezier }; #endregion } } ```