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//------------------------------------------------------------------------------
// 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
{
/// <summary>
/// This is the Geometry class for Circles and Ellipses
/// </summary>
public sealed partial class EllipseGeometry : Geometry
{
#region Constructors
/// <summary>
///
/// </summary>
public EllipseGeometry()
{
}
/// <summary>
/// Constructor - sets the ellipse to the paramters with the given transformation
/// </summary>
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);
}
/// <summary>
/// Constructor - sets the ellipse to the parameters
/// </summary>
public EllipseGeometry(
Point center,
double radiusX,
double radiusY)
{
Center = center;
RadiusX = radiusX;
RadiusY = radiusY;
}
/// <summary>
/// Constructor - sets the ellipse to the parameters
/// </summary>
public EllipseGeometry(
Point center,
double radiusX,
double radiusY,
Transform transform) : this(center, radiusX, radiusY)
{
Transform = transform;
}
#endregion
/// <summary>
/// Gets the bounds of this Geometry as an axis-aligned bounding box
/// </summary>
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;
}
}
/// <summary>
/// Returns the axis-aligned bounding rectangle when stroked with a pen, after applying
/// the supplied transform (if non-null).
/// </summary>
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);
}
/// <SecurityNote>
/// Critical - it calls a critical method, Geometry.GetBoundsHelper and has an unsafe block
/// TreatAsSafe - returning an EllipseGeometry's bounds is considered safe
/// </SecurityNote>
[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;
}
/// <SecurityNote>
/// Critical - contains unsafe block and calls critical method Geometry.ContainsInternal.
/// TreatAsSafe - as this doesn't expose anything sensitive.
/// </SecurityNote>
[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
/// <summary>
/// Returns true if this geometry is empty
/// </summary>
public override bool IsEmpty()
{
return false;
}
/// <summary>
/// Returns true if this geometry may have curved segments
/// </summary>
public override bool MayHaveCurves()
{
return true;
}
/// <summary>
/// Gets the area of this geometry
/// </summary>
/// <param name="tolerance">The computational error tolerance</param>
/// <param name="type">The way the error tolerance will be interpreted - realtive or absolute</param>
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<points.Length; i++)
{
points[i] *= matrix;
}
}
PathFigureCollection figureCollection = new PathFigureCollection();
figureCollection.Add(
new PathFigure(
points[0],
new PathSegment[]{
new BezierSegment(points[1], points[2], points[3], true, true),
new BezierSegment(points[4], points[5], points[6], true, true),
new BezierSegment(points[7], points[8], points[9], true, true),
new BezierSegment(points[10], points[11], points[12], true, true)},
true
)
);
return figureCollection;
}
/// <summary>
/// GetAsPathGeometry - return a PathGeometry version of this Geometry
/// </summary>
internal override PathGeometry GetAsPathGeometry()
{
PathStreamGeometryContext ctx = new PathStreamGeometryContext(FillRule.EvenOdd, Transform);
PathGeometry.ParsePathGeometryData(GetPathGeometryData(), ctx);
return ctx.GetPathGeometry();
}
/// <summary>
/// GetPathGeometryData - returns a byte[] which contains this Geometry represented
/// as a path geometry's serialized format.
/// </summary>
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;
}
/// <summary>
/// </summary>
/// <returns></returns>
/// <SecurityNote>
/// Critical - Calls critical code
/// TreatAsSafe - returning a EllipseGeometry's point list is considered safe
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
private Point[] GetPointList()
{
Point[] points = new Point[GetPointCount()];
unsafe
{
fixed(Point *pPoints = points)
{
EllipseGeometry.GetPointList(pPoints, GetPointCount(), Center, RadiusX, RadiusY);
}
}
return points;
}
/// <SecurityNote>
/// Critical - Accepts pointer arguments
/// </SecurityNote>
[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
}
}
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