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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
//
// Description: Impelementation of ArcSegment
//
//
using MS.Internal;
using System.Windows.Media.Composition;
namespace System.Windows.Media
{
/// <summary>
/// ArcSegment
/// </summary>
public sealed partial class ArcSegment : PathSegment
{
#region Constructors
/// <summary>
///
/// </summary>
public ArcSegment()
{
}
/// <summary>
///
/// </summary>
public ArcSegment(
Point point,
Size size,
double rotationAngle,
bool isLargeArc,
SweepDirection sweepDirection,
bool isStroked)
{
Size = size;
RotationAngle = rotationAngle;
IsLargeArc = isLargeArc;
SweepDirection = sweepDirection;
Point = point;
IsStroked = isStroked;
}
#endregion
#region AddToFigure
internal override void AddToFigure(
Matrix matrix, // The transformation matrid
PathFigure figure, // The figure to add to
ref Point current) // In: Segment start point, Out: Segment endpoint, neither transformed
{
Point endPoint = Point;
if (matrix.IsIdentity)
{
figure.Segments.Add(this);
}
else
{
// The arc segment is approximated by up to 4 Bezier segments
unsafe
{
int count;
Point* points = stackalloc Point[12];
Size size = Size;
Double rotation = RotationAngle;
MilMatrix3x2D mat3X2 = CompositionResourceManager.MatrixToMilMatrix3x2D(ref matrix);
Composition.MilCoreApi.MilUtility_ArcToBezier(
current, // =start point
size,
rotation,
IsLargeArc,
SweepDirection,
endPoint,
&mat3X2,
points,
out count); // = number of Bezier segments
Invariant.Assert(count <= 4);
// To ensure no buffer overflows
count = Math.Min(count, 4);
bool isStroked = IsStroked;
bool isSmoothJoin = IsSmoothJoin;
// Add the segments
if (count > 0)
{
for (int i = 0; i < count; i++)
{
figure.Segments.Add(new BezierSegment(
points[3*i],
points[3*i + 1],
points[3*i + 2],
isStroked,
(i < count - 1) || isSmoothJoin)); // Smooth join between arc pieces
}
}
else if (count == 0)
{
figure.Segments.Add(new LineSegment(points[0], isStroked, isSmoothJoin));
}
}
// Update the last point
current = endPoint;
}
}
#endregion
/// <summary>
/// SerializeData - Serialize the contents of this Segment to the provided context.
/// </summary>
internal override void SerializeData(StreamGeometryContext ctx)
{
ctx.ArcTo(Point, Size, RotationAngle, IsLargeArc, SweepDirection, IsStroked, IsSmoothJoin);
}
internal override bool IsCurved()
{
return true;
}
/// <summary>
/// Creates a string representation of this object based on the format string
/// and IFormatProvider passed in.
/// If the provider is null, the CurrentCulture is used.
/// See the documentation for IFormattable for more information.
/// </summary>
/// <returns>
/// A string representation of this object.
/// </returns>
internal override string ConvertToString(string format, IFormatProvider provider)
{
// Helper to get the numeric list separator for a given culture.
char separator = MS.Internal.TokenizerHelper.GetNumericListSeparator(provider);
return String.Format(provider,
"A{1:" + format + "}{0}{2:" + format + "}{0}{3}{0}{4}{0}{5:" + format + "}",
separator,
Size,
RotationAngle,
IsLargeArc ? "1" : "0",
SweepDirection == SweepDirection.Clockwise ? "1" : "0",
Point);
}
//
// This property
// 1. Finds the correct initial size for the _effectiveValues store on the current DependencyObject
// 2. This is a performance optimization
//
internal override int EffectiveValuesInitialSize
{
get { return 6; }
}
/// <summary>
/// For the purposes of this class, Size.Empty should be treated as if it were Size(0,0).
/// </summary>
private static object CoerceSize(DependencyObject d, object value)
{
if (((Size)value).IsEmpty)
{
return new Size(0,0);
}
else
{
return value;
}
}
}
}
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