373 lines
16 KiB
C#
373 lines
16 KiB
C#
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using System.Windows;
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using System.Windows.Controls;
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using System.Windows.Media;
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namespace PCL;
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public class MyDropShadow : Decorator
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{
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public static readonly DependencyProperty ColorProperty = DependencyProperty.Register("Color", typeof(Color),
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typeof(MyDropShadow),
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new FrameworkPropertyMetadata(Color.FromArgb(0x71, 0x0, 0x0, 0x0),
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FrameworkPropertyMetadataOptions.AffectsRender, ClearBrushes));
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public static readonly DependencyProperty ShadowRadiusProperty = DependencyProperty.Register("ShadowRadius",
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typeof(double), typeof(MyDropShadow),
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new FrameworkPropertyMetadata(5d, FrameworkPropertyMetadataOptions.AffectsRender, ClearBrushes));
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public static readonly DependencyProperty CornerRadiusProperty = DependencyProperty.Register("CornerRadius",
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typeof(CornerRadius), typeof(MyDropShadow),
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new FrameworkPropertyMetadata(new CornerRadius(), FrameworkPropertyMetadataOptions.AffectsRender, ClearBrushes),
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IsCornerRadiusValid);
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private static Brush[] _commonBrushes;
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private static CornerRadius _commonCornerRadius;
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private static readonly object _resourceAccess = new();
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private Brush[] _brushes;
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/// <summary>
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/// 阴影颜色。
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/// </summary>
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public Color Color
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{
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get => (Color)GetValue(ColorProperty);
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set => SetValue(ColorProperty, value);
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}
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/// <summary>
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/// 阴影模糊半径。
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/// </summary>
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public double ShadowRadius
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{
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get => (double)GetValue(ShadowRadiusProperty);
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set => SetValue(ShadowRadiusProperty, value);
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}
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/// <summary>
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/// 圆角大小。
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/// </summary>
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public CornerRadius CornerRadius
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{
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get => (CornerRadius)GetValue(CornerRadiusProperty);
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set => SetValue(CornerRadiusProperty, value);
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}
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private static bool IsCornerRadiusValid(object value)
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{
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var cr = (CornerRadius)value;
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return !(cr.TopLeft < 0.0d || cr.TopRight < 0.0d || cr.BottomLeft < 0.0d || cr.BottomRight < 0.0d ||
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double.IsNaN(cr.TopLeft) || double.IsNaN(cr.TopRight) || double.IsNaN(cr.BottomLeft) ||
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double.IsNaN(cr.BottomRight) || double.IsInfinity(cr.TopLeft) || double.IsInfinity(cr.TopRight) ||
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double.IsInfinity(cr.BottomLeft) || double.IsInfinity(cr.BottomRight));
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}
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// =======================================
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// 渲染
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// =======================================
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protected override void OnRender(DrawingContext drawingContext)
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{
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var cornerRadius = CornerRadius;
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var shadowBounds = new Rect(0d, 0d, RenderSize.Width, RenderSize.Height);
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var color = Color;
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if (shadowBounds.Width > 0d && shadowBounds.Height > 0d && color.A > 0)
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{
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var centerWidth = shadowBounds.Right - shadowBounds.Left - 2d * ShadowRadius;
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var centerHeight = shadowBounds.Bottom - shadowBounds.Top - 2d * ShadowRadius;
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var maxRadius = Math.Min(centerWidth * 0.5d, centerHeight * 0.5d);
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cornerRadius.TopLeft = Math.Min(cornerRadius.TopLeft, maxRadius);
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cornerRadius.TopRight = Math.Min(cornerRadius.TopRight, maxRadius);
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cornerRadius.BottomLeft = Math.Min(cornerRadius.BottomLeft, maxRadius);
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cornerRadius.BottomRight = Math.Min(cornerRadius.BottomRight, maxRadius);
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var brushes = GetBrushes(color, cornerRadius);
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var centerTop = shadowBounds.Top + ShadowRadius;
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var centerLeft = shadowBounds.Left + ShadowRadius;
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var centerRight = shadowBounds.Right - ShadowRadius;
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var centerBottom = shadowBounds.Bottom - ShadowRadius;
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var guidelineSetX = new[]
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{
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centerLeft, centerLeft + cornerRadius.TopLeft, centerRight - cornerRadius.TopRight,
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centerLeft + cornerRadius.BottomLeft, centerRight - cornerRadius.BottomRight, centerRight
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};
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var guidelineSetY = new[]
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{
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centerTop, centerTop + cornerRadius.TopLeft, centerTop + cornerRadius.TopRight,
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centerBottom - cornerRadius.BottomLeft, centerBottom - cornerRadius.BottomRight, centerBottom
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};
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drawingContext.PushGuidelineSet(new GuidelineSet(guidelineSetX, guidelineSetY));
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cornerRadius.TopLeft += ShadowRadius;
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cornerRadius.TopRight += ShadowRadius;
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cornerRadius.BottomLeft += ShadowRadius;
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cornerRadius.BottomRight += ShadowRadius;
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var topLeft = new Rect(shadowBounds.Left, shadowBounds.Top, cornerRadius.TopLeft, cornerRadius.TopLeft);
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drawingContext.DrawRectangle(brushes[(int)Placement.TopLeft], null, topLeft);
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var topWidth = guidelineSetX[2] - guidelineSetX[1];
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if (topWidth > 0d)
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{
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var top = new Rect(guidelineSetX[1], shadowBounds.Top, topWidth, ShadowRadius);
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drawingContext.DrawRectangle(brushes[(int)Placement.Top], null, top);
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}
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var topRight = new Rect(guidelineSetX[2], shadowBounds.Top, cornerRadius.TopRight, cornerRadius.TopRight);
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drawingContext.DrawRectangle(brushes[(int)Placement.TopRight], null, topRight);
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var leftHeight = guidelineSetY[3] - guidelineSetY[1];
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if (leftHeight > 0d)
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{
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var left = new Rect(shadowBounds.Left, guidelineSetY[1], ShadowRadius, leftHeight);
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drawingContext.DrawRectangle(brushes[(int)Placement.Left], null, left);
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}
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var rightHeight = guidelineSetY[4] - guidelineSetY[2];
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if (rightHeight > 0d)
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{
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var right = new Rect(guidelineSetX[5], guidelineSetY[2], ShadowRadius, rightHeight);
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drawingContext.DrawRectangle(brushes[(int)Placement.Right], null, right);
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}
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var bottomLeft = new Rect(shadowBounds.Left, guidelineSetY[3], cornerRadius.BottomLeft,
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cornerRadius.BottomLeft);
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drawingContext.DrawRectangle(brushes[(int)Placement.BottomLeft], null, bottomLeft);
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var bottomWidth = guidelineSetX[4] - guidelineSetX[3];
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if (bottomWidth > 0d)
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{
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var bottom = new Rect(guidelineSetX[3], guidelineSetY[5], bottomWidth, ShadowRadius);
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drawingContext.DrawRectangle(brushes[(int)Placement.Bottom], null, bottom);
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}
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var bottomRight = new Rect(guidelineSetX[4], guidelineSetY[4], cornerRadius.BottomRight,
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cornerRadius.BottomRight);
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drawingContext.DrawRectangle(brushes[(int)Placement.BottomRight], null, bottomRight);
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if (cornerRadius.TopLeft == ShadowRadius && cornerRadius.TopLeft == cornerRadius.TopRight &&
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cornerRadius.TopLeft == cornerRadius.BottomLeft && cornerRadius.TopLeft == cornerRadius.BottomRight)
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{
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var center = new Rect(guidelineSetX[0], guidelineSetY[0], centerWidth, centerHeight);
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drawingContext.DrawRectangle(brushes[(int)Placement.Center], null, center);
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}
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else
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{
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var figure = new PathFigure();
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if (cornerRadius.TopLeft > ShadowRadius)
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{
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figure.StartPoint = new Point(guidelineSetX[1], guidelineSetY[0]);
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[1], guidelineSetY[1]), true));
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[0], guidelineSetY[1]), true));
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}
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else
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{
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figure.StartPoint = new Point(guidelineSetX[0], guidelineSetY[0]);
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}
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if (cornerRadius.BottomLeft > ShadowRadius)
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{
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[0], guidelineSetY[3]), true));
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[3], guidelineSetY[3]), true));
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[3], guidelineSetY[5]), true));
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}
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else
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{
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[0], guidelineSetY[5]), true));
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}
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if (cornerRadius.BottomRight > ShadowRadius)
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{
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[4], guidelineSetY[5]), true));
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[4], guidelineSetY[4]), true));
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[5], guidelineSetY[4]), true));
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}
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else
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{
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[5], guidelineSetY[5]), true));
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}
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if (cornerRadius.TopRight > ShadowRadius)
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{
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[5], guidelineSetY[2]), true));
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[2], guidelineSetY[2]), true));
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[2], guidelineSetY[0]), true));
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}
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else
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{
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figure.Segments.Add(new LineSegment(new Point(guidelineSetX[5], guidelineSetY[0]), true));
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}
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figure.IsClosed = true;
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figure.Freeze();
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var geometry = new PathGeometry();
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geometry.Figures.Add(figure);
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geometry.Freeze();
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drawingContext.DrawGeometry(brushes[(int)Placement.Center], null, geometry);
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}
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drawingContext.Pop();
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}
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}
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private static void ClearBrushes(DependencyObject o, DependencyPropertyChangedEventArgs e)
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{
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((MyDropShadow)o)._brushes = null;
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}
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private GradientStopCollection CreateStops(Color c, double cornerRadius)
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{
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var gradientScale = 1d / (ShadowRadius + cornerRadius);
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var gsc = new GradientStopCollection();
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var stopColor = c;
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gsc.Add(new GradientStop(stopColor, (ShadowRadius * 0.1d + cornerRadius) * gradientScale));
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stopColor.A = (byte)Math.Round(0.74336d * c.A);
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gsc.Add(new GradientStop(stopColor, (ShadowRadius * 0.3d + cornerRadius) * gradientScale));
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stopColor.A = (byte)Math.Round(0.38053d * c.A);
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gsc.Add(new GradientStop(stopColor, (ShadowRadius * 0.5d + cornerRadius) * gradientScale));
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stopColor.A = (byte)Math.Round(0.12389d * c.A);
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gsc.Add(new GradientStop(stopColor, (ShadowRadius * 0.7d + cornerRadius) * gradientScale));
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stopColor.A = (byte)Math.Round(0.02654d * c.A);
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gsc.Add(new GradientStop(stopColor, (ShadowRadius * 0.9d + cornerRadius) * gradientScale));
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stopColor.A = 0;
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gsc.Add(new GradientStop(stopColor, (ShadowRadius + cornerRadius) * gradientScale));
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gsc.Freeze();
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return gsc;
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}
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private Brush[] CreateBrushes(Color c, CornerRadius cornerRadius)
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{
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var brushes = new Brush[9];
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brushes[(int)Placement.Center] = new SolidColorBrush(c);
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brushes[(int)Placement.Center].Freeze();
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var sideStops = CreateStops(c, 0d);
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var top = new LinearGradientBrush(sideStops, new Point(0d, 1d), new Point(0d, 0d));
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top.Freeze();
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brushes[(int)Placement.Top] = top;
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var left = new LinearGradientBrush(sideStops, new Point(1d, 0d), new Point(0d, 0d));
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left.Freeze();
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brushes[(int)Placement.Left] = left;
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var right = new LinearGradientBrush(sideStops, new Point(0d, 0d), new Point(1d, 0d));
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right.Freeze();
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brushes[(int)Placement.Right] = right;
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var bottom = new LinearGradientBrush(sideStops, new Point(0d, 0d), new Point(0d, 1d));
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bottom.Freeze();
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brushes[(int)Placement.Bottom] = bottom;
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GradientStopCollection topLeftStops;
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if (cornerRadius.TopLeft == 0d)
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topLeftStops = sideStops;
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else
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topLeftStops = CreateStops(c, cornerRadius.TopLeft);
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var topLeft = new RadialGradientBrush(topLeftStops)
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{
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RadiusX = 1d,
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RadiusY = 1d,
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Center = new Point(1d, 1d),
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GradientOrigin = new Point(1d, 1d)
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};
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topLeft.Freeze();
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brushes[(int)Placement.TopLeft] = topLeft;
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GradientStopCollection topRightStops;
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if (cornerRadius.TopRight == 0d)
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topRightStops = sideStops;
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else if (cornerRadius.TopRight == cornerRadius.TopLeft)
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topRightStops = topLeftStops;
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else
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topRightStops = CreateStops(c, cornerRadius.TopRight);
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var topRight = new RadialGradientBrush(topRightStops)
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{
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RadiusX = 1d,
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RadiusY = 1d,
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Center = new Point(0d, 1d),
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GradientOrigin = new Point(0d, 1d)
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};
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topRight.Freeze();
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brushes[(int)Placement.TopRight] = topRight;
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GradientStopCollection bottomLeftStops;
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if (cornerRadius.BottomLeft == 0d)
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bottomLeftStops = sideStops;
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else if (cornerRadius.BottomLeft == cornerRadius.TopLeft)
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bottomLeftStops = topLeftStops;
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else if (cornerRadius.BottomLeft == cornerRadius.TopRight)
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bottomLeftStops = topRightStops;
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else
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bottomLeftStops = CreateStops(c, cornerRadius.BottomLeft);
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var bottomLeft = new RadialGradientBrush(bottomLeftStops)
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{
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RadiusX = 1d,
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RadiusY = 1d,
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Center = new Point(1d, 0d),
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GradientOrigin = new Point(1d, 0d)
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};
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bottomLeft.Freeze();
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brushes[(int)Placement.BottomLeft] = bottomLeft;
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GradientStopCollection bottomRightStops;
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if (cornerRadius.BottomRight == 0d)
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bottomRightStops = sideStops;
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else if (cornerRadius.BottomRight == cornerRadius.TopLeft)
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bottomRightStops = topLeftStops;
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else if (cornerRadius.BottomRight == cornerRadius.TopRight)
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bottomRightStops = topRightStops;
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else if (cornerRadius.BottomRight == cornerRadius.BottomLeft)
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bottomRightStops = bottomLeftStops;
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else
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bottomRightStops = CreateStops(c, cornerRadius.BottomRight);
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var bottomRight = new RadialGradientBrush(bottomRightStops)
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{
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RadiusX = 1d,
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RadiusY = 1d,
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Center = new Point(0d, 0d),
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GradientOrigin = new Point(0d, 0d)
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};
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bottomRight.Freeze();
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brushes[(int)Placement.BottomRight] = bottomRight;
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return brushes;
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}
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private Brush[] GetBrushes(Color c, CornerRadius cornerRadius)
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{
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if (_commonBrushes is null)
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lock (_resourceAccess)
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{
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if (_commonBrushes is null)
|
||
|
|
{
|
||
|
|
_commonBrushes = CreateBrushes(c, cornerRadius);
|
||
|
|
_commonCornerRadius = cornerRadius;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (c == ((SolidColorBrush)_commonBrushes[(int)Placement.Center]).Color && cornerRadius == _commonCornerRadius)
|
||
|
|
{
|
||
|
|
_brushes = null;
|
||
|
|
return _commonBrushes;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (_brushes is null) _brushes = CreateBrushes(c, cornerRadius);
|
||
|
|
|
||
|
|
return _brushes;
|
||
|
|
}
|
||
|
|
|
||
|
|
private enum Placement
|
||
|
|
{
|
||
|
|
TopLeft = 0,
|
||
|
|
Top = 1,
|
||
|
|
TopRight = 2,
|
||
|
|
Left = 3,
|
||
|
|
Center = 4,
|
||
|
|
Right = 5,
|
||
|
|
BottomLeft = 6,
|
||
|
|
Bottom = 7,
|
||
|
|
BottomRight = 8
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// 参考自：https://referencesource.microsoft.com/#PresentationFramework.Aero/parent/Shared/Microsoft/Windows/Themes/SystemDropShadowChrome.cs,6d9c27d92a8128c1
|