/// <summary>
/// create the path points
/// </summary>
/// <param name="stroke">the stroke</param>
/// <returns>the path points</returns>
public static SKPoint[] CreatePathPoints(XInkStroke stroke)
{
if (stroke == null)
{
throw new ArgumentNullException(nameof(stroke));
}
var inkPoints = stroke.GetInkPoints().ToArray();
if (inkPoints.Length < 2)
{
return(null);
}
var pointCount = inkPoints.Length * 2 + 2;
var allPoints = new SKPoint[pointCount];
double angle = 0.0;
for (var i = 0; i < inkPoints.Length; i++)
{
var point1 = inkPoints[i];
if (i < inkPoints.Length - 1)
{
var point2 = inkPoints[i + 1];
var x = point2.Position.X - point1.Position.X;
var y = point2.Position.Y - point1.Position.Y;
angle = Math.Atan2(y, x) - Math.PI / 2;
}
var h = stroke.DrawingAttributes.Size * 0.5;
if (!stroke.DrawingAttributes.IgnorePressure)
{
h *= point1.Pressure;
}
var leftX = point1.Position.X + (Math.Cos(angle) * h);
var leftY = point1.Position.Y + (Math.Sin(angle) * h);
var rightX = point1.Position.X - (Math.Cos(angle) * h);
var rightY = point1.Position.Y - (Math.Sin(angle) * h);
allPoints[i + 1] = new Point(leftX, leftY).ToSKPoint();
allPoints[pointCount - i - 1] = new Point(rightX, rightY).ToSKPoint();
}
allPoints[0] = GetModifiedFirstPoint(stroke, inkPoints).ToSKPoint();
allPoints[inkPoints.Length + 1] = GetModifiedLastPoint(stroke, inkPoints).ToSKPoint();
return(allPoints);
}
/// <summary>
/// Add a stroke
/// </summary>
/// <param name="inkStroke">the ink stroke to add</param>
public void Add(XInkStroke inkStroke)
{
var newStroke = inkStroke.ToInkStroke();
if (newStroke == null)
{
return;
}
NativeStrokeContainer.AddStroke(newStroke);
InkChanged?.Invoke(this, new EventArgs());
}
/// <summary>
/// Create a variable thickness path
/// </summary>
/// <param name="stroke">the stroke</param>
/// <returns>a variable thickness path</returns>
public static SKPath CreateVariableThicknessPath(this XInkStroke stroke)
{
var pathPoints = CreatePathPoints(stroke);
if (pathPoints == null || pathPoints.Length == 0)
{
return(null);
}
var newPath = new SKPath();
newPath.AddPoly(pathPoints);
return(newPath);
}
/// <summary>
/// Remove an ink stroke
/// </summary>
/// <param name="item">the stroke to remove</param>
public void Remove(XInkStroke item)
{
if (item == null)
{
throw new ArgumentNullException(nameof(item));
}
foreach (var stroke in NativeStrokeContainer.GetStrokes())
{
if (stroke.Id.ToString(CultureInfo.InvariantCulture) == item.Id)
{
stroke.Selected = true;
}
}
NativeStrokeContainer.DeleteSelected();
InkChanged?.Invoke(this, new EventArgs());
}
/// <summary>
/// create a path for the stroke
/// </summary>
/// <param name="stroke">the stroke</param>
/// <returns>a new path</returns>
public static SKPath CreatePath(this XInkStroke stroke)
{
if (stroke == null)
{
throw new ArgumentNullException(nameof(stroke));
}
var path = new SKPath();
var inkPoints = stroke.GetInkPoints();
var points = from point in inkPoints
let x = (float)point.Position.X
let y = (float)point.Position.Y
select new SKPoint(x, y);
var count = points.Count();
//path.AddPoly(points.ToArray(), false);
if (count > 1)
{
var firstPoints = new Point[count - 1];
var secondPoints = new Point[count - 1];
var controlPoints = (from item in inkPoints
select item.Position).ToArray();
BezierSpline.GetCurveControlPoints(controlPoints, out firstPoints, out secondPoints);
path.MoveTo(controlPoints.First().ToSKPoint());
for (var i = 1; i < count; i++)
{
path.CubicTo(firstPoints[i - 1].ToSKPoint(), secondPoints[i - 1].ToSKPoint(), points.ElementAt(i));
}
}
return(path);
}
/// <summary>
/// Convert a Xamarin Ink Stroke to a UWP InkStroke
/// </summary>
/// <param name="xInkStroke">a Xamarin Ink Stroke</param>
/// <returns>a UWP Ink Stroke</returns>
public static InkStroke ToInkStroke(this XInkStroke xInkStroke)
{
if (xInkStroke == null)
{
throw new ArgumentNullException(nameof(xInkStroke));
}
var builder = new InkStrokeBuilder();
var inkPoints = from item in xInkStroke.GetInkPoints()
select new InkPoint(new Point(item.Position.X, item.Position.Y), item.Pressure);
if (!inkPoints.Any())
{
return(null);
}
var stroke = builder.CreateStrokeFromInkPoints(inkPoints, Matrix3x2.Identity);
stroke.DrawingAttributes = xInkStroke.DrawingAttributes.ToInkDrawingAttributes();
return(stroke);
}
private static Point GetModifiedLastPoint(XInkStroke stroke, XInkPoint[] inkPoints)
{
var lastPoint = inkPoints[inkPoints.Length - 1];
var secondLastPoint = inkPoints[inkPoints.Length - 2];
var x1 = lastPoint.Position.X - secondLastPoint.Position.X;
var y1 = lastPoint.Position.Y - secondLastPoint.Position.Y;
var angle1 = Math.Atan2(y1, x1);
var h1 = stroke.DrawingAttributes.Size * 0.5;
if (!stroke.DrawingAttributes.IgnorePressure)
{
h1 *= lastPoint.Pressure;
}
var lastX = lastPoint.Position.X + (Math.Cos(angle1) * h1);
var lastY = lastPoint.Position.Y + (Math.Sin(angle1) * h1);
var modifiedLastPoint = new Point(lastX, lastY);
return(modifiedLastPoint);
}
public static Tuple <SKPaint, IEnumerable <IDisposable> > CreatePaint(this XInkStroke stroke, SKPaintStyle paintStyle = SKPaintStyle.Stroke, SKBlendMode blendMode = SKBlendMode.SrcATop)
{
if (stroke == null)
{
throw new ArgumentNullException(nameof(stroke));
}
var disposables = new List <IDisposable>();
SKShader shader = null;
if (stroke.DrawingAttributes.Kind == XInkDrawingAttributesKind.Pencil)
{
var perlin = SKShader.CreatePerlinNoiseFractalNoise(0.01f, 0.01f, 1, 1.0f);
var color = SKShader.CreateColor(stroke.DrawingAttributes.Color.ToSKColor().WithAlpha(0x7F));
disposables.Add(perlin);
disposables.Add(color);
shader = SKShader.CreateCompose(
perlin,
color,
blendMode);
}
Tuple <SKPaint, IEnumerable <IDisposable> > tuple = null;
SKPaint paint = null;
if (!stroke.DrawingAttributes.IgnorePressure)
{
paintStyle = SKPaintStyle.Fill;
}
try
{
paint = new SKPaint
{
Color = stroke.DrawingAttributes.Kind == XInkDrawingAttributesKind.Default ? stroke.DrawingAttributes.Color.ToSKColor() : new SKColor(),
StrokeWidth = stroke.DrawingAttributes.IgnorePressure? stroke.DrawingAttributes.Size : 0.0f,
Style = paintStyle,
IsAntialias = true,
StrokeCap = stroke.DrawingAttributes.PenTip == Inking.XPenTipShape.Circle ? SKStrokeCap.Round : SKStrokeCap.Butt,
PathEffect = SKPathEffect.CreateCorner(100)
};
if (shader != null)
{
paint.Shader = shader;
}
tuple = Tuple.Create(paint, disposables as IEnumerable <IDisposable>);
paint = null;
}
finally
{
paint?.Dispose();
}
return(tuple);
}
/// <summary>
/// Draw an ink stroke
/// </summary>
/// <param name="canvas">the canvas</param>
/// <param name="stroke">the stroke</param>
/// <param name="useCache">true to use cached data</param>
public static void Draw(this SKCanvas canvas, XInkStroke stroke, bool useCache)
{
_ = canvas ?? throw new ArgumentNullException(nameof(canvas));
_ = stroke ?? throw new ArgumentNullException(nameof(stroke));
var inkPoints = stroke.GetInkPoints();
if (useCache)
{
if (inkPoints.Count == 1)
{
if (stroke.Paint == null)
{
var paintResult = stroke.CreatePaint(SKPaintStyle.Fill);
stroke.Paint = paintResult.Item1;
stroke.Resources = paintResult.Item2;
}
canvas.DrawCircle(
stroke.GetInkPoints()[0].Position.ToSKPoint(),
stroke.DrawingAttributes.Size / 4.0f,
stroke.Paint);
}
else
{
stroke.Path ??= stroke.DrawingAttributes.IgnorePressure
? stroke.CreatePath()
: stroke.CreateVariableThicknessPath();
if (stroke.Paint == null)
{
var paintResult = stroke.CreatePaint();
stroke.Resources = paintResult.Item2;
stroke.Paint = paintResult.Item1;
}
if (stroke.Path != null)
{
canvas.DrawPath(stroke.Path, stroke.Paint);
}
}
}
else
{
if (inkPoints.Count == 1)
{
var paintResult = stroke.CreatePaint(SKPaintStyle.Fill);
using (var paint = paintResult.Item1)
{
paint.IsStroke = false;
var radius = stroke.DrawingAttributes.Size / 4.0f;
//System.Diagnostics.Debug.WriteLine($"Drawing dot radius {radius}");
canvas.DrawCircle(
inkPoints[0].Position.ToSKPoint(),
radius,
paint);
}
if (paintResult.Item2 != null)
{
foreach (var item in paintResult.Item2)
{
item.Dispose();
}
}
}
else
{
using var path = stroke.DrawingAttributes.IgnorePressure ? stroke.CreatePath() : stroke.CreateVariableThicknessPath();
if (path == null)
{
return;
}
var paintResult = stroke.CreatePaint();
using (var paint = paintResult.Item1)
{
canvas.DrawPath(path, paint);
}
if (paintResult.Item2 != null)
{
foreach (var item in paintResult.Item2)
{
item.Dispose();
}
}
}
}
}
public void TestCreatePathPointsEmpty()
{
using var inkStroke = new XInkStroke();
InkRenderer.CreatePathPoints(inkStroke);
}
