wpf inkcanvas customink 毛笔效果

鸿蛟家平 2017-08-11

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用wpf来做毛笔书写效果，需要自定义inkcanvas，基本效果可以，就是连续画很长的笔触时会有卡顿现象。解决方法，做一个判断，当笔触超过一定长度则停止。

核心代码：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Windows.Controls;

using System.Windows.Input.StylusPlugIns;

using System.Windows.Media;

using System.Windows;

using System.Windows.Input;

using System.Windows.Ink;

using System.Windows.Media.Imaging;

namespace WpfApplication1

{

class CustomRenderingInkCanvas:InkCanvas

{

CustomDynamicRenderer customRenderer = new CustomDynamicRenderer();

public CustomRenderingInkCanvas()

: base()

{

// Use the custom dynamic renderer on the

// custom InkCanvas.

this.DynamicRenderer = customRenderer;

}

protected override void OnStrokeCollected(InkCanvasStrokeCollectedEventArgs e)

{

// Remove the original stroke and add a custom stroke.

this.Strokes.Remove(e.Stroke);

CustomStroke customStroke = new CustomStroke(e.Stroke.StylusPoints);

this.Strokes.Add(customStroke);

// Pass the custom stroke to base class' OnStrokeCollected method.

InkCanvasStrokeCollectedEventArgs args =

new InkCanvasStrokeCollectedEventArgs(customStroke);

base.OnStrokeCollected(args);

}

// A class for rendering custom strokes

class CustomStroke : Stroke

{

Brush brush;

Pen pen;

public CustomStroke(StylusPointCollection stylusPoints)

: base(stylusPoints)

{

// Create the Brush and Pen used for drawing.

brush = new LinearGradientBrush(Colors.Red, Colors.Blue, 10d);

pen = new Pen(brush, 2d);

}

protected override void DrawCore(DrawingContext drawingContext,

DrawingAttributes drawingAttributes)

{

ImageSource img = new BitmapImage(new Uri(@"1.png", UriKind.RelativeOrAbsolute));

//前一个点的绘制。

Point prevPoint = new Point(double.NegativeInfinity,

double.NegativeInfinity);

int w = 10 + 15; //输出时笔刷的实际大小

Point pt = new Point(0, 0);

Vector v = new Vector(); //前一个点与当前点的距离

var subtractY = 0d; //当前点处前一点的Y偏移

var subtractX = 0d; //当前点处前一点的X偏移

var pointWidth = 10;

double x = 0, y = 0;

for (int i = 0; i < this.StylusPoints.Count; i++)

{

pt = (Point)this.StylusPoints[i];

v = Point.Subtract(prevPoint, pt);

// Debug.WriteLine("X " + pt.X + "\t" + pt.Y);

subtractY = (pt.Y - prevPoint.Y) / v.Length; //设置stylusPoints两个点之间需要填充的XY偏移

subtractX = (pt.X - prevPoint.X) / v.Length;

if (w - v.Length < 10) //控制笔刷大小

{

pointWidth = 10;

}

else

{

pointWidth = w - Convert.ToInt32(v.Length); //在两个点距离越大的时候，笔刷所展示的大小越小

}

for (double j = 0; j < v.Length; j = j + 1d) //填充stylusPoints两个点之间

{

x = 0; y = 0;

if (prevPoint.X == double.NegativeInfinity || prevPoint.Y == double.NegativeInfinity || double.PositiveInfinity == prevPoint.X || double.PositiveInfinity == prevPoint.Y)

{

y = pt.Y;

x = pt.X;

}

else

{

y = prevPoint.Y + subtractY;

x = prevPoint.X + subtractX;

}

drawingContext.DrawImage(img, new Rect(x - pointWidth / 2, y - pointWidth / 2, pointWidth, pointWidth)); //在当前点画笔刷图片

prevPoint = new Point(x, y);

if (double.IsNegativeInfinity(v.Length) || double.IsPositiveInfinity(v.Length))

{ break; }

}

// this.StylusPoints = null;

//// Allocate memory to store the previous point to draw from.

//Point prevPoint = new Point(double.NegativeInfinity,

// double.NegativeInfinity);

//// Draw linear gradient ellipses between

//// all the StylusPoints in the Stroke.

//for (int i = 0; i < this.StylusPoints.Count; i++)

//{

// Point pt = (Point)this.StylusPoints[i];

// Vector v = Point.Subtract(prevPoint, pt);

// // Only draw if we are at least 4 units away

// // from the end of the last ellipse. Otherwise,

// // we're just redrawing and wasting cycles.

// if (v.Length > 4)

// {

// // Set the thickness of the stroke

// // based on how hard the user pressed.

// double radius = this.StylusPoints[i].PressureFactor * 10d;

// drawingContext.DrawEllipse(brush, pen, pt, radius, radius);

// prevPoint = pt;

// }

//}

}

class CustomDynamicRenderer : DynamicRenderer

{

[ThreadStatic]

static private Brush brush = null;

[ThreadStatic]

static private Pen pen = null;

private Point prevPoint;

protected override void OnStylusDown(RawStylusInput rawStylusInput)

{

// Allocate memory to store the previous point to draw from.

prevPoint = new Point(double.NegativeInfinity, double.NegativeInfinity);

base.OnStylusDown(rawStylusInput);

}

protected override void OnDraw(DrawingContext drawingContext,

StylusPointCollection stylusPoints,

Geometry geometry, Brush fillBrush)

{

ImageSource img = new BitmapImage(new Uri(@"1.png",UriKind.RelativeOrAbsolute));

//前一个点的绘制。

Point prevPoint = new Point(double.NegativeInfinity,

double.NegativeInfinity);

int w = 10 + 15; //输出时笔刷的实际大小

Point pt = new Point(0, 0);

Vector v = new Vector(); //前一个点与当前点的距离

var subtractY = 0d; //当前点处前一点的Y偏移

var subtractX = 0d; //当前点处前一点的X偏移

var pointWidth = 10;

double x = 0, y = 0;

for (int i = 0; i < stylusPoints.Count; i++)

{

pt = (Point)stylusPoints[i];

v = Point.Subtract(prevPoint, pt);

// Debug.WriteLine("X " + pt.X + "\t" + pt.Y);

subtractY = (pt.Y - prevPoint.Y) / v.Length; //设置stylusPoints两个点之间需要填充的XY偏移

subtractX = (pt.X - prevPoint.X) / v.Length;

if (w - v.Length < 10) //控制笔刷大小

{

pointWidth = 10;

}

else

{

pointWidth = w - Convert.ToInt32(v.Length); //在两个点距离越大的时候，笔刷所展示的大小越小

}

for (double j = 0; j < v.Length; j = j + 1d) //填充stylusPoints两个点之间

{

x = 0; y = 0;

if (prevPoint.X == double.NegativeInfinity || prevPoint.Y == double.NegativeInfinity || double.PositiveInfinity == prevPoint.X || double.PositiveInfinity == prevPoint.Y)

{

y = pt.Y;

x = pt.X;

}

else

{

y = prevPoint.Y + subtractY;

x = prevPoint.X + subtractX;

}

drawingContext.DrawImage(img, new Rect(x - pointWidth / 2, y - pointWidth / 2, pointWidth, pointWidth)); //在当前点画笔刷图片

prevPoint = new Point(x, y);

if (double.IsNegativeInfinity(v.Length) || double.IsPositiveInfinity(v.Length))