CJKmkp/community
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

improve:插入图片及墨迹平滑

Browse Source
This commit is contained in:
CJKmkp
2025-08-30 22:54:16 +08:00
parent 4690ab3c30
commit b64cefad46
8 changed files with 786 additions and 91 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Ink Canvas/Helpers/ImprovedBezierSmoothing.cs
+325
View File
@@ -0,0 +1,325 @@
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Ink;
using System.Windows.Input;
namespace Ink_Canvas.Helpers
{
/// <summary>
/// 改进的三次贝塞尔曲线平滑算法
/// </summary>
public class ImprovedBezierSmoothing
{
private readonly InkSmoothingConfig _config;
public ImprovedBezierSmoothing(InkSmoothingConfig config = null)
{
_config = config ?? new InkSmoothingConfig();
}
/// <summary>
/// 使用改进的贝塞尔曲线算法平滑笔画
/// </summary>
public Stroke SmoothStroke(Stroke originalStroke)
{
if (originalStroke == null || originalStroke.StylusPoints.Count < 3)
return originalStroke;
var originalPoints = originalStroke.StylusPoints.ToArray();
// 预处理：去除噪声点
var cleanedPoints = RemoveNoisePoints(originalPoints);
// 使用改进的贝塞尔曲线拟合
var smoothedPoints = ApplyCubicBezierSmoothing(cleanedPoints);
// 后处理：重采样和优化
var finalPoints = PostProcessPoints(smoothedPoints);
return new Stroke(new StylusPointCollection(finalPoints))
{
DrawingAttributes = originalStroke.DrawingAttributes.Clone()
};
}
/// <summary>
/// 去除噪声点
/// </summary>
private StylusPoint[] RemoveNoisePoints(StylusPoint[] points)
{
if (points.Length < 3) return points;
var result = new List<StylusPoint> { points[0] };
double minDistance = _config.ResampleInterval * 0.5;
for (int i = 1; i < points.Length - 1; i++)
{
var prev = result[result.Count - 1];
var curr = points[i];
var next = points[i + 1];
// 计算到前一个点的距离
double distToPrev = Math.Sqrt((curr.X - prev.X) * (curr.X - prev.X) +
(curr.Y - prev.Y) * (curr.Y - prev.Y));
// 如果距离太近，跳过这个点
if (distToPrev < minDistance)
continue;
// 检查是否为异常点（与前后点形成锐角）
if (IsOutlierPoint(prev, curr, next))
continue;
result.Add(curr);
}
result.Add(points[points.Length - 1]);
return result.ToArray();
}
/// <summary>
/// 检查是否为异常点
/// </summary>
private bool IsOutlierPoint(StylusPoint prev, StylusPoint curr, StylusPoint next)
{
var v1 = new Vector(curr.X - prev.X, curr.Y - prev.Y);
var v2 = new Vector(next.X - curr.X, next.Y - curr.Y);
if (v1.Length == 0 || v2.Length == 0) return false;
v1.Normalize();
v2.Normalize();
double dotProduct = Vector.Multiply(v1, v2);
double angle = Math.Acos(Math.Max(-1, Math.Min(1, dotProduct)));
// 如果角度小于30度，认为是异常点
return angle < Math.PI / 6;
}
/// <summary>
/// 应用三次贝塞尔曲线平滑
/// </summary>
private StylusPoint[] ApplyCubicBezierSmoothing(StylusPoint[] points)
{
if (points.Length < 4) return points;
var result = new List<StylusPoint>();
result.Add(points[0]);
// 使用滑动窗口进行贝塞尔曲线拟合
for (int i = 0; i <= points.Length - 4; i++)
{
var p0 = points[i];
var p1 = points[i + 1];
var p2 = points[i + 2];
var p3 = points[i + 3];
// 计算控制点
var controlPoints = CalculateOptimalControlPoints(p0, p1, p2, p3);
// 计算插值步数
int steps = CalculateInterpolationSteps(p0, p1, p2, p3);
// 生成贝塞尔曲线点
for (int j = 1; j <= steps; j++)
{
double t = (double)j / steps;
var bezierPoint = CalculateBezierPoint(p0, controlPoints.cp1, controlPoints.cp2, p3, t);
result.Add(bezierPoint);
}
}
result.Add(points[points.Length - 1]);
return result.ToArray();
}
/// <summary>
/// 计算最优控制点
/// </summary>
private (Point cp1, Point cp2) CalculateOptimalControlPoints(StylusPoint p0, StylusPoint p1, StylusPoint p2, StylusPoint p3)
{
// 计算切线方向
var tangent1 = CalculateTangent(p0, p1, p2);
var tangent2 = CalculateTangent(p1, p2, p3);
// 计算控制点距离
double dist1 = CalculateDistance(p0, p1);
double dist2 = CalculateDistance(p2, p3);
double controlDist1 = dist1 * _config.CurveTension;
double controlDist2 = dist2 * _config.CurveTension;
// 计算控制点
var cp1 = new Point(
p1.X + tangent1.X * controlDist1,
p1.Y + tangent1.Y * controlDist1
);
var cp2 = new Point(
p2.X - tangent2.X * controlDist2,
p2.Y - tangent2.Y * controlDist2
);
return (cp1, cp2);
}
/// <summary>
/// 计算切线方向
/// </summary>
private Vector CalculateTangent(StylusPoint p0, StylusPoint p1, StylusPoint p2)
{
var v1 = new Vector(p1.X - p0.X, p1.Y - p0.Y);
var v2 = new Vector(p2.X - p1.X, p2.Y - p1.Y);
// 如果向量长度为零，返回零向量
if (v1.Length == 0 || v2.Length == 0)
return new Vector(0, 0);
v1.Normalize();
v2.Normalize();
// 返回平均方向
var tangent = (v1 + v2) / 2;
if (tangent.Length > 0)
tangent.Normalize();
return tangent;
}
/// <summary>
/// 计算两点间距离
/// </summary>
private double CalculateDistance(StylusPoint p1, StylusPoint p2)
{
double dx = p2.X - p1.X;
double dy = p2.Y - p1.Y;
return Math.Sqrt(dx * dx + dy * dy);
}
/// <summary>
/// 计算插值步数
/// </summary>
private int CalculateInterpolationSteps(StylusPoint p0, StylusPoint p1, StylusPoint p2, StylusPoint p3)
{
if (!_config.UseAdaptiveInterpolation)
return _config.InterpolationSteps;
// 计算曲线长度
double totalLength = CalculateDistance(p0, p1) + CalculateDistance(p1, p2) + CalculateDistance(p2, p3);
// 计算曲率
double curvature = CalculateCurvature(p0, p1, p2, p3);
// 基于长度和曲率计算步数
int baseSteps = Math.Max(8, Math.Min(20, (int)(totalLength / 10)));
int curvatureSteps = (int)(curvature * 15);
return Math.Max(_config.InterpolationSteps, Math.Min(30, baseSteps + curvatureSteps));
}
/// <summary>
/// 计算曲率
/// </summary>
private double CalculateCurvature(StylusPoint p0, StylusPoint p1, StylusPoint p2, StylusPoint p3)
{
var v1 = new Vector(p1.X - p0.X, p1.Y - p0.Y);
var v2 = new Vector(p2.X - p1.X, p2.Y - p1.Y);
var v3 = new Vector(p3.X - p2.X, p3.Y - p2.Y);
if (v1.Length == 0 || v2.Length == 0 || v3.Length == 0) return 0;
v1.Normalize();
v2.Normalize();
v3.Normalize();
// 计算角度变化
double angle1 = Math.Acos(Math.Max(-1, Math.Min(1, Vector.Multiply(v1, v2))));
double angle2 = Math.Acos(Math.Max(-1, Math.Min(1, Vector.Multiply(v2, v3))));
return (angle1 + angle2) / Math.PI; // 归一化到0-1
}
/// <summary>
/// 计算贝塞尔曲线上的点
/// </summary>
private StylusPoint CalculateBezierPoint(StylusPoint p0, Point cp1, Point cp2, StylusPoint p3, double t)
{
double u = 1 - t;
double tt = t * t;
double uu = u * u;
double uuu = uu * u;
double ttt = tt * t;
// 预计算系数
double c0 = uuu;
double c1 = 3 * uu * t;
double c2 = 3 * u * tt;
double c3 = ttt;
double x = c0 * p0.X + c1 * cp1.X + c2 * cp2.X + c3 * p3.X;
double y = c0 * p0.Y + c1 * cp1.Y + c2 * cp2.Y + c3 * p3.Y;
// 插值压力值
float pressure = (float)(p0.PressureFactor * u + p3.PressureFactor * t);
pressure = Math.Max(pressure, 0.1f);
return new StylusPoint(x, y, pressure);
}
/// <summary>
/// 后处理点集
/// </summary>
private StylusPoint[] PostProcessPoints(StylusPoint[] points)
{
if (points.Length == 0) return points;
// 如果点数过多，进行重采样
if (points.Length > _config.MaxPointsPerStroke)
{
return ResamplePoints(points, _config.ResampleInterval);
}
return points;
}
/// <summary>
/// 重采样点集
/// </summary>
private StylusPoint[] ResamplePoints(StylusPoint[] points, double interval)
{
var result = new List<StylusPoint> { points[0] };
double accumulated = 0;
for (int i = 1; i < points.Length; i++)
{
var prev = result[result.Count - 1];
var curr = points[i];
double dx = curr.X - prev.X;
double dy = curr.Y - prev.Y;
double dist = Math.Sqrt(dx * dx + dy * dy);
if (dist + accumulated >= interval)
{
double t = (interval - accumulated) / dist;
double x = prev.X + t * dx;
double y = prev.Y + t * dy;
float pressure = (float)(prev.PressureFactor * (1 - t) + curr.PressureFactor * t);
pressure = Math.Max(pressure, 0.1f);
result.Add(new StylusPoint(x, y, pressure));
accumulated = 0;
i--; // 重新处理当前点
}
else
{
accumulated += dist;
}
}
return result.ToArray();
}
}
}