是否可以绘制一条沿笔触宽度具有线性渐变的折线?也就是说,如果您有一个渐变,黑色为 0 和 100%,白色为 50%,无论角度如何,黑色将始终位于线条边缘,白色位于中间。将其视为某种 3D 管道。当然,线条的笔触宽度至少为 10px。这里的所有问题都询问如何在两端之间填充一条线。我绝对对此不感兴趣。我正在使用 GDI+ 在 C# 中工作,可以是任何 .NET 版本。
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3035 次
1 回答
7
我认为这就是你想要的:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.SmoothingMode=SmoothingMode.AntiAlias;
DrawPipe(e.Graphics, 10f, new PointF(10, 10), new PointF(250, 80), Color.White, Color.Black);
DrawPipe(e.Graphics, 10f, new PointF(15, 60), new PointF(280, 120), Color.BlueViolet, Color.Black);
}
private void DrawPipe(Graphics g, float width, PointF p1, PointF p2, Color mid_color, Color edge_color)
{
SizeF along=new SizeF(p2.X-p1.X, p2.Y-p1.Y);
float mag=(float)Math.Sqrt(along.Width*along.Width+along.Height*along.Height);
along=new SizeF(along.Width/mag, along.Height/mag);
SizeF perp=new SizeF(-along.Height, along.Width);
PointF p1L=new PointF(p1.X+width/2*perp.Width, p1.Y+width/2*perp.Height);
PointF p1R=new PointF(p1.X-width/2*perp.Width, p1.Y-width/2*perp.Height);
PointF p2L=new PointF(p2.X+width/2*perp.Width, p2.Y+width/2*perp.Height);
PointF p2R=new PointF(p2.X-width/2*perp.Width, p2.Y-width/2*perp.Height);
GraphicsPath gp=new GraphicsPath();
gp.AddLines(new PointF[] { p1L, p2L, p2R, p1R});
gp.CloseFigure();
Region region=new Region(gp);
using(LinearGradientBrush brush=new LinearGradientBrush(
p1L, p1R, Color.Black, Color.Black))
{
ColorBlend color_blend=new ColorBlend();
color_blend.Colors=new Color[] { edge_color, mid_color, edge_color };
color_blend.Positions=new float[] { 0f, 0.5f, 1f };
brush.InterpolationColors=color_blend;
g.FillRegion(brush, region);
}
}
}
编辑 1
另一种方法是使用PathGradientBrush
GraphicsPath gp = new GraphicsPath();
gp.AddLines(new PointF[] { p1, p1L, p2L, p2, p2R, p1R });
gp.CloseFigure();
Region region = new Region(gp);
using (PathGradientBrush brush = new PathGradientBrush(gp))
{
brush.CenterColor = mid_color;
brush.SurroundColors = new Color[]
{
mid_color, edge_color,edge_color,mid_color,edge_color,edge_color
};
g.FillRegion(brush, region);
}
编辑 2
要使边缘更平滑,请使用一些 alpha 透明度:
using(LinearGradientBrush brush=new LinearGradientBrush(
p1L, p1R, Color.Black, Color.Black))
{
ColorBlend color_blend=new ColorBlend();
color_blend.Colors=new Color[] {
Color.FromArgb(0, edge_color), edge_color, mid_color,
edge_color, Color.FromArgb(0, edge_color) };
color_blend.Positions=new float[] { 0f, 0.1f, 0.5f, 0.9f, 1f };
brush.InterpolationColors=color_blend;
g.FillRegion(brush, region);
}
编辑 3 使用一些工件绘制多条线,方法是先在线条之间渲染圆圈,然后再在线条之间渲染
private void DrawPipes(Graphics g, float width, PointF[] points, Color mid_color, Color edge_color)
{
for (int i = 0; i < points.Length; i++)
{
using (GraphicsPath gp = new GraphicsPath())
{
gp.AddEllipse(points[i].X - width / 2, points[i].Y - width / 2, width, width);
using (PathGradientBrush brush = new PathGradientBrush(gp))
{
brush.CenterColor = mid_color;
brush.SurroundColors = new Color[] { edge_color };
brush.CenterPoint = points[i];
g.FillPath(brush, gp);
}
}
if (i > 0)
{
DrawPipe(g, width, points[i - 1], points[i], mid_color, edge_color);
}
}
}
于 2012-09-14T14:08:06.793 回答