使用C#绘制矩形,需要在每个边缘绘制弧线。首先绘制矩形,然后点击按钮,在边缘处绘制弧线。我该如何实现?
C#中的Graphics类没有内置方法来绘制圆角矩形,但是有几种方法可以实现这个效果。在Jay Riggs回答中提供了一些好的建议,此外我建议您查看这篇文章:
首先,我们创建一个GraphicsPath,然后调用StartFigure以开始向路径添加边缘。这段代码的其余部分是为了绘制圆角矩形的左上角和顶部线条。如果我们需要将这个角落变成圆角,则添加一个弧-否则...
设置窗口区域以及创建用于追踪浅色和深色笔进行阴影处理的左上角/右下角路径的示例用法:
Region = new Region(RoundedRectangles.RoundedRectangle.Create(new Rectangle(0, 0, Size.Width, Size.Height), 8, RoundedRectangles.RoundedRectangle.RectangleCorners.TopRight | RoundedRectangles.RoundedRectangle.RectangleCorners.TopLeft));
TopLeftPath = RoundedRectangles.RoundedRectangle.Create(new Rectangle(0, 0, Size.Width, Size.Height), 8, RoundedRectangles.RoundedRectangle.RectangleCorners.TopRight | RoundedRectangles.RoundedRectangle.RectangleCorners.TopLeft, RoundedRectangles.RoundedRectangle.WhichHalf.TopLeft);
BottomRightPath = RoundedRectangles.RoundedRectangle.Create(new Rectangle(0, 0, Size.Width-1, Size.Height-1), 8, RoundedRectangles.RoundedRectangle.RectangleCorners.TopRight | RoundedRectangles.RoundedRectangle.RectangleCorners.TopLeft, RoundedRectangles.RoundedRectangle.WhichHalf.BottomRight);
最后,这是代码:
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
namespace RoundedRectangles
{
public abstract class RoundedRectangle
{
[Flags]
public enum RectangleCorners
{
None = 0, TopLeft = 1, TopRight = 2, BottomLeft = 4, BottomRight = 8,
All = TopLeft | TopRight | BottomLeft | BottomRight
}
public enum WhichHalf
{
TopLeft,
BottomRight,
Both
}
static void Corner(GraphicsPath path, int x1, int y1, int x2, int y2, int x3, int y3)
{
path.AddLine(x1, y1, x2, y2);
path.AddLine(x2, y2, x3, y3);
}
public static GraphicsPath Create(int x, int y, int width, int height, int radius, RectangleCorners corners, WhichHalf half)
{
if (radius <= 0)
{
GraphicsPath rectp = new GraphicsPath();
rectp.AddRectangle(new Rectangle(x, y, width, height));
return rectp;
}
int dia = radius * 2;
Rectangle TLarc = new Rectangle(x, y, dia, dia);
Rectangle TRarc = new Rectangle(x + width - dia - 1, y, dia, dia);
Rectangle BRarc = new Rectangle(x + width - dia - 1, y + height - dia - 1, dia, dia);
Rectangle BLarc = new Rectangle(x, y + height - dia - 1, dia, dia);
Rectangle TLsquare = new Rectangle(x, y, radius, radius);
Rectangle TRsquare = new Rectangle(x + width - radius, y, radius, radius);
Rectangle BRsquare = new Rectangle(x + width - radius, y + height - radius, radius, radius);
Rectangle BLsquare = new Rectangle(x, y + height - radius, radius, radius);
GraphicsPath p = new GraphicsPath();
p.StartFigure();
if (half == WhichHalf.Both || half == WhichHalf.TopLeft)
{
if (corners.HasFlag(RectangleCorners.BottomLeft))
p.AddArc(BLarc, 135, 45);
else
p.AddLine(BLsquare.Left, BLsquare.Bottom, BLsquare.Left, BLsquare.Top);
p.AddLine(BLsquare.Left, BLsquare.Top - 1, TLsquare.Left, TLsquare.Bottom + 1);
if (corners.HasFlag(RectangleCorners.TopLeft))
p.AddArc(TLarc, 180, 90);
else
Corner(p, TLsquare.Left, TLsquare.Bottom, TLsquare.Left, TLsquare.Top, TLsquare.Right, TLsquare.Top);
p.AddLine(TLsquare.Right + 1, TLsquare.Top, TRsquare.Left - 1, TRsquare.Top);
if (corners.HasFlag(RectangleCorners.TopRight))
p.AddArc(TRarc, -90, 45);
}
if (half == WhichHalf.Both || half == WhichHalf.BottomRight)
{
if (corners.HasFlag(RectangleCorners.TopRight))
p.AddArc(TRarc, -45, 45);
else
p.AddLine(TRsquare.Right, TRsquare.Top, TRsquare.Right, TRsquare.Bottom);
p.AddLine(TRsquare.Right, TRsquare.Bottom + 1, BRsquare.Right, BRsquare.Top - 1);
if (corners.HasFlag(RectangleCorners.BottomRight))
p.AddArc(BRarc, 0, 90);
else
Corner(p, BRsquare.Right, BRsquare.Top, BRsquare.Right, BRsquare.Bottom, BRsquare.Left, BRsquare.Bottom);
p.AddLine(BRsquare.Left - 1, BRsquare.Bottom, BLsquare.Right + 1, BLsquare.Bottom);
if (corners.HasFlag(RectangleCorners.BottomLeft))
p.AddArc(BLarc, 90, 45);
else
p.AddLine(BLsquare.Right, BLsquare.Bottom, BLsquare.Left, BLsquare.Bottom);
}
return p;
}
public static GraphicsPath Create(Rectangle rect, int radius, RectangleCorners c, WhichHalf which_half)
{ return Create(rect.X, rect.Y, rect.Width, rect.Height, radius, c, which_half); }
public static GraphicsPath Create(Rectangle rect, int radius, RectangleCorners c)
{ return Create(rect.X, rect.Y, rect.Width, rect.Height, radius, c, WhichHalf.Both); }
public static GraphicsPath Create(Rectangle rect, int radius)
{ return Create(rect.X, rect.Y, rect.Width, rect.Height, radius, RectangleCorners.All, WhichHalf.Both); }
}
}
首先画出四条线,然后在四个角落处画弧线。
以上所有内容都适用于绘图,但如果您想将图形路径转换为自定义控件的区域,我认为您应该使用CreateRoundRectRgn函数(来自gdi32)以获得顶部右侧、底部左侧和底部右侧边缘的正确曲线(根据半径正确绘制了左上角边缘)。快速查看http://pages.citebite.com/e1u2t5b7t4bih(来自instanceofTom的答案的网站)。
Pen myPen = new Pen(Brushes.Black);
myPen.Width = 8.0f;
// Set the LineJoin property
myPen.LineJoin = System.Drawing.Drawing2D.LineJoin.Round;
// Draw the rectangle
e.Graphics.DrawRectangle(myPen, new Rectangle(50, 50, 200, 200));