c#如何使用图形路径制作平滑的圆弧区域 [英] c# How to make smooth arc region using graphics path
问题描述
我正在尝试制作带有圆形边的标签控件.这是我在继承自 Label 的类中的 OnPaint() 重写方法中的代码.
I'm trying to make a label control with rounded sides. Here is my code in OnPaint() overridden method in myclass inherited from Label.
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.InterpolationMode = InterpolationMode.HighQualityBilinear;
e.Graphics.CompositingQuality = CompositingQuality.HighQuality;
e.Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
LinearGradientBrush brush = new LinearGradientBrush(this.ClientRectangle, GradientColor1, GradientColor2, 90);
e.Graphics.FillRectangle(brush, new Rectangle(new Point(0, 0), new Size(this.Width, this.Height)));
using (GraphicsPath gp = new GraphicsPath())
{
gp.AddArc(new Rectangle(new Point(0, 0), new Size(this.Height, this.Height)), 90, 180);
gp.AddLine(new Point(this.Height / 2, 0), new Point(this.Width - (this.Height / 2), 0));
gp.AddArc(new Rectangle(new Point(this.Width - this.Height, 0), new Size(this.Height, this.Height)), -90, 180);
gp.CloseFigure();
this.Region = new Region(gp);
}
base.OnPaint(e);
}
问题在于它没有平滑侧面的曲线并显示故障.这是控件的屏幕截图:
The problem is that it is not smoothing the curve on the sides and showing the glitches. Here is the screenshot of the control :
推荐答案
如评论中所述,您不能对区域进行抗锯齿处理,因此必须使用图形的 FillPath 方法才能使绘图抗锯齿别名
As stated in the comments, you can't anti-alias the region, so you have to use graphic's FillPath method in order for the drawing to be anti-aliased
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.InterpolationMode = InterpolationMode.HighQualityBilinear;
e.Graphics.CompositingQuality = CompositingQuality.HighQuality;
e.Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
LinearGradientBrush brush = new LinearGradientBrush(this.ClientRectangle, Color.Aqua, Color.Blue, 90);
using (GraphicsPath gp = new GraphicsPath())
{
gp.AddArc(new Rectangle(new Point(0, 0), new Size(this.Height, this.Height)), 90, 180);
gp.AddLine(new Point(this.Height / 2, 0), new Point(this.Width - (this.Height / 2), 0));
gp.AddArc(new Rectangle(new Point(this.Width - this.Height, 0), new Size(this.Height, this.Height)), -90, 180);
gp.CloseFigure();
e.Graphics.FillPath(brush, gp);
}
base.OnPaint(e);
}
如果您真的需要更改区域,我想您必须使用比用于绘图的区域稍大的区域:
If you really need to change the region I guess you would have to use a slightly bigger region then the one used for the drawing:
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.InterpolationMode = InterpolationMode.HighQualityBilinear;
e.Graphics.CompositingQuality = CompositingQuality.HighQuality;
e.Graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
LinearGradientBrush brush = new LinearGradientBrush(this.ClientRectangle, Color.Aqua, Color.Blue, 90);
using (GraphicsPath gp = new GraphicsPath())
{
AddRoundedRectangle(gp, new Point(1, 1), new Size(this.Size.Width - 2, Size.Height - 2));
e.Graphics.FillPath(brush, gp);
}
using (GraphicsPath gp = new GraphicsPath())
{
AddRoundedRectangle(gp, new Point(0, 0), this.Size);
this.Region = new Region(gp);
}
base.OnPaint(e);
}
private void AddRoundedRectangle(GraphicsPath gp, Point upperLeft, Size size)
{
gp.AddArc(new Rectangle(upperLeft, new Size(size.Height, size.Height)), 90, 180);
gp.AddLine(new Point(size.Height / 2 , upperLeft.Y), new Point(size.Width - (size.Height / 2), upperLeft.Y));
gp.AddArc(new Rectangle(new Point(size.Width - size.Height, upperLeft.Y), new Size(size.Height, size.Height)), -90, 180);
gp.CloseFigure();
}
第二个选项的优点是可以影响像 MouseHover 这样的事件,但可能会遇到您看到区域边界"的问题.
The second option has the advantage of affecting events like MouseHover but may run into problems of you seeing the region's "border".
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