Windows 11下所有控件已经默认采用圆角,其效果更好、相对有着更好的优化,只是这是默认的行为,无法进一步自定义。
注意两点:
- Paint事件方法中实现圆角控件不要通过事件参数
e.ClipRectangle
获取控件区域范围,原因见最后介绍的Paint事件中绘制控件的问题- 注意设置控件背景透明(虽然Winform中的透明不是完全透明,参见Winform控件优化之背景透明那些事
实现圆角控件比较好的一个思路是在控件的Paint事件中进行绘制,不太好的地方在于每次实现时都要添加事件处理,且不能在设计器中实时看到效果。
只要有Paint事件的组件都实现绘制圆角【如果没有,也可以通过将控件放在Panel中,借助Panel的圆角实现】。
Paint事件中实现圆角控件
注意:由于控件在Paint事件方法中进行了重新绘制,因此文本也被覆盖了,需要处理文本的绘制显示
新建项目 CustomControlRound
,窗体中添加两个Panel、三个Button、一个Label控件。button设置Flat样式、边框为0。
然后在Paint事件方法中调用绘制圆角区域的方法(具体代码参见下一部分的扩展方法),具体如下:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
panel1.Paint += Panel1_Paint;
panel2.Paint += Panel2_Paint;
panel1.BackColor = panel2.BackColor = Color.Transparent;
button1.Paint += Button1_Paint;
button1.FlatStyle = FlatStyle.Flat;
button1.FlatAppearance.BorderSize = 0;
button1.FlatAppearance.MouseDownBackColor = Color.Transparent;
button1.FlatAppearance.MouseOverBackColor = Color.Transparent;
button1.FlatAppearance.CheckedBackColor = Color.Transparent;
button2.Paint += Button1_Paint;
button2.FlatStyle = FlatStyle.Flat;
button2.FlatAppearance.BorderSize = 0;
//button2.FlatAppearance.BorderColor = SystemColors.ButtonFace;
button2.FlatAppearance.MouseDownBackColor = Color.Transparent;
button2.FlatAppearance.MouseOverBackColor = Color.Transparent;
button2.FlatAppearance.CheckedBackColor = Color.Transparent;
button3.Paint += Button1_Paint;
button3.FlatStyle = FlatStyle.Flat;
button3.FlatAppearance.BorderSize = 0;
//button3.FlatAppearance.BorderColor = SystemColors.ButtonFace;
button3.FlatAppearance.MouseDownBackColor = Color.Transparent;
button3.FlatAppearance.MouseOverBackColor = Color.Transparent;
button3.FlatAppearance.CheckedBackColor = Color.Transparent;
label1.Paint += Label1_Paint;
label1.BackColor = Color.Transparent;
}
private void Label1_Paint(object sender, PaintEventArgs e)
{
var l = (Label)sender;
// e.Graphics.DrawRoundRectAndCusp(e.ClipRectangle, 18, Color.FromArgb(180, 200, 210), Color.FromArgb(120, 120, 100)); // 不推荐
e.Graphics.DrawRoundRectAndCusp(new Rectangle(0,0, l.Width,l.Height), 18, Color.FromArgb(180, 200, 210), Color.FromArgb(120, 120, 100));
}
private void Button1_Paint(object sender, PaintEventArgs e)
{
var btn = (Button)sender;
e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, btn.Width, btn.Height), 18, Color.FromArgb(0, 122, 204), Color.FromArgb(8, 39, 57));
((Button)sender).NotifyDefault(false); // 去除窗体失去焦点时最新激活的按钮边框外观样式
}
private void Panel1_Paint(object sender, PaintEventArgs e)
{
var panel = sender as Panel;
var rect=e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);
}
private void Panel2_Paint(object sender, PaintEventArgs e)
{
var panel = sender as Panel;
var rect = e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(113, 113, 113), Color.FromArgb(0, 0, 0));
}
}
查看效果:
在Paint事件中不需要调用
base.OnPaint(e);
,只有在继承控件重写OnPaint
方法时,才应该(在函数方法开始时)调用base.OnPaint(e);
。
提取绘制圆角矩形和旁边小尖角的代码为扩展方法
介绍
下面是提取的扩展方法,对源代码进行了修改和优化。
1、可绘制渐变背景色、指定背景色、指定画刷绘制的背景;可指定渐变背景的方向
2、指定圆角半径的绘制,如果半径小于等于0,将绘制直角矩形。
3、指定三角小尖,默认不绘制;指定三角小尖的位置,可供八个位置选择
4、三角小尖的大小,目前感觉作为参数传递不够灵活,如果需要调整可直接从代码中修改,主要修改部分为:
// 尖角的大小 默认为 开始位置为_radius 底边为20,高度为13的等腰三角形
var cuspHemlineStart = _radius;
var cuspHemlineLength = 20;
var cuspHeight = 13;
扩展方法
扩展方法代码如下,将其放在namespace System.Drawing.Drawing2D
下,可直接方便的从Graphics对象调用。
/// <summary>
/// 绘制可渐变的圆角矩形,并指定是否有三角小尖及其位置
/// </summary>
/// <param name="g"></param>
/// <param name="rectangle">矩形区域</param>
/// <param name="_radius">圆角半径</param>
/// <param name="begin_bgcolor">背景渐变开始色</param>
/// <param name="end_bgcolor">背景渐变结束色</param>
/// <param name="cusp">是否有三角小尖,默认无</param>
/// <param name="rectAlign">三角小尖的位置,默认右上</param>
/// <param name="gradientMode">渐变模式,默认垂直方向渐变</param>
public static void DrawRoundRectAndCusp(this Graphics g, Rectangle rectangle, int _radius, Color begin_bgcolor, Color end_bgcolor, bool cusp = false, RectangleAlign rectAlign= RectangleAlign.RightTop, LinearGradientMode gradientMode = LinearGradientMode.Vertical)
{
////抗锯齿 等模式在Graphics外层自定义设置
//g.SmoothingMode = SmoothingMode.AntiAlias;
//渐变填充
LinearGradientBrush linearGradientBrush = new LinearGradientBrush(rectangle, begin_bgcolor, end_bgcolor, gradientMode);
g.DrawRoundRectAndCusp(rectangle, _radius, linearGradientBrush, cusp, rectAlign);
}
/// <summary>
/// 绘制指定背景的圆角矩形,并指定是否有三角小尖及其位置
/// </summary>
/// <param name="g"></param>
/// <param name="rectangle">矩形区域</param>
/// <param name="_radius">圆角半径</param>
/// <param name="bgcolor">指定背景色</param>
/// <param name="cusp">是否有三角小尖,默认无</param>
/// <param name="rectAlign">三角小尖的位置,默认右上</param>
public static void DrawRoundRectAndCusp(this Graphics g, Rectangle rectangle, int _radius, Color bgcolor, bool cusp = false, RectangleAlign rectAlign = RectangleAlign.RightTop)
{
////抗锯齿 等模式在Graphics外层自定义设置
//g.SmoothingMode = SmoothingMode.AntiAlias;
//渐变填充
var brush = new SolidBrush(bgcolor);
g.DrawRoundRectAndCusp(rectangle, _radius, brush, cusp, rectAlign);
}
/// <summary>
/// 绘制Brush画刷的圆角矩形,并指定是否有三角小尖及其位置
/// </summary>
/// <param name="g"></param>
/// <param name="rectangle">矩形区域</param>
/// <param name="_radius">圆角半径</param>
/// <param name="bgbrush">指定背景画刷</param>
/// <param name="cusp">是否有三角小尖,默认无</param>
/// <param name="rectAlign">三角小尖的位置,默认右上</param>
public static void DrawRoundRectAndCusp(this Graphics g, Rectangle rectangle, int _radius, Brush bgbrush, bool cusp = false, RectangleAlign rectAlign = RectangleAlign.RightTop)
{
////抗锯齿 尽可能高质量绘制
g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.SmoothingMode = SmoothingMode.AntiAlias; // SmoothingMode.HighQuality
g.CompositingQuality = CompositingQuality.HighQuality;
g.InterpolationMode = InterpolationMode.HighQualityBilinear;
var rect = rectangle;
//画尖角 对应的变更rect区域
if (cusp)
{
// 尖角的大小 默认为 开始位置为_radius 底边为20,高度为13的等腰三角形
var cuspHemlineStart = _radius;
var cuspHemlineLength = 20;
var cuspHeight = 13;
// 让位出来的间隔暂时为尖角高度-1
var span = cuspHeight - 1;
// 三角顶点
PointF p1, p2, p3;
switch (rectAlign)
{
case RectangleAlign.AboveLeft:
p1 = new PointF(rectangle.X + cuspHemlineStart, rectangle.Y + cuspHeight);
p2 = new PointF(rectangle.X + cuspHemlineStart + cuspHemlineLength, rectangle.Y + cuspHeight);
p3 = new PointF(rectangle.X + cuspHemlineStart + cuspHemlineLength / 2, rectangle.Y);
rect = new Rectangle(rectangle.X, rectangle.Y + span, rectangle.Width, rectangle.Height - span);
break;
case RectangleAlign.AboveRight:
p1 = new PointF(rectangle.Right - cuspHemlineStart, rectangle.Y + cuspHeight);
p2 = new PointF(rectangle.Right - cuspHemlineStart - cuspHemlineLength, rectangle.Y + cuspHeight);
p3 = new PointF(rectangle.Right - cuspHemlineStart - cuspHemlineLength / 2, rectangle.Y);
rect = new Rectangle(rectangle.X, rectangle.Y + span, rectangle.Width, rectangle.Height - span);
break;
case RectangleAlign.RightBottom:
p1 = new PointF(rectangle.Right - cuspHeight, rectangle.Bottom - cuspHemlineStart);
p2 = new PointF(rectangle.Right - cuspHeight, rectangle.Bottom - cuspHemlineStart - cuspHemlineLength);
p3 = new PointF(rectangle.Right, rectangle.Bottom - cuspHemlineStart - cuspHemlineLength / 2);
rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width - span, rectangle.Height);
break;
case RectangleAlign.BelowRight:
p1 = new PointF(rectangle.Right - cuspHemlineStart, rectangle.Bottom - cuspHeight);
p2 = new PointF(rectangle.Right - cuspHemlineStart - cuspHemlineLength, rectangle.Bottom - cuspHeight);
p3 = new PointF(rectangle.Right - cuspHemlineStart - cuspHemlineLength / 2, rectangle.Bottom);
rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width, rectangle.Height - span);
break;
case RectangleAlign.BelowLeft:
p1 = new PointF(rectangle.X + cuspHemlineStart, rectangle.Bottom - cuspHeight);
p2 = new PointF(rectangle.X + cuspHemlineStart + cuspHemlineLength, rectangle.Bottom - cuspHeight);
p3 = new PointF(rectangle.X + cuspHemlineStart + cuspHemlineLength / 2, rectangle.Bottom);
rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width, rectangle.Height - span);
break;
case RectangleAlign.LeftBottom:
p1 = new PointF(rectangle.X + cuspHeight, rectangle.Bottom - cuspHemlineStart);
p2 = new PointF(rectangle.X + cuspHeight, rectangle.Bottom - cuspHemlineStart - cuspHemlineLength);
p3 = new PointF(rectangle.X, rectangle.Bottom - cuspHemlineStart - cuspHemlineLength / 2);
rect = new Rectangle(rectangle.X + span, rectangle.Y, rectangle.Width - span, rectangle.Height);
break;
case RectangleAlign.LeftTop:
p1 = new PointF(rectangle.X + cuspHeight, rectangle.Y + cuspHemlineStart);
p2 = new PointF(rectangle.X + cuspHeight, rectangle.Y + cuspHemlineStart + cuspHemlineLength);
p3 = new PointF(rectangle.X, rectangle.Y + cuspHemlineStart + cuspHemlineLength / 2);
rect = new Rectangle(rectangle.X + span, rectangle.Y, rectangle.Width - span, rectangle.Height);
break;
case RectangleAlign.RightTop:
default:
p1 = new PointF(rectangle.Right - cuspHeight, rectangle.Y + cuspHemlineStart);
p2 = new PointF(rectangle.Right - cuspHeight, rectangle.Y + cuspHemlineStart + cuspHemlineLength);
p3 = new PointF(rectangle.Right, rectangle.Y + cuspHemlineStart + cuspHemlineLength / 2);
rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width - span, rectangle.Height);
break;
}
PointF[] ptsArray = new PointF[] { p1, p2, p3 };
// 填充参数点所指定的多边形内部
g.FillPolygon(bgbrush, ptsArray);
}
//填充
g.FillPath(bgbrush, rect.GetRoundedRectPath(_radius));
}
/// <summary>
/// 根据普通矩形得到圆角矩形的路径 【根据矩形区域rect,计算呈现radius圆角的Graphics路径】
/// </summary>
/// <param name="rect">原始矩形</param>
/// <param name="radius">半径</param>
/// <returns>图形路径</returns>
public static GraphicsPath GetRoundedRectPath(this Rectangle rect, int radius)
{
#region 正确绘制圆角矩形区域
int R = radius*2;
Rectangle arcRect = new Rectangle(rect.Location, new Size(R, R));
GraphicsPath path = new GraphicsPath();
if (radius <= 0)
{
path.AddRectangle(rect);
}
else
{
// 左上圆弧 左手坐标系,顺时针为正 从180开始,转90度
path.AddArc(arcRect, 180, 90);
// 右上圆弧
arcRect.X = rect.Right - R;
path.AddArc(arcRect, 270, 90);
// 右下圆弧
arcRect.Y = rect.Bottom - R;
path.AddArc(arcRect, 0, 90);
// 左下圆弧
arcRect.X = rect.Left;
path.AddArc(arcRect, 90, 90);
}
//path.CloseFigure();
// 闭合路径中所有开放图形,并形成新图形
path.CloseAllFigures();
return path;
#endregion
}
/// <summary>
/// 获取圆角矩形的路径
/// </summary>
/// <param name="rect">原始矩形</param>
/// <param name="radius">半径</param>
/// <returns>图形路径</returns>
public static GraphicsPath GetRoundedRectPath(int x, int y, int width, int height, int radius)
{
Rectangle rect = new Rectangle(x, y, width, height);
return rect.GetRoundedRectPath(radius);
}
测试尖角的显示位置
复制几个Panel,在Paint事件中分别处理尖角的位置
panel1.Paint += Panel1_Paint;
panel3.Paint += Panel1_Paint;
panel4.Paint += Panel1_Paint;
panel5.Paint += Panel1_Paint;
panel6.Paint += Panel1_Paint;
panel7.Paint += Panel1_Paint;
panel8.Paint += Panel1_Paint;
panel9.Paint += Panel1_Paint;
/// ......
private void Panel1_Paint(object sender, PaintEventArgs e)
{
var panel = sender as Panel;
var rectAlign = RectangleAlign.RightTop;
switch (panel.Name)
{
case "panel3":
rectAlign = RectangleAlign.AboveLeft;
break;
case "panel4":
rectAlign = RectangleAlign.AboveRight;
break;
case "panel5":
rectAlign = RectangleAlign.BelowLeft;
break;
case "panel6":
rectAlign = RectangleAlign.BelowRight;
break;
case "panel7":
rectAlign = RectangleAlign.LeftBottom;
break;
case "panel8":
rectAlign = RectangleAlign.LeftTop;
break;
case "panel9":
rectAlign = RectangleAlign.RightBottom;
break;
default:
break;
}
var rect=e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);
e.Graphics.DrawText(rect, "这是一个Panel控件,非常适合显示消息", Color.White, panel.Font);
}
查看效果
重绘控件后文本的处理
由于重新绘制导致文本也被覆盖的情况,有比较常见的两种处理方法:
- 重绘控件的同时,重绘文本文字
- 通过添加Label控件实现文本处理
同时重绘文本
同样将绘制文本的方法提取为扩展方法,借助StringFormat
字符串格式对象实现文字的布局处理。
不推荐使用
Graphics.DrawString
绘制按钮控件(Rectangle区域)内的文字,当然DrawString也有一定有时比如文字方向的处理。
/// <summary>
/// 绘制(控件区域)文本内容
/// </summary>
/// <param name="g"></param>
/// <param name="rect"></param>
/// <param name="text"></param>
/// <param name="color"></param>
/// <param name="font"></param>
/// <param name="_textAlign">文字布局,默认居中。实际测试并未真正的居中,垂直方向偏上,改为通过计算rect的中心位置实现,使用微软雅黑还好点,字体大小最好偶数</param>
/// <param name="rtl">是否RightToLeft 无效果,不推荐使用</param>
public static void DrawText(this Graphics g, Rectangle rect, string text, Color color, Font font, ContentAlignment _textAlign = ContentAlignment.MiddleCenter, bool rtl=false)
{
var formatFlags = TextFormatFlags.HorizontalCenter | TextFormatFlags.VerticalCenter; // 默认居中
switch (_textAlign)
{
case ContentAlignment.TopLeft:
formatFlags = TextFormatFlags.Top | TextFormatFlags.Left;
break;
case ContentAlignment.TopCenter:
formatFlags = TextFormatFlags.Top | TextFormatFlags.HorizontalCenter;
break;
case ContentAlignment.TopRight:
formatFlags = TextFormatFlags.Top | TextFormatFlags.Right;
break;
case ContentAlignment.MiddleLeft:
formatFlags = TextFormatFlags.VerticalCenter | TextFormatFlags.Left;
break;
case ContentAlignment.MiddleRight:
formatFlags = TextFormatFlags.VerticalCenter | TextFormatFlags.Right;
break;
case ContentAlignment.BottomLeft:
formatFlags = TextFormatFlags.Bottom | TextFormatFlags.Left;
break;
case ContentAlignment.BottomCenter:
formatFlags = TextFormatFlags.Bottom | TextFormatFlags.HorizontalCenter;
break;
case ContentAlignment.BottomRight:
formatFlags = TextFormatFlags.Bottom | TextFormatFlags.Right;
break;
case ContentAlignment.MiddleCenter:
default:
break;
}
if (rtl)
{
formatFlags |= TextFormatFlags.RightToLeft; // 无效果
}
TextRenderer.DrawText(g, text, font, rect, color, formatFlags);
}
要注意添加了小三角后的文字绘制区域问题,如果使用默认的全部预期有可能导致文字超出范围,且,布局也不是相对于绘制的主体。如下图对比的效果。
因此,可修改圆角绘制的函数,使其返回绘制后的主体区域。
private void Panel1_Paint(object sender, PaintEventArgs e)
{
var panel = sender as Panel;
var rect=e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);
//e.Graphics.DrawText(e.ClipRectangle, "这是一个Panel控件,非常适合显示消息", Color.White, panel.Font);
// 使用合适的区域
e.Graphics.DrawText(rect, "这是一个Panel控件,非常适合显示消息", Color.White, panel.Font);
}
通过添加Label控件实现对文本的处理【有尖角时需要额外处理】
label2.Text = "我是Label显示在圆角按钮上";
label2.Parent = button1;
label2.AutoSize = false;
label2.Dock = DockStyle.Fill;
label2.BackColor = Color.Transparent;
label2.TextAlign = ContentAlignment.MiddleCenter;
label2.ForeColor = Color.Wheat;
Paint事件中绘制圆角的优点
完全由用户绘制按钮区域实现圆角【之前文章介绍过】,可以发现,与直接在Paint事件中实现圆角,有着一定的锯齿,虽然不是很严重,但是还是Paint事件中实现的圆角看着相对好一些。
之前完全由用户绘制控件区域出现锯齿的问题,原因在于使用
new Region(graphicPath)
构造函数创建的新Region对象,创建的Region无法实现抗锯齿,即使开始抗锯齿和高质量绘制(无法应用到最终的Region)。[唯一的]解决办法,是不创建新的Region,直接绘制无锯齿图形【无法对Region进行抗锯齿】。
窗体失去焦点时按钮外观边框问题
窗体失去焦点后,Button会显示出一个边框(即使已经设置BorderSize为0),只有在窗体失去焦点后,最后一个被激活过的Button(点击过的)才会出现。
比较好的解决办法是在Button的Paint事件中执行Button.NotifyDefault(false)
方法。
下面是几种解决方式:
- 通过继承Button控件,重写NotifyDefault方法实现。
class MyButton:Button
{
public override void NotifyDefault(bool value)
{
base.NotifyDefault(false);
}
}
参考自 Removing the focus rectangle from a flat button when the form itself does not have focus
- 设置FlatAppearance.BorderColor颜色与下层背景色一致
或者,还有一个取巧的解决办法,就是,设置FlatAppearance.BorderColor
为Button按钮后面的背景色,这样就看不出来,类似没有的效果。如 button1.FlatAppearance.BorderColor = SystemColors.Control;
。
- 在Button的Paint事件方法中调用
NotifyDefault(false)
或者,不是继承重写Button控件,直接在Button的Paint事件中,调用Button.NotifyDefault(false);
方法。
private void Button1_Paint(object sender, PaintEventArgs e)
{
var btn = (Button)sender;
e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, btn.Width, btn.Height), 18, Color.FromArgb(0, 122, 204), Color.FromArgb(8, 39, 57));
((Button)sender).NotifyDefault(false); // 去除窗体失去焦点时最新激活的按钮边框外观样式
}
Paint事件中绘制控件的问题【不要使用(事件)参数e.ClipRectangle
】
直接看下图演示,在发生控件大小、位置调整等需要重绘时,会发生控件错乱、显示不完整重叠等问题。
比如Panel事件中,原本的写法为:
var rect=e.Graphics.DrawRoundRectAndCusp(e.ClipRectangle, 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);
将其改为转换传递过来的控件参数为Panel对象,并通过其宽高获取其绘制区域:
var rect=e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);
修改后错乱问题就不存在了: