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C# Changing color of group box border color [duplicate]

In C#.NET I am trying to programmatically change the color of the border in a group box.
Update: This question was asked when I was working on a winforms system before we switched to .NET.

Just add paint event.
private void groupBox1_Paint(object sender, PaintEventArgs e)
{
GroupBox box = sender as GroupBox;
DrawGroupBox(box, e.Graphics, Color.Red, Color.Blue);
}
private void DrawGroupBox(GroupBox box, Graphics g, Color textColor, Color borderColor)
{
if (box != null)
{
Brush textBrush = new SolidBrush(textColor);
Brush borderBrush = new SolidBrush(borderColor);
Pen borderPen = new Pen(borderBrush);
SizeF strSize = g.MeasureString(box.Text, box.Font);
Rectangle rect = new Rectangle(box.ClientRectangle.X,
box.ClientRectangle.Y + (int)(strSize.Height / 2),
box.ClientRectangle.Width - 1,
box.ClientRectangle.Height - (int)(strSize.Height / 2) - 1);
// Clear text and border
g.Clear(this.BackColor);
// Draw text
g.DrawString(box.Text, box.Font, textBrush, box.Padding.Left, 0);
// Drawing Border
//Left
g.DrawLine(borderPen, rect.Location, new Point(rect.X, rect.Y + rect.Height));
//Right
g.DrawLine(borderPen, new Point(rect.X + rect.Width, rect.Y), new Point(rect.X + rect.Width, rect.Y + rect.Height));
//Bottom
g.DrawLine(borderPen, new Point(rect.X, rect.Y + rect.Height), new Point(rect.X + rect.Width, rect.Y + rect.Height));
//Top1
g.DrawLine(borderPen, new Point(rect.X, rect.Y), new Point(rect.X + box.Padding.Left, rect.Y));
//Top2
g.DrawLine(borderPen, new Point(rect.X + box.Padding.Left + (int)(strSize.Width), rect.Y), new Point(rect.X + rect.Width, rect.Y));
}
}

Building on the previous answer, a better solution that includes the label for the group box:
groupBox1.Paint += PaintBorderlessGroupBox;
private void PaintBorderlessGroupBox(object sender, PaintEventArgs p)
{
GroupBox box = (GroupBox)sender;
p.Graphics.Clear(SystemColors.Control);
p.Graphics.DrawString(box.Text, box.Font, Brushes.Black, 0, 0);
}
You might want to adjust the x/y for the text, but for my use this is just right.

Just set the paint action on any object (not just buttons) to this method to draw a border.
private void UserControl1_Paint(object sender, PaintEventArgs e)
{
ControlPaint.DrawBorder(e.Graphics, this.ClientRectangle, Color.Red, ButtonBorderStyle.Solid);
}
It still wont be pretty and rounded like the original, but it is much simpler.

FWIW, this is the implementation I used. It's a child of GroupBox but allows setting not only the BorderColor, but also the thickness of the border and the radius of the rounded corners. Also, you can set the amount of indent you want for the GroupBox label, and using a negative indent indents from the right side.
using System;
using System.Drawing;
using System.Windows.Forms;
namespace BorderedGroupBox
{
public class BorderedGroupBox : GroupBox
{
private Color _borderColor = Color.Black;
private int _borderWidth = 2;
private int _borderRadius = 5;
private int _textIndent = 10;
public BorderedGroupBox() : base()
{
InitializeComponent();
this.Paint += this.BorderedGroupBox_Paint;
}
public BorderedGroupBox(int width, float radius, Color color) : base()
{
this._borderWidth = Math.Max(1,width);
this._borderColor = color;
this._borderRadius = Math.Max(0,radius);
InitializeComponent();
this.Paint += this.BorderedGroupBox_Paint;
}
public Color BorderColor
{
get => this._borderColor;
set
{
this._borderColor = value;
DrawGroupBox();
}
}
public int BorderWidth
{
get => this._borderWidth;
set
{
if (value > 0)
{
this._borderWidth = Math.Min(value, 10);
DrawGroupBox();
}
}
}
public int BorderRadius
{
get => this._borderRadius;
set
{ // Setting a radius of 0 produces square corners...
if (value >= 0)
{
this._borderRadius = value;
this.DrawGroupBox();
}
}
}
public int LabelIndent
{
get => this._textIndent;
set
{
this._textIndent = value;
this.DrawGroupBox();
}
}
private void BorderedGroupBox_Paint(object sender, PaintEventArgs e) =>
DrawGroupBox(e.Graphics);
private void DrawGroupBox() =>
this.DrawGroupBox(this.CreateGraphics());
private void DrawGroupBox(Graphics g)
{
Brush textBrush = new SolidBrush(this.ForeColor);
SizeF strSize = g.MeasureString(this.Text, this.Font);
Brush borderBrush = new SolidBrush(this.BorderColor);
Pen borderPen = new Pen(borderBrush,(float)this._borderWidth);
Rectangle rect = new Rectangle(this.ClientRectangle.X,
this.ClientRectangle.Y + (int)(strSize.Height / 2),
this.ClientRectangle.Width - 1,
this.ClientRectangle.Height - (int)(strSize.Height / 2) - 1);
Brush labelBrush = new SolidBrush(this.BackColor);
// Clear text and border
g.Clear(this.BackColor);
// Drawing Border (added "Fix" from Jim Fell, Oct 6, '18)
int rectX = (0 == this._borderWidth % 2) ? rect.X + this._borderWidth / 2 : rect.X + 1 + this._borderWidth / 2;
int rectHeight = (0 == this._borderWidth % 2) ? rect.Height - this._borderWidth / 2 : rect.Height - 1 - this._borderWidth / 2;
// NOTE DIFFERENCE: rectX vs rect.X and rectHeight vs rect.Height
g.DrawRoundedRectangle(borderPen, rectX, rect.Y, rect.Width, rectHeight, (float)this._borderRadius);
// Draw text
if (this.Text.Length > 0)
{
// Do some work to ensure we don't put the label outside
// of the box, regardless of what value is assigned to the Indent:
int width = (int)rect.Width, posX;
posX = (this._textIndent < 0) ? Math.Max(0-width,this._textIndent) : Math.Min(width, this._textIndent);
posX = (posX < 0) ? rect.Width + posX - (int)strSize.Width : posX;
g.FillRectangle(labelBrush, posX, 0, strSize.Width, strSize.Height);
g.DrawString(this.Text, this.Font, textBrush, posX, 0);
}
}
#region Component Designer generated code
/// <summary>Required designer variable.</summary>
private System.ComponentModel.IContainer components = null;
/// <summary>Clean up any resources being used.</summary>
/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
components.Dispose();
base.Dispose(disposing);
}
/// <summary>Required method for Designer support - Don't modify!</summary>
private void InitializeComponent() => components = new System.ComponentModel.Container();
#endregion
}
}
To make it work, you also have to extend the base Graphics class (Note: this is derived from some code I found on here once when I was trying to create a rounded-corners Panel control, but I can't find the original post to link here):
static class GraphicsExtension
{
private static GraphicsPath GenerateRoundedRectangle(
this Graphics graphics,
RectangleF rectangle,
float radius)
{
float diameter;
GraphicsPath path = new GraphicsPath();
if (radius <= 0.0F)
{
path.AddRectangle(rectangle);
path.CloseFigure();
return path;
}
else
{
if (radius >= (Math.Min(rectangle.Width, rectangle.Height)) / 2.0)
return graphics.GenerateCapsule(rectangle);
diameter = radius * 2.0F;
SizeF sizeF = new SizeF(diameter, diameter);
RectangleF arc = new RectangleF(rectangle.Location, sizeF);
path.AddArc(arc, 180, 90);
arc.X = rectangle.Right - diameter;
path.AddArc(arc, 270, 90);
arc.Y = rectangle.Bottom - diameter;
path.AddArc(arc, 0, 90);
arc.X = rectangle.Left;
path.AddArc(arc, 90, 90);
path.CloseFigure();
}
return path;
}
private static GraphicsPath GenerateCapsule(
this Graphics graphics,
RectangleF baseRect)
{
float diameter;
RectangleF arc;
GraphicsPath path = new GraphicsPath();
try
{
if (baseRect.Width > baseRect.Height)
{
diameter = baseRect.Height;
SizeF sizeF = new SizeF(diameter, diameter);
arc = new RectangleF(baseRect.Location, sizeF);
path.AddArc(arc, 90, 180);
arc.X = baseRect.Right - diameter;
path.AddArc(arc, 270, 180);
}
else if (baseRect.Width < baseRect.Height)
{
diameter = baseRect.Width;
SizeF sizeF = new SizeF(diameter, diameter);
arc = new RectangleF(baseRect.Location, sizeF);
path.AddArc(arc, 180, 180);
arc.Y = baseRect.Bottom - diameter;
path.AddArc(arc, 0, 180);
}
else path.AddEllipse(baseRect);
}
catch { path.AddEllipse(baseRect); }
finally { path.CloseFigure(); }
return path;
}
/// <summary>
/// Draws a rounded rectangle specified by a pair of coordinates, a width, a height and the radius
/// for the arcs that make the rounded edges.
/// </summary>
/// <param name="brush">System.Drawing.Pen that determines the color, width and style of the rectangle.</param>
/// <param name="x">The x-coordinate of the upper-left corner of the rectangle to draw.</param>
/// <param name="y">The y-coordinate of the upper-left corner of the rectangle to draw.</param>
/// <param name="width">Width of the rectangle to draw.</param>
/// <param name="height">Height of the rectangle to draw.</param>
/// <param name="radius">The radius of the arc used for the rounded edges.</param>
public static void DrawRoundedRectangle(
this Graphics graphics,
Pen pen,
float x,
float y,
float width,
float height,
float radius)
{
RectangleF rectangle = new RectangleF(x, y, width, height);
GraphicsPath path = graphics.GenerateRoundedRectangle(rectangle, radius);
SmoothingMode old = graphics.SmoothingMode;
graphics.SmoothingMode = SmoothingMode.AntiAlias;
graphics.DrawPath(pen, path);
graphics.SmoothingMode = old;
}
/// <summary>
/// Draws a rounded rectangle specified by a pair of coordinates, a width, a height and the radius
/// for the arcs that make the rounded edges.
/// </summary>
/// <param name="brush">System.Drawing.Pen that determines the color, width and style of the rectangle.</param>
/// <param name="x">The x-coordinate of the upper-left corner of the rectangle to draw.</param>
/// <param name="y">The y-coordinate of the upper-left corner of the rectangle to draw.</param>
/// <param name="width">Width of the rectangle to draw.</param>
/// <param name="height">Height of the rectangle to draw.</param>
/// <param name="radius">The radius of the arc used for the rounded edges.</param>
public static void DrawRoundedRectangle(
this Graphics graphics,
Pen pen,
int x,
int y,
int width,
int height,
int radius)
{
graphics.DrawRoundedRectangle(
pen,
Convert.ToSingle(x),
Convert.ToSingle(y),
Convert.ToSingle(width),
Convert.ToSingle(height),
Convert.ToSingle(radius));
}
}

I'm not sure this applies to every case, but thanks to this thread, we quickly hooked into the Paint event programmatically using:
GroupBox box = new GroupBox();
[...]
box.Paint += delegate(object o, PaintEventArgs p)
{
p.Graphics.Clear(someColorHere);
};
Cheers!

I have achieved same border with something which might be simpler to understand for newbies:
private void groupSchitaCentru_Paint(object sender, PaintEventArgs e)
{
Pen blackPen = new Pen(Color.Black, 2);
Point pointTopLeft = new Point(0, 7);
Point pointBottomLeft = new Point(0, groupSchitaCentru.ClientRectangle.Height);
Point pointTopRight = new Point(groupSchitaCentru.ClientRectangle.Width, 7);
Point pointBottomRight = new Point(groupSchitaCentru.ClientRectangle.Width, groupSchitaCentru.ClientRectangle.Height);
e.Graphics.DrawLine(blackPen, pointTopLeft, pointBottomLeft);
e.Graphics.DrawLine(blackPen, pointTopLeft, pointTopRight);
e.Graphics.DrawLine(blackPen, pointBottomRight, pointTopRight);
e.Graphics.DrawLine(blackPen, pointBottomLeft, pointBottomRight);
}
Set the Paint event on the GroupBox control. In this example the name of my control is "groupSchitaCentru". One needs this event because of its parameter e.
Set up a pen object by making use of the System.Drawing.Pen class : https://msdn.microsoft.com/en-us/library/f956fzw1(v=vs.110).aspx
Set the points which represent the corners of the rectangle represented by the control. Used the property ClientRectangle of the the control to get its dimensions.
I used for TopLeft (0,7) because I want to respect the borders of the control, and draw the line about the its text.
To get more information about the coordinates system walk here : https://learn.microsoft.com/en-us/dotnet/framework/winforms/windows-forms-coordinates
I do not know, may be it helps someone looking to achieve this border adjustment thing.

This tweak to Jim Fell's code placed the borders a little better for me, but it's too long to add as a comment
...
Rectangle rect = new Rectangle(this.ClientRectangle.X,
this.ClientRectangle.Y + (int)(strSize.Height / 2),
this.ClientRectangle.Width,
this.ClientRectangle.Height - (int)(strSize.Height / 2));
Brush labelBrush = new SolidBrush(this.BackColor);
// Clear text and border
g.Clear(this.BackColor);
int drawX = rect.X;
int drawY = rect.Y;
int drawWidth = rect.Width;
int drawHeight = rect.Height;
if (this._borderWidth > 0)
{
drawX += this._borderWidth / 2;
drawY += this._borderWidth / 2;
drawWidth -= this._borderWidth;
drawHeight -= this._borderWidth;
if (this._borderWidth % 2 == 0)
{
drawX -= 1;
drawWidth += 1;
drawY -= 1;
drawHeight += 1;
}
}
g.DrawRoundedRectangle(borderPen, drawX, drawY, drawWidth, drawHeight, (float)this._borderRadius);

I can't make a normal rounding of a standard button

I was trying to make a normal rounding. And I can't smooth out the rounding itself for the button.
And the second question, how do I round off the button so that the photo that is used in BackgroundImage doesn't get rounded off???
using System;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
namespace Test_Project.SupportClass
{
public class Buttom_Class4 : Button
{
public Buttom_Class4()
{
SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
SetStyle(ControlStyles.Opaque, true);
SetStyle(ControlStyles.ResizeRedraw, true);
}
private int radius = 20;
[DefaultValue(20)]
public int Radius
{
get { return radius; }
set
{
radius = value;
this.RecreateRegion();
}
}
private GraphicsPath GetRoundRectagle(Rectangle bounds, int radius)
{
GraphicsPath path = new GraphicsPath();
path.AddArc(bounds.X, bounds.Y, radius, radius, 180, 90);
path.AddArc(bounds.X + bounds.Width - radius, bounds.Y, radius, radius, 270, 90);
path.AddArc(bounds.X + bounds.Width - radius, bounds.Y + bounds.Height - radius,
radius, radius, 0, 90);
path.AddArc(bounds.X, bounds.Y + bounds.Height - radius, radius, radius, 90, 90);
path.CloseAllFigures();
return path;
}
private void RecreateRegion()
{
var bounds = ClientRectangle;
bounds.Width--; bounds.Height--;
using (var path = GetRoundRectagle(bounds, this.Radius))
this.Region = new Region(path);
this.Invalidate();
}
protected override void OnSizeChanged(EventArgs e)
{
base.OnSizeChanged(e);
this.RecreateRegion();
}
}
}

Label with smooth rounded corners

Both labels have AutoSize true & TextAlign MiddleCenter.
How can also label2 show smooth borders?
Here is the test code for handlers Form.Load(...) & Form.Paint(...):
int _cornerRadius = 10;
Point _locationLabel2;
// Form.Load(...)
private void Form3_Load(object sender, EventArgs e)
{
// Step 1: Cut the label regions (seems to be ok, result is the same for both labels)
GraphicsPath graphicsPath = _getRoundPath(label1.ClientRectangle, _cornerRadius);
label1.Region = new Region(graphicsPath);
graphicsPath = _getRoundPath(label2.ClientRectangle, _cornerRadius);
label2.Region = new Region(graphicsPath);
_locationLabel2 = this.PointToClient(label2.Parent.PointToScreen(label2.Location));
}
// Form.Paint(...)
private void Form3_Paint(object sender, PaintEventArgs e)
{
using (Pen pen = new Pen(label1.BackColor, 3.0f))
{
// Step 2: Smooth the label borders (ok only for label1)
_drawRoundedRectangle(e.Graphics, pen, label1.Location.X, label1.Location.Y,
label1.ClientRectangle.Width, label1.ClientRectangle.Height, _cornerRadius);
_drawRoundedRectangle(e.Graphics, pen, _locationLabel2.X, _locationLabel2.Y,
label2.ClientRectangle.Width, label2.ClientRectangle.Height, _cornerRadius);
}
}
// Helper 1/3
private static GraphicsPath _getRoundPath(Rectangle rectangle, int radius)
{
int x = rectangle.X;
int y = rectangle.Y;
int width = rectangle.Width;
int height = rectangle.Height;
radius = radius << 1;
GraphicsPath path = new GraphicsPath();
if (radius > 0)
{
if (radius > height) radius = height;
if (radius > width) radius = width;
path.AddArc(x, y, radius, radius, 180, 90);
path.AddArc(x + width - radius, y, radius, radius, 270, 90);
path.AddArc(x + width - radius, y + height - radius, radius, radius, 0, 90);
path.AddArc(x, y + height - radius, radius, radius, 90, 90);
path.CloseFigure();
}
else
{
path.AddRectangle(rectangle);
}
return path;
}
// Helper 2/3
private void _drawRoundedRectangle(Graphics graphics, Pen pen, int x, int y, int width, int height, int radius)
{
RectangleF rectangle = new RectangleF(x, y, width, height);
GraphicsPath path = _generateRoundedRectangle(graphics, rectangle, radius);
SmoothingMode old = graphics.SmoothingMode;
graphics.SmoothingMode = SmoothingMode.AntiAlias;
graphics.DrawPath(pen, path);
graphics.SmoothingMode = old;
}
// Helper 3/3
private static GraphicsPath _generateRoundedRectangle(Graphics graphics, RectangleF rectangle, int radius)
{
GraphicsPath path = new GraphicsPath();
float diameter = radius * 2.0F;
SizeF sizeF = new SizeF(diameter, diameter);
RectangleF arc = new RectangleF(rectangle.Location, sizeF);
path.AddArc(arc, 180, 90);
arc.X = rectangle.Right - diameter;
path.AddArc(arc, 270, 90);
arc.Y = rectangle.Bottom - diameter;
path.AddArc(arc, 0, 90);
arc.X = rectangle.Left;
path.AddArc(arc, 90, 90);
path.CloseFigure();
return path;
}
Main code parts are from Arun Reginald Zaheeruddin

Solved it according to this answer by #Reza Aghaei.
Solution
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
public class RoundLabel : Label
{
[Browsable(true)]
public Color _BackColor { get; set; }
public RoundLabel()
{
this.DoubleBuffered = true;
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
using (var graphicsPath = _getRoundRectangle(this.ClientRectangle))
{
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
using (var brush = new SolidBrush(_BackColor))
e.Graphics.FillPath(brush, graphicsPath);
using (var pen = new Pen(_BackColor, 1.0f))
e.Graphics.DrawPath(pen, graphicsPath);
TextRenderer.DrawText(e.Graphics, Text, this.Font, this.ClientRectangle, this.ForeColor);
}
}
private GraphicsPath _getRoundRectangle(Rectangle rectangle)
{
int cornerRadius = 15; // change this value according to your needs
int diminisher = 1;
GraphicsPath path = new GraphicsPath();
path.AddArc(rectangle.X, rectangle.Y, cornerRadius, cornerRadius, 180, 90);
path.AddArc(rectangle.X + rectangle.Width - cornerRadius - diminisher, rectangle.Y, cornerRadius, cornerRadius, 270, 90);
path.AddArc(rectangle.X + rectangle.Width - cornerRadius - diminisher, rectangle.Y + rectangle.Height - cornerRadius - diminisher, cornerRadius, cornerRadius, 0, 90);
path.AddArc(rectangle.X, rectangle.Y + rectangle.Height - cornerRadius - diminisher, cornerRadius, cornerRadius, 90, 90);
path.CloseAllFigures();
return path;
}
}

Using C# Pens and Brushes in WinApi?

How can I get HBRUSH from Brush and HPEN from Pen ?
I wonder is there any connection between the two sides ?
(I want to use WinApi functions that are not implemented in .NET's System.Drawing such as DrawRoundRect/CreateRoundRectRgn and I want to use brushes from .NET for that instead of creating them on my own.)

The Brush class does have a private field called nativeBrush which holds the HBRUSH handle as an IntPtr.
Because it's a private field, it could change with any revision to .Net, but if you don't mind using some dodgy, brittle reflection to get at its value, you could do something nasty like this:
Brush brush = ...the brush that you want to get at the handle for
FieldInfo field = typeof(Brush).GetField("nativeBrush",BindingFlags.NonPublic|BindingFlags.Instance);
IntPtr hbrush = (IntPtr)field.GetValue(brush);
There is a similar field for Pen called nativePen which you can access using similar reflection code.
However, if you can use GraphicsPath as Don shows above, that would be much less risky.
Also check out this article on creating rounded rectangles using GraphicsPath

I don't have the original source any longer, might even have been a SO item. At any rate, here's a class someone provided a while back that I use:
/// <summary>
/// Collection of often-used classes and methods for easy access.
/// </summary>
public class RoundedDrawing
{
private static GraphicsPath GetRoundedRectanglePath(Int32 x, Int32 y, Int32 width, Int32 height, Int32 radius)
{
GraphicsPath path = new GraphicsPath();
path.AddLine(x + radius, y, x + width - radius, y);
if (radius > 0)
path.AddArc(x + width - 2 * radius, y, 2 * radius, 2 * radius, 270.0f, 90.0f);
path.AddLine(x + width, y + radius, x + width, y + height - radius);
if (radius > 0)
path.AddArc(x + width - 2 * radius, y + height - 2 * radius, 2 * radius, 2 * radius, 0.0f, 90.0f);
path.AddLine(x + width - radius, y + height, x + radius, y + height);
if (radius > 0)
path.AddArc(x, y + height - 2 * radius, 2 * radius, 2 * radius, 90.0f, 90.0f);
path.AddLine(x, y + height - radius, x, y + radius);
if (radius > 0)
path.AddArc(x, y, 2 * radius, 2 * radius, 180.0f, 90.0f);
return path;
}
/// <summary>
/// Fills the interior of a rounded rectangle.
/// </summary>
public static void FillRoundedRectangle(Graphics graphics, Brush brush, float x, float y, float width, float height, float radius)
{
FillRoundedRectangle(graphics, brush, (Int32)x, (Int32)y, (Int32)width, (Int32)height, (Int32)radius);
}
/// <summary>
/// Fills the interior of a rounded rectangle.
/// </summary>
public static void FillRoundedRectangle(Graphics graphics, Brush brush, Rectangle rect, Int32 radius)
{
FillRoundedRectangle(graphics, brush, rect.Left, rect.Top, rect.Width, rect.Height, radius);
}
/// <summary>
/// Fills the interior of a rounded rectangle.
/// </summary>
public static void FillRoundedRectangle(Graphics graphics, Brush brush, RectangleF rect, float radius)
{
FillRoundedRectangle(graphics, brush, (Int32)rect.Left, (Int32)rect.Top, (Int32)rect.Width, (Int32)rect.Height, (Int32)radius);
}
/// <summary>
/// Fills the interior of a rounded rectangle.
/// </summary>
public static void FillRoundedRectangle(Graphics graphics, Brush brush, Int32 x, Int32 y, Int32 width, Int32 height, Int32 radius)
{
using (GraphicsPath path = GetRoundedRectanglePath(x, y, width, height, radius))
graphics.FillPath(brush, path);
}
/// <summary>
/// Draws the outline of a rounded rectangle.
/// </summary>
public static void DrawRoundedRectangle(Graphics graphics, Pen pen, float x, float y, float width, float height, float radius)
{
DrawRoundedRectangle(graphics, pen, (Int32)x, (Int32)y, (Int32)width, (Int32)height, (Int32)radius);
}
/// <summary>
/// Draws the outline of a rounded rectangle.
/// </summary>
public static void DrawRoundedRectangle(Graphics graphics, Pen pen, Rectangle rect, Int32 radius)
{
DrawRoundedRectangle(graphics, pen, rect.Left, rect.Top, rect.Width, rect.Height, radius);
}
/// <summary>
/// Draws the outline of a rounded rectangle.
/// </summary>
public static void DrawRoundedRectangle(Graphics graphics, Pen pen, RectangleF rect, float radius)
{
DrawRoundedRectangle(graphics, pen, (Int32)rect.Left, (Int32)rect.Top, (Int32)rect.Width, (Int32)rect.Height, (Int32)radius);
}
/// <summary>
/// Draws the outline of a rounded rectangle.
/// </summary>
public static void DrawRoundedRectangle(Graphics graphics, Pen pen, Int32 x, Int32 y, Int32 width, Int32 height, Int32 radius)
{
using (GraphicsPath path = GetRoundedRectanglePath(x, y, width, height, radius))
graphics.DrawPath(pen, path);
}
}
Just make calls from within any Paint or PaintBackground event where you're handed a Graphics object. Pass that in along with whatever else, and draw rounded stuff.
It's an option to keep it all in .NET without external P/Invokes.

Override Paint a control in C#

Can anybody provide a basic tutorial on how to override the paint event in C#? I dont have much experience in C# and this is some part that I dont get easily as I cannot follow some tutorials and tricks as I dont get the concept of overriding in C#.

This is a very basic example, which will (should!) draw a red 'X':
public class FacadeControl : Control
{
private Pen invalidPen;
public FacadeControl()
{
invalidPen = new Pen(Color.Red, 2);
SetStyle(ControlStyles.ResizeRedraw, true); // make sure the control is redrawn every time it is resized
}
protected override void OnPaint(PaintEventArgs pe)
{
// get the graphics object to use to draw
Graphics g = pe.Graphics;
g.DrawLine(invalidPen, 0, 0, Width, Height);
g.DrawLine(invalidPen, 0, Height, Width, 0);
}
}
}

For example :
public class FirstControl : Control{
public FirstControl() {}
protected override void OnPaint(PaintEventArgs e) {
base.OnPaint(e);
e.Graphics.DrawString(Text, Font, new SolidBrush(ForeColor), ClientRectangle);
}
}
just don't forget to call the base paint handler before writing yours

this is the button
I would like to share my code:
The button class:
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Text;
using System.Windows.Forms;
namespace Controles.Buttons
{
/// <summary>
/// Clase personalizada button.
/// Jorge Arturo Avilés Nuñez
/// Zapopan, Jalisco, México
/// 18-DIC-2017
/// </summary>
public class SansationRoundButton : Button
{
#region members
private TextRenderingHint _hint = TextRenderingHint.AntiAlias;
private const int FlagMouseOver = 0x0001;
private const int FlagMouseDown = 0x0002;
private int state = 0;
#endregion
#region Constructor
public SansationRoundButton()
{
this.FlatStyle = FlatStyle.Flat;
this.FlatAppearance.BorderSize = 0;
this.Font = new System.Drawing.Font("Sansation", 21.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, 0);
this.UseVisualStyleBackColor = true;
this.Cursor = Cursors.Hand;
}
#endregion
#region Internal methods and properties
internal bool OwnerDraw
{
get
{
return FlatStyle != FlatStyle.System;
}
}
internal bool MouseIsOver
{
get
{
return GetFlag(FlagMouseOver);
}
}
#endregion
#region Private methods
private bool GetFlag(int flag)
{
return ((state & flag) == flag);
}
private void SetFlag(int flag, bool value)
{
bool oldValue = ((state & flag) != 0);
if (value)
state |= flag;
else
state &= ~flag;
if (OwnerDraw && (flag & FlagMouseDown) != 0 && value != oldValue)
AccessibilityNotifyClients(AccessibleEvents.StateChange, -1);
}
#endregion
#region Overrides
protected override void OnMouseEnter(EventArgs e)
{
base.OnMouseEnter(e);
SetFlag(FlagMouseOver, true);
}
protected override void OnMouseLeave(EventArgs e)
{
base.OnMouseLeave(e);
SetFlag(FlagMouseOver, false);
}
protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
{
e.Graphics.Clear(Color.White);
e.Graphics.TextRenderingHint = this.TextRenderingHint;
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
Color backColor = this.MouseIsOver ? this.BackColorMouseOver : this.BackColor;
Color borderColor = this.MouseIsOver ? this.BorderColorMouseOver : this.BorderColor;
e.Graphics.DrawRoundedRectangle(new Pen(borderColor), 0, 0, this.Width - 1, this.Height - 1, 10);
e.Graphics.FillRoundedRectangle(new SolidBrush(backColor), 0, 0, this.Width - 1, this.Height - 1, 10);
StringFormat sr = BaseControl.CreateStringFormat(this, this.TextAlign, false, this.UseMnemonic);
e.Graphics.DrawString(this.Text, this.Font, new SolidBrush(ForeColor), ClientRectangle, sr);
}
#endregion
#region public properties
public TextRenderingHint TextRenderingHint
{
get { return this._hint; }
set { this._hint = value; }
}
public new bool ShowKeyboardCues
{
get
{
return base.ShowKeyboardCues;
}
}
public Color BackColorMouseOver { get; set; } = Color.Red;
public Color BorderColor { get; set; } = Color.Black;
public Color BorderColorMouseOver { get; set; } = Color.Black;
#endregion
}
}
this class BaseControl creates a new instance of StringFormat object that is needed to call the DrawString method from the Graphics object.
using System.Drawing;
using System.Windows.Forms;
namespace Controles.Buttons
{
public class BaseControl
{
private static readonly ContentAlignment anyRight = ContentAlignment.TopRight | ContentAlignment.MiddleRight | ContentAlignment.BottomRight;
private static readonly ContentAlignment anyBottom = ContentAlignment.BottomLeft | ContentAlignment.BottomCenter | ContentAlignment.BottomRight;
private static readonly ContentAlignment anyCenter = ContentAlignment.TopCenter | ContentAlignment.MiddleCenter | ContentAlignment.BottomCenter;
private static readonly ContentAlignment anyMiddle = ContentAlignment.MiddleLeft | ContentAlignment.MiddleCenter | ContentAlignment.MiddleRight;
static StringAlignment TranslateAlignment(ContentAlignment align)
{
StringAlignment result;
if ((align & anyRight) != 0)
result = StringAlignment.Far;
else if ((align & anyCenter) != 0)
result = StringAlignment.Center;
else
result = StringAlignment.Near;
return result;
}
static StringAlignment TranslateLineAlignment(ContentAlignment align)
{
StringAlignment result;
if ((align & anyBottom) != 0)
{
result = StringAlignment.Far;
}
else if ((align & anyMiddle) != 0)
{
result = StringAlignment.Center;
}
else
{
result = StringAlignment.Near;
}
return result;
}
static StringFormat StringFormatForAlignment(ContentAlignment align)
{
StringFormat output = new StringFormat();
output.Alignment = TranslateAlignment(align);
output.LineAlignment = TranslateLineAlignment(align);
return output;
}
public static StringFormat CreateStringFormat(SansationRoundButton ctl, ContentAlignment textAlign, bool showEllipsis, bool useMnemonic)
{
StringFormat stringFormat = StringFormatForAlignment(textAlign);
// Adjust string format for Rtl controls
if (ctl.RightToLeft == RightToLeft.Yes)
{
stringFormat.FormatFlags |= StringFormatFlags.DirectionRightToLeft;
}
if (showEllipsis)
{
stringFormat.Trimming = StringTrimming.EllipsisCharacter;
stringFormat.FormatFlags |= StringFormatFlags.LineLimit;
}
if (!useMnemonic)
{
stringFormat.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.None;
}
else if (ctl.ShowKeyboardCues)
{
stringFormat.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.Show;
}
else
{
stringFormat.HotkeyPrefix = System.Drawing.Text.HotkeyPrefix.Hide;
}
if (ctl.AutoSize)
{
stringFormat.FormatFlags |= StringFormatFlags.MeasureTrailingSpaces;
}
return stringFormat;
}
}
}
finally this class is used to create and fill the rectangles.
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
namespace Plasmoid.Extensions
{
static class GraphicsExtension
{
private static GraphicsPath GenerateRoundedRectangle(
this Graphics graphics,
RectangleF rectangle,
float radius)
{
float diameter;
GraphicsPath path = new GraphicsPath();
if (radius <= 0.0F)
{
path.AddRectangle(rectangle);
path.CloseFigure();
return path;
}
else
{
if (radius >= (Math.Min(rectangle.Width, rectangle.Height)) / 2.0)
return graphics.GenerateCapsule(rectangle);
diameter = radius * 2.0F;
SizeF sizeF = new SizeF(diameter, diameter);
RectangleF arc = new RectangleF(rectangle.Location, sizeF);
path.AddArc(arc, 180, 90);
arc.X = rectangle.Right - diameter;
path.AddArc(arc, 270, 90);
arc.Y = rectangle.Bottom - diameter;
path.AddArc(arc, 0, 90);
arc.X = rectangle.Left;
path.AddArc(arc, 90, 90);
path.CloseFigure();
}
return path;
}
private static GraphicsPath GenerateCapsule(
this Graphics graphics,
RectangleF baseRect)
{
float diameter;
RectangleF arc;
GraphicsPath path = new GraphicsPath();
try
{
if (baseRect.Width > baseRect.Height)
{
diameter = baseRect.Height;
SizeF sizeF = new SizeF(diameter, diameter);
arc = new RectangleF(baseRect.Location, sizeF);
path.AddArc(arc, 90, 180);
arc.X = baseRect.Right - diameter;
path.AddArc(arc, 270, 180);
}
else if (baseRect.Width < baseRect.Height)
{
diameter = baseRect.Width;
SizeF sizeF = new SizeF(diameter, diameter);
arc = new RectangleF(baseRect.Location, sizeF);
path.AddArc(arc, 180, 180);
arc.Y = baseRect.Bottom - diameter;
path.AddArc(arc, 0, 180);
}
else path.AddEllipse(baseRect);
}
catch { path.AddEllipse(baseRect); }
finally { path.CloseFigure(); }
return path;
}
/// <summary>
/// Draws a rounded rectangle specified by a pair of coordinates, a width, a height and the radius
/// for the arcs that make the rounded edges.
/// </summary>
/// <param name="brush">System.Drawing.Pen that determines the color, width and style of the rectangle.</param>
/// <param name="x">The x-coordinate of the upper-left corner of the rectangle to draw.</param>
/// <param name="y">The y-coordinate of the upper-left corner of the rectangle to draw.</param>
/// <param name="width">Width of the rectangle to draw.</param>
/// <param name="height">Height of the rectangle to draw.</param>
/// <param name="radius">The radius of the arc used for the rounded edges.</param>
public static void DrawRoundedRectangle(
this Graphics graphics,
Pen pen,
float x,
float y,
float width,
float height,
float radius)
{
RectangleF rectangle = new RectangleF(x, y, width, height);
GraphicsPath path = graphics.GenerateRoundedRectangle(rectangle, radius);
SmoothingMode old = graphics.SmoothingMode;
graphics.SmoothingMode = SmoothingMode.AntiAlias;
graphics.DrawPath(pen, path);
graphics.SmoothingMode = old;
}
/// <summary>
/// Draws a rounded rectangle specified by a pair of coordinates, a width, a height and the radius
/// for the arcs that make the rounded edges.
/// </summary>
/// <param name="brush">System.Drawing.Pen that determines the color, width and style of the rectangle.</param>
/// <param name="x">The x-coordinate of the upper-left corner of the rectangle to draw.</param>
/// <param name="y">The y-coordinate of the upper-left corner of the rectangle to draw.</param>
/// <param name="width">Width of the rectangle to draw.</param>
/// <param name="height">Height of the rectangle to draw.</param>
/// <param name="radius">The radius of the arc used for the rounded edges.</param>
public static void DrawRoundedRectangle(
this Graphics graphics,
Pen pen,
int x,
int y,
int width,
int height,
int radius)
{
graphics.DrawRoundedRectangle(
pen,
Convert.ToSingle(x),
Convert.ToSingle(y),
Convert.ToSingle(width),
Convert.ToSingle(height),
Convert.ToSingle(radius));
}
/// <summary>
/// Fills the interior of a rounded rectangle specified by a pair of coordinates, a width, a height
/// and the radius for the arcs that make the rounded edges.
/// </summary>
/// <param name="brush">System.Drawing.Brush that determines the characteristics of the fill.</param>
/// <param name="x">The x-coordinate of the upper-left corner of the rectangle to fill.</param>
/// <param name="y">The y-coordinate of the upper-left corner of the rectangle to fill.</param>
/// <param name="width">Width of the rectangle to fill.</param>
/// <param name="height">Height of the rectangle to fill.</param>
/// <param name="radius">The radius of the arc used for the rounded edges.</param>
public static void FillRoundedRectangle(
this Graphics graphics,
Brush brush,
float x,
float y,
float width,
float height,
float radius)
{
RectangleF rectangle = new RectangleF(x, y, width, height);
GraphicsPath path = graphics.GenerateRoundedRectangle(rectangle, radius);
SmoothingMode old = graphics.SmoothingMode;
graphics.SmoothingMode = SmoothingMode.AntiAlias;
graphics.FillPath(brush, path);
graphics.SmoothingMode = old;
}
/// <summary>
/// Fills the interior of a rounded rectangle specified by a pair of coordinates, a width, a height
/// and the radius for the arcs that make the rounded edges.
/// </summary>
/// <param name="brush">System.Drawing.Brush that determines the characteristics of the fill.</param>
/// <param name="x">The x-coordinate of the upper-left corner of the rectangle to fill.</param>
/// <param name="y">The y-coordinate of the upper-left corner of the rectangle to fill.</param>
/// <param name="width">Width of the rectangle to fill.</param>
/// <param name="height">Height of the rectangle to fill.</param>
/// <param name="radius">The radius of the arc used for the rounded edges.</param>
public static void FillRoundedRectangle(
this Graphics graphics,
Brush brush,
int x,
int y,
int width,
int height,
int radius)
{
graphics.FillRoundedRectangle(
brush,
Convert.ToSingle(x),
Convert.ToSingle(y),
Convert.ToSingle(width),
Convert.ToSingle(height),
Convert.ToSingle(radius));
}
}
}
Enjoy!