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I am working on a Windows Forms application where I have implemented code to curve the corners of the form. While the code successfully curves the form itself, it does not work for controls like Panel within the form. Additionally, when a Panel is added to the form, the corner curvature effect of the form also stops working as expected.
I need a solution that allows me to curve the corners of both the form and other controls (e.g., Panel) consistently. The implementation should ensure that:
The corner curves of the form are preserved even when other controls are added. Controls like Panel can also have curved corners with smooth blending.
protected override void OnLoad(EventArgs e) { if (!DesignMode) { drawTimer.Interval = 1000 / 60; drawTimer.Tick += DrawForm; drawTimer.Start(); } base.OnLoad(e); }
private void DrawForm(object pSender, EventArgs pE) { using (Bitmap backImage = new Bitmap(this.Width, this.Height)) { using (Graphics graphics = Graphics.FromImage(backImage)) { Rectangle gradientRectangle = new Rectangle(0, 0, this.Width - 1, this.Height - 1); using (Brush b = new LinearGradientBrush(gradientRectangle, Color.FromArgb(70, 95, 122), Color.FromArgb(70, 95, 122), 0.0f)) { graphics.SmoothingMode = SmoothingMode.HighQuality;
RoundedRectangle.FillRoundedRectangle(graphics, b, gradientRectangle, 20);
foreach (Control ctrl in this.Controls) { using (Bitmap bmp = new Bitmap(ctrl.Width, ctrl.Height)) { Rectangle rect = new Rectangle(0, 0, ctrl.Width, ctrl.Height); ctrl.DrawToBitmap(bmp, rect); graphics.DrawImage(bmp, ctrl.Location); } }
PerPixelAlphaBlend.SetBitmap(backImage, Left, Top, Handle); } } } }
protected override void OnPaint(PaintEventArgs e) { if (DesignMode) { Graphics graphics = e.Graphics;
Rectangle gradientRectangle = new Rectangle(0, 0, this.Width - 1, this.Height - 1);
Brush b = new LinearGradientBrush(gradientRectangle, Color.FromArgb(70, 95, 122), Color.FromArgb(70, 95, 122), 0.0f);
graphics.SmoothingMode = SmoothingMode.HighQuality;
RoundedRectangle.FillRoundedRectangle(graphics, b, gradientRectangle, 20); }
base.OnPaint(e); }
protected override CreateParams CreateParams { get { CreateParams cp = base.CreateParams; if (!DesignMode) { cp.ExStyle |= 0x00080000; } return cp; } }
private void pictureBox1_Click(object sender, EventArgs e) { this.Close(); } }
public static class RoundedRectangle { public static GraphicsPath RoundedRect(Rectangle bounds, int radius) { int diameter = radius * 2; Size size = new Size(diameter, diameter); Rectangle arc = new Rectangle(bounds.Location, size); GraphicsPath path = new GraphicsPath();
if (radius == 0) { path.AddRectangle(bounds); return path; }
// top left arc path.AddArc(arc, 180, 90);
// top right arc arc.X = bounds.Right - diameter; path.AddArc(arc, 270, 90);
// bottom right arc arc.Y = bounds.Bottom - diameter; path.AddArc(arc, 0, 90);
// bottom left arc arc.X = bounds.Left; path.AddArc(arc, 90, 90);
path.CloseFigure(); return path; }
public static void FillRoundedRectangle(Graphics graphics, Brush brush, Rectangle bounds, int cornerRadius) { if (graphics == null) throw new ArgumentNullException("graphics"); if (brush == null) throw new ArgumentNullException("brush");
using (GraphicsPath path = RoundedRect(bounds, cornerRadius)) { graphics.FillPath(brush, path); } } }
internal static class PerPixelAlphaBlend { public static void SetBitmap(Bitmap bitmap, int left, int top, IntPtr handle) { SetBitmap(bitmap, 255, left, top, handle); }
public static void SetBitmap(Bitmap bitmap, byte opacity, int left, int top, IntPtr handle) { //if (bitmap.PixelFormat != PixelFormat.Format32bppArgb) // throw new ApplicationException("The bitmap must be 32ppp with alpha-channel.");
IntPtr screenDc = Win32.GetDC(IntPtr.Zero); IntPtr memDc = Win32.CreateCompatibleDC(screenDc); IntPtr hBitmap = IntPtr.Zero; IntPtr oldBitmap = IntPtr.Zero;
try { hBitmap = bitmap.GetHbitmap(Color.FromArgb(0)); oldBitmap = Win32.SelectObject(memDc, hBitmap);
Win32.Size size = new Win32.Size(bitmap.Width, bitmap.Height); Win32.Point pointSource = new Win32.Point(0, 0); Win32.Point topPos = new Win32.Point(left, top); Win32.BLENDFUNCTION blend = new Win32.BLENDFUNCTION(); blend.BlendOp = Win32.AC_SRC_OVER; blend.BlendFlags = 0; blend.SourceConstantAlpha = opacity; blend.AlphaFormat = Win32.AC_SRC_ALPHA;
Win32.UpdateLayeredWindow(handle, screenDc, ref topPos, ref size, memDc, ref pointSource, 0, ref blend, Win32.ULW_ALPHA); } finally { Win32.ReleaseDC(IntPtr.Zero, screenDc); if (hBitmap != IntPtr.Zero) { Win32.SelectObject(memDc, oldBitmap); Win32.DeleteObject(hBitmap); }
Win32.DeleteDC(memDc); } } }
internal class Win32 { public enum Bool { False = 0, True };
[StructLayout(LayoutKind.Sequential)] public struct Point { public Int32 x; public Int32 y;
public Point(Int32 x, Int32 y) { this.x = x; this.y = y; } }
[StructLayout(LayoutKind.Sequential)] public struct Size { public Int32 cx; public Int32 cy;
public Size(Int32 cx, Int32 cy) { this.cx = cx; this.cy = cy; } }
[StructLayout(LayoutKind.Sequential, Pack = 1)] struct ARGB { public byte Blue; public byte Green; public byte Red; public byte Alpha; }
[StructLayout(LayoutKind.Sequential, Pack = 1)] public struct BLENDFUNCTION { public byte BlendOp; public byte BlendFlags; public byte SourceConstantAlpha; public byte AlphaFormat; }
public const Int32 ULW_COLORKEY = 0x00000001; public const Int32 ULW_ALPHA = 0x00000002; public const Int32 ULW_OPAQUE = 0x00000004;
public const byte AC_SRC_OVER = 0x00; public const byte AC_SRC_ALPHA = 0x01;
[DllImport("user32.dll", ExactSpelling = true, SetLastError = true)] public static extern Bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst, ref Point pptDst, ref Size psize, IntPtr hdcSrc, ref Point pprSrc, Int32 crKey, ref BLENDFUNCTION pblend, Int32 dwFlags);
[DllImport("user32.dll", ExactSpelling = true, SetLastError = true)] public static extern IntPtr GetDC(IntPtr hWnd);
[DllImport("user32.dll", ExactSpelling = true)] public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)] public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
[DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)] public static extern Bool DeleteDC(IntPtr hdc);
[DllImport("gdi32.dll", ExactSpelling = true)] public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
[DllImport("gdi32.dll", ExactSpelling = true, SetLastError = true)] public static extern Bool DeleteObject(IntPtr hObject);