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POWindows 7 style Dropshadow in borderless form
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copied!<blockquote> <p><strong><em>Short Version:</em></strong></p> </blockquote> <p><strong>Goal:</strong> A deep, dark, Windows 7 dropshadow in borderless WinForm in C#</p> <hr> <p><strong>Known existing solutions 1:</strong> Simple XP-style dropshadow using CreateParams.</p> <p><strong>Problem:</strong> Too weak, too light, too ugly.</p> <hr> <p><strong>Known existing solutions 2:</strong> Replace GDI of form with bitmap.</p> <p><strong>Problem:</strong> Lose the ability to use controls, only functional as a splash screen.</p> <hr> <p><strong>Objective by this post:</strong> Find a median solution to this problem or an all together better one. </p> <p>. . .</p> <blockquote> <p><strong><em>Long Version:</em></strong></p> </blockquote> <p>(Edit: I am referring to the drop-shadow going along the border of any windows form, if that wasn't clear.) I understand that there is a way to make XP style dropshadows in C# using: </p> <p><strong>C# Code 1 - Simple XP-style dropshadow (Problem: to light, to weak, to ugly)</strong></p> <pre><code>// Define the CS_DROPSHADOW constant private const int CS_DROPSHADOW = 0x00020000; // Override the CreateParams property protected override CreateParams CreateParams { get { CreateParams cp = base.CreateParams; cp.ClassStyle |= CS_DROPSHADOW; return cp; } } </code></pre> <p>However, I am trying to figure out how to make them appear like the do in Windows 7 (deeper and larger shadows) and can't figure out the best way of doing this. </p> <p>I have a method now created that will let me override the entire form GDI and appear like a splash screen would (credit not mine):</p> <p><strong>C# Code 2: Replace form GDI with Bitmap (Problem: can't use form controls, hard to maintain GUI)</strong> </p> <pre><code> public void SetBitmap(Bitmap bitmap, byte opacity) { if (bitmap.PixelFormat != PixelFormat.Format32bppArgb) throw new ApplicationException("The bitmap must be 32ppp with alpha-channel."); // 1. Create a compatible DC with screen; // 2. Select the bitmap with 32bpp with alpha-channel in the compatible DC; // 3. Call the UpdateLayeredWindow. 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)); // grab a GDI handle from this GDI+ bitmap 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(this.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); } } protected override CreateParams CreateParams { get { CreateParams cp = base.CreateParams; cp.ExStyle |= 0x00080000; // This form has to have the WS_EX_LAYERED extended style return cp; } } </code></pre> <p>However, this does give me a full 32-bit background (as I require to add the dropshadow manually), but I lose the ability to create form elements that are visible. </p> <p>So basically, I am trying to figure out a median between these two methods. Something that will give me deep and dark drop shadows without losing other functionality / causing excessive repainting requirements. </p>

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