Shaped Windows Forms and Controls in C# .NET

Question

I followed the instructions MSDN suggests as far as creating a custom-shaped form. You can find the write up by going to: Shaped Windows Forms and Controls in Visual Studio .NET If you happen to actually read it, you'll notice it says, "Monitors set to a color depth of greater than 24-bit can display problems with certain parts of the form not being transparent, despite setting of the TransparencyKey property. To avoid this problem, ensure that the monitor's color depth is set to less than 24-bit in the Display control panel. When developing applications that feature this transparency, keep in mind that you will have to make your users aware of this issue." Well, they weren't fooling anyone. I'm current viewing at 1280 x 1024 @ 32-bit. When my display settings are 1024 x 768 @ 16-bit (24 not available) my image actually seems transparent but with a noticable reduction in image quality. My question is, how does Microsoft get WMP9's background to be transparent? GDI+? I'm unfamiliar with GDI however very eager to learn if anyone has any great tutorials on the web. I scanned the forums and came up short. That link was actually provided by someone else who wrote a tutorial on the very subject. Thank you in advance. Matt

playboy2446 · Answer

Thank you Tristan for the tip. I am in need of some clarification as I've only touched the surface of Regions in .NET. Where abouts should I initialize the GraphicsPath; in the constructor or am I supposed to override the Form_Paint function? I've already tried overriding the Form_Paint function and the following code shows exactly how I did this. The only problem I've had with this method is that I can't seem to draw a perfect arc (eg rounded corner in which I want to make transparent). My form (the image I'm using as my background) has 4 rounded corners. The following Form_Paint function crops the top bottom left and right portion of the image (basically just 4 rectangles) and then I try to crop the top left corner of the image unsuccessfully. There always seems to be a visible portion of the background peeking from the edge. When I change one point it throws off all of the rest of the points. I even tried adding another point for precision however that method doesn't do me any justice. Here's the overridden Form_Paint function: [CODE] private void Form_Paint(object sender PaintEventArgs e) { Graphics g = e.Graphics; Rectangle mainRect = new Rectangle(0 0 800 568); Region mainRegion = new Region(mainRect); e.Graphics.SetClip(mainRegion CombineMode.Replace); // Create a GraphicsPath object. // Trim top GraphicsPath myPath = new GraphicsPath(); myPath.AddLine(0 8 800 8); myPath.AddLine(800 0 0 0); Region ExcludeRegion = new Region(myPath); e.Graphics.ExcludeClip(ExcludeRegion); // Trim bottom GraphicsPath myPath2 = new GraphicsPath(); myPath2.AddLine(0 560 800 560); myPath2.AddLine(800 568 0 568); Region ExcludeRegion2 = new Region(myPath2); e.Graphics.ExcludeClip(ExcludeRegion2); // Trim left GraphicsPath myPath3 = new GraphicsPath(); myPath3.AddLine(0 568 7 568); myPath3.AddLine(7 0 0 0); Region ExcludeRegion3 = new Region(myPath3); e.Graphics.ExcludeClip(ExcludeRegion3); // Trim right GraphicsPath myPath4 = new GraphicsPath(); myPath4.AddLine(792 568 800 568); myPath4.AddLine(800 0 792 0); Region ExcludeRegion4 = new Region(myPath4); e.Graphics.ExcludeClip(ExcludeRegion4); Point point1 = new Point(7 80); Point point2 = new Point(17 50); Point point3 = new Point(27 35); Point point4 = new Point(57 15); // Create an array of the points. Point[] curvePoints = { point1 point2 point3 point4 }; GraphicsPath myPath5 = new GraphicsPath(); myPath5.AddCurve(curvePoints 0 3 1.0f); myPath5.AddLine(80878); Region ExcludeRegion5 = new Region(myPath5); e.Graphics.ExcludeClip(ExcludeRegion5); e.Graphics.DrawImage(img 0 0 800568); } [/CODE] Thank you again for your help. Matt

Tristan · Answer

Instead of using color keying [through the TransparencyKey property] try to set the forms region property. You say that you are not familiar with GDI(+) so try the folowing: - Create a new System.Drawing.Drawing2D.GraphicsPath and add some shapes. - Create a System.Drawing.Region providing the newly created GraphicsPath object as an argument. - Set the forms Region property to the newly created Region object. Hope this helps :) [Regions don't use 'Transparency Colors' so they don't depend on color depths etc.]