Drawing a TextBox in an extended Glass Frame w/o WPF
- by Lazlo
I am trying to draw a TextBox on the extended glass frame of my form. I won't describe this technique, it's well-known. Here's an example for those who haven't heard of it: http://www.danielmoth.com/Blog/Vista-Glass-In-C.aspx
The thing is, it is complex to draw over this glass frame. Since black is considered to be the 0-alpha color, anything black disappears.
There are apparently ways of countering this problem: drawing complex GDI+ shapes are not affected by this alpha-ness. For example, this code can be used to draw a Label on glass (note: GraphicsPath is used instead of DrawString in order to get around the horrible ClearType problem):
public class GlassLabel : Control
{
public GlassLabel()
{
this.BackColor = Color.Black;
}
protected override void OnPaint(PaintEventArgs e)
{
GraphicsPath font = new GraphicsPath();
font.AddString(
this.Text,
this.Font.FontFamily,
(int)this.Font.Style,
this.Font.Size,
Point.Empty,
StringFormat.GenericDefault);
e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
e.Graphics.FillPath(new SolidBrush(this.ForeColor), font);
}
}
Similarly, such an approach can be used to create a container on the glass area. Note the use of the polygons instead of the rectangle - when using the rectangle, its black parts are considered as alpha.
public class GlassPanel : Panel
{
public GlassPanel()
{
this.BackColor = Color.Black;
}
protected override void OnPaint(PaintEventArgs e)
{
Point[] area = new Point[]
{
new Point(0, 1),
new Point(1, 0),
new Point(this.Width - 2, 0),
new Point(this.Width - 1, 1),
new Point(this.Width -1, this.Height - 2),
new Point(this.Width -2, this.Height-1),
new Point(1, this.Height -1),
new Point(0, this.Height - 2)
};
Point[] inArea = new Point[]
{
new Point(1, 1),
new Point(this.Width - 1, 1),
new Point(this.Width - 1, this.Height - 1),
new Point(this.Width - 1, this.Height - 1),
new Point(1, this.Height - 1)
};
e.Graphics.FillPolygon(new SolidBrush(Color.FromArgb(240, 240, 240)), inArea);
e.Graphics.DrawPolygon(new Pen(Color.FromArgb(55, 0, 0, 0)), area);
base.OnPaint(e);
}
}
Now my problem is: How can I draw a TextBox?
After lots of Googling, I came up with the following solutions:
Subclassing the TextBox's OnPaint method. This is possible, although I could not get it to work properly. It should involve painting some magic things I don't know how to do yet.
Making my own custom TextBox, perhaps on a TextBoxBase. If anyone has good, valid and working examples, and thinks this could be a good overall solution, please tell me.
Using BufferedPaintSetAlpha. (http://msdn.microsoft.com/en-us/library/ms649805.aspx). The downsides of this method may be that the corners of the textbox might look odd, but I can live with that. If anyone knows how to implement that method properly from a Graphics object, please tell me. I personally don't, but this seems the best solution so far. To be honest, I found a great C++ article, but I am way too lazy to convert it. http://weblogs.asp.net/kennykerr/archive/2007/01/23/controls-and-the-desktop-window-manager.aspx
Note: If I ever succeed with the BufferedPaint methods, I swear to s/o that I will make a simple DLL with all the common Windows Forms controls drawable on glass.
