My label resizing class won't work with bold font

[headkaze]

Hi, my first post to the boards so hello! Ive written a class that will auto size the height of a label based on the text inside. It works fine for normal text, but if I make the text bold it seems to ignore that its bold and still measure the label as if it was regular text. This means it wont resize the label properly. I have to have this working for bold text! Does anyone have any ideas how I can modify it to work with bold text?

public class clsAutoSizeLabel
{
	[DllImport("gdi32.dll")]
	private static extern bool DeleteObject(IntPtr hObject);

	[DllImport("user32.dll")]
	private static extern int DrawText(IntPtr hDC, string lpString, int nCount, ref RECT lpRect, uint uFormat);

	[DllImport("gdi32.dll")]
	private static extern IntPtr SelectObject(IntPtr hdc, IntPtr hgdiobj);

	private struct RECT
	{
		public int Left;
		public int Top;
		public int Right;
		public int Bottom;
	}

	private const int DT_CALCRECT = 0x400;
	private const int DT_WORDBREAK = 0x10;

	public static void AutoSizeLabelHeight(Label ctlLabel)
	{
		RECT uRECT;

		uRECT.Left=0;
		uRECT.Top=0;
		uRECT.Right=0;
		uRECT.Bottom=0;

		try
		{
			Graphics objGraphics = ctlLabel.CreateGraphics();

			IntPtr hDc = objGraphics.GetHdc();
			IntPtr hFont = ctlLabel.Font.ToHfont();
			IntPtr hFontOld = SelectObject(hDc, hFont);

			uRECT.Right = ctlLabel.Width - 4;

			if(DrawText(hDc, ctlLabel.Text, -1, ref uRECT, DT_CALCRECT | DT_WORDBREAK) != 0)
				ctlLabel.Height = uRECT.Bottom + 4;

			SelectObject(hDc, hFontOld);
			DeleteObject(hFont);

			objGraphics.ReleaseHdc(hDc);
			objGraphics.Dispose();
		}
		catch
		{
		}
	}
}

Here is an example of how I would call the method. If I change it from bold to regular the measurement is the same.

myLabel.Font = new System.Drawing.Font("Verdana", 12F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
myLabel.Location = new System.Drawing.Point(168, 8);
myLabel.Name = "myLabel";
myLabel.Size = new System.Drawing.Size(432, 32);
myLabel.Text = "This is the text inside the label, but it dosnt seem to work properlly when I use bold!";
myLabel.BackColor = System.Drawing.Color.Blue; // set background to blue so we can see the sizing properly
clsAutoSizeLabel.AutoSizeLabelHeight(myLabel);
this.Controls.Add(myLabel);

 

[headkaze]

Found the solution to this problem... changed the following line:

myLabel.Font = new System.Drawing.Font("Verdana Bold", 12F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));

Notice, the name of the font is now "Verdana Bold". It seems you need to specify bold in the name for it to measure a bold font properly

 

[snarfblam]

Just out of curiousity, why GDI instead of GDI+?

 

[headkaze]

Just out of curiousity, why GDI instead of GDI+?

What would the GDI+ equivelent of this class be?

Of course if I could write this class using GDI+ and even the System.Drawing.Graphics namespace using pure managed code I would. As far as I know there is no method in managed code that can measure multi-line text. Please correct me if Im wrong.

 

[Cags]

Heres a quick test I knocked up, it seems to work ok. You should be able to adopt this technique to create an inherited control if you wish.

// init vars
Graphics g = this.CreateGraphics();
string testString = "This is a test to see if the graphics object measurestring works.";
int maxWidth = 30;
Font testFont = new Font("Tahoma", 12);
StringFormat sf = new StringFormat();

// measure string
SizeF stringSize = g.MeasureString(testString, testFont, maxWidth, sf);

// create label and add to form
Label myLbl = new Label();
myLbl.Text = testString;
myLbl.Size = new Size(maxWidth, stringSize.Height);
this.Controls.Add(myLbl);

 

[headkaze]

Heres a quick test I knocked up, it seems to work ok. You should be able to adopt this technique to create an inherited control if you wish.

Works great and in managed code, thanks for that mate!

Heres the class in managed code:

public class AutoSizeLabel
{
	public static void AutoSizeLabelHeight(Label ctlLabel)
	{
		Graphics g = ctlLabel.CreateGraphics();
		Font font = new Font(ctlLabel.Font.Name, ctlLabel.Font.Size);
		StringFormat sf = new StringFormat();

		SizeF stringSize = g.MeasureString(ctlLabel.Text, font, ctlLabel.Width, sf);

		ctlLabel.Height = (int) stringSize.Height + 2;

		g.Dispose();
	}
}

 

[snarfblam]

Much, much easier on the eyes.