My label resizing class won't work with bold font

[headkaze]

Hi, my first post to the boards so hello! :) I've 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 it's bold and still measure the label as if it was regular text. This means it won't 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 dosn't 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 :rolleyes:

[snarfblam]

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

[headkaze]

Just out of curiousity' date=' why GDI instead of GDI+?[/quote']

 

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 I'm 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' date=' it seems to work ok. You should be able to adopt this technique to create an inherited control if you wish.[/quote']

 

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

 

Here's 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();
}
}

Edited September 8, 2006 by headkaze

[snarfblam]

Much, much easier on the eyes.