Adjust font size to fit string in gap

[Cags]

I'm creating what is essentially a custom control which consists of a grid with text values being included in the 'cells'. The entire control is being drawn using DrawLine, DrawString etc. What I am trying todo is have it so that if a 'cell' is resized, the control automatically selects (or at least tries to select) a font size that will still allow the entire string to stay within the sections.

 

I know there is a MeasureString function, but I'm not sure how much help it would be in this instance, I might come up with an idea after some sleep, but if anyone has anyone can point me in the right direction, it'd be much appreciated?

[snarfblam]

Why not find the width of the string, and if it is greater than the size available, do some simple division and multiplication to find the size needed.

[Vb]

'Limit how small the font can be

Const MinSize As Single = 8.0F

 

Dim MeasuredWidth, AvailableWidth, FontSize As Single

 

'Get some values

FontSize = Me.Font.Size()

AvailableWidth = Me.Width ' minus border width?

MeasuredWidth = e.Graphics.MeasureString(Me.Text, Me.Font).Width

 

'Take either the current font size, or the sized-to-fit size, whichever

'is appropriate

FontSize = Math.Max(FontSize, FontSize * AvailableWidth / MeasuredWidth)

'Make sure that we are at least the minimum size

FontSize = Math.Max(FontSize, MinSize)

 

'Create The Font

MyFont = New Font(Me.Font, FontSize, Me.Font.Style, GraphicsUnit.Point)

[/code]

That might need some tweaking, but I think it is the jist of what you need. It will also probably work better when a user has font anti-aliasing on, which allows for fractional character widths and therefore more percise sizing.

[Cags]

Thanks for the idea its a good suggestion however as far as I can tell it won't work in this situation. The string that will be held in the cell uses the overload

 

DrawString(string, Font, Brush, RectangleF);

 

Thus the string is automatically wrapped to fit into the rect. Due to the multiline nature measuring the string width won't work in this manner (I don't think :S)

 

I've found a solution that ensures the string fits in the box unfortunately it merely ensures its small enough for the entire string to be displayed, not necessarily a good fit.

 

		SizeF stringSize = gTemp.MeasureString(sString , fOptions, iSquareSize );
		double aspect = 0.0;

		if( iSquareSize / stringSize.Width < iSquareSize / stringSize.Height )
			aspect = iSquareSize / stringSize.Width;
		else
			aspect = iSquareSize / stringSize.Height;

		float new_size = ( float )( fOptions.Size * aspect );

		fOptions = new Font(fOptions.FontFamily, new_size);

[Cags]

Found a better solution...

 

int iMeasuredHeight = (int)e.Graphics.MeasureString( sString, fOptions, iSquareSize).Height;

while(iSquareSize < iMeasuredHeight)
{
	iFontSize --;
	fOptions = new Font(fOptions.FontFamily, iFontSize);
	iMeasuredHeight = (int)e.Graphics.MeasureString( sString, fOptions,  iSquareSize).Height;			
}

 

NB: iFontSize starts at the maximum size you wish the text to be. Due to the nature of the control my grid cells are always square.