问使用Graphics.DrawString时动态调整字体大小以适应空间

EN

// This function checks the room size and your text and appropriate font
//  for your text to fit in room
// PreferedFont is the Font that you wish to apply
// Room is your space in which your text should be in.
// LongString is the string which it's bounds is more than room bounds.
private Font FindFont(
   System.Drawing.Graphics g,
   string longString,
   Size Room,
   Font PreferedFont
) {
   // you should perform some scale functions!!!
   SizeF RealSize = g.MeasureString(longString, PreferedFont);
   float HeightScaleRatio = Room.Height / RealSize.Height;
   float WidthScaleRatio = Room.Width / RealSize.Width;

   float ScaleRatio = (HeightScaleRatio < WidthScaleRatio)
      ? ScaleRatio = HeightScaleRatio
      : ScaleRatio = WidthScaleRatio;

   float ScaleFontSize = PreferedFont.Size * ScaleRatio;

   return new Font(PreferedFont.FontFamily, ScaleFontSize);
}

Bitmap bitmap = new Bitmap(800, 110);

using (System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(bitmap))
using (Font font1 = new Font("Arial", 120, FontStyle.Regular, GraphicsUnit.Pixel))
{
   Rectangle rect1 = new Rectangle(0, 0, 800, 110);

   StringFormat stringFormat = new StringFormat();
   stringFormat.Alignment = StringAlignment.Center;
   stringFormat.LineAlignment = StringAlignment.Center;
   graphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;

   Font goodFont = FindFont(graphics, "Billy Reallylonglastnameinstein", rect1.Size, font1);

   graphics.DrawString(
      "Billy Reallylonglastnameinstein",
      goodFont,
      Brushes.Red,
      rect1,
      stringFormat
   );
}

    // You hand this the text that you need to fit inside some
    // available room, and the font you'd like to use.
    // If the text fits nothing changes
    // If the text does not fit then it is reduced in size to
    // make it fit.
    // PreferedFont is the Font that you wish to apply
    // FontUnit is there because the default font unit is not
    // always the one you use, and it is info required in the
    // constructor for the new Font.
    public static void FindGoodFont(Graphics Graf, string sStringToFit,
                                    Size TextRoomAvail, 
                                    ref Font FontToUse,
                                    GraphicsUnit FontUnit)
    {
        // Find out what the current size of the string in this font is
        SizeF RealSize = Graf.MeasureString(sStringToFit, FontToUse);
        Debug.WriteLine("big string is {0}, orig size = {1},{2}",
                         sStringToFit, RealSize.Width, RealSize.Height);
        if ((RealSize.Width <= TextRoomAvail.Width) && (RealSize.Height <= TextRoomAvail.Height))
        {
            Debug.WriteLine("The space is big enough already");
            // The current font is fine...
            return;
        }

        // Either width or height is too big...
        // Usually either the height ratio or the width ratio
        // will be less than 1. Work them out...
        float HeightScaleRatio = TextRoomAvail.Height / RealSize.Height;
        float WidthScaleRatio = TextRoomAvail.Width / RealSize.Width;

        // We'll scale the font by the one which is furthest out of range...
        float ScaleRatio = (HeightScaleRatio < WidthScaleRatio) ? ScaleRatio = HeightScaleRatio : ScaleRatio = WidthScaleRatio;
        float ScaleFontSize = FontToUse.Size * ScaleRatio;

        Debug.WriteLine("Resizing with scales {0},{1} chose {2}",
                         HeightScaleRatio, WidthScaleRatio, ScaleRatio);

        Debug.WriteLine("Old font size was {0}, new={1} ",FontToUse.Size,ScaleFontSize);

        // Retain whatever the style was in the old font...
        FontStyle OldFontStyle = FontToUse.Style;

        // Get rid of the old non working font...
        FontToUse.Dispose();

        // Tell the caller to use this newer smaller font.
        FontToUse = new Font(FontToUse.FontFamily,
                                ScaleFontSize,
                                OldFontStyle,
                                FontUnit);
    }

    private Font FindFont(  System.Drawing.Graphics g , string longString , Size Room , Font PreferedFont)
    {
        SizeF RealSize = g.MeasureString(longString, PreferedFont);
        float HeightScaleRatio = Room.Height / RealSize.Height;
        float WidthScaleRatio = Room.Width / RealSize.Width;
        float ScaleRatio = (HeightScaleRatio < WidthScaleRatio) ? ScaleRatio = HeightScaleRatio : ScaleRatio = WidthScaleRatio;
        float ScaleFontSize = PreferedFont.Size * ScaleRatio;
        return new Font(PreferedFont.FontFamily, ScaleFontSize,PreferedFont.Style,GraphicsUnit.Pixel);
    }