C#文字绘图源码

//绘图源码(Begin)

using System.Drawing;
using System.Drawing.Imaging;
using System;

public class Overlay //yxy absolute
{
 // "Old" signature overloaded to call new method w/extra parameters
 public static Bitmap TextOverlay(string imgs,  string  OverlayText,  Font OverlayFont, 
  Color OverlayColor,  bool AddAlpha,  bool AddShadow)
 {
  return TextOverlay(imgs, OverlayText, OverlayFont, OverlayColor, AddAlpha, AddShadow,
   ContentAlignment.MiddleCenter, 0.8F);
 }

 // Draw text directly onto an image (scaled for best-fit)
 // Written to be called from a module (just on the form for simplicity)
 public  static Bitmap TextOverlay( string imgs,  string  OverlayText,  Font OverlayFont, 
  Color OverlayColor,  bool AddAlpha,  bool AddShadow, 
  System.Drawing.ContentAlignment Position,  float PercentFill)
 {
  Bitmap bmp = new Bitmap(imgs);
  if ( OverlayText != null && OverlayText.Length > 0 && PercentFill > 0 )
  {
   // create bitmap and graphics used for drawing
   // "clone" image but use 24RGB format

   Graphics g = Graphics.FromImage(bmp);
   g.DrawImage(bmp, 0, 0);

   int alpha = 255;
   if ( AddAlpha )
   {
    // Compute transparency: Longer text should be less transparent or it gets lost.
    alpha = 90 + (OverlayText.Length * 2);
    if ( alpha >= 255 )  alpha = 255;
   }
   // Create the brush based on the color and alpha
   SolidBrush  b = new SolidBrush(Color.FromArgb(alpha, OverlayColor));

   // Measure the text to render (unscaled, unwrapped)
   StringFormat strFormat = StringFormat.GenericTypographic;
   SizeF s = g.MeasureString(OverlayText, OverlayFont, 100000, strFormat);

   // Enlarge font to specified fill (estimated by AREA)
   //float zoom = OverlayFont.Size ;//(float)(Math.Sqrt(((double)(bmp.Width * bmp.Height) * PercentFill) / (double)(s.Width * s.Height)));
   FontStyle sty = OverlayFont.Style;
   Font  f = new Font(OverlayFont.FontFamily, ((float)OverlayFont.Size), sty);
   //Console.WriteLine(String.Format("Starting Zoom: {0}, Font Size: {1}, Alpha: {2}", zoom, f.Size, alpha));

   // Measure using new font size, allow to wrap as needed.
   // Could rotate the overlay at a 30-45 deg. angle (trig would give correct angle).
   // Of course, then the area covered would be less than "straight" text.
   // I'll leave those calculations for someone else....
   int  charFit;
   int linesFit;
   float SQRTFill = (float)(Math.Sqrt(PercentFill));
   strFormat.FormatFlags = StringFormatFlags.NoClip; //|| StringFormatFlags.LineLimit || StringFormatFlags.MeasureTrailingSpaces;
   strFormat.Trimming = StringTrimming.Word;
   SizeF  layout = new SizeF(((float)bmp.Width) * SQRTFill, ((float)bmp.Height) * 1.5F); // fit to width, allow height to go over
   Console.WriteLine(String.Format("Target size: {0}, {1}", layout.Width, layout.Height));
   s = g.MeasureString(OverlayText, f, layout, strFormat, out charFit, out linesFit);

   // Reduce size until it actually fits...
   // Most text only has to be reduced 1 or 2 times.
   if ((s.Height > (float)(bmp.Height) * SQRTFill) || (s.Width > layout.Width))
   {
    do
    {
     Console.WriteLine(String.Format("Reducing font size: area required = {0}, {1}", s.Width, s.Height));
     //zoom = Math.Max((s.Height / (((float)bmp.Height) * SQRTFill)), s.Width / layout.Width);
     //zoom = 0;//f.Size / zoom;
     
     //if ( zoom > 16F )  zoom = (float)(Math.Floor(zoom)); // use a whole number to reduce "jaggies"
     //if ( zoom >= f.Size )  zoom -= 1;
     f = new Font(OverlayFont.FontFamily, OverlayFont.Size, sty);
     s = g.MeasureString(OverlayText, f, layout, strFormat, out charFit, out linesFit);
     //if ( zoom <= 1 ) break; // bail
    } while ((s.Height > (float)(bmp.Height) * SQRTFill) || (s.Width > layout.Width));
   }
   Console.WriteLine(String.Format("Final Font Size: {0}, area: {1}, {2}", f.Size, s.Width, s.Height));

   // Determine draw area based on placement
   RectangleF rect;
   switch (Position)
   {
    case ContentAlignment.TopLeft: // =1
     rect = new RectangleF(f.Size * 0.15F,
      (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.TopCenter: // =2
     rect = new RectangleF((bmp.Width - s.Width) / 2F,
      (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.TopRight: // =4
     rect = new RectangleF((bmp.Width - s.Width) - (f.Size * 0.1F),
      (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.MiddleLeft: // =16  huh?  where's 8?
     rect = new RectangleF(f.Size * 0.15F,
      (bmp.Height - s.Height) / 2F,
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.MiddleCenter: // =32
     rect = new RectangleF((bmp.Width - s.Width) / 2F,
      (bmp.Height - s.Height) / 2F,
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.MiddleRight: //=64
     rect = new RectangleF((bmp.Width - s.Width) - (f.Size * 0.1F),
      (bmp.Height - s.Height) / 2F,
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.BottomLeft: // =256  and 128?;
     rect = new RectangleF(f.Size * 0.15F,
      (bmp.Height - s.Height) - (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.BottomCenter: // =512
     rect = new RectangleF((bmp.Width - s.Width) / 2F,
      (bmp.Height - s.Height) - (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.BottomRight: // =1024
     rect = new RectangleF((bmp.Width - s.Width) - (f.Size * 0.1F),
      (bmp.Height - s.Height) - (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    default:;
     rect = new RectangleF((bmp.Width - s.Width) / 2F,
      (bmp.Height - s.Height) / 2F,
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
   }

   // Add rendering hint (thx to Thomas)
   g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;

   if ( AddShadow )
   {
    // Add "drop shadow" at half transparency and offset by 1/10 font size
    SolidBrush  shadow = new SolidBrush(Color.FromArgb((int)(alpha / 2.0), OverlayColor));
    RectangleF  sRect = new RectangleF((float)rect.X - (f.Size * 0.1F), (float)rect.Y - (f.Size * 0.1F), rect.Width, rect.Height);
    g.DrawString(OverlayText, f, shadow, sRect, strFormat);
   }

   // finally, draw centered text!
   g.DrawString(OverlayText, f, b, rect, strFormat);

   // clean-up
   g.Dispose();
   b.Dispose();
   f.Dispose();
   return bmp;
  }
  else
  {
   // nothing to overlay!  regurgitate image
   return new Bitmap(bmp);
  }
 }
}

//绘图源码(End)

public class OverlayOld
{
 // "Old" signature overloaded to call new method w/extra parameters
 public static Bitmap TextOverlay(string imgs,  string  OverlayText,  Font OverlayFont, 
  Color OverlayColor,  bool AddAlpha,  bool AddShadow)
 {
  return TextOverlay(imgs, OverlayText, OverlayFont, OverlayColor, AddAlpha, AddShadow,
   ContentAlignment.MiddleCenter, 0.8F);
 }

 // Draw text directly onto an image (scaled for best-fit)
 // Written to be called from a module (just on the form for simplicity)
 public  static Bitmap TextOverlay( string imgs,  string  OverlayText,  Font OverlayFont, 
  Color OverlayColor,  bool AddAlpha,  bool AddShadow, 
  System.Drawing.ContentAlignment Position,  float PercentFill)
 {
  Bitmap bmp = new Bitmap(imgs);
  if ( OverlayText != null && OverlayText.Length > 0 && PercentFill > 0 )
  {
   // create bitmap and graphics used for drawing
   // "clone" image but use 24RGB format

   Graphics g = Graphics.FromImage(bmp);
   g.DrawImage(bmp, 0, 0);

   int alpha = 255;
   if ( AddAlpha )
   {
    // Compute transparency: Longer text should be less transparent or it gets lost.
    alpha = 90 + (OverlayText.Length * 2);
    if ( alpha >= 255 )  alpha = 255;
   }
   // Create the brush based on the color and alpha
   SolidBrush  b = new SolidBrush(Color.FromArgb(alpha, OverlayColor));

   // Measure the text to render (unscaled, unwrapped)
   StringFormat strFormat = StringFormat.GenericTypographic;
   SizeF s = g.MeasureString(OverlayText, OverlayFont, 100000, strFormat);

   // Enlarge font to specified fill (estimated by AREA)
   float zoom = 15;//(float)(Math.Sqrt(((double)(bmp.Width * bmp.Height) * PercentFill) / (double)(s.Width * s.Height)));
   FontStyle sty = OverlayFont.Style;
   Font  f = new Font(OverlayFont.FontFamily, ((float)OverlayFont.Size) * zoom, sty);
   Console.WriteLine(String.Format("Starting Zoom: {0}, Font Size: {1}, Alpha: {2}", zoom, f.Size, alpha));

   // Measure using new font size, allow to wrap as needed.
   // Could rotate the overlay at a 30-45 deg. angle (trig would give correct angle).
   // Of course, then the area covered would be less than "straight" text.
   // I'll leave those calculations for someone else....
   int  charFit;
   int linesFit;
   float SQRTFill = (float)(Math.Sqrt(PercentFill));
   strFormat.FormatFlags = StringFormatFlags.NoClip; //|| StringFormatFlags.LineLimit || StringFormatFlags.MeasureTrailingSpaces;
   strFormat.Trimming = StringTrimming.Word;
   SizeF  layout = new SizeF(((float)bmp.Width) * SQRTFill, ((float)bmp.Height) * 1.5F); // fit to width, allow height to go over
   Console.WriteLine(String.Format("Target size: {0}, {1}", layout.Width, layout.Height));
   s = g.MeasureString(OverlayText, f, layout, strFormat, out charFit, out linesFit);

   // Reduce size until it actually fits...
   // Most text only has to be reduced 1 or 2 times.
   if ((s.Height > (float)(bmp.Height) * SQRTFill) || (s.Width > layout.Width))
   {
    do
    {
     Console.WriteLine(String.Format("Reducing font size: area required = {0}, {1}", s.Width, s.Height));
     //zoom = Math.Max((s.Height / (((float)bmp.Height) * SQRTFill)), s.Width / layout.Width);
     zoom = 15;//f.Size / zoom;
     if ( zoom > 16F )  zoom = (float)(Math.Floor(zoom)); // use a whole number to reduce "jaggies"
     if ( zoom >= f.Size )  zoom -= 1;
     f = new Font(OverlayFont.FontFamily, zoom, sty);
     s = g.MeasureString(OverlayText, f, layout, strFormat, out charFit, out linesFit);
     if ( zoom <= 1 ) break; // bail
    } while ((s.Height > (float)(bmp.Height) * SQRTFill) || (s.Width > layout.Width));
   }
   Console.WriteLine(String.Format("Final Font Size: {0}, area: {1}, {2}", f.Size, s.Width, s.Height));

   // Determine draw area based on placement
   RectangleF rect;
   switch (Position)
   {
    case ContentAlignment.TopLeft: // =1
     rect = new RectangleF(f.Size * 0.15F,
      (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.TopCenter: // =2
     rect = new RectangleF((bmp.Width - s.Width) / 2F,
      (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.TopRight: // =4
     rect = new RectangleF((bmp.Width - s.Width) - (f.Size * 0.1F),
      (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.MiddleLeft: // =16  huh?  where's 8?
     rect = new RectangleF(f.Size * 0.15F,
      (bmp.Height - s.Height) / 2F,
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.MiddleCenter: // =32
     rect = new RectangleF((bmp.Width - s.Width) / 2F,
      (bmp.Height - s.Height) / 2F,
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.MiddleRight: //=64
     rect = new RectangleF((bmp.Width - s.Width) - (f.Size * 0.1F),
      (bmp.Height - s.Height) / 2F,
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.BottomLeft: // =256  and 128?;
     rect = new RectangleF(f.Size * 0.15F,
      (bmp.Height - s.Height) - (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.BottomCenter: // =512
     rect = new RectangleF((bmp.Width - s.Width) / 2F,
      (bmp.Height - s.Height) - (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    case ContentAlignment.BottomRight: // =1024
     rect = new RectangleF((bmp.Width - s.Width) - (f.Size * 0.1F),
      (bmp.Height - s.Height) - (f.Size * 0.1F),
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
    default:;
     rect = new RectangleF((bmp.Width - s.Width) / 2F,
      (bmp.Height - s.Height) / 2F,
      layout.Width,
      ((float)bmp.Height) * SQRTFill);
     break;
   }

   // Add rendering hint (thx to Thomas)
   g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;

   if ( AddShadow )
   {
    // Add "drop shadow" at half transparency and offset by 1/10 font size
    SolidBrush  shadow = new SolidBrush(Color.FromArgb((int)(alpha / 2.0), OverlayColor));
    RectangleF  sRect = new RectangleF((float)rect.X - (f.Size * 0.1F), (float)rect.Y - (f.Size * 0.1F), rect.Width, rect.Height);
    g.DrawString(OverlayText, f, shadow, sRect, strFormat);
   }

   // finally, draw centered text!
   g.DrawString(OverlayText, f, b, rect, strFormat);

   // clean-up
   g.Dispose();
   b.Dispose();
   f.Dispose();
   return bmp;
  }
  else
  {
   // nothing to overlay!  regurgitate image
   return new Bitmap(bmp);
  }
 }
}