参考Knight 的代码如下：
生成印章准备的类文件：
namespace Seal
...{
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Diagnostics;
/**////
/// Summary description for TextOnSeal.
///
public class TextOnSeal
...{
private string _text;
private Font _font;
private Color _pathcolor = Color.Red;
private Color _color = Color.Black;
private Color _fillcolor = Color.Black;
private int _letterspace = 10;
private bool _showpath = true;
private Rectangle _rectcircle;
private Rectangle _rect;
private int _intentlength = 10;
private Char_Direction _chardirect = Char_Direction.Center;
private int _degree = 90;
private string _basestring;
Class_Properties#region Class_Properties
public Char_Direction CharDirection
...{
get ...{ return _chardirect; }
set
...{
if (_chardirect != value)
...{
_chardirect = value;
switch (_chardirect)
...{
case Char_Direction.Center:
_degree = 90;
break;
case Char_Direction.ClockWise:
_degree = 0;
break;
case Char_Direction.OutSide:
_degree = -90;
break;
case Char_Direction.AntiClockWise:
_degree = 180;
break;
}
}
}
}
public string BaseString
...{
get ...{ return _basestring; }
set ...{ _basestring = value; }
}
public string Text
...{
get ...{ return _text; }
set ...{ _text = value; }
}
public Font TextFont
...{
get ...{ return _font; }
set ...{ _font = value; }
}
public Color PathColor
...{
get ...{ return _pathcolor; }
set ...{ _pathcolor = value; }
}
public Color ColorTOP
...{
get ...{ return _color; }
set ...{ _color = value; }
}
public Color FillColor
...{
get ...{ return _fillcolor; }
set ...{ _fillcolor = value; }
}
public int LetterSpace
...{
get ...{ return _letterspace; }
set ...{ _letterspace = value; }
}
public bool ShowPath
...{
get ...{ return _showpath; }
set ...{ _showpath = value; }
}
public int SealSize
...{
set
...{
_rect = new Rectangle(0, 0, value, value);
_rectcircle = new Rectangle(
new Point(_rect.X + _intentlength, _rect.Y + _intentlength),
new Size(_rect.Width - 2 * _intentlength, _rect.Height - 2 * _intentlength));
}
}
#endregion {Class_Properties}
public void SetIndent(int IntentLength)
...{
_intentlength = IntentLength;
_rectcircle = new Rectangle(_intentlength, _intentlength,
_rect.Width - _intentlength * 2, _rect.Height - _intentlength * 2);
}
public TextOnSeal()
...{
}
public Bitmap TextOnPathBitmap(
Rectangle rectCircle,
string strText,
Font fntText,
Color clrColor,
Color clrFill,
int nPercentage)
...{
_rect = rectCircle;
_rectcircle = new Rectangle(
new Point(_rect.X + _intentlength, _rect.Y + _intentlength),
new Size(_rect.Width - 2 * _intentlength, _rect.Height - 2 * _intentlength));
_text = strText;
_font = fntText;
_color = clrColor;
_fillcolor = clrFill;
_letterspace = nPercentage;
return TextOnPathBitmap();
}
/**////
/// Compute string total length and every char length
///
///
///
///
///
///
private float ComputeStringLength(string sText, Graphics g, float[] fCharWidth,
float fIntervalWidth,
Char_Direction Direction)
...{
// Init string format
StringFormat sf = new StringFormat();
sf.Trimming = StringTrimming.None;
sf.FormatFlags = StringFormatFlags.NoClip | StringFormatFlags.NoWrap
| StringFormatFlags.LineLimit;
// Measure whole string length
SizeF size = g.MeasureString(sText, _font, (int)_font.Style);
RectangleF rect = new RectangleF(0f, 0f, size.Width, size.Height);
// Measure every character size
CharacterRange[] crs = new CharacterRange[sText.Length];
for (int i = 0; i < sText.Length; i++)
crs[i] = new CharacterRange(i, 1);
// Reset string format
sf.FormatFlags = StringFormatFlags.NoClip;
sf.SetMeasurableCharacterRanges(crs);
sf.Alignment = StringAlignment.Near;
// Get every character size
Region[] regs = g.MeasureCharacterRanges(sText,
_font, rect, sf);
// Re-compute whole string length with space interval width
float fTotalWidth = 0f;
for (int i = 0; i < regs.Length; i++)
...{
if (Direction == Char_Direction.Center || Direction == Char_Direction.OutSide)
fCharWidth[i] = regs[i].GetBounds(g).Width;
else
fCharWidth[i] = regs[i].GetBounds(g).Height;
fTotalWidth += fCharWidth[i] + fIntervalWidth;
}
fTotalWidth -= fIntervalWidth;//Remove the last interval width
return fTotalWidth;
}
/**////
/// Compute every char position
///
///
///
///
///
private void ComputeCharPos(
float[] CharWidth,
PointF[] recChars,
double[] CharAngle,
double StartAngle)
...{
double fSweepAngle, fCircleLength;
//Compute the circumference
fCircleLength = _rectcircle.Width * Math.PI;
for (int i = 0; i < CharWidth.Length; i++)
...{
//Get char sweep angle
fSweepAngle = CharWidth[i] * 360 / fCircleLength;
//Set point angle
CharAngle[i] = StartAngle + fSweepAngle / 2;
//Get char position
if (CharAngle[i] < 270f)
recChars[i] = new PointF(
_rectcircle.X + _rectcircle.Width / 2
- (float)(_rectcircle.Width / 2 *
Math.Sin(Math.Abs(CharAngle[i] - 270) * Math.PI / 180)),
_rectcircle.Y + _rectcircle.Width / 2
- (float)(_rectcircle.Width / 2 * Math.Cos(
Math.Abs(CharAngle[i] - 270) * Math.PI / 180)));
else
recChars[i] = new PointF(
_rectcircle.X + _rectcircle.Width / 2
+ (float)(_rectcircle.Width / 2 *
Math.Sin(Math.Abs(CharAngle[i] - 270) * Math.PI / 180)),
_rectcircle.Y + _rectcircle.Width / 2
- (float)(_rectcircle.Width / 2 * Math.Cos(
Math.Abs(CharAngle[i] - 270) * Math.PI / 180)));
//Get total sweep angle with interval space
fSweepAngle = (CharWidth[i] + _letterspace) * 360 / fCircleLength;
StartAngle += fSweepAngle;
}
}
/**////
/// Generate seal bitmap
///
///
public Bitmap TextOnPathBitmap()
...{
// Create bitmap and graphics
Bitmap bit = new Bitmap(_rect.Width, _rect.Height);
Graphics g = Graphics.FromImage(bit);
// Compute string length in graphics
float[] fCharWidth = new float[_text.Length];
float fTotalWidth = ComputeStringLength(_text, g, fCharWidth,
_letterspace, _chardirect);
// Compute arc's start-angle and end-angle
double fStartAngle, fSweepAngle;
fSweepAngle = fTotalWidth * 360 / (_rectcircle.Width * Math.PI);
fStartAngle = 270 - fSweepAngle / 2;
// Compute every character's position and angle
PointF[] pntChars = new PointF[_text.Length];
double[] fCharAngle = new double[_text.Length];
ComputeCharPos(fCharWidth, pntChars, fCharAngle, fStartAngle);
g.SmoothingMode = SmoothingMode.HighQuality;
g.CompositingQuality = CompositingQuality.HighQuality;
g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
DrawSealBase(g);
// Draw every character
for (int i = 0; i < _text.Length; i++)
DrawRotatedText(g, _text[i].ToString(), (float)(fCharAngle[i] + _degree), pntChars[i]);
g.Dispose();
// Return bitmap
return bit;
}
/**////
/// Draw seal base
///
///
private void DrawSealBase(Graphics g)
...{
// Draw background
g.FillRectangle(Brushes.Black, _rect);
g.FillEllipse(new SolidBrush(_fillcolor),
new Rectangle(1, 1, _rect.Width - 2, _rect.Height - 2));
g.FillEllipse(Brushes.White,
new Rectangle(4, 4, _rect.Width - 8, _rect.Height - 8));
// Draw start signal
StringFormat sf = new StringFormat();
string strStar = "★";
Font fnt = new Font(_font.FontFamily, _font.Size * 3);
sf.Alignment = StringAlignment.Center;
sf.LineAlignment = StringAlignment.Center;
SizeF siz = g.MeasureString(strStar, fnt);
g.DrawString(strStar, fnt, new SolidBrush(_fillcolor),
new RectangleF(_rect.Width / 2 - siz.Width / 2,
_rect.Height / 2 - siz.Height / 2,
siz.Width, siz.Height), sf);
// Draw base string
float[] fCharWidth = new float[_basestring.Length];
float fTotalWidths = ComputeStringLength(_basestring, g, fCharWidth, 0,
Char_Direction.Center);
float fLeftPos = (_rect.Width - fTotalWidths) / 2;
PointF pt;
for (int i = 0; i < _basestring.Length; i++)
...{
pt = new PointF(fLeftPos + fCharWidth[i] / 2,
_rect.Height / 2 + siz.Height / 2 + 10);
DrawRotatedText(g, _basestring[i].ToString(), 0, pt);
fLeftPos += fCharWidth[i];
}
}
/**////
/// Draw every rotated character
///
///
///
///
///
private void DrawRotatedText(Graphics g, string _text, float _angle, PointF _PointCenter)
...{
StringFormat sf = new StringFormat();
sf.Alignment = StringAlignment.Center;
sf.LineAlignment = StringAlignment.Center;
GraphicsPath gp = new GraphicsPath(System.Drawing.Drawing2D.FillMode.Winding);
int x = (int)_PointCenter.X;
int y = (int)_PointCenter.Y;
gp.AddString(_text, _font.FontFamily, (int)_font.Style,
_font.Size, new Point(x, y), sf);
Matrix m = new Matrix();
m.RotateAt(_angle, new PointF(x, y));
g.Transform = m;
g.DrawPath(new Pen(_color), gp);
g.FillPath(new SolidBrush(_fillcolor), gp);
}
}
public enum Char_Direction
...{
Center = 0,
OutSide = 1,
ClockWise = 2,
AntiClockWise = 3,
}
}
Web 调用方法如下：
TextOnSeal _top = new TextOnSeal();
_top.TextFont = new Font("宋体", 20, FontStyle.Regular);
_top.FillColor = Color.Red;
_top.ColorTOP = Color.Black;
_top.Text = "北京拓创股份有限公司";
_top.BaseString = "邹氏印章";
_top.ShowPath = true;
_top.LetterSpace = 5;
_top.SealSize = 220;
_top.CharDirection = Char_Direction.Center;
_top.SetIndent(20);
//Graphics g = this.CreateGraphics();
//g.DrawImage(_top.TextOnPathBitmap(), 0, 0);
//画图初始化
Bitmap bMap = new Bitmap(500, 500);
Graphics gph = Graphics.FromImage(bMap);
gph.Clear(Color.White);
gph.DrawImage(_top.TextOnPathBitmap(), 0, 0);
//保存输出图片
bMap.Save(Response.OutputStream, ImageFormat.Gif);
显示结果如下：
本文作者:佚名 来源:http://www.zu14.cn/2008/11/05/net_mail/
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