绘制每个字符

由于每个字符所在的点以及相对于圆心的角度都已经计算出来，那么进行绘制就相对简单多了，这里只是通过Matrix来转换一下坐标而已。

具体代码如下。

    /// <summary>

    /// Draw every rotated character

    /// </summary>

    /// <param name="g"></param>

    /// <param name="_text"></param>

    /// <param name="_angle"></param>

    /// <param name="_PointCenter"></param>

    private void DrawRotatedText( Graphics g, string _text, float _angle, PointF _PointCenter )

    {

        // Init format

        StringFormat sf = new StringFormat();

        sf.Alignment = StringAlignment.Center;

        sf.LineAlignment = StringAlignment.Center;

        // Create graphics path

        GraphicsPath gp = new GraphicsPath( System.Drawing.Drawing2D.FillMode.Winding );

        int x = (int)_PointCenter.X;

        int y = (int)_PointCenter.Y;

        // Add string

        gp.AddString( _text, _font.FontFamily, (int)_font.Style,

            _font.Size, new Point( x, y ), sf );

        // Rotate string and draw it

        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 );

    }

以上就是绘制印章的核心算法。对于这个类的调用，如下即可。

    TextOnSeal _top = new TextOnSeal();

    _top.TextFont = new Font("宋体", 16, FontStyle.Regular);

    _top.FillColor = Color.Red;

    _top.ColorTOP = Color.Black;

    _top.Text = "中华人民共和国";

    _top.BaseString = "愚翁专用章";

    _top.ShowPath = true;

    _top.LetterSpace = 20;

    _top.SealSize = 180;

    _top.CharDirection = Char_Direction.Center;

    _top.SetIndent( 20 );

    Graphics g = this.CreateGraphics();

    g.DrawImage( _top.TextOnPathBitmap(), 0, 0 );

    _top.CharDirection = Char_Direction.ClockWise;

    g.DrawImage( _top.TextOnPathBitmap(), 180, 0 );

    _top.CharDirection = Char_Direction.AntiClockWise;

    g.DrawImage( _top.TextOnPathBitmap(), 0, 180 );

    _top.SetIndent( 20 );

    _top.CharDirection = Char_Direction.OutSide;

    g.DrawImage( _top.TextOnPathBitmap(), 180, 180 );

通过如上的代码，可以得到如下的效果。

其实如果做印章来说，还有很多地方需要细化，那么如果网友对此有兴趣，可以在我的基础上进行扩展，在此我就不一一述说。