关于Textbox 中字体重绘问题 求助

Question

http://blog.163.com/zhoutingshuai@126/blog/static/1068818812010102722230126/

Answer 1

class TextShadow
    {
        private int radius = 5;
        private int distance = 10;
        private double angle = 60;
        private byte alpha = 192;        /// <summary>
        /// 高斯卷积矩阵
        /// </summary>
        private int[] gaussMatrix;
        /// <summary>
        /// 卷积核
        /// </summary>
        private int nuclear = 0;        /// <summary>
        /// 阴影半径
        /// </summary>
        public int Radius
        {
            get
            {
                return radius;
            }
            set
            {
                if (radius != value)
                {
                    radius = value;
                    MakeGaussMatrix();
                }
            }
        }        /// <summary>
        ///  阴影距离
        /// </summary>
        public int Distance
        {
            get
            {
                return distance;
            }
            set
            {
                distance = value;
            }
        }        /// <summary>
        ///  阴影输出角度(左边平行处为0度。顺时针方向)
        /// </summary>
        public double Angle
        {
            get
            {
                return angle;
            }
            set
            {
                angle = value;
            }
        }        /// <summary>
        /// 阴影文字的不透明度
        /// </summary>
        public byte Alpha
        {
            get
            {
                return alpha;
            }
            set
            {
                alpha = value;
            }
        }        /// <summary>
        /// 对文字阴影位图按阴影半径计算的高斯矩阵进行卷积模糊
        /// </summary>
        /// <param name="bmp">文字阴影位图</param>
        private unsafe void MaskShadow(Bitmap bmp)
        {
            if (nuclear == 0)
                MakeGaussMatrix();
            Rectangle r = new Rectangle(0, 0, bmp.Width, bmp.Height);
            // 克隆临时位图，作为卷积源
            Bitmap tmp = (Bitmap)bmp.Clone();
            BitmapData dest = bmp.LockBits(r, ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
            BitmapData source = tmp.LockBits(r, ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
            try
            {
                // 源首地址(0, 0)的Alpha字节，也就是目标首像素的第一个卷积乘数的像素点
                byte* ps = (byte*)source.Scan0;
                ps += 3;
                // 目标地址为卷积半径点(radius, radius)的Alpha字节
                byte* pd = (byte*)dest.Scan0;
                pd += (radius * (dest.Stride + 4) + 3);
                // 位图实际卷积的部分
                int width = dest.Width - radius * 2;
                int height = dest.Height - radius * 2;
                int matrixSize = radius * 2 + 1;
                // 卷积矩阵字节偏移
                int mOffset = dest.Stride - matrixSize * 4;
                // 行尾卷积半径(radius)的偏移
                int rOffset = radius * 8;
                int count = matrixSize * matrixSize;                for (int y = 0; y < height; y++)
                {
                    for (int x = 0; x < width; x++)
                    {                        byte* s = ps - mOffset;
                        int v = 0;
                        for (int i = 0; i < count; i++, s += 4)
                        {
                            if ((i % matrixSize) == 0)
                                s += mOffset;           // 卷积矩阵的换行
                            v += gaussMatrix[i] * *s;   // 位图像素点Alpha的卷积值求和
                        }
                        // 目标位图被卷积像素点Alpha等于卷积和除以卷积核
                        *pd = (byte)(v / nuclear);
                        pd += 4;
                        ps += 4;
                    }
                    pd += rOffset;
                    ps += rOffset;
                }
            }
            finally { }        }        /// <summary>
        /// 按给定的阴影半径生成高斯卷积矩阵
        /// </summary>
        protected virtual void MakeGaussMatrix()
        {
            double Q = (double)radius / 2.0;
            if (Q == 0.0)
                Q = 0.1;
            int n = radius * 2 + 1;
            int index = 0;
            nuclear = 0;
            gaussMatrix = new int[n * n];            for (int x = -radius; x <= radius; x++)
            {
                for (int y = -radius; y <= radius; y++)
                {
                    gaussMatrix[index] = (int)Math.Round(Math.Exp(-((double)x * x + y * y) / (2.0 * Q * Q)) /
                                                         (2.0 * Math.PI * Q * Q) * 1000.0);
                    nuclear += gaussMatrix[index];
                    index++;
                }
            }
        }        public TextShadow()
        {
            //
            // TODO: Add constructor logic here
            //
        }        /// <summary>
        /// 画文字阴影
        /// </summary>
        /// <param name="g">画布</param>
        /// <param name="text">文字串</param>
        /// <param name="font">字体</param>
        /// <param name="layoutRect">文字串的布局矩形</param>
        /// <param name="format">文字串输出格式</param>
        public void Draw(Graphics g, string text, Font font, RectangleF layoutRect, StringFormat format)
    {
        RectangleF sr = new RectangleF((float)(radius * 2), (float)(radius * 2), layoutRect.Width, layoutRect.Height);
        // 根据文字布局矩形长宽扩大文字阴影半径4倍建立一个32位ARGB格式的位图
        Bitmap bmp = new Bitmap((int)sr.Width + radius * 4, (int)sr.Height + radius * 4, PixelFormat.Format32bppArgb);
        // 按文字阴影不透明度建立阴影画刷
        Brush brush = new SolidBrush(Color.FromArgb(alpha, Color.Black));
        Graphics bg = Graphics.FromImage(bmp);
        try
        {
            // 在位图上画文字阴影
            bg.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
            bg.DrawString(text, font, brush, sr, format);
            // 制造阴影模糊
            MaskShadow(bmp);
            // 按文字阴影角度、半径和距离输出文字阴影到给定的画布
            RectangleF dr = layoutRect;
            dr.Offset((float)(Math.Cos(Math.PI * angle / 180.0) * distance),
                      (float)(Math.Sin(Math.PI * angle / 180.0) * distance));
            sr.Inflate((float)radius, (float)radius);
            dr.Inflate((float)radius, (float)radius);
            g.DrawImage(bmp, dr, sr, GraphicsUnit.Pixel);
        }
        finally { }
        
    }        /// <summary>
        /// 画文字阴影
        /// </summary>
        /// <param name="g">画布</param>
        /// <param name="text">文字串</param>
        /// <param name="font">字体</param>
        /// <param name="layoutRect">文字串的布局矩形</param>
        public void Draw(Graphics g, string text, Font font, RectangleF layoutRect)
        {
            Draw(g, text, font, layoutRect, null);
        }        /// <summary>
        /// 画文字阴影
        /// </summary>
        /// <param name="g">画布</param>
        /// <param name="text">文字串</param>
        /// <param name="font">字体</param>
        /// <param name="origin">文字串的输出原点</param>
        /// <param name="format">文字串输出格式</param>
        public void Draw(Graphics g, string text, Font font, PointF origin, StringFormat format)
        {
            RectangleF rect = new RectangleF(origin, g.MeasureString(text, font, origin, format));
            Draw(g, text, font, rect, format);
        }        /// <summary>
        /// 画文字阴影
        /// </summary>
        /// <param name="g">画布</param>
        /// <param name="text">文字串</param>
        /// <param name="font">字体</param>
        /// <param name="origin">文字串的输出原点</param>
        public void Draw(Graphics g, string text, Font font, PointF origin)
        {
            Draw(g, text, font, origin, null);
        }
    }
没弄过这个可以画出阴影拦截消息应该拦截哪些   怎么弄  求解