C# System.Drawing.Drawing2D.GraphicsPath.Warp方法代码示例

        protected void GenerateImage()
        {
            Random random = new Random();
            // Create a new 32-bit bitmap image.
            Bitmap bitmap = new Bitmap(230,37,PixelFormat.Format32bppArgb);

            // Create a graphics object for drawing.
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            Rectangle rect = new Rectangle(0, 0, 230, 37);

            // Fill in the background.
            System.Drawing.Drawing2D.HatchBrush hatchBrush = new System.Drawing.Drawing2D.HatchBrush(System.Drawing.Drawing2D.HatchStyle.Percent50, Color.LightGray, Color.White);
            //SolidBrush hatchBrush = new SolidBrush(Color.Red);

            String strText =(String)Session["ImageSID"];
            g.FillRectangle(hatchBrush, rect);

            // Set up the text font.
            SizeF size;
            float fontSize = rect.Height -12;
            // Adjust the font size until the text fits within the image.
             Font font = new Font("Century Schoolbook",fontSize, FontStyle.Bold);
                size = g.MeasureString(strText, font);
            // Set up the text format.
            StringFormat format = new StringFormat();
            format.Alignment = StringAlignment.Center;
            format.LineAlignment = StringAlignment.Center;

            // Create a path using the text and warp it randomly.
            System.Drawing.Drawing2D.GraphicsPath path = new System.Drawing.Drawing2D.GraphicsPath();
            path.AddString(
              strText,
              font.FontFamily,
              (int)font.Style,
              font.Size, rect,
              format);
            float v = 12F;
            PointF[] points =
              {
            new PointF(
              random.Next(rect.Width) / v,
              random.Next(rect.Height) / v),
            new PointF(
              rect.Width - random.Next(rect.Width) / v,
              random.Next(rect.Height) / v),
            new PointF(
              random.Next(rect.Width) / v,
              rect.Height - random.Next(rect.Height) / v),
            new PointF(
              rect.Width - random.Next(rect.Width) / v,
              rect.Height - random.Next(rect.Height) / v)
              };
            //points={0,0,0,0};
            System.Drawing.Drawing2D.Matrix matrix = new System.Drawing.Drawing2D.Matrix();
            matrix.Translate(0F, 0F);
            path.Warp(points, rect, matrix, System.Drawing.Drawing2D.WarpMode.Perspective, 0F);

            // Draw the text.
            hatchBrush = new System.Drawing.Drawing2D.HatchBrush(
              System.Drawing.Drawing2D.HatchStyle.Percent50,
              Color.LightSlateGray,
              Color.DarkGray);
            g.FillPath(hatchBrush, path);

            // Add some random noise.
            int m = Math.Max(rect.Width, rect.Height);
            for (int i = 0; i < (int)(rect.Width * rect.Height / 30F); i++)
            {
                int x = random.Next(rect.Width);
                int y = random.Next(rect.Height);
                int w = random.Next(m / 50);
                int h = random.Next(m / 50);
                g.FillEllipse(hatchBrush, x, y, w, h);
            }

            // Clean up.
            font.Dispose();
            hatchBrush.Dispose();
            g.Dispose();

            // Set the image.
            this.Response.Clear();
            this.Response.ContentType = "image/jpeg";

            // Write the image to the response stream in JPEG format.
            bitmap.Save(this.Response.OutputStream, ImageFormat.Jpeg);

            // Dispose of the CAPTCHA image object.
            bitmap.Dispose();
        }

        private byte[] GenerateCaptchaImage(string text, int width, int height)
        {
            Random random = new Random(int.Parse(Guid.NewGuid().ToString().Substring(0, 8), System.Globalization.NumberStyles.HexNumber));

            System.Drawing.Font font;
            System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
            System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(bmp);
            graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            System.Drawing.Rectangle rect = new System.Drawing.Rectangle(0, 0, width, height);
            System.Drawing.Drawing2D.HatchBrush brush = new System.Drawing.Drawing2D.HatchBrush(System.Drawing.Drawing2D.HatchStyle.SmallConfetti, System.Drawing.Color.LightGray, System.Drawing.Color.White);
            graphics.FillRectangle(brush, rect);

            float emSize = rect.Height + 1;

            do {
                emSize--;
                font = new System.Drawing.Font(System.Drawing.FontFamily.GenericSansSerif, emSize, System.Drawing.FontStyle.Bold);
            } while (graphics.MeasureString(text, font).Width > rect.Width);

            System.Drawing.StringFormat format = new System.Drawing.StringFormat {
                Alignment = System.Drawing.StringAlignment.Center,
                LineAlignment = System.Drawing.StringAlignment.Center
            };

            System.Drawing.Drawing2D.GraphicsPath path = new System.Drawing.Drawing2D.GraphicsPath();
            path.AddString(text, font.FontFamily, (int)font.Style, 75f, rect, format);
            float num2 = 4f;
            System.Drawing.PointF[] destPoints = new System.Drawing.PointF[] { new System.Drawing.PointF(((float)random.Next(rect.Width)) / num2, ((float)random.Next(rect.Height)) / num2), new System.Drawing.PointF(rect.Width - (((float)random.Next(rect.Width)) / num2), ((float)random.Next(rect.Height)) / num2), new System.Drawing.PointF(((float)random.Next(rect.Width)) / num2, rect.Height - (((float)random.Next(rect.Height)) / num2)), new System.Drawing.PointF(rect.Width - (((float)random.Next(rect.Width)) / num2), rect.Height - (((float)random.Next(rect.Height)) / num2)) };
            System.Drawing.Drawing2D.Matrix matrix = new System.Drawing.Drawing2D.Matrix();
            matrix.Translate(0f, 0f);
            path.Warp(destPoints, rect, matrix, System.Drawing.Drawing2D.WarpMode.Perspective, 0f);
            brush = new System.Drawing.Drawing2D.HatchBrush(System.Drawing.Drawing2D.HatchStyle.Percent10, System.Drawing.Color.Black, System.Drawing.Color.SkyBlue);
            graphics.FillPath(brush, path);

            int num3 = Math.Max(rect.Width, rect.Height);
            for (int i = 0; i < ((int)(((float)(rect.Width * rect.Height)) / 30f)); i++) {
                int x = random.Next(rect.Width);
                int y = random.Next(rect.Height);
                int w = random.Next(num3 / 50);
                int h = random.Next(num3 / 50);
                graphics.FillEllipse(brush, x, y, w, h);
            }
            font.Dispose();
            brush.Dispose();
            graphics.Dispose();

            System.IO.MemoryStream imageStream = new System.IO.MemoryStream();
            bmp.Save(imageStream, System.Drawing.Imaging.ImageFormat.Jpeg);

            byte[] imageContent = new Byte[imageStream.Length];
            imageStream.Position = 0;
            imageStream.Read(imageContent, 0, (int)imageStream.Length);
            return imageContent;
        }