问题描述

求一个C#生成印章的代码

我在做一个模拟真实印章效果的小程序,需要能看起来类似真实的印章效果。哪位有这方面的代码求赏赐。
要求：1、印章的颜色要跟真实印章效果类似，能模拟真实印章的颜色不均匀。
2、背景要能透明，即要像真实的盖在纸上的印章，能看到底下的文字。

解决方案

很简单，创建一个带透明颜色的位图，画上圆圈、文字和五角星，颜色这个不好说，不同的显示器，不同人的判断都不同，你选一个差不多就可以。然后随机将某些地方设置为透明色，模仿不均匀的效果
最后将这个图层和你的背景文档合成下，用drawimage绘图。

解决方案二：

估计网上生成的电子印章，都不能满足你的要求。
特别是颜色要跟真实印章效果类似！可行方法就是实物拍照，获取印章的底色。然后再完成其它元素增加到底色上的过程。

解决方案三：

页面：
using System;

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void uploadFileBtn_Click(object sender, EventArgs e)
{
    if (FileUpload1.HasFile)
    {
        string contentType = FileUpload1.PostedFile.ContentType;
        if (contentType.StartsWith("image/"))
        {
            string filePath = Server.MapPath(string.Format("~/{0}", FileUpload1.PostedFile.FileName));
            ///保存文件
            FileUpload1.SaveAs(filePath);
            ///加水印
            this.AddWatermark(filePath, this.watermarkTextBox.Text);
            image.ImageUrl = string.Format("~/{0}", FileUpload1.PostedFile.FileName);
         }
    }
}

/**/
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImagePath">源图路径（物理路径）</param>
/// <param name="thumbnailPath">缩略图路径（物理路径）</param>
/// <param name="width">缩略图宽度</param>
/// <param name="height">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
{
    System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

    int towidth = width;
    int toheight = height;

    int x = 0;
    int y = 0;
    int ow = originalImage.Width;
    int oh = originalImage.Height;

    switch (mode)
    {
        case "HW"://指定高宽缩放（可能变形）
            break;
        case "W"://指定宽，高按比例
            toheight = originalImage.Height * width / originalImage.Width;
            break;
        case "H"://指定高，宽按比例
            towidth = originalImage.Width * height / originalImage.Height;
            break;
        case "Cut"://指定高宽裁减（不变形）
            if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
            {
                oh = originalImage.Height;
                ow = originalImage.Height * towidth / toheight;
                y = 0;
                x = (originalImage.Width - ow) / 2;
            }
            else
            {
                ow = originalImage.Width;
                oh = originalImage.Width * height / towidth;
                x = 0;
                y = (originalImage.Height - oh) / 2;
            }
            break;
        default:
            break;
    }

    //新建一个bmp图片
    System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

    //新建一个画板
    System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);

    //设置高质量插值法
    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

    //设置高质量,低速度呈现平滑程度
    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

    //清空画布并以透明背景色填充
    g.Clear(System.Drawing.Color.Transparent);

    //在指定位置并且按指定大小绘制原图片的指定部分
    g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight),
        new System.Drawing.Rectangle(x, y, ow, oh),
        System.Drawing.GraphicsUnit.Pixel);

    try
    {
        //以jpg格式保存缩略图
        bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
    }
    catch (System.Exception e)
    {
        throw e;
    }
    finally
    {
        originalImage.Dispose();
        bitmap.Dispose();
        g.Dispose();
    }
}

/// <summary>
/// 添加水印
/// </summary>
/// <param name="filePath"></param>
/// <param name="watermaterText"></param>
private void AddWatermark(string filePath, string watermaterText)
{
    using (TextWatermarkPainter painter = new TextWatermarkPainter(filePath, 80, watermaterText))
    {
        painter.FontColor = System.Drawing.Color.Gray;
        painter.PaintWaterMark();
    }

}

}

解决方案四：

写文字水印

 using System.Drawing;

/// <summary>
    /// 添加文字水印
    /// </summary>

public sealed class TextWatermarkPainter : WatermarkPainter
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="rawImagePath"></param>
        /// <param name="alpha"></param>
        /// <param name="text"></param>
        public TextWatermarkPainter(string rawImagePath, int alpha, string text)
            : base(rawImagePath, alpha)
        {
            WatermarkText = text;
        }

        private Font m_Font;

        /// <summary>
        /// 水印文字的字体
        /// </summary>
        public Font Font
        {
            get
            {
                if (null == m_Font)
                    m_Font = new Font("Arial Black", 30, FontStyle.Bold, GraphicsUnit.Pixel);
                return m_Font;
            }
            set { m_Font = value; }
        }

        private Color m_FontColor;

        /// <summary>
        /// 字体颜色
        /// </summary>
        public Color FontColor
        {
            get
            {
                if (m_FontColor == null)
                    m_FontColor = Color.DarkSeaGreen;
                return m_FontColor;
            }
            set { m_FontColor = value; }
        }

        private string m_WatermarkText;

        /// <summary>
        /// 水印的文字
        /// </summary>
        public string WatermarkText
        {
            get { return m_WatermarkText; }
            set { m_WatermarkText = value; }
        }

        /// <summary>
        /// 实现添加水印的方法
        /// </summary>
        /// <param name="graphics"></param>
        /// <param name="newImage"></param>
        /// <returns></returns>
        protected override bool AddWatermark(Graphics graphics, Bitmap newImage)
        {
            if (string.IsNullOrEmpty(WatermarkText))
                return true;
            using (SolidBrush brush = new SolidBrush(Color.FromArgb(WatermarkAlpha, FontColor.R, FontColor.G, FontColor.B)))
            {
                Font font;
                ///添加文字位置
                PointF f = new PointF();
                float totalWidth = Font.Size * WatermarkText.Length;
                f.X = newImage.Width - totalWidth - 100;
                f.Y = newImage.Height - Font.Height;
                if (f.X < 0)
                {
                    ///自动调整字体的大小
                    float width = newImage.Width / WatermarkText.Length;
                    font = new Font(Font.FontFamily, width, GraphicsUnit.Pixel);
                }
                else
                    font = Font;
                graphics.DrawString(WatermarkText, font, brush, f);
            }
            return true;
        }

        #region IDisposable 成员

        public override void Dispose()
        {
            Font.Dispose();
            base.Dispose();
        }

        #endregion
    }

解决方案五：

图标水印

 using System;
using System.Drawing;
using System.IO;

/// <summary>
/// 图片水印绘制器
/// </summary>
public abstract class WatermarkPainter : IDisposable
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="rawImagePath"></param>
        /// <param name="alpha"></param>
        /// <param name="replaceRawImage"></param>
        protected WatermarkPainter(string rawImagePath, int alpha, bool replaceRawImage)
        {
            ImageToBePainted = rawImagePath;
            WatermarkAlpha = alpha;
            ReplaceRawImage = replaceRawImage;
        }

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="rawImagePath"></param>
        /// <param name="alpha"></param>
        protected WatermarkPainter(string rawImagePath, int alpha)
            : this(rawImagePath, alpha, true)
        { }

        /// <summary>
        /// 为临时存储文件添加的后缀
        /// </summary>
        private string m_TempFileSuffix = ".juice.watermark.temp";

        /// <summary>
        /// 水印的透明度
        /// </summary>
        private int m_WatermarkAlpha;

        /// <summary>
        /// 水印透明度
        /// </summary>
        public int WatermarkAlpha
        {
            get
            {
                if (m_WatermarkAlpha > 255)
                    m_WatermarkAlpha = 255;
                else if (m_WatermarkAlpha < 0)
                    m_WatermarkAlpha = 0;
                return m_WatermarkAlpha;
            }
            set { m_WatermarkAlpha = value; }
        }

        private string m_ImageToBePainted;

        /// <summary>
        /// 添加水印的图片的物理路径
        /// </summary>
        public string ImageToBePainted
        {
            get { return m_ImageToBePainted; }
            set { m_ImageToBePainted = value; }
        }

        private bool m_ReplaceRawImage;

        /// <summary>
        /// 是否用加了水印的图片替换原有的图片
        /// </summary>
        public bool ReplaceRawImage
        {
            get { return m_ReplaceRawImage; }
            set { m_ReplaceRawImage = value; }
        }

        private string m_TempImagePath;

        /// <summary>
        /// 加了水印后的临时储存名称
        /// </summary>
        protected string TempImagePath
        {
            get
            {
                if (string.IsNullOrEmpty(this.m_TempImagePath))
                {
                    System.Text.StringBuilder s = new System.Text.StringBuilder(ImageToBePainted);
                    s.Append(this.m_TempFileSuffix);
                    this.m_TempImagePath = s.ToString();
                }
                return m_TempImagePath;
            }
            set { m_TempImagePath = value; }
        }

        /// <summary>
        /// 原始图像
        /// </summary>
        private Image m_RawImage;

        /// <summary>
        /// 为图片添加水印
        /// </summary>
        public void PaintWaterMark()
        {
            if (string.IsNullOrEmpty(ImageToBePainted))
                return;
            if (!File.Exists(ImageToBePainted))
                throw new FileNotFoundException(string.Format("file {0} not found.", ImageToBePainted));
            bool succeed;
            if (m_RawImage == null)
                m_RawImage = Image.FromFile(ImageToBePainted);
            ///原始的图片
            using (Bitmap newImage = new Bitmap(m_RawImage.Width, m_RawImage.Height))
            {
                ///创建绘制图片的图面
                using (Graphics g = Graphics.FromImage(newImage))
                {
                    g.DrawImage(m_RawImage, 0, 0, m_RawImage.Width, m_RawImage.Height);
                    ///开始绘制水印
                    succeed = AddWatermark(g, newImage);
                }
                if (succeed)
                    ///将图片保存到临时的文件
                    newImage.Save(TempImagePath);
                if (m_RawImage != null)
                    m_RawImage.Dispose();
            }
            if (succeed && ReplaceRawImage)
            {
                //删除原来的文件
                if (File.Exists(ImageToBePainted))
                    File.Delete(ImageToBePainted);
                FileInfo info = new FileInfo(TempImagePath);
                if (info.Exists)
                {
                    info.MoveTo(ImageToBePainted);
                }
            }

        }

        /// <summary>
        /// 添加水印，继承类可以用来添加自己的水印
        /// </summary>
        /// <param name="graphics"></param>
        /// <param name="newImage"></param>
        /// <returns></returns>
        protected abstract bool AddWatermark(Graphics graphics, Bitmap newImage);

        #region IDisposable 成员

        public virtual void Dispose()
        {

        }

        #endregion
    }