多次寫文字到圖片上的水印效果

1.方法   

    /// <summary>
    /// 在圖片上添加水印文字
    /// </summary>
    /// <param name="sourcePicture">源圖片文件</param>
    /// <param name="waterWords">需要添加到圖片上的文字</param>
    /// <param name="fontSize">字體大小</param>
    /// <param name="paddingLeft">文字離左邊的距離</param>
    /// <param name="paddingTop">文字離上邊的距離</param>
    /// <param name="alpha">透明度</param>
    /// <param name="color">文字顏色</param>
    /// <param name="PicturePath">文件路徑</param>
    /// <param name="bSave">是否保存</param>
    /// <param name="fileName">保存文件名稱</param>
    /// <param name="img">圖片文件對象</param>
    /// <returns>返回文件保存路徑，如果不保存，則返回爲string.Empty</returns>
    public string DrawWords(string sourcePicture, string waterWords, float fontSize, float paddingLeft, float paddingTop, float alpha,Color color, string PicturePath,bool bSave,string fileName, ref Image img)
    {       
        //創建一個圖片對象用來裝載要被添加水印的圖片
        Image imgPhoto = null;
        string targetImage = string.Empty;      

        if (img != null)
        {
            imgPhoto = img;
        }
       
        if (img == null || bSave)
        {
            // 判斷參數是否有效
            if (sourcePicture == string.Empty || waterWords == string.Empty || alpha == 0.0 ||
                (bSave && PicturePath == string.Empty))
            {
                return targetImage;
            }

            // 源圖片全路徑
            string sourcePictureName = PicturePath + sourcePicture;
            targetImage = sourcePictureName.Replace(System.IO.Path.GetExtension(sourcePictureName), "") + fileName;

            if (img == null)
            {
                imgPhoto = Image.FromFile(sourcePictureName);
            }
        }

        //獲取圖片的寬和高
        int phWidth = imgPhoto.Width;
        int phHeight = imgPhoto.Height;

        //建立一個bitmap，和我們需要加水印的圖片一樣大小
        Bitmap bmPhoto = new Bitmap(phWidth, phHeight, PixelFormat.Format24bppRgb);

        //SetResolution：設置此 Bitmap 的分辨率
        //這裏直接將我們需要添加水印的圖片的分辨率賦給了bitmap
        bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

        //Graphics：封裝一個 GDI+ 繪圖圖面。
        Graphics grPhoto = Graphics.FromImage(bmPhoto);

        //設置圖形的品質
        grPhoto.SmoothingMode = SmoothingMode.AntiAlias;

        //將我們要添加水印的圖片按照原始大小描繪（複製）到圖形中
        grPhoto.DrawImage(
         imgPhoto,                                           //   要添加水印的圖片
         new Rectangle(0, 0, phWidth, phHeight), //  根據要添加的水印圖片的寬和高
         0,                                                     //  X方向從0點開始描繪
         0,                                                     // Y方向
         phWidth,                                            //  X方向描繪長度
         phHeight,                                           //  Y方向描繪長度
         GraphicsUnit.Pixel);                              // 描繪的單位，這裏用的是像素
       
        //字體
        Font crFont = null;
        //矩形的寬度和高度，SizeF有三個屬性，分別爲Height高，width寬，IsEmpty是否爲空
        SizeF crSize = new SizeF();

        //直到它的長度比圖片的寬度小
        crFont = new Font("arial", fontSize, FontStyle.Regular);
        //測量用指定的 Font 對象繪製並用指定的 StringFormat 對象格式化的指定字符串。
        crSize = grPhoto.MeasureString(waterWords, crFont);

        //截邊5%的距離，定義文字顯示(由於不同的圖片顯示的高和寬不同，所以按百分比截取)
        int yPixlesFromBottom = (int)(phHeight * .05);

        //定義在圖片上文字的大小
        float wmHeight = crSize.Height;
        float wmWidth = crSize.Width;

        //定義在圖片上文字的位置
        float xPosOfWm;
        float yPosOfWm;

        if (paddingLeft > 0)
        {
            xPosOfWm = paddingLeft;
        }
        else
        {
            xPosOfWm = phWidth / 2;
        }

        if (paddingTop > 0)
        {
            yPosOfWm = paddingTop;
        }
        else
        {
            yPosOfWm = phHeight / 2;
        }
       
        //封裝文本佈局信息（如對齊、文字方向和 Tab 停靠位），顯示操作（如省略號插入和國家標準 (National) 數字替換）和 OpenType 功能。
        StringFormat StrFormat = new StringFormat();

        //定義需要印的文字居中對齊
        StrFormat.Alignment = StringAlignment.Center;

        //SolidBrush:定義單色畫筆。畫筆用於填充圖形形狀，如矩形、橢圓、扇形、多邊形和封閉路徑。
        //這個畫筆爲描繪陰影的畫筆，呈灰色
        int m_alpha = Convert.ToInt32(256 * alpha);

        //從四個 ARGB 分量（alpha、紅色、綠色和藍色）值創建 Color 結構，這裏設置透明度爲153
        //這個畫筆爲描繪正式文字的筆刷，呈白色
        SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(m_alpha, color.R, color.G, color.B));

        //第二次繪製這個圖形，建立在第一次描繪的基礎上
        grPhoto.DrawString(waterWords,                 //string of text
                                   crFont,                                   //font
                                   semiTransBrush,                           //Brush
                                   new PointF(xPosOfWm, yPosOfWm),  //Position
                                   StrFormat);

        //imgPhoto是我們建立的用來裝載最終圖形的Image對象
        //bmPhoto是我們用來製作圖形的容器，爲Bitmap對象
        imgPhoto = bmPhoto;
        //釋放資源，將定義的Graphics實例grPhoto釋放，grPhoto功德圓滿
        grPhoto.Dispose();

        if (bSave)
        {
            //將grPhoto保存
            imgPhoto.Save(targetImage, ImageFormat.Jpeg);
        }
        img = imgPhoto;

        return bSave ? targetImage.Replace(PicturePath, "") : string.Empty;
    }

 

2.調用：

           WaterImageManage water = new WaterImageManage();
            Image img = null;
            water.DrawWords("123.jpg", "姓名：張三", 26, 0, 200, 0.8f, Color.Red, MapPath("/Images/"), false, string.Empty, ref img);
            water.DrawWords("", "手機：[phone]", 26, 0, 200, 0.8f, Color.Red, MapPath("/Images/"), false, string.Empty, ref img);
            water.DrawWords("", "QQ：8474939612", 20, 0, 240, 0.8f, Color.Black, MapPath("/Images/"), true, "123456.jpg", ref img);