C#加水印～

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;

namespace Tutorial
{
    class WaterMark
    {

        [STAThread]
        static void Main(string[] args)
        {
            //set a working directory
            string WorkingDirectory = @"C:\Documents and Settings\administrator.JAZZMINE\My Documents\Projects\Tutorials\WaterMark";

            //define a string of text to use as the Copyright message
            string Copyright = "Copyright ?2002 - AP Photo/David Zalubowski";

            //create a image object containing the photograph to watermark
            Image imgPhoto = Image.FromFile(WorkingDirectory + "\\watermark_photo.jpg");
            int phWidth = imgPhoto.Width;
            int phHeight = imgPhoto.Height;

            //create a Bitmap the Size of the original photograph
            Bitmap bmPhoto = new Bitmap(phWidth, phHeight, PixelFormat.Format24bppRgb);

            bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);

            //load the Bitmap into a Graphics object 
            Graphics grPhoto = Graphics.FromImage(bmPhoto);

            //create a image object containing the watermark
            Image imgWatermark = new Bitmap(WorkingDirectory + "\\watermark.bmp");
            int wmWidth = imgWatermark.Width;
            int wmHeight = imgWatermark.Height;

            //------------------------------------------------------------
            //Step #1 - Insert Copyright message
            //------------------------------------------------------------

            //Set the rendering quality for this Graphics object
            grPhoto.SmoothingMode = SmoothingMode.AntiAlias;

            //Draws the photo Image object at original size to the graphics object.
            grPhoto.DrawImage(
                imgPhoto,                               // Photo Image object
                new Rectangle(0, 0, phWidth, phHeight), // Rectangle structure
                0,                                      // x-coordinate of the portion of the source image to draw. 
                0,                                      // y-coordinate of the portion of the source image to draw. 
                phWidth,                                // Width of the portion of the source image to draw. 
                phHeight,                               // Height of the portion of the source image to draw. 
                GraphicsUnit.Pixel);                    // Units of measure 

            //-------------------------------------------------------
            //to maximize the size of the Copyright message we will 
            //test multiple Font sizes to determine the largest posible 
            //font we can use for the width of the Photograph
            //define an array of point sizes you would like to consider as possiblities
            //-------------------------------------------------------
            int[] sizes = new int[]{16,14,12,10,8,6,4};

            Font crFont = null;
            SizeF crSize = new SizeF();

            //Loop through the defined sizes checking the length of the Copyright string
            //If its length in pixles is less then the image width choose this Font size.
            for (int i=0 ;i<7; i++)
            {
                //set a Font object to Arial (i)pt, Bold
                crFont = new Font("arial", sizes[i], FontStyle.Bold);
                //Measure the Copyright string in this Font
                crSize = grPhoto.MeasureString(Copyright, crFont);

                if((ushort)crSize.Width < (ushort)phWidth)
                    break;
            }

            //Since all photographs will have varying heights, determine a 
            //position 5% from the bottom of the image
            int yPixlesFromBottom = (int)(phHeight *.05);

            //Now that we have a point size use the Copyrights string height 
            //to determine a y-coordinate to draw the string of the photograph
            float yPosFromBottom = ((phHeight - yPixlesFromBottom)-(crSize.Height/2));

            //Determine its x-coordinate by calculating the center of the width of the image
            float xCenterOfImg = (phWidth/2);

            //Define the text layout by setting the text alignment to centered
            StringFormat StrFormat = new StringFormat();
            StrFormat.Alignment = StringAlignment.Center;

            //define a Brush which is semi trasparent black (Alpha set to 153)
            SolidBrush semiTransBrush2 = new SolidBrush(Color.FromArgb(153, 0, 0, 0));

            //Draw the Copyright string
            grPhoto.DrawString(Copyright,                 //string of text
                crFont,                                   //font
                semiTransBrush2,                           //Brush
                new PointF(xCenterOfImg+1,yPosFromBottom+1),  //Position
                StrFormat);

            //define a Brush which is semi trasparent white (Alpha set to 153)
            SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(153, 255, 255, 255));

            //Draw the Copyright string a second time to create a shadow effect
            //Make sure to move this text 1 pixel to the right and down 1 pixel
            grPhoto.DrawString(Copyright,                 //string of text
                crFont,                                   //font
                semiTransBrush,                           //Brush
                new PointF(xCenterOfImg,yPosFromBottom),  //Position
                StrFormat);                               //Text alignment

            

            //------------------------------------------------------------
            //Step #2 - Insert Watermark image
            //------------------------------------------------------------

            //Create a Bitmap based on the previously modified photograph Bitmap
            Bitmap bmWatermark = new Bitmap(bmPhoto);
            bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
            //Load this Bitmap into a new Graphic Object
            Graphics grWatermark = Graphics.FromImage(bmWatermark);

            //To achieve a transulcent watermark we will apply (2) color 
            //manipulations by defineing a ImageAttributes object and 
            //seting (2) of its properties.
            ImageAttributes imageAttributes = new ImageAttributes();

            //The first step in manipulating the watermark image is to replace 
            //the background color with one that is trasparent (Alpha=0, R=0, G=0, B=0)
            //to do this we will use a Colormap and use this to define a RemapTable
            ColorMap colorMap = new ColorMap();

            //My watermark was defined with a background of 100% Green this will
            //be the color we search for and replace with transparency
            colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
            colorMap.NewColor = Color.FromArgb(0, 0, 0, 0); 

            ColorMap[] remapTable = {colorMap};

            imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);

            //The second color manipulation is used to change the opacity of the 
            //watermark.  This is done by applying a 5x5 matrix that contains the 
            //coordinates for the RGBA space.  By setting the 3rd row and 3rd column 
            //to 0.3f we achive a level of opacity
            float[][] colorMatrixElements = { 
                                                new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},       
                                                new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},        
                                                new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},        
                                                new float[] {0.0f,  0.0f,  0.0f,  0.3f, 0.0f},        
                                                new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}}; 
            ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);

            imageAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default,
                ColorAdjustType.Bitmap);

            //For this example we will place the watermark in the upper right
            //hand corner of the photograph. offset down 10 pixels and to the 
            //left 10 pixles

            int xPosOfWm = ((phWidth - wmWidth)-10);
            int yPosOfWm = 10;

            grWatermark.DrawImage(imgWatermark, 
                new Rectangle(xPosOfWm,yPosOfWm,wmWidth,wmHeight),  //Set the detination Position
                0,                  // x-coordinate of the portion of the source image to draw. 
                0,                  // y-coordinate of the portion of the source image to draw. 
                wmWidth,            // Watermark Width
                wmHeight,            // Watermark Height
                GraphicsUnit.Pixel, // Unit of measurment
                imageAttributes);   //ImageAttributes Object

            //Replace the original photgraphs bitmap with the new Bitmap
            imgPhoto = bmWatermark;
            grPhoto.Dispose();
            grWatermark.Dispose();

            //save new image to file system.
            imgPhoto.Save(WorkingDirectory + "\\watermark_final.jpg", ImageFormat.Jpeg);
            imgPhoto.Dispose();
            imgWatermark.Dispose();

        }
    }
}