首页 > 代码库 > C#图像处理(各种旋转、改变大小、柔化、锐化、雾化、底片、浮雕、黑白、滤镜效果)

C#图像处理(各种旋转、改变大小、柔化、锐化、雾化、底片、浮雕、黑白、滤镜效果)

C#图像处理(各种旋转、改变大小、柔化、锐化、雾化、底片、浮雕、黑白、滤镜效果)

标签: c#图像处理gdi
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    一、各种旋转、改变大小

    注意:先要添加画图相关的using引用。

    [csharp] view plain copy
     
    print?
    1. //向右旋转图像90°代码如下:  
    2. private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)  
    3. {  
    4. Graphics g = e.Graphics;  
    5. Bitmap bmp = new Bitmap("rama.jpg");//加载图像  
    6. g.FillRectangle(Brushes.White, this.ClientRectangle);//填充窗体背景为白色  
    7. Point[] destinationPoints = {  
    8. new Point(100, 0), // destination for upper-left point of original  
    9. new Point(100, 100),// destination for upper-right point of original  
    10. new Point(0, 0)}; // destination for lower-left point of original  
    11. g.DrawImage(bmp, destinationPoints);  
    12. }  
    13.   
    14. //旋转图像180°代码如下:  
    15. private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)  
    16. {  
    17. Graphics g = e.Graphics;  
    18. Bitmap bmp = new Bitmap("rama.jpg");  
    19. g.FillRectangle(Brushes.White, this.ClientRectangle);  
    20. Point[] destinationPoints = {  
    21. new Point(0, 100), // destination for upper-left point of original  
    22. new Point(100, 100),// destination for upper-right point of original  
    23. new Point(0, 0)}; // destination for lower-left point of original  
    24. g.DrawImage(bmp, destinationPoints);  
    25. }  
    26.   
    27. //图像切变代码:  
    28. private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)  
    29. {  
    30. Graphics g = e.Graphics;  
    31. Bitmap bmp = new Bitmap("rama.jpg");  
    32. g.FillRectangle(Brushes.White, this.ClientRectangle);  
    33. Point[] destinationPoints = {  
    34. new Point(0, 0), // destination for upper-left point of original  
    35. new Point(100, 0), // destination for upper-right point of original  
    36. new Point(50, 100)};// destination for lower-left point of original  
    37. g.DrawImage(bmp, destinationPoints);  
    38. }  
    39.   
    40. //图像截取:  
    41. private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)  
    42. {  
    43. Graphics g = e.Graphics;  
    44. Bitmap bmp = new Bitmap("rama.jpg");  
    45. g.FillRectangle(Brushes.White, this.ClientRectangle);  
    46. Rectangle sr = new Rectangle(80, 60, 400, 400);//要截取的矩形区域  
    47. Rectangle dr = new Rectangle(0, 0, 200, 200);//要显示到Form的矩形区域  
    48. g.DrawImage(bmp, dr, sr, GraphicsUnit.Pixel);  
    49. }  
    50.   
    51. //改变图像大小:  
    52. private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)  
    53. {  
    54. Graphics g = e.Graphics;  
    55. Bitmap bmp = new Bitmap("rama.jpg");  
    56. g.FillRectangle(Brushes.White, this.ClientRectangle);  
    57. int width = bmp.Width;  
    58. int height = bmp.Height;  
    59. // 改变图像大小使用低质量的模式  
    60. g.InterpolationMode = InterpolationMode.NearestNeighbor;  
    61. g.DrawImage(bmp, new Rectangle(10, 10, 120, 120), // source rectangle  
    62. new Rectangle(0, 0, width, height), // destination rectangle  
    63. GraphicsUnit.Pixel);  
    64. // 使用高质量模式  
    65. //g.CompositingQuality = CompositingQuality.HighSpeed;  
    66. g.InterpolationMode = InterpolationMode.HighQualityBicubic;  
    67. g.DrawImage(  
    68. bmp,  
    69. new Rectangle(130, 10, 120, 120),   
    70. new Rectangle(0, 0, width, height),  
    71. GraphicsUnit.Pixel);  
    72. }  
    73.   
    74. //设置图像的分辩率:  
    75. private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)  
    76. {  
    77. Graphics g = e.Graphics;  
    78. Bitmap bmp = new Bitmap("rama.jpg");  
    79. g.FillRectangle(Brushes.White, this.ClientRectangle);  
    80. bmp.SetResolution(300f, 300f);  
    81. g.DrawImage(bmp, 0, 0);  
    82. bmp.SetResolution(1200f, 1200f);  
    83. g.DrawImage(bmp, 180, 0);  
    84. }  
    85.   
    86. //用GDI+画图  
    87. private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)  
    88. {  
    89. Graphics gForm = e.Graphics;  
    90. gForm.FillRectangle(Brushes.White, this.ClientRectangle);  
    91. for (int i = 1; i <= 7; ++i)  
    92. {  
    93. //在窗体上面画出橙色的矩形  
    94. Rectangle r = new Rectangle(i*40-15, 0, 15,  
    95. this.ClientRectangle.Height);  
    96. gForm.FillRectangle(Brushes.Orange, r);  
    97. }  
    98. //在内存中创建一个Bitmap并设置CompositingMode  
    99. Bitmap bmp = new Bitmap(260, 260,  
    100. System.Drawing.Imaging.PixelFormat.Format32bppArgb);  
    101. Graphics gBmp = Graphics.FromImage(bmp);  
    102. gBmp.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;  
    103. // 创建一个带有Alpha的红色区域  
    104. // 并将其画在内存的位图里面  
    105. Color red = Color.FromArgb(0x60, 0xff, 0, 0);  
    106. Brush redBrush = new SolidBrush(red);  
    107. gBmp.FillEllipse(redBrush, 70, 70, 160, 160);  
    108. // 创建一个带有Alpha的绿色区域  
    109. Color green = Color.FromArgb(0x40, 0, 0xff, 0);  
    110. Brush greenBrush = new SolidBrush(green);  
    111. gBmp.FillRectangle(greenBrush, 10, 10, 140, 140);  
    112. //在窗体上面画出位图 now draw the bitmap on our window  
    113. gForm.DrawImage(bmp, 20, 20, bmp.Width, bmp.Height);  
    114. // 清理资源  
    115. bmp.Dispose();  
    116. gBmp.Dispose();  
    117. redBrush.Dispose();  
    118. greenBrush.Dispose();  
    119. }  
    120.   
    121. //在窗体上面绘图并显示图像  
    122. private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)  
    123. {  
    124. Graphics g = e.Graphics;  
    125. Pen blackPen = new Pen(Color.Black, 1);  
    126. if (ClientRectangle.Height / 10 > 0)  
    127. {  
    128. for (int y = 0; y < ClientRectangle.Height; y += ClientRectangle.Height / 10)  
    129. {  
    130. g.DrawLine(blackPen, new Point(0, 0), new Point(ClientRectangle.Width, y));  
    131. }  
    132. }  
    133. blackPen.Dispose();  
    134. }  
    技术分享
    //向右旋转图像90°代码如下:
    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    Graphics g = e.Graphics;
    Bitmap bmp = new Bitmap("rama.jpg");//加载图像
    g.FillRectangle(Brushes.White, this.ClientRectangle);//填充窗体背景为白色
    Point[] destinationPoints = {
    new Point(100, 0), // destination for upper-left point of original
    new Point(100, 100),// destination for upper-right point of original
    new Point(0, 0)}; // destination for lower-left point of original
    g.DrawImage(bmp, destinationPoints);
    }
    
    //旋转图像180°代码如下:
    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    Graphics g = e.Graphics;
    Bitmap bmp = new Bitmap("rama.jpg");
    g.FillRectangle(Brushes.White, this.ClientRectangle);
    Point[] destinationPoints = {
    new Point(0, 100), // destination for upper-left point of original
    new Point(100, 100),// destination for upper-right point of original
    new Point(0, 0)}; // destination for lower-left point of original
    g.DrawImage(bmp, destinationPoints);
    }
    
    //图像切变代码:
    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    Graphics g = e.Graphics;
    Bitmap bmp = new Bitmap("rama.jpg");
    g.FillRectangle(Brushes.White, this.ClientRectangle);
    Point[] destinationPoints = {
    new Point(0, 0), // destination for upper-left point of original
    new Point(100, 0), // destination for upper-right point of original
    new Point(50, 100)};// destination for lower-left point of original
    g.DrawImage(bmp, destinationPoints);
    }
    
    //图像截取:
    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    Graphics g = e.Graphics;
    Bitmap bmp = new Bitmap("rama.jpg");
    g.FillRectangle(Brushes.White, this.ClientRectangle);
    Rectangle sr = new Rectangle(80, 60, 400, 400);//要截取的矩形区域
    Rectangle dr = new Rectangle(0, 0, 200, 200);//要显示到Form的矩形区域
    g.DrawImage(bmp, dr, sr, GraphicsUnit.Pixel);
    }
    
    //改变图像大小:
    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    Graphics g = e.Graphics;
    Bitmap bmp = new Bitmap("rama.jpg");
    g.FillRectangle(Brushes.White, this.ClientRectangle);
    int width = bmp.Width;
    int height = bmp.Height;
    // 改变图像大小使用低质量的模式
    g.InterpolationMode = InterpolationMode.NearestNeighbor;
    g.DrawImage(bmp, new Rectangle(10, 10, 120, 120), // source rectangle
    new Rectangle(0, 0, width, height), // destination rectangle
    GraphicsUnit.Pixel);
    // 使用高质量模式
    //g.CompositingQuality = CompositingQuality.HighSpeed;
    g.InterpolationMode = InterpolationMode.HighQualityBicubic;
    g.DrawImage(
    bmp,
    new Rectangle(130, 10, 120, 120), 
    new Rectangle(0, 0, width, height),
    GraphicsUnit.Pixel);
    }
    
    //设置图像的分辩率:
    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    Graphics g = e.Graphics;
    Bitmap bmp = new Bitmap("rama.jpg");
    g.FillRectangle(Brushes.White, this.ClientRectangle);
    bmp.SetResolution(300f, 300f);
    g.DrawImage(bmp, 0, 0);
    bmp.SetResolution(1200f, 1200f);
    g.DrawImage(bmp, 180, 0);
    }
    
    //用GDI+画图
    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    Graphics gForm = e.Graphics;
    gForm.FillRectangle(Brushes.White, this.ClientRectangle);
    for (int i = 1; i <= 7; ++i)
    {
    //在窗体上面画出橙色的矩形
    Rectangle r = new Rectangle(i*40-15, 0, 15,
    this.ClientRectangle.Height);
    gForm.FillRectangle(Brushes.Orange, r);
    }
    //在内存中创建一个Bitmap并设置CompositingMode
    Bitmap bmp = new Bitmap(260, 260,
    System.Drawing.Imaging.PixelFormat.Format32bppArgb);
    Graphics gBmp = Graphics.FromImage(bmp);
    gBmp.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
    // 创建一个带有Alpha的红色区域
    // 并将其画在内存的位图里面
    Color red = Color.FromArgb(0x60, 0xff, 0, 0);
    Brush redBrush = new SolidBrush(red);
    gBmp.FillEllipse(redBrush, 70, 70, 160, 160);
    // 创建一个带有Alpha的绿色区域
    Color green = Color.FromArgb(0x40, 0, 0xff, 0);
    Brush greenBrush = new SolidBrush(green);
    gBmp.FillRectangle(greenBrush, 10, 10, 140, 140);
    //在窗体上面画出位图 now draw the bitmap on our window
    gForm.DrawImage(bmp, 20, 20, bmp.Width, bmp.Height);
    // 清理资源
    bmp.Dispose();
    gBmp.Dispose();
    redBrush.Dispose();
    greenBrush.Dispose();
    }
    
    //在窗体上面绘图并显示图像
    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
    {
    Graphics g = e.Graphics;
    Pen blackPen = new Pen(Color.Black, 1);
    if (ClientRectangle.Height / 10 > 0)
    {
    for (int y = 0; y < ClientRectangle.Height; y += ClientRectangle.Height / 10)
    {
    g.DrawLine(blackPen, new Point(0, 0), new Point(ClientRectangle.Width, y));
    }
    }
    blackPen.Dispose();
    }

     

    C# 使用Bitmap类进行图片裁剪

     

     在Mapwin(手机游戏地图编辑器)生成的地图txt文件中添加自己需要处理的数据后转换成可在手机(Ophone)开发环境中使用的字节流地图文件的小工具,其中就涉及到图片的裁剪和生成了。有以下几种方式。

     

    方法一:拷贝像素。

     

    当然这种方法是最笨的,效率也就低了些。

    在Bitmap类中我们可以看到这样两个方法:GetPixel(int x, int y)和SetPixel(int x, int y, Color color)方法。从字面的含以上就知道前者是获取图像某点像素值,是用Color对象返回的;后者是将已知像素描画到制定的位置。

    下面就来做个实例检验下:

    1.首先创建一个Windows Form窗体程序,往该窗体上拖放7个PictureBox控件,第一个用于放置并显示原始的大图片,其后6个用于放置并显示裁剪后新生成的6个小图;

    2.放置原始大图的PictureBox控件name属性命名为pictureBoxBmpRes,其后pictureBox1到pictureBox6依次命名,并放置在合适的位置;

    3.双击Form窗体,然后在Form1_Load事件中加入下面的代码即可。

    [csharp] view plain copy
     
    print?
    1. //导入图像资源  
    2.             Bitmap bmpRes = null;  
    3.             String strPath = Application.ExecutablePath;  
    4.             try{  
    5.                 int nEndIndex = strPath.LastIndexOf(‘//‘);  
    6.                 strPath = strPath.Substring(0,nEndIndex) + "//Bmp//BmpResMM.bmp";  
    7.                 bmpRes = new Bitmap(strPath);  
    8.    
    9.                 //窗体上显示加载图片  
    10.                 pictureBoxBmpRes.Width = bmpRes.Width;  
    11.                 pictureBoxBmpRes.Height = bmpRes.Height;  
    12.                 pictureBoxBmpRes.Image = bmpRes;  
    13.             }  
    14.             catch(Exception ex)  
    15.             {  
    16.                System.Windows.Forms.MessageBox.Show("图片资源加载失败!/r/n" + ex.ToString());  
    17.             }  
    18.    
    19.             //裁剪图片(裁成2行3列的6张图片)  
    20.             int nYClipNum = 2, nXClipNum = 3;  
    21.             Bitmap[] bmpaClipBmpArr = new Bitmap[nYClipNum * nXClipNum];              
    22.             for (int nYClipNumIndex = 0; nYClipNumIndex < nYClipNum; nYClipNumIndex++)  
    23.             {  
    24.                 for (int nXClipNumIndex = 0; nXClipNumIndex < nXClipNum; nXClipNumIndex++)  
    25.                 {  
    26.                     int nClipWidth = bmpRes.Width / nXClipNum;  
    27.                     int nClipHight = bmpRes.Height / nYClipNum;  
    28.                     int nBmpIndex = nXClipNumIndex + nYClipNumIndex * nYClipNum + (nYClipNumIndex > 0?1:0);  
    29.                     bmpaClipBmpArr[nBmpIndex] = new Bitmap(nClipWidth, nClipHight);  
    30.    
    31.                     for(int nY = 0; nY < nClipHight; nY++)  
    32.                     {  
    33.                         for(int nX = 0; nX < nClipWidth; nX++)  
    34.                         {  
    35.                             int nClipX = nX + nClipWidth * nXClipNumIndex;  
    36.                             int nClipY = nY + nClipHight * nYClipNumIndex;  
    37.                             Color cClipPixel = bmpRes.GetPixel(nClipX, nClipY);  
    38.                             bmpaClipBmpArr[nBmpIndex].SetPixel(nX, nY, cClipPixel);  
    39.                         }  
    40.                     }                     
    41.                 }  
    42.             }  
    43.             PictureBox[] picbShow = new PictureBox[nYClipNum * nXClipNum];  
    44.             picbShow[0] = pictureBox1;  
    45.             picbShow[1] = pictureBox2;  
    46.             picbShow[2] = pictureBox3;  
    47.             picbShow[3] = pictureBox4;  
    48.             picbShow[4] = pictureBox5;  
    49.             picbShow[5] = pictureBox6;  
    50.             for (int nLoop = 0; nLoop < nYClipNum * nXClipNum; nLoop++)  
    51.             {  
    52.                 picbShow[nLoop].Width = bmpRes.Width / nXClipNum;  
    53.                 picbShow[nLoop].Height = bmpRes.Height / nYClipNum;  
    54.                 picbShow[nLoop].Image = bmpaClipBmpArr[nLoop];                 
    55.             }  
    技术分享
    //导入图像资源
                Bitmap bmpRes = null;
                String strPath = Application.ExecutablePath;
                try{
                    int nEndIndex = strPath.LastIndexOf(‘//‘);
                    strPath = strPath.Substring(0,nEndIndex) + "//Bmp//BmpResMM.bmp";
                    bmpRes = new Bitmap(strPath);
     
                    //窗体上显示加载图片
                    pictureBoxBmpRes.Width = bmpRes.Width;
                    pictureBoxBmpRes.Height = bmpRes.Height;
                    pictureBoxBmpRes.Image = bmpRes;
                }
                catch(Exception ex)
                {
                   System.Windows.Forms.MessageBox.Show("图片资源加载失败!/r/n" + ex.ToString());
                }
     
                //裁剪图片(裁成2行3列的6张图片)
                int nYClipNum = 2, nXClipNum = 3;
                Bitmap[] bmpaClipBmpArr = new Bitmap[nYClipNum * nXClipNum];            
                for (int nYClipNumIndex = 0; nYClipNumIndex < nYClipNum; nYClipNumIndex++)
                {
                    for (int nXClipNumIndex = 0; nXClipNumIndex < nXClipNum; nXClipNumIndex++)
                    {
                        int nClipWidth = bmpRes.Width / nXClipNum;
                        int nClipHight = bmpRes.Height / nYClipNum;
                        int nBmpIndex = nXClipNumIndex + nYClipNumIndex * nYClipNum + (nYClipNumIndex > 0?1:0);
                        bmpaClipBmpArr[nBmpIndex] = new Bitmap(nClipWidth, nClipHight);
     
                        for(int nY = 0; nY < nClipHight; nY++)
                        {
                            for(int nX = 0; nX < nClipWidth; nX++)
                            {
                                int nClipX = nX + nClipWidth * nXClipNumIndex;
                                int nClipY = nY + nClipHight * nYClipNumIndex;
                                Color cClipPixel = bmpRes.GetPixel(nClipX, nClipY);
                                bmpaClipBmpArr[nBmpIndex].SetPixel(nX, nY, cClipPixel);
                            }
                        }                   
                    }
                }
                PictureBox[] picbShow = new PictureBox[nYClipNum * nXClipNum];
                picbShow[0] = pictureBox1;
                picbShow[1] = pictureBox2;
                picbShow[2] = pictureBox3;
                picbShow[3] = pictureBox4;
                picbShow[4] = pictureBox5;
                picbShow[5] = pictureBox6;
                for (int nLoop = 0; nLoop < nYClipNum * nXClipNum; nLoop++)
                {
                    picbShow[nLoop].Width = bmpRes.Width / nXClipNum;
                    picbShow[nLoop].Height = bmpRes.Height / nYClipNum;
                    picbShow[nLoop].Image = bmpaClipBmpArr[nLoop];               
                }

     

     现在看看那些地方需要注意的了。其中

    int nBmpIndex =

    nXClipNumIndex + nYClipNumIndex * nYClipNum + (nYClipNumIndex > 0?1:0);

     这句定义了存储裁剪图片对象在数组中的索引,需要注意的就是后面的(nYClipNumIndex > 0?1:0)——因为只有当裁剪的对象处于第一行以外的行时需要将索引加1;

    另外,因为这种方法的效率不高,程序运行起来还是顿了下。如果有兴趣的话,可以将以上的代码放到一个按钮Click事件函数中,当单击该按钮时就可以感觉到了。

     

     方法二:运用Clone函数局部复制。

     

    同样在Bitmap中可以找到Clone()方法,该方法有三个重载方法。Clone(),Clone(Rectangle, PixelFormat)和Clone(RectangleF, PixelFormat)。第一个方法将创建并返回一个精确的实例对象,后两个就是我们这里需要用的局部裁剪了(其实后两个方法本人觉得用法上差不多)。

    将上面的程序稍稍改进下——将裁剪的处理放到一个按钮事件函数中,然后再托一个按钮好窗体上,最后将下面的代码复制到该按钮的事件函数中。

    [csharp] view plain copy
     
    print?
    1. for (int nYClipNumIndex = 0; nYClipNumIndex < nYClipNum; nYClipNumIndex++)  
    2. {  
    3.        for (int nXClipNumIndex = 0; nXClipNumIndex < nXClipNum; nXClipNumIndex++)  
    4.          {  
    5.               int nClipWidth = bmpRes.Width / nXClipNum;  
    6.                       int nClipHight = bmpRes.Height / nYClipNum;  
    7.                 int nBmpIndex =  
    8. nXClipNumIndex + nYClipNumIndex * nYClipNum + (nYClipNumIndex > 0 ? 1 : 0);  
    9.                
    10.         Rectangle rClipRect = new Rectangle(nClipWidth * nXClipNumIndex,  
    11.                                                             nClipHight * nYClipNumIndex,  
    12.                                                             nClipWidth,  
    13.                                                             nClipHight);  
    14.                
    15.                 bmpaClipBmpArr[nBmpIndex] = bmpRes.Clone(rClipRect, bmpRes.PixelFormat);  
    16.             }  
    17. }  
    18.    
    技术分享
    for (int nYClipNumIndex = 0; nYClipNumIndex < nYClipNum; nYClipNumIndex++)
    {
           for (int nXClipNumIndex = 0; nXClipNumIndex < nXClipNum; nXClipNumIndex++)
             {
                  int nClipWidth = bmpRes.Width / nXClipNum;
                          int nClipHight = bmpRes.Height / nYClipNum;
                    int nBmpIndex =
    nXClipNumIndex + nYClipNumIndex * nYClipNum + (nYClipNumIndex > 0 ? 1 : 0);
                 
            Rectangle rClipRect = new Rectangle(nClipWidth * nXClipNumIndex,
                                                                nClipHight * nYClipNumIndex,
                                                                nClipWidth,
                                                                nClipHight);
                 
                    bmpaClipBmpArr[nBmpIndex] = bmpRes.Clone(rClipRect, bmpRes.PixelFormat);
                }
    }
     

     

    运行程序,单击按钮检验下,发现速度明显快可很多。

    其实这种方法较第一中方法不同的地方仅只是变换了for循环中的拷贝部分的处理,

    [csharp] view plain copy
     
    print?
    1. Rectangle rClipRect = new Rectangle(nClipWidth * nXClipNumIndex,  
    2.                                                             nClipHight * nYClipNumIndex,  
    3.                                                             nClipWidth,  
    4.                                                             nClipHight);  
    5.    
    6. bmpaClipBmpArr[nBmpIndex] = bmpRes.Clone(rClipRect, bmpRes.PixelFormat);  
    7.    
    技术分享
    Rectangle rClipRect = new Rectangle(nClipWidth * nXClipNumIndex,
                                                                nClipHight * nYClipNumIndex,
                                                                nClipWidth,
                                                                nClipHight);
     
    bmpaClipBmpArr[nBmpIndex] = bmpRes.Clone(rClipRect, bmpRes.PixelFormat);
     

     

    一. 底片效果
    原理: GetPixel方法获得每一点像素的值, 然后再使用SetPixel方法将取反后的颜色值设置到对应的点.
    效果图:

    技术分享

    代码实现:

     

    [csharp] view plain copy
     
    print?
    1. private void button1_Click(object sender, EventArgs e)  
    2.      {  
    3.          //以底片效果显示图像  
    4.          try  
    5.          {  
    6.              int Height = this.pictureBox1.Image.Height;  
    7.              int Width = this.pictureBox1.Image.Width;  
    8.              Bitmap newbitmap = new Bitmap(Width, Height);  
    9.              Bitmap oldbitmap = (Bitmap)this.pictureBox1.Image;  
    10.              Color pixel;  
    11.              for (int x = 1; x < Width; x++)  
    12.              {  
    13.                  for (int y = 1; y < Height; y++)  
    14.                  {  
    15.                      int r, g, b;  
    16.                      pixel = oldbitmap.GetPixel(x, y);  
    17.                      r = 255 - pixel.R;  
    18.                      g = 255 - pixel.G;  
    19.                      b = 255 - pixel.B;  
    20.                      newbitmap.SetPixel(x, y, Color.FromArgb(r, g, b));  
    21.                  }  
    22.              }  
    23.              this.pictureBox1.Image = newbitmap;  
    24.          }  
    25.          catch (Exception ex)  
    26.          {  
    27.              MessageBox.Show(ex.Message, "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);  
    28.          }  
    29.      }  
    技术分享
       private void button1_Click(object sender, EventArgs e)
            {
                //以底片效果显示图像
                try
                {
                    int Height = this.pictureBox1.Image.Height;
                    int Width = this.pictureBox1.Image.Width;
                    Bitmap newbitmap = new Bitmap(Width, Height);
                    Bitmap oldbitmap = (Bitmap)this.pictureBox1.Image;
                    Color pixel;
                    for (int x = 1; x < Width; x++)
                    {
                        for (int y = 1; y < Height; y++)
                        {
                            int r, g, b;
                            pixel = oldbitmap.GetPixel(x, y);
                            r = 255 - pixel.R;
                            g = 255 - pixel.G;
                            b = 255 - pixel.B;
                            newbitmap.SetPixel(x, y, Color.FromArgb(r, g, b));
                        }
                    }
                    this.pictureBox1.Image = newbitmap;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
            }

     

    二. 浮雕效果

    原理: 对图像像素点的像素值分别与相邻像素点的像素值相减后加上128, 然后将其作为新的像素点的值.

    效果图:

     

     

    技术分享

     

     

     

    代码实现:

    [csharp] view plain copy
     
    print?
    1. private void button1_Click(object sender, EventArgs e)  
    2.         {  
    3.             //以浮雕效果显示图像  
    4.             try  
    5.             {  
    6.                 int Height = this.pictureBox1.Image.Height;  
    7.                 int Width = this.pictureBox1.Image.Width;  
    8.                 Bitmap newBitmap = new Bitmap(Width, Height);  
    9.                 Bitmap oldBitmap = (Bitmap)this.pictureBox1.Image;  
    10.                 Color pixel1, pixel2;  
    11.                 for (int x = 0; x < Width - 1; x++)  
    12.                 {  
    13.                     for (int y = 0; y < Height - 1; y++)  
    14.                     {  
    15.                         int r = 0, g = 0, b = 0;  
    16.                         pixel1 = oldBitmap.GetPixel(x, y);  
    17.                         pixel2 = oldBitmap.GetPixel(x + 1, y + 1);  
    18.                         r = Math.Abs(pixel1.R - pixel2.R + 128);  
    19.                         g = Math.Abs(pixel1.G - pixel2.G + 128);  
    20.                         b = Math.Abs(pixel1.B - pixel2.B + 128);  
    21.                         if (r > 255)  
    22.                             r = 255;  
    23.                         if (r < 0)  
    24.                             r = 0;  
    25.                         if (g > 255)  
    26.                             g = 255;  
    27.                         if (g < 0)  
    28.                             g = 0;  
    29.                         if (b > 255)  
    30.                             b = 255;  
    31.                         if (b < 0)  
    32.                             b = 0;  
    33.                         newBitmap.SetPixel(x, y, Color.FromArgb(r, g, b));  
    34.                     }  
    35.                 }  
    36.                 this.pictureBox1.Image = newBitmap;  
    37.             }  
    38.             catch (Exception ex)  
    39.             {  
    40.                 MessageBox.Show(ex.Message, "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);  
    41.             }  
    42.         }  
    技术分享
    private void button1_Click(object sender, EventArgs e)
            {
                //以浮雕效果显示图像
                try
                {
                    int Height = this.pictureBox1.Image.Height;
                    int Width = this.pictureBox1.Image.Width;
                    Bitmap newBitmap = new Bitmap(Width, Height);
                    Bitmap oldBitmap = (Bitmap)this.pictureBox1.Image;
                    Color pixel1, pixel2;
                    for (int x = 0; x < Width - 1; x++)
                    {
                        for (int y = 0; y < Height - 1; y++)
                        {
                            int r = 0, g = 0, b = 0;
                            pixel1 = oldBitmap.GetPixel(x, y);
                            pixel2 = oldBitmap.GetPixel(x + 1, y + 1);
                            r = Math.Abs(pixel1.R - pixel2.R + 128);
                            g = Math.Abs(pixel1.G - pixel2.G + 128);
                            b = Math.Abs(pixel1.B - pixel2.B + 128);
                            if (r > 255)
                                r = 255;
                            if (r < 0)
                                r = 0;
                            if (g > 255)
                                g = 255;
                            if (g < 0)
                                g = 0;
                            if (b > 255)
                                b = 255;
                            if (b < 0)
                                b = 0;
                            newBitmap.SetPixel(x, y, Color.FromArgb(r, g, b));
                        }
                    }
                    this.pictureBox1.Image = newBitmap;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
            }

     

    三. 黑白效果

    原理: 彩色图像处理成黑白效果通常有3种算法;

    (1).最大值法: 使每个像素点的 R, G, B 值等于原像素点的 RGB (颜色值) 中最大的一个;

    (2).平均值法: 使用每个像素点的 R,G,B值等于原像素点的RGB值的平均值;

    (3).加权平均值法: 对每个像素点的 R, G, B值进行加权

          ---自认为第三种方法做出来的黑白效果图像最 "真实".

    效果图:

     

    技术分享

     

    代码实现:

    [csharp] view plain copy
     
    print?
    1. private void button1_Click(object sender, EventArgs e)  
    2.         {  
    3.             //以黑白效果显示图像  
    4.             try  
    5.             {  
    6.                 int Height = this.pictureBox1.Image.Height;  
    7.                 int Width = this.pictureBox1.Image.Width;  
    8.                 Bitmap newBitmap = new Bitmap(Width, Height);  
    9.                 Bitmap oldBitmap = (Bitmap)this.pictureBox1.Image;  
    10.                 Color pixel;  
    11.                 for (int x = 0; x < Width; x++)  
    12.                     for (int y = 0; y < Height; y++)  
    13.                     {  
    14.                         pixel = oldBitmap.GetPixel(x, y);  
    15.                         int r, g, b, Result = 0;  
    16.                         r = pixel.R;  
    17.                         g = pixel.G;  
    18.                         b = pixel.B;  
    19.                         //实例程序以加权平均值法产生黑白图像  
    20.                         int iType =2;  
    21.                         switch (iType)  
    22.                         {  
    23.                             case 0://平均值法  
    24.                                 Result = ((r + g + b) / 3);  
    25.                                 break;  
    26.                             case 1://最大值法  
    27.                                 Result = r > g ? r : g;  
    28.                                 Result = Result > b ? Result : b;  
    29.                                 break;  
    30.                             case 2://加权平均值法  
    31.                                 Result = ((int)(0.7 * r) + (int)(0.2 * g) + (int)(0.1 * b));  
    32.                                 break;  
    33.                         }  
    34.                         newBitmap.SetPixel(x, y, Color.FromArgb(Result, Result, Result));  
    35.                     }  
    36.                 this.pictureBox1.Image = newBitmap;  
    37.             }  
    38.             catch (Exception ex)  
    39.             {  
    40.                 MessageBox.Show(ex.Message, "信息提示");  
    41.             }  
    42.         }  
    技术分享
    private void button1_Click(object sender, EventArgs e)
            {
                //以黑白效果显示图像
                try
                {
                    int Height = this.pictureBox1.Image.Height;
                    int Width = this.pictureBox1.Image.Width;
                    Bitmap newBitmap = new Bitmap(Width, Height);
                    Bitmap oldBitmap = (Bitmap)this.pictureBox1.Image;
                    Color pixel;
                    for (int x = 0; x < Width; x++)
                        for (int y = 0; y < Height; y++)
                        {
                            pixel = oldBitmap.GetPixel(x, y);
                            int r, g, b, Result = 0;
                            r = pixel.R;
                            g = pixel.G;
                            b = pixel.B;
                            //实例程序以加权平均值法产生黑白图像
                            int iType =2;
                            switch (iType)
                            {
                                case 0://平均值法
                                    Result = ((r + g + b) / 3);
                                    break;
                                case 1://最大值法
                                    Result = r > g ? r : g;
                                    Result = Result > b ? Result : b;
                                    break;
                                case 2://加权平均值法
                                    Result = ((int)(0.7 * r) + (int)(0.2 * g) + (int)(0.1 * b));
                                    break;
                            }
                            newBitmap.SetPixel(x, y, Color.FromArgb(Result, Result, Result));
                        }
                    this.pictureBox1.Image = newBitmap;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "信息提示");
                }
            }

     

    四. 柔化效果

    原理: 当前像素点与周围像素点的颜色差距较大时取其平均值.

    效果图:

     

     

    技术分享

     

     

    代码实现:

    [csharp] view plain copy
     
    print?
    1. private void button1_Click(object sender, EventArgs e)  
    2.        {  
    3.            //以柔化效果显示图像  
    4.            try  
    5.            {  
    6.                int Height = this.pictureBox1.Image.Height;  
    7.                int Width = this.pictureBox1.Image.Width;  
    8.                Bitmap bitmap = new Bitmap(Width, Height);  
    9.                Bitmap MyBitmap = (Bitmap)this.pictureBox1.Image;  
    10.                Color pixel;  
    11.                //高斯模板  
    12.                int[] Gauss ={ 1, 2, 1, 2, 4, 2, 1, 2, 1 };  
    13.                for (int x = 1; x < Width - 1; x++)  
    14.                    for (int y = 1; y < Height - 1; y++)  
    15.                    {  
    16.                        int r = 0, g = 0, b = 0;  
    17.                        int Index = 0;  
    18.                        for (int col = -1; col <= 1; col++)  
    19.                            for (int row = -1; row <= 1; row++)  
    20.                            {  
    21.                                pixel = MyBitmap.GetPixel(x + row, y + col);  
    22.                                r += pixel.R * Gauss[Index];  
    23.                                g += pixel.G * Gauss[Index];  
    24.                                b += pixel.B * Gauss[Index];  
    25.                                Index++;  
    26.                            }  
    27.                        r /= 16;  
    28.                        g /= 16;  
    29.                        b /= 16;  
    30.                        //处理颜色值溢出  
    31.                        r = r > 255 ? 255 : r;  
    32.                        r = r < 0 ? 0 : r;  
    33.                        g = g > 255 ? 255 : g;  
    34.                        g = g < 0 ? 0 : g;  
    35.                        b = b > 255 ? 255 : b;  
    36.                        b = b < 0 ? 0 : b;  
    37.                        bitmap.SetPixel(x - 1, y - 1, Color.FromArgb(r, g, b));  
    38.                    }  
    39.                this.pictureBox1.Image = bitmap;  
    40.            }  
    41.            catch (Exception ex)  
    42.            {  
    43.                MessageBox.Show(ex.Message, "信息提示");  
    44.            }  
    45.        }  
    技术分享
     private void button1_Click(object sender, EventArgs e)
            {
                //以柔化效果显示图像
                try
                {
                    int Height = this.pictureBox1.Image.Height;
                    int Width = this.pictureBox1.Image.Width;
                    Bitmap bitmap = new Bitmap(Width, Height);
                    Bitmap MyBitmap = (Bitmap)this.pictureBox1.Image;
                    Color pixel;
                    //高斯模板
                    int[] Gauss ={ 1, 2, 1, 2, 4, 2, 1, 2, 1 };
                    for (int x = 1; x < Width - 1; x++)
                        for (int y = 1; y < Height - 1; y++)
                        {
                            int r = 0, g = 0, b = 0;
                            int Index = 0;
                            for (int col = -1; col <= 1; col++)
                                for (int row = -1; row <= 1; row++)
                                {
                                    pixel = MyBitmap.GetPixel(x + row, y + col);
                                    r += pixel.R * Gauss[Index];
                                    g += pixel.G * Gauss[Index];
                                    b += pixel.B * Gauss[Index];
                                    Index++;
                                }
                            r /= 16;
                            g /= 16;
                            b /= 16;
                            //处理颜色值溢出
                            r = r > 255 ? 255 : r;
                            r = r < 0 ? 0 : r;
                            g = g > 255 ? 255 : g;
                            g = g < 0 ? 0 : g;
                            b = b > 255 ? 255 : b;
                            b = b < 0 ? 0 : b;
                            bitmap.SetPixel(x - 1, y - 1, Color.FromArgb(r, g, b));
                        }
                    this.pictureBox1.Image = bitmap;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "信息提示");
                }
            }


    五.锐化效果

    原理:突出显示颜色值大(即形成形体边缘)的像素点.

    效果图:

     

    技术分享

     

     

     

    实现代码:

    [csharp] view plain copy
     
    print?
    1. private void button1_Click(object sender, EventArgs e)  
    2.       {  
    3.           //以锐化效果显示图像  
    4.           try  
    5.           {  
    6.               int Height = this.pictureBox1.Image.Height;  
    7.               int Width = this.pictureBox1.Image.Width;  
    8.               Bitmap newBitmap = new Bitmap(Width, Height);  
    9.               Bitmap oldBitmap = (Bitmap)this.pictureBox1.Image;  
    10.               Color pixel;  
    11.               //拉普拉斯模板  
    12.               int[] Laplacian ={ -1, -1, -1, -1, 9, -1, -1, -1, -1 };  
    13.               for (int x = 1; x < Width - 1; x++)  
    14.                   for (int y = 1; y < Height - 1; y++)  
    15.                   {  
    16.                       int r = 0, g = 0, b = 0;  
    17.                       int Index = 0;  
    18.                       for (int col = -1; col <= 1; col++)  
    19.                           for (int row = -1; row <= 1; row++)  
    20.                           {  
    21.                               pixel = oldBitmap.GetPixel(x + row, y + col); r += pixel.R * Laplacian[Index];  
    22.                               g += pixel.G * Laplacian[Index];  
    23.                               b += pixel.B * Laplacian[Index];  
    24.                               Index++;  
    25.                           }  
    26.                       //处理颜色值溢出  
    27.                       r = r > 255 ? 255 : r;  
    28.                       r = r < 0 ? 0 : r;  
    29.                       g = g > 255 ? 255 : g;  
    30.                       g = g < 0 ? 0 : g;  
    31.                       b = b > 255 ? 255 : b;  
    32.                       b = b < 0 ? 0 : b;  
    33.                       newBitmap.SetPixel(x - 1, y - 1, Color.FromArgb(r, g, b));  
    34.                   }  
    35.               this.pictureBox1.Image = newBitmap;  
    36.           }  
    37.           catch (Exception ex)  
    38.           {  
    39.               MessageBox.Show(ex.Message, "信息提示");  
    40.           }  
    41.       }  
    技术分享
      private void button1_Click(object sender, EventArgs e)
            {
                //以锐化效果显示图像
                try
                {
                    int Height = this.pictureBox1.Image.Height;
                    int Width = this.pictureBox1.Image.Width;
                    Bitmap newBitmap = new Bitmap(Width, Height);
                    Bitmap oldBitmap = (Bitmap)this.pictureBox1.Image;
                    Color pixel;
                    //拉普拉斯模板
                    int[] Laplacian ={ -1, -1, -1, -1, 9, -1, -1, -1, -1 };
                    for (int x = 1; x < Width - 1; x++)
                        for (int y = 1; y < Height - 1; y++)
                        {
                            int r = 0, g = 0, b = 0;
                            int Index = 0;
                            for (int col = -1; col <= 1; col++)
                                for (int row = -1; row <= 1; row++)
                                {
                                    pixel = oldBitmap.GetPixel(x + row, y + col); r += pixel.R * Laplacian[Index];
                                    g += pixel.G * Laplacian[Index];
                                    b += pixel.B * Laplacian[Index];
                                    Index++;
                                }
                            //处理颜色值溢出
                            r = r > 255 ? 255 : r;
                            r = r < 0 ? 0 : r;
                            g = g > 255 ? 255 : g;
                            g = g < 0 ? 0 : g;
                            b = b > 255 ? 255 : b;
                            b = b < 0 ? 0 : b;
                            newBitmap.SetPixel(x - 1, y - 1, Color.FromArgb(r, g, b));
                        }
                    this.pictureBox1.Image = newBitmap;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "信息提示");
                }
            }

     

    六. 雾化效果

    原理: 在图像中引入一定的随机值, 打乱图像中的像素值

    效果图:

     

    技术分享

     

     

    实现代码:

    [csharp] view plain copy
     
    print?
    1. private void button1_Click(object sender, EventArgs e)  
    2.  {  
    3.      //以雾化效果显示图像  
    4.      try  
    5.      {  
    6.          int Height = this.pictureBox1.Image.Height;  
    7.          int Width = this.pictureBox1.Image.Width;  
    8.          Bitmap newBitmap = new Bitmap(Width, Height);  
    9.          Bitmap oldBitmap = (Bitmap)this.pictureBox1.Image;  
    10.          Color pixel;  
    11.          for (int x = 1; x < Width - 1; x++)  
    12.              for (int y = 1; y < Height - 1; y++)  
    13.              {  
    14.                  System.Random MyRandom = new Random();  
    15.                  int k = MyRandom.Next(123456);  
    16.                  //像素块大小  
    17.                  int dx = x + k % 19;  
    18.                  int dy = y + k % 19;  
    19.                  if (dx >= Width)  
    20.                      dx = Width - 1;  
    21.                  if (dy >= Height)  
    22.                      dy = Height - 1;  
    23.                  pixel = oldBitmap.GetPixel(dx, dy);  
    24.                  newBitmap.SetPixel(x, y, pixel);  
    25.              }  
    26.          this.pictureBox1.Image = newBitmap;  
    27.      }  
    28.      catch (Exception ex)  
    29.      {  
    30.          MessageBox.Show(ex.Message, "信息提示");  
    31.      }  
    32.  }  
    技术分享
           private void button1_Click(object sender, EventArgs e)
            {
                //以雾化效果显示图像
                try
                {
                    int Height = this.pictureBox1.Image.Height;
                    int Width = this.pictureBox1.Image.Width;
                    Bitmap newBitmap = new Bitmap(Width, Height);
                    Bitmap oldBitmap = (Bitmap)this.pictureBox1.Image;
                    Color pixel;
                    for (int x = 1; x < Width - 1; x++)
                        for (int y = 1; y < Height - 1; y++)
                        {
                            System.Random MyRandom = new Random();
                            int k = MyRandom.Next(123456);
                            //像素块大小
                            int dx = x + k % 19;
                            int dy = y + k % 19;
                            if (dx >= Width)
                                dx = Width - 1;
                            if (dy >= Height)
                                dy = Height - 1;
                            pixel = oldBitmap.GetPixel(dx, dy);
                            newBitmap.SetPixel(x, y, pixel);
                        }
                    this.pictureBox1.Image = newBitmap;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "信息提示");
                }
            }

    浅谈Visual C#进行图像处理

     

    作者:彭军 http://pengjun.org.cn

    这里之所以说“浅谈”是因为我这里只是简单的介绍如何使用Visual C#进行图像的读入、保存以及对像素的访问。而不涉及太多的算法。

    一、读入图像

    在Visual C#中我们可以使用一个Picture Box控件来显示图片,如下

    [csharp] view plain copy
     
    print?
    1. private void btnOpenImage_Click(object sender, EventArgs e)  
    2.       {  
    3.           OpenFileDialog ofd = new OpenFileDialog();  
    4.           ofd.Filter = "BMP Files(*.bmp)|*.bmp|JPG Files(*.jpg;*.jpeg)|*.jpg;*.jpeg|All Files(*.*)|*.*";  
    5.           ofd.CheckFileExists = true;  
    6.           ofd.CheckPathExists = true;  
    7.           if (ofd.ShowDialog() == DialogResult.OK)  
    8.           {  
    9.               //pbxShowImage.ImageLocation = ofd.FileName;  
    10.               bmp = new Bitmap(ofd.FileName);  
    11.               if (bmp==null)  
    12.               {  
    13.                   MessageBox.Show("加载图片失败!", "错误");  
    14.                   return;  
    15.               }  
    16.               pbxShowImage.Image = bmp;  
    17.               ofd.Dispose();  
    18.           }  
    19.       }  
    技术分享
      private void btnOpenImage_Click(object sender, EventArgs e)
            {
                OpenFileDialog ofd = new OpenFileDialog();
                ofd.Filter = "BMP Files(*.bmp)|*.bmp|JPG Files(*.jpg;*.jpeg)|*.jpg;*.jpeg|All Files(*.*)|*.*";
                ofd.CheckFileExists = true;
                ofd.CheckPathExists = true;
                if (ofd.ShowDialog() == DialogResult.OK)
                {
                    //pbxShowImage.ImageLocation = ofd.FileName;
                    bmp = new Bitmap(ofd.FileName);
                    if (bmp==null)
                    {
                        MessageBox.Show("加载图片失败!", "错误");
                        return;
                    }
                    pbxShowImage.Image = bmp;
                    ofd.Dispose();
                }
            }

    其中bmp为类的一个对象:private Bitmap bmp=null;
    在使用Bitmap类和BitmapData类之前,需要使用using System.Drawing.Imaging;
    二、保存图像
    [csharp] view plain copy
     
    print?
    1. private void btnSaveImage_Click(object sender, EventArgs e)  
    2.      {  
    3.          if (bmp == null) return;  
    4.          SaveFileDialog sfd = new SaveFileDialog();  
    5.          sfd.Filter = "BMP Files(*.bmp)|*.bmp|JPG Files(*.jpg;*.jpeg)|*.jpg;*.jpeg|All Files(*.*)|*.*";  
    6.          if (sfd.ShowDialog() == DialogResult.OK)  
    7.          {  
    8.              pbxShowImage.Image.Save(sfd.FileName);  
    9.              MessageBox.Show("保存成功!","提示");  
    10.              sfd.Dispose();  
    11.          }  
    12.      }  
    技术分享
       private void btnSaveImage_Click(object sender, EventArgs e)
            {
                if (bmp == null) return;
                SaveFileDialog sfd = new SaveFileDialog();
                sfd.Filter = "BMP Files(*.bmp)|*.bmp|JPG Files(*.jpg;*.jpeg)|*.jpg;*.jpeg|All Files(*.*)|*.*";
                if (sfd.ShowDialog() == DialogResult.OK)
                {
                    pbxShowImage.Image.Save(sfd.FileName);
                    MessageBox.Show("保存成功!","提示");
                    sfd.Dispose();
                }
            }


    三、对像素的访问
    我们可以来建立一个GrayBitmapData类来做相关的处理。整个类的程序如下:

    [csharp] view plain copy
     
    print?
    1. using System;  
    2. using System.Collections.Generic;  
    3. using System.Linq;  
    4. using System.Text;  
    5. using System.Drawing;  
    6. using System.Drawing.Imaging;  
    7. using System.Windows.Forms;  
    8. namespace ImageElf  
    9. {  
    10.     class GrayBitmapData  
    11.     {  
    12.         public byte[,] Data;//保存像素矩阵  
    13.         public int Width;//图像的宽度  
    14.         public int Height;//图像的高度  
    15.         public GrayBitmapData()  
    16.         {  
    17.             this.Width = 0;  
    18.             this.Height = 0;  
    19.             this.Data = null;  
    20.         }  
    21.         public GrayBitmapData(Bitmap bmp)  
    22.         {  
    23.             BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);  
    24.             this.Width = bmpData.Width;  
    25.             this.Height = bmpData.Height;  
    26.             Data = new byte[Height, Width];  
    27.             unsafe  
    28.             {  
    29.                 byte* ptr = (byte*)bmpData.Scan0.ToPointer();  
    30.                 for (int i = 0; i < Height; i++)  
    31.                 {  
    32.                     for (int j = 0; j < Width; j++)  
    33.                     {  
    34.     //将24位的RGB彩色图转换为灰度图  
    35.                         int temp = (int)(0.114 * (*ptr++)) + (int)(0.587 * (*ptr++))+(int)(0.299 * (*ptr++));  
    36.                         Data[i, j] = (byte)temp;  
    37.                     }  
    38.                     ptr += bmpData.Stride - Width * 3;//指针加上填充的空白空间  
    39.                 }  
    40.             }  
    41.             bmp.UnlockBits(bmpData);  
    42.         }  
    43.         public GrayBitmapData(string path)  
    44.             : this(new Bitmap(path))  
    45.         {  
    46.         }  
    47.         public Bitmap ToBitmap()  
    48.         {  
    49.             Bitmap bmp=new Bitmap(Width,Height,PixelFormat.Format24bppRgb);  
    50.             BitmapData bmpData=http://www.mamicode.com/bmp.LockBits(new Rectangle(0,0,Width,Height),ImageLockMode.WriteOnly,PixelFormat.Format24bppRgb);  
    51.             unsafe  
    52.             {  
    53.                 byte* ptr=(byte*)bmpData.Scan0.ToPointer();  
    54.                 for(int i=0;i<Height;i++)  
    55.                 {  
    56.                     for(int j=0;j<Width;j++)  
    57.                     {  
    58.                         *(ptr++)=Data[i,j];  
    59.                         *(ptr++)=Data[i,j];  
    60.                         *(ptr++)=Data[i,j];  
    61.                     }  
    62.                     ptr+=bmpData.Stride-Width*3;  
    63.                 }  
    64.             }  
    65.             bmp.UnlockBits(bmpData);  
    66.             return bmp;  
    67.         }  
    68.         public void ShowImage(PictureBox pbx)  
    69.         {  
    70.             Bitmap b = this.ToBitmap();  
    71.             pbx.Image = b;  
    72.             //b.Dispose();  
    73.         }  
    74.         public void SaveImage(string path)  
    75.         {  
    76.             Bitmap b=ToBitmap();  
    77.             b.Save(path);  
    78.             //b.Dispose();  
    79.         }  
    80. //均值滤波  
    81.         public void AverageFilter(int windowSize)  
    82.         {  
    83.             if (windowSize % 2 == 0)  
    84.             {  
    85.                 return;  
    86.             }  
    87.             for (int i = 0; i < Height; i++)  
    88.             {  
    89.                 for (int j = 0; j < Width; j++)  
    90.                 {  
    91.                     int sum = 0;  
    92.                     for (int g = -(windowSize - 1) / 2; g <= (windowSize - 1) / 2; g++)  
    93.                     {  
    94.                         for (int k = -(windowSize - 1) / 2; k <= (windowSize - 1) / 2; k++)  
    95.                         {  
    96.                             int a = i + g, b = j + k;  
    97.                             if (a < 0) a = 0;  
    98.                             if (a > Height - 1) a = Height - 1;  
    99.                             if (b < 0) b = 0;  
    100.                             if (b > Width - 1) b = Width - 1;  
    101.                             sum += Data[a, b];  
    102.                         }  
    103.                     }  
    104.                     Data[i,j]=(byte)(sum/(windowSize*windowSize));  
    105.                 }  
    106.             }  
    107.         }  
    108. //中值滤波  
    109.         public void MidFilter(int windowSize)  
    110.         {  
    111.             if (windowSize % 2 == 0)  
    112.             {  
    113.                 return;  
    114.             }  
    115.             int[] temp = new int[windowSize * windowSize];  
    116.             byte[,] newdata = new byte[Height, Width];  
    117.             for (int i = 0; i < Height; i++)  
    118.             {  
    119.                 for (int j = 0; j < Width; j++)  
    120.                 {  
    121.                     int n = 0;  
    122.                     for (int g = -(windowSize - 1) / 2; g <= (windowSize - 1) / 2; g++)  
    123.                     {  
    124.                         for (int k = -(windowSize - 1) / 2; k <= (windowSize - 1) / 2; k++)  
    125.                         {  
    126.                             int a = i + g, b = j + k;  
    127.                             if (a < 0) a = 0;  
    128.                             if (a > Height - 1) a = Height - 1;  
    129.                             if (b < 0) b = 0;  
    130.                             if (b > Width - 1) b = Width - 1;  
    131.                             temp[n++]= Data[a, b];  
    132.                         }  
    133.                     }  
    134.                     newdata[i, j] = GetMidValue(temp,windowSize*windowSize);  
    135.                 }  
    136.             }  
    137.             for (int i = 0; i < Height; i++)  
    138.             {  
    139.                 for (int j = 0; j < Width; j++)  
    140.                 {  
    141.                     Data[i, j] = newdata[i, j];  
    142.                 }  
    143.             }  
    144.         }  
    145. //获得一个向量的中值  
    146.         private byte GetMidValue(int[] t, int length)  
    147.         {  
    148.             int temp = 0;  
    149.             for (int i = 0; i < length - 2; i++)  
    150.             {  
    151.                 for (int j = i + 1; j < length - 1; j++)  
    152.                 {  
    153.                     if (t[i] > t[j])  
    154.                     {  
    155.                         temp = t[i];  
    156.                         t[i] = t[j];  
    157.                         t[j] = temp;  
    158.                     }  
    159.                 }  
    160.             }  
    161.             return (byte)t[(length - 1) / 2];  
    162.         }  
    163. //一种新的滤波方法,是亮的更亮、暗的更暗  
    164.         public void NewFilter(int windowSize)  
    165.         {  
    166.             if (windowSize % 2 == 0)  
    167.             {  
    168.                 return;  
    169.             }  
    170.             for (int i = 0; i < Height; i++)  
    171.             {  
    172.                 for (int j = 0; j < Width; j++)  
    173.                 {  
    174.                     int sum = 0;  
    175.                     for (int g = -(windowSize - 1) / 2; g <= (windowSize - 1) / 2; g++)  
    176.                     {  
    177.                         for (int k = -(windowSize - 1) / 2; k <= (windowSize - 1) / 2; k++)  
    178.                         {  
    179.                             int a = i + g, b = j + k;  
    180.                             if (a < 0) a = 0;  
    181.                             if (a > Height - 1) a = Height - 1;  
    182.                             if (b < 0) b = 0;  
    183.                             if (b > Width - 1) b = Width - 1;  
    184.                             sum += Data[a, b];  
    185.                         }  
    186.                     }  
    187.                     double avg = (sum+0.0) / (windowSize * windowSize);  
    188.                     if (avg / 255 < 0.5)  
    189.                     {  
    190.                         Data[i, j] = (byte)(2 * avg / 255 * Data[i, j]);  
    191.                     }  
    192.                     else  
    193.                     {  
    194.                         Data[i,j]=(byte)((1-2*(1-avg/255.0)*(1-Data[i,j]/255.0))*255);  
    195.                     }  
    196.                 }  
    197.             }  
    198.         }  
    199. //直方图均衡  
    200.         public void HistEqual()  
    201.         {  
    202.             double[] num = new double[256] ;  
    203.             for(int i=0;i<256;i++) num[i]=0;  
    204.             for (int i = 0; i < Height; i++)  
    205.             {  
    206.                 for (int j = 0; j < Width; j++)  
    207.                 {  
    208.                     num[Data[i, j]]++;  
    209.                 }  
    210.             }  
    211.             double[] newGray = new double[256];  
    212.             double n = 0;  
    213.             for (int i = 0; i < 256; i++)  
    214.             {  
    215.                 n += num[i];  
    216.                 newGray[i] = n * 255 / (Height * Width);  
    217.             }  
    218.             for (int i = 0; i < Height; i++)  
    219.             {  
    220.                 for (int j = 0; j < Width; j++)  
    221.                 {  
    222.                     Data[i,j]=(byte)newGray[Data[i,j]];  
    223.                 }  
    224.             }  
    225.         }  
    226. }  
    227. }  
    技术分享
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Drawing;
    using System.Drawing.Imaging;
    using System.Windows.Forms;
    namespace ImageElf
    {
        class GrayBitmapData
        {
            public byte[,] Data;//保存像素矩阵
            public int Width;//图像的宽度
            public int Height;//图像的高度
            public GrayBitmapData()
            {
                this.Width = 0;
                this.Height = 0;
                this.Data = http://www.mamicode.com/null;>
    


    GrayBitmapData类中,只要我们对一个二维数组Data进行一系列的操作就是对图片的操作处理。在窗口上,我们可以使用
    一个按钮来做各种调用:

     

    [csharp] view plain copy
     
    print?
    1. //均值滤波  
    2.         private void btnAvgFilter_Click(object sender, EventArgs e)  
    3.         {  
    4.             if (bmp == null) return;  
    5.             GrayBitmapData gbmp = new GrayBitmapData(bmp);  
    6.             gbmp.AverageFilter(3);  
    7.             gbmp.ShowImage(pbxShowImage);  
    8.         }  
    9. //转换为灰度图  
    10.         private void btnToGray_Click(object sender, EventArgs e)  
    11.         {  
    12.             if (bmp == null) return;  
    13.             GrayBitmapData gbmp = new GrayBitmapData(bmp);  
    14.             gbmp.ShowImage(pbxShowImage);  
    15.         }  
    16.    
    技术分享
    //均值滤波
            private void btnAvgFilter_Click(object sender, EventArgs e)
            {
                if (bmp == null) return;
                GrayBitmapData gbmp = new GrayBitmapData(bmp);
                gbmp.AverageFilter(3);
                gbmp.ShowImage(pbxShowImage);
            }
    //转换为灰度图
            private void btnToGray_Click(object sender, EventArgs e)
            {
                if (bmp == null) return;
                GrayBitmapData gbmp = new GrayBitmapData(bmp);
                gbmp.ShowImage(pbxShowImage);
            }
     

     

     

    四、总结

    在Visual c#中对图像进行处理或访问,需要先建立一个Bitmap对象,然后通过其LockBits方法来获得一个BitmapData类的对象,然后通过获得其像素数据的首地址来对Bitmap对象的像素数据进行操作。当然,一种简单但是速度慢的方法是用Bitmap类的GetPixel和SetPixel方法。其中BitmapData类的Stride属性为每行像素所占的字节。

     

    C# colorMatrix 对图片的处理 : 亮度调整 抓屏 翻转 随鼠标画矩形

    1.图片亮度处理

    [csharp] view plain copy
     
    print?
    1. private void btn_Grap_Click(object sender, EventArgs e)  
    2.        {  
    3.            //亮度百分比  
    4.            int percent = 50;  
    5.            Single v = 0.006F * percent;      
    6.            Single[][] matrix = {           
    7.                new Single[] { 1, 0, 0, 0, 0 },           
    8.                new Single[] { 0, 1, 0, 0, 0 },            
    9.                new Single[] { 0, 0, 1, 0, 0 },           
    10.                new Single[] { 0, 0, 0, 1, 0 },           
    11.                new Single[] { v, v, v, 0, 1 }       
    12.            };      
    13.            System.Drawing.Imaging.ColorMatrix cm = new System.Drawing.Imaging.ColorMatrix(matrix);  
    14.            System.Drawing.Imaging.ImageAttributes attr = new System.Drawing.Imaging.ImageAttributes();      
    15.            attr.SetColorMatrix(cm);      
    16.            //Image tmp   
    17.            Image tmp = Image.FromFile("1.png");  
    18.   
    19.            this.pictureBox_Src.Image = Image.FromFile("1.png");  
    20.   
    21.            Graphics g = Graphics.FromImage(tmp);    
    22.            try    
    23.            {  
    24.                Rectangle destRect = new Rectangle(0, 0, tmp.Width, tmp.Height);          
    25.                g.DrawImage(tmp, destRect, 0, 0, tmp.Width, tmp.Height, GraphicsUnit.Pixel, attr);      
    26.            }      
    27.            finally      
    28.            {          
    29.                g.Dispose();      
    30.            }  
    31.   
    32.            this.pictureBox_Dest.Image = (Image)tmp.Clone();  
    33.        }  
    技术分享
     private void btn_Grap_Click(object sender, EventArgs e)
            {
                //亮度百分比
                int percent = 50;
                Single v = 0.006F * percent;    
                Single[][] matrix = {         
                    new Single[] { 1, 0, 0, 0, 0 },         
                    new Single[] { 0, 1, 0, 0, 0 },          
                    new Single[] { 0, 0, 1, 0, 0 },         
                    new Single[] { 0, 0, 0, 1, 0 },         
                    new Single[] { v, v, v, 0, 1 }     
                };    
                System.Drawing.Imaging.ColorMatrix cm = new System.Drawing.Imaging.ColorMatrix(matrix);
                System.Drawing.Imaging.ImageAttributes attr = new System.Drawing.Imaging.ImageAttributes();    
                attr.SetColorMatrix(cm);    
                //Image tmp 
                Image tmp = Image.FromFile("1.png");
     
                this.pictureBox_Src.Image = Image.FromFile("1.png");
     
                Graphics g = Graphics.FromImage(tmp);  
                try  
                {
                    Rectangle destRect = new Rectangle(0, 0, tmp.Width, tmp.Height);        
                    g.DrawImage(tmp, destRect, 0, 0, tmp.Width, tmp.Height, GraphicsUnit.Pixel, attr);    
                }    
                finally    
                {        
                    g.Dispose();    
                }
     
                this.pictureBox_Dest.Image = (Image)tmp.Clone();
            }
     


    2.抓屏将生成的图片显示在pictureBox

    [csharp] view plain copy
     
    print?
    1. private void btn_Screen_Click(object sender, EventArgs e)  
    2.       {  
    3.           Image myImage = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);  
    4.           Graphics g = Graphics.FromImage(myImage);  
    5.           g.CopyFromScreen(new Point(0, 0), new Point(0, 0), new Size(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height));  
    6.           //IntPtr dc1 = g.GetHdc();      //此处这两句多余,具体看最后GetHdc()定义  
    7.           //g.ReleaseHdc(dc1);             
    8.           g.Dispose();  
    9.           this.pictureBox_Src.SizeMode = PictureBoxSizeMode.StretchImage;  
    10.           this.pictureBox_Src.Image = myImage;  
    11.           myImage.Save("Screen", ImageFormat.Png);  
    12.    }  
    技术分享
      private void btn_Screen_Click(object sender, EventArgs e)
            {
                Image myImage = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
                Graphics g = Graphics.FromImage(myImage);
                g.CopyFromScreen(new Point(0, 0), new Point(0, 0), new Size(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height));
                //IntPtr dc1 = g.GetHdc();      //此处这两句多余,具体看最后GetHdc()定义
                //g.ReleaseHdc(dc1);           
                g.Dispose();
                this.pictureBox_Src.SizeMode = PictureBoxSizeMode.StretchImage;
                this.pictureBox_Src.Image = myImage;
                myImage.Save("Screen", ImageFormat.Png);
         }


    3.翻转

     

    [csharp] view plain copy
     
    print?
    1. private void btn_RotateFlip_Click(object sender, EventArgs e)  
    2.      {  
    3.          this.pictureBox_Src.Image = Image.FromFile("1.png");  
    4.   
    5.          Image tmp = Image.FromFile("1.png");  
    6.   
    7.          tmp.RotateFlip(RotateFlipType.Rotate90FlipNone);  
    8.          this.pictureBox_Dest.Image = tmp;  
    9.      }  
    技术分享
       private void btn_RotateFlip_Click(object sender, EventArgs e)
            {
                this.pictureBox_Src.Image = Image.FromFile("1.png");
     
                Image tmp = Image.FromFile("1.png");
     
                tmp.RotateFlip(RotateFlipType.Rotate90FlipNone);
                this.pictureBox_Dest.Image = tmp;
            }

     

     

    4.跟随鼠标在 pictureBox的图片上画矩形

    [csharp] view plain copy
     
    print?
    1. private int intStartX = 0;  
    2.       private int intStartY = 0;  
    3.       private bool isMouseDraw = false;  
    4.   
    5.       private void pictureBox_Src_MouseDown(object sender, MouseEventArgs e)  
    6.       {  
    7.           isMouseDraw = true;  
    8.   
    9.           intStartX = e.X;  
    10.           intStartY = e.Y;  
    11.       }  
    12.   
    13.       private void pictureBox_Src_MouseMove(object sender, MouseEventArgs e)  
    14.       {  
    15.           if (isMouseDraw)  
    16.           {  
    17.               try  
    18.               {  
    19.                   //Image tmp = Image.FromFile("1.png");  
    20.                   Graphics g = this.pictureBox_Src.CreateGraphics();  
    21.                   //清空上次画下的痕迹  
    22.                   g.Clear(this.pictureBox_Src.BackColor);  
    23.                   Brush brush = new SolidBrush(Color.Red);  
    24.                   Pen pen = new Pen(brush, 1);  
    25.                   pen.DashStyle = DashStyle.Solid;  
    26.                   g.DrawRectangle(pen, new Rectangle(intStartX > e.X ? e.X : intStartX, intStartY > e.Y ? e.Y : intStartY, Math.Abs(e.X - intStartX), Math.Abs(e.Y - intStartY)));  
    27.                   g.Dispose();  
    28.                   //this.pictureBox_Src.Image = tmp;  
    29.               }  
    30.               catch (Exception ex)  
    31.               {  
    32.                   ex.ToString();  
    33.               }  
    34.           }  
    35.       }  
    36.   
    37.       private void pictureBox_Src_MouseUp(object sender, MouseEventArgs e)  
    38.       {  
    39.           isMouseDraw = false;  
    40.   
    41.           intStartX = 0;  
    42.           intStartY = 0;  
    43.       }  
    技术分享
      private int intStartX = 0;
            private int intStartY = 0;
            private bool isMouseDraw = false;
     
            private void pictureBox_Src_MouseDown(object sender, MouseEventArgs e)
            {
                isMouseDraw = true;
     
                intStartX = e.X;
                intStartY = e.Y;
            }
     
            private void pictureBox_Src_MouseMove(object sender, MouseEventArgs e)
            {
                if (isMouseDraw)
                {
                    try
                    {
                        //Image tmp = Image.FromFile("1.png");
                        Graphics g = this.pictureBox_Src.CreateGraphics();
                        //清空上次画下的痕迹
                        g.Clear(this.pictureBox_Src.BackColor);
                        Brush brush = new SolidBrush(Color.Red);
                        Pen pen = new Pen(brush, 1);
                        pen.DashStyle = DashStyle.Solid;
                        g.DrawRectangle(pen, new Rectangle(intStartX > e.X ? e.X : intStartX, intStartY > e.Y ? e.Y : intStartY, Math.Abs(e.X - intStartX), Math.Abs(e.Y - intStartY)));
                        g.Dispose();
                        //this.pictureBox_Src.Image = tmp;
                    }
                    catch (Exception ex)
                    {
                        ex.ToString();
                    }
                }
            }
     
            private void pictureBox_Src_MouseUp(object sender, MouseEventArgs e)
            {
                isMouseDraw = false;
     
                intStartX = 0;
                intStartY = 0;
            }


    5.取灰度

     

    [csharp] view plain copy
     
    print?
    1. private void btn_GetGray_Click(object sender, EventArgs e)  
    2.        {  
    3.            this.pictureBox_Src.Image = Image.FromFile("1.png");  
    4.            Bitmap currentBitmap = new Bitmap(this.pictureBox_Src.Image);  
    5.            Graphics g = Graphics.FromImage(currentBitmap);  
    6.            ImageAttributes ia = new ImageAttributes();  
    7.            float[][] colorMatrix =   {      
    8.                new   float[]   {0.299f,   0.299f,   0.299f,   0,   0},  
    9.                new   float[]   {0.587f,   0.587f,   0.587f,   0,   0},  
    10.                new   float[]   {0.114f,   0.114f,   0.114f,   0,   0},  
    11.                new   float[]   {0,   0,   0,   1,   0},  
    12.                new   float[]   {0,   0,   0,   0,   1}  
    13.            };  
    14.            ColorMatrix cm = new ColorMatrix(colorMatrix);  
    15.            ia.SetColorMatrix(cm, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);  
    16.            g.DrawImage(currentBitmap, new Rectangle(0, 0, currentBitmap.Width, currentBitmap.Height), 0, 0, currentBitmap.Width, currentBitmap.Height, GraphicsUnit.Pixel, ia);  
    17.            this.pictureBox_Dest.Image = (Image)(currentBitmap.Clone());  
    18.            g.Dispose();  
    19.        }  
    技术分享
     private void btn_GetGray_Click(object sender, EventArgs e)
            {
                this.pictureBox_Src.Image = Image.FromFile("1.png");
                Bitmap currentBitmap = new Bitmap(this.pictureBox_Src.Image);
                Graphics g = Graphics.FromImage(currentBitmap);
                ImageAttributes ia = new ImageAttributes();
                float[][] colorMatrix =   {    
                    new   float[]   {0.299f,   0.299f,   0.299f,   0,   0},
                    new   float[]   {0.587f,   0.587f,   0.587f,   0,   0},
                    new   float[]   {0.114f,   0.114f,   0.114f,   0,   0},
                    new   float[]   {0,   0,   0,   1,   0},
                    new   float[]   {0,   0,   0,   0,   1}
                };
                ColorMatrix cm = new ColorMatrix(colorMatrix);
                ia.SetColorMatrix(cm, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
                g.DrawImage(currentBitmap, new Rectangle(0, 0, currentBitmap.Width, currentBitmap.Height), 0, 0, currentBitmap.Width, currentBitmap.Height, GraphicsUnit.Pixel, ia);
                this.pictureBox_Dest.Image = (Image)(currentBitmap.Clone());
                g.Dispose();
            }
     

     

     

    Graphics.GetHdc 方法

    .NET Framework 4

    获取与此 Graphics 关联的设备上下文的句柄。

    命名空间:  System.Drawing
    程序集:  System.Drawing(在 System.Drawing.dll 中)

    语法

    [SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags =

    SecurityPermissionFlag.UnmanagedCode)]

    public IntPtr GetHdc()

    返回值

    类型:System.IntPtr
    与此 Graphics 关联的设备上下文的句柄。

    实现

    IDeviceContext.GetHdc()

    备注


    设备上下文是一个基于 GDI 的 Windows 结构,它定义一组图形对象及其关联的特性,以及影响输出的图形模式。 此方法返回该设备上下文(字体除外)。由于未选择字体,使用 GetHdc 方法返回的句柄对 FromHdc 方法进行调用将会失败。

    GetHdc 方法调用和 ReleaseHdc 方法调用必须成对出现。 在 GetHdc 和 ReleaseHdc 方法对的范围内,通常仅调用 GDI 函数。 在该范围内对 Graphics(它产生 hdc 参数)的 GDI+ 方法的调用因 ObjectBusy 错误而失败。 此外,GDI+ 忽略后续操作中对 hdc 参数的 Graphics 所做的所有状态更改。

    示例


    下面的代码示例设计为与 Windows 窗体一起使用,它需要 PaintEventArgse,即 Paint 事件处理程序的一个参数。 该示例演示如何调用 Windows GDI 函数以执行与 GDI+ Graphics 方法相同的任务。 代码执行下列操作:

    • 为 Windows DLL 文件 gdi32.dll 定义互操作性 DllImportAttribute 特性。 此 DLL 包含所需的 GDI 函数。
    • 将该 DLL 中的 Rectangle 函数定义为外部函数。
    • 创建一支红色钢笔。
    • 利用该钢笔,使用 GDI+ DrawRectangle 方法将矩形绘制到屏幕。
    • 定义内部指针类型变量 hdc 并将它的值设置为窗体的设备上下文句柄。
    • 使用 GDI Rectangle 函数将矩形绘制到屏幕。

    释放由 hdc 参数表示的设备上下文。

    [csharp] view plain copy
     
    print?
    1. public class GDI  
    2. {  
    3.     [System.Runtime.InteropServices.DllImport("gdi32.dll")]  
    4.     internal static extern bool Rectangle(  
    5.        IntPtr hdc,  
    6.        int ulCornerX, int ulCornerY,  
    7.        int lrCornerX, int lrCornerY);  
    8. }  
    9.    
    10. [System.Security.Permissions.SecurityPermission(  
    11. System.Security.Permissions.SecurityAction.LinkDemand, Flags =  
    12. System.Security.Permissions.SecurityPermissionFlag.UnmanagedCode)]             
    13. private void GetHdcForGDI1(PaintEventArgs e)  
    14. {  
    15.     // Create pen.  
    16.     Pen redPen = new Pen(Color.Red, 1);  
    17.    
    18.     // Draw rectangle with GDI+.  
    19.     e.Graphics.DrawRectangle(redPen, 10, 10, 100, 50);  
    20.    
    21.     // Get handle to device context.  
    22.     IntPtr hdc = e.Graphics.GetHdc();  
    23.    
    24.     // Draw rectangle with GDI using default pen.  
    25.     GDI.Rectangle(hdc, 10, 70, 110, 120);  
    26.    
    27.     // Release handle to device context.  
    28.     e.Graphics.ReleaseHdc(hdc);  
    29. }  
    技术分享
    public class GDI
    {
        [System.Runtime.InteropServices.DllImport("gdi32.dll")]
        internal static extern bool Rectangle(
           IntPtr hdc,
           int ulCornerX, int ulCornerY,
           int lrCornerX, int lrCornerY);
    }
     
    [System.Security.Permissions.SecurityPermission(
    System.Security.Permissions.SecurityAction.LinkDemand, Flags =
    System.Security.Permissions.SecurityPermissionFlag.UnmanagedCode)]           
    private void GetHdcForGDI1(PaintEventArgs e)
    {
        // Create pen.
        Pen redPen = new Pen(Color.Red, 1);
     
        // Draw rectangle with GDI+.
        e.Graphics.DrawRectangle(redPen, 10, 10, 100, 50);
     
        // Get handle to device context.
        IntPtr hdc = e.Graphics.GetHdc();
     
        // Draw rectangle with GDI using default pen.
        GDI.Rectangle(hdc, 10, 70, 110, 120);
     
        // Release handle to device context.
        e.Graphics.ReleaseHdc(hdc);
    }

    C#图像处理(各种旋转、改变大小、柔化、锐化、雾化、底片、浮雕、黑白、滤镜效果)