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)

一、各种旋转、改变大小

注意：先要添加画图相关的using引用。

//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。

//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。

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，

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:

代码实现:

          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:

 

 

 

 

 

代码实现:

       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:

 

 

 

 

代码实现:

        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:

 

 

 

 

代码实现:

        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:

 

 

 

 

实现代码:

       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:

 

 

实现代码:

       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：
        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
        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：
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 = null;
        }

        public GrayBitmapData(Bitmap bmp)
        {
            BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
            this.Width = bmpData.Width;
            this.Height = bmpData.Height;
            Data = new byte[Height, Width];
            unsafe
            {
                byte* ptr = (byte*)bmpData.Scan0.ToPointer();
                for (int i = 0; i < Height; i++)
                {
                    for (int j = 0; j < Width; j++)
                    {
    //将24位的RGB彩色图转换为灰度图
                        int temp = (int)(0.114 * (*ptr++)) + (int)(0.587 * (*ptr++))+(int)(0.299 * (*ptr++));
                        Data[i, j] = (byte)temp;
                    }
                    ptr += bmpData.Stride - Width * 3;//指针加上填充的空白空间
                }
            }
            bmp.UnlockBits(bmpData);
        }

        public GrayBitmapData(string path)
            : this(new Bitmap(path))
        {
        }

        public Bitmap ToBitmap()
        {
            Bitmap bmp=new Bitmap(Width,Height,PixelFormat.Format24bppRgb);
            BitmapData bmpData=bmp.LockBits(new Rectangle(0,0,Width,Height),ImageLockMode.WriteOnly,PixelFormat.Format24bppRgb);
            unsafe
            {
                byte* ptr=(byte*)bmpData.Scan0.ToPointer();
                for(int i=0;i<Height;i++)
                {
                    for(int j=0;j<Width;j++)
                    {
                        *(ptr++)=Data[i,j];
                        *(ptr++)=Data[i,j];
                        *(ptr++)=Data[i,j];
                    }
                    ptr+=bmpData.Stride-Width*3;
                }
            }
            bmp.UnlockBits(bmpData);
            return bmp;
        }

        public void ShowImage(PictureBox pbx)
        {
            Bitmap b = this.ToBitmap();
            pbx.Image = b;
            //b.Dispose();
        }

        public void SaveImage(string path)
        {
            Bitmap b=ToBitmap();
            b.Save(path);
            //b.Dispose();
        }
//均值滤波
        public void AverageFilter(int windowSize)
        {
            if (windowSize % 2 == 0)
            {
                return;
            }

            for (int i = 0; i < Height; i++)
            {
                for (int j = 0; j < Width; j++)
                {
                    int sum = 0;
                    for (int g = -(windowSize - 1) / 2; g <= (windowSize - 1) / 2; g++)
                    {
                        for (int k = -(windowSize - 1) / 2; k <= (windowSize - 1) / 2; k++)
                        {
                            int a = i + g, b = j + k;
                            if (a < 0) a = 0;
                            if (a > Height - 1) a = Height - 1;
                            if (b < 0) b = 0;
                            if (b > Width - 1) b = Width - 1;
                            sum += Data[a, b];
                        }
                    }
                    Data[i,j]=(byte)(sum/(windowSize*windowSize));
                }
            }
        }
//中值滤波
        public void MidFilter(int windowSize)
        {
            if (windowSize % 2 == 0)
            {
                return;
            }

            int[] temp = new int[windowSize * windowSize];
            byte[,] newdata = new byte[Height, Width];
            for (int i = 0; i < Height; i++)
            {
                for (int j = 0; j < Width; j++)
                {
                    int n = 0;
                    for (int g = -(windowSize - 1) / 2; g <= (windowSize - 1) / 2; g++)
                    {
                        for (int k = -(windowSize - 1) / 2; k <= (windowSize - 1) / 2; k++)
                        {
                            int a = i + g, b = j + k;
                            if (a < 0) a = 0;
                            if (a > Height - 1) a = Height - 1;
                            if (b < 0) b = 0;
                            if (b > Width - 1) b = Width - 1;
                            temp[n++]= Data[a, b];
                        }
                    }
                    newdata[i, j] = GetMidValue(temp,windowSize*windowSize);
                }
            }

            for (int i = 0; i < Height; i++)
            {
                for (int j = 0; j < Width; j++)
                {
                    Data[i, j] = newdata[i, j];
                }
            }
        }
//获得一个向量的中值
        private byte GetMidValue(int[] t, int length)
        {
            int temp = 0;
            for (int i = 0; i < length - 2; i++)
            {
                for (int j = i + 1; j < length - 1; j++)
                {
                    if (t[i] > t[j])
                    {
                        temp = t[i];
                        t[i] = t[j];
                        t[j] = temp;
                    }
                }
            }

            return (byte)t[(length - 1) / 2];
        }
//一种新的滤波方法，是亮的更亮、暗的更暗
        public void NewFilter(int windowSize)
        {
            if (windowSize % 2 == 0)
            {
                return;
            }

            for (int i = 0; i < Height; i++)
            {
                for (int j = 0; j < Width; j++)
                {
                    int sum = 0;
                    for (int g = -(windowSize - 1) / 2; g <= (windowSize - 1) / 2; g++)
                    {
                        for (int k = -(windowSize - 1) / 2; k <= (windowSize - 1) / 2; k++)
                        {
                            int a = i + g, b = j + k;
                            if (a < 0) a = 0;
                            if (a > Height - 1) a = Height - 1;
                            if (b < 0) b = 0;
                            if (b > Width - 1) b = Width - 1;
                            sum += Data[a, b];
                        }
                    }
                    double avg = (sum+0.0) / (windowSize * windowSize);
                    if (avg / 255 < 0.5)
                    {
                        Data[i, j] = (byte)(2 * avg / 255 * Data[i, j]);
                    }
                    else
                    {
                        Data[i,j]=(byte)((1-2*(1-avg/255.0)*(1-Data[i,j]/255.0))*255);
                    }
                }
            }
        }
//直方图均衡
        public void HistEqual()
        {
            double[] num = new double[256] ;
            for(int i=0;i<256;i++) num[i]=0;

            for (int i = 0; i < Height; i++)
            {
                for (int j = 0; j < Width; j++)
                {
                    num[Data[i, j]]++;
                }
            }

            double[] newGray = new double[256];
            double n = 0;
            for (int i = 0; i < 256; i++)
            {
                n += num[i];
                newGray[i] = n * 255 / (Height * Width);
            }

            for (int i = 0; i < Height; i++)
            {
                for (int j = 0; j < Width; j++)
                {
                    Data[i,j]=(byte)newGray[Data[i,j]];
                }
            }
        }

}
}
在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：
//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

 

        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 = newSystem.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

 

        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), newSize(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

 

        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

        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

 

        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。

 

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);

}