C# Image to CSV

這是一張10x10 pixel的點陣圖，我將它利用Photoshop放大成3200%















這個CSV檔是由上圖所讀取出來的，0代表黑色，255代表白色

以觀念來說這個CSV檔裡的數值是表示最上面那張10x10的圖沒錯

為了好看我用較好理解的寫法實現它，C#寫法如下:

   //開啟圖至pictureBox1
   private void btnOpen_Click(object sender, EventArgs e)
   {
       OpenFileDialog openFileDialog = new OpenFileDialog();
       openFileDialog.Filter = "BMP(*.BMP)|*.bmp|" + "所有檔案|*.*";
       if (openFileDialog.ShowDialog() == DialogResult.OK)
       {
           pictureBox1.Width = Image.FromFile(openFileDialog.FileName).Width;
           pictureBox1.Height = Image.FromFile(openFileDialog.FileName).Height;
           pictureBox1.Image = Image.FromFile(openFileDialog.FileName);
       }
   }

因為是黑白影像，這邊我只對R讀取。

private void btnProcess_Click(object sender, EventArgs e)
{           
 FileStream fw = new FileStream( @"c:\r.csv", FileMode.Open);
 StreamWriter sw = new StreamWriter(fw, System.Text.Encoding.Default);
 string str;
 Bitmap p1 = (Bitmap)pictureBox1.Image;
 int[,] r = new int[p1.Height, p1.Width];
 int[,] g = new int[p1.Height, p1.Width];
 int[,] b = new int[p1.Height, p1.Width];

 for (int i = 0; i < p1.Height; i++)
 {
  for (int j = 0; j < p1.Width; j++)
  {
   r[i, j] = p1.GetPixel(j, i).R; 
   if (j < p1.Width )
   {
    //最後一個值後面不用逗號
    if (j == p1.Width -1)
    {
     str = r[i, j] + "";
     sw.Write(str);
    }
    else
    {
     str = r[i, j] + ",";
     sw.Write(str);
    }
   }                   
  }
  //換行繼續下一個j迴圈寫入
  sw.Write('\n');
 } 
 sw.Flush();
 fw.Close();
 MessageBox.Show("執行完畢");
}

範例檔下載

C# picturebox1上圖片轉為矩陣

假設form上有picturebox1及picturebox2
我想做的事就是將picturebox1上圖片轉存為矩陣
對這矩陣做一些演算法之類的手腳，再將這矩陣轉換為影像顯示在picturebox2上...
雖然人的腦容量很大，但常常會忘了怎麼寫...

我這裡只是將lena存到矩陣再將矩陣轉存為影像顯示在picturebox2上















上圖Process按鈕的寫法為：

private void btnProcess_Click(object sender, EventArgs e)
{
 Bitmap p1 = (Bitmap)pictureBox1.Image;
 int[,] r = new int[p1.Height, p1.Width];
 int[,] g = new int[p1.Height, p1.Width];
 int[,] b = new int[p1.Height, p1.Width];
 
 for (int i = 0; i < p1.Height; i++)
 {
  for (int j = 0; j < p1.Width; j++)
  {
   r[i, j] = p1.GetPixel(j, i).R;
   g[i, j] = p1.GetPixel(j, i).G;
   b[i, j] = p1.GetPixel(j, i).B;
  }
 }
 
 Bitmap p2 = new Bitmap(p1.Height,p1.Width);
 for (int i = 0; i < p1.Height; i++)
 {
  for (int j = 0; j < p1.Width; j++)
  {
   p2.SetPixel(j,i,Color.FromArgb(r[i,j],g[i,j],b[i,j]));
  }
 }
 pictureBox2.Image = p2;
}

C# picturebox1與picturebox2 影像處理問題

如果說實際上原圖與修改過後的圖要放在同一個form裡做比較，如果拿我之前寫的GetPixel與SetPixel方式下去改，以當下直覺寫法可能會為

private void btnGray_Click(object sender, EventArgs e)
{
 try
 {
  Bitmap bm1 = (Bitmap)pictureBox1.Image;
  Bitmap bm2 = bm1;        
  int w1 = pictureBox1.Image.Width;
  int h1 = pictureBox1.Image.Width;
  int x;
  int y;
  for (y = 0; y <= h1 - 1; y++)
  {
   for (x = 0; x <= w1 - 1; x++)
   {
    Color c1 = bm1.GetPixel(x, y);
    int r1 = c1.R;
    int g1 = c1.G;
    int b1 = c1.B;
    int avg1 = (r1 + g1 + b1) / 3;
    bm2.SetPixel(x, y, Color.FromArgb(avg1, avg1, avg1));
   }
  }
  pictureBox2.Image = bm2;
 }
 
 catch (Exception ex)
 {
  MessageBox.Show(ex.Message);
 }
}

而立即顯示出來的圖可能是沒有問題或是怪怪的...















而當我按下Refresh按鍵時會發現...
















實質上bm2=bm1以為是另外複製一個圖片到picturebox2上，但當我們在做影像處理時在記憶體中是用相同的區塊...

所以可以寫成這樣...

private void btnProcess_Click(object sender, EventArgs e)
{
 Bitmap p1 = (Bitmap)pictureBox1.Image;
 Bitmap p2 = new Bitmap(p1.Height, p1.Width);
 int avg;
 for (int i = 0; i < p1.Height; i++)
 {
  for (int j = 0; j < p1.Width; j++)
  {
   avg = (p1.GetPixel(i,j).R + p1.GetPixel(i,j).G + p1.GetPixel(i,j).B)/3;
   p2.SetPixel(i, j, Color.FromArgb(avg, avg, avg));
  }
 }
 pictureBox2.Image = p2;
}

當我按完Process再按Refresh時，picturebox1還是保持彩色圖片...

C# 連接 MySQL

下載MySQL Connector Net 5.2.5並安裝
加入參考MySql.Data

using MySql.Data.MySqlClient;
//...
//略
//...
 
//連接按鈕
private void connectBtn_Click(object sender, System.EventArgs e)
{
 if (conn != null)
 conn.Close();
 //連接字串
 string connStr = String.Format("server=localhost;user id=root; password=123456; database=addressbook; pooling=false");
 
 try
 {
  conn = new MySqlConnection( connStr );
  conn.Open();
  //取得資料表
  GetTable();        
 }
 catch (MySqlException ex)
 {
  MessageBox.Show( "連接失敗：" + ex.Message );
 }
}
 
//取得資料表
private void GetTable()
{
 try
 {
  data = new DataTable();
  //顯示好友名單資料表
  da = new MySqlDataAdapter("SELECT * FROM friend" , conn);
  cb = new MySqlCommandBuilder(da);
  da.Fill(data);
  //放到DataGrid顯示
  dataGrid.DataSource = data;
 }
 catch (MySqlException ex)
 {
  MessageBox.Show("資料表顯示異常：" + ex.Message);
 }
            
}
 
//更新按鈕
private void updateBtn_Click(object sender, System.EventArgs e)
{
 DataTable changes = data.GetChanges();
 da.Update( changes );
 data.AcceptChanges();
}

將addressbook資料庫裡的friend資料表顯示到DataGrid
在DataGrid裡修改完資料可按更新按鈕來更新資料庫裡的資料
參考於MySQL Connector Net 5.2.5裡的Samples

如果有安裝MySQL Connector Net 5.2.5可以到以下路徑找
C:\Program Files\MySQL\MySQL Connector Net 5.2.5\Samples\Table Editor\cs

C# 利用指標灰階化影像

這個方法比起GetPixel、SetPixel方法速度較為優秀許多，但是撰寫起來也是相較之下較困難，當然這是對於我這個C功力較不深厚的我而言，在這裡做個筆記，以防每次突然要用到還得翻箱倒櫃。
參考了「井民全」先生的這篇「撰寫影像處理程式 難不倒我 !! - 簡單的數位影像處理 ( C# 篇)」從而得知「Christian Graus」的這篇「http://www.codeproject.com/KB/GDI-plus/csharpgraphicfilters11.aspx」，而裡面就有一小段GrayScale灰階化的程式碼，這段程式碼實際上run起來跟我另外用VB6的GetPixel、SetPixel撰寫比較起來執行效率真的有很明顯的差異。

開啟圖片





















灰階化
利用Christian Graus的方式

public static bool GrayScale(Bitmap b)
{      
 BitmapData bmData = b.LockBits(new Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb); 
 int stride = bmData.Stride;
 System.IntPtr Scan0 = bmData.Scan0; 
 unsafe
 {
  byte * p = (byte *)(void *)Scan0; 
  int nOffset = stride - b.Width*3; 
  byte red, green, blue;  
  for(int y=0; y< b.Height ; ++y)
  {
   for(int x=0; x < b.Width; ++x )
   {
    blue = p[0];
    green = p[1];
    red = p[2]; 
    p[0] = p[1] = p[2] = (byte)(.299 * red + .587 * green + .114 * blue); 
    p += 3;
   }
   p += nOffset;
  }
 } 
 b.UnlockBits(bmData); 
 return true;
}

Sample SourceCode:
Download

C# 簡單一鍵影像灰階化

利用GetPixel與SetPixel達到簡易的圖片灰階化處理。

開啟圖檔

private void btnOpen_Click(object sender, EventArgs e)
{
    OpenFileDialog openFileDialog = new OpenFileDialog();
    openFileDialog.Filter = "JPG(*.jpg)|*.jpg|" + "BMP(*.BMP)|*.bmp|" + "GIF(*.GIT)|*.gif|" + "所有檔案|*.*";
    if (openFileDialog.ShowDialog() == DialogResult.OK)
    {
        pictureBox1.Width = Image.FromFile(openFileDialog.FileName).Width;
        pictureBox1.Height = Image.FromFile(openFileDialog.FileName).Height;
        pictureBox1.Image = Image.FromFile(openFileDialog.FileName);
    }
}

灰階化

private void btnGray_Click(object sender, EventArgs e)
{
    //前提利用OpenFileDialog將影像放到pictureBox1
    try
    {
        //並宣告bm1為Bitmap
        Bitmap bm1 = (Bitmap)pictureBox1.Image;
        //宣告寬及高
        int w1 = pictureBox1.Image.Width;
        int h1 = pictureBox1.Image.Width;
        int x;
        int y;
        //掃影像每一個pixel並做處理
        for (y = 0; y <= h1 - 1; y++)
        {
            for (x = 0; x <= w1 - 1; x++)
            {
                Color c1 = bm1.GetPixel(x, y);
                int r1 = c1.R;
                int g1 = c1.G;
                int b1 = c1.B;
                int avg1 = (r1 + g1 + b1) / 3;
                bm1.SetPixel(x, y, Color.FromArgb(avg1, avg1,avg1));
            }
        }
        //處理完後放回pictureBox1
        pictureBox1.Image = bm1;
    }
 
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

Sample SourceCode：
Download



Reference：

日向俊二、陳亦苓 譯，”Visual Basic 2005 功能索引式參考手冊”

C# 利用SaveFileDialog儲存pictureBox1圖片於自設路徑

private void button1_Click(object sender, EventArgs e)
{
    try
    {
        SaveFileDialog saveFileDialog1 = new SaveFileDialog();
        saveFileDialog1.Filter = "Bitmap Image|*.bmp";
        saveFileDialog1.Title = "儲存圖片";
        saveFileDialog1.ShowDialog();
        if (saveFileDialog1.FileName != "")
        {
            System.IO.FileStream fs = (System.IO.FileStream)saveFileDialog1.OpenFile();
                
            switch (saveFileDialog1.FilterIndex)
            {
                case 1:
                    this.pictureBox1.Image.Save(fs,
                              System.Drawing.Imaging.ImageFormat.Bmp);
                    break;
            }
 
            fs.Close();
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

C# 直接儲存圖片於當前資料夾

儲存在執行檔同一資料夾裡

pictureBox1.Image.Save(Application.ExecutablePath + "sample.bmp");

C# 顯示AboutBox

加入->新增項目->關於對話方塊(AboutBox1.cs)

private void button1_Click(object sender, EventArgs e)
{
    AboutBox1 about1 = new AboutBox1();
    about1.Show();
}

C# 利用OpenFileDialog顯示圖片於pictureBox1

利用OpenFileDialog顯示圖片於pictureBox1
pictureBox1的寬及高決定於圖片來源大小

private void btnOpen_Click(object sender, EventArgs e)
{
    OpenFileDialog openFileDialog = new OpenFileDialog();
    openFileDialog.Filter = "BMP(*.BMP)|*.bmp|" + "所有檔案|*.*";
    if (openFileDialog.ShowDialog() == DialogResult.OK)
    {
        pictureBox1.Width = Image.FromFile(openFileDialog.FileName).Width;
        pictureBox1.Height = Image.FromFile(openFileDialog.FileName).Height;
        pictureBox1.Image = Image.FromFile(openFileDialog.FileName);
    }
}