Create Bitmap example

 #include <stdio.h>  
 const int BYTES_PER_PIXEL = 3; /// red, green, & blue  
 const int FILE_HEADER_SIZE = 14;  
 const int INFO_HEADER_SIZE = 40;  
 void generateBitmapImage(unsigned char* image, int height, int width, char* imageFileName);  
 unsigned char* createBitmapFileHeader(int height, int stride);  
 unsigned char* createBitmapInfoHeader(int height, int width);  
 int main()  
 {  
   int height = 361;  
   int width = 867;  
   unsigned char image[361][867][BYTES_PER_PIXEL];  
   char* imageFileName = (char*)"c:\\Work\\bitmapImage.bmp";  
   int i, j;  
   for (i = 0; i < height; i++) {  
     for (j = 0; j < width; j++) {  
       image[i][j][2] = (unsigned char)(i * 255 / height);       ///red  
       image[i][j][1] = (unsigned char)(j * 255 / width);       ///green  
       image[i][j][0] = (unsigned char)((i + j) * 255 / (height + width)); ///blue  
     }  
   }  
   generateBitmapImage((unsigned char*)image, height, width, imageFileName);  
   printf("Image generated!!");  
 }  
 void generateBitmapImage(unsigned char* image, int height, int width, char* imageFileName)  
 {  
   int widthInBytes = width * BYTES_PER_PIXEL;  
   unsigned char padding[3] = { 0, 0, 0 };  
   int paddingSize = (4 - (widthInBytes) % 4) % 4;  
   int stride = (widthInBytes)+paddingSize;  
   FILE* imageFile = fopen(imageFileName, "wb");  
   unsigned char* fileHeader = createBitmapFileHeader(height, stride);  
   fwrite(fileHeader, 1, FILE_HEADER_SIZE, imageFile);  
   unsigned char* infoHeader = createBitmapInfoHeader(height, width);  
   fwrite(infoHeader, 1, INFO_HEADER_SIZE, imageFile);  
   int i;  
   for (i = 0; i < height; i++) {  
     fwrite(image + (i * widthInBytes), BYTES_PER_PIXEL, width, imageFile);  
     fwrite(padding, 1, paddingSize, imageFile);  
   }  
   fclose(imageFile);  
 }  
 unsigned char* createBitmapFileHeader(int height, int stride)  
 {  
   int fileSize = FILE_HEADER_SIZE + INFO_HEADER_SIZE + (stride * height);  
   static unsigned char fileHeader[] = {  
     0,0,   /// signature  
     0,0,0,0, /// image file size in bytes  
     0,0,0,0, /// reserved  
     0,0,0,0, /// start of pixel array  
   };  
   fileHeader[0] = (unsigned char)('B');  
   fileHeader[1] = (unsigned char)('M');  
   fileHeader[2] = (unsigned char)(fileSize);  
   fileHeader[3] = (unsigned char)(fileSize >> 8);  
   fileHeader[4] = (unsigned char)(fileSize >> 16);  
   fileHeader[5] = (unsigned char)(fileSize >> 24);  
   fileHeader[10] = (unsigned char)(FILE_HEADER_SIZE + INFO_HEADER_SIZE);  
   return fileHeader;  
 }  
 unsigned char* createBitmapInfoHeader(int height, int width)  
 {  
   static unsigned char infoHeader[] = {  
     0,0,0,0, /// header size  
     0,0,0,0, /// image width  
     0,0,0,0, /// image height  
     0,0,   /// number of color planes  
     0,0,   /// bits per pixel  
     0,0,0,0, /// compression  
     0,0,0,0, /// image size  
     0,0,0,0, /// horizontal resolution  
     0,0,0,0, /// vertical resolution  
     0,0,0,0, /// colors in color table  
     0,0,0,0, /// important color count  
   };  
   infoHeader[0] = (unsigned char)(INFO_HEADER_SIZE);  
   infoHeader[4] = (unsigned char)(width);  
   infoHeader[5] = (unsigned char)(width >> 8);  
   infoHeader[6] = (unsigned char)(width >> 16);  
   infoHeader[7] = (unsigned char)(width >> 24);  
   infoHeader[8] = (unsigned char)(height);  
   infoHeader[9] = (unsigned char)(height >> 8);  
   infoHeader[10] = (unsigned char)(height >> 16);  
   infoHeader[11] = (unsigned char)(height >> 24);  
   infoHeader[12] = (unsigned char)(1);  
   infoHeader[14] = (unsigned char)(BYTES_PER_PIXEL * 8);  
   return infoHeader;  
 }  

Easy way of finding centriod using octave

Octave code:
A=[10 11; 20 21; 30 31; 40 41; 50 51; 60 61; 70 71]
PB = [1 1 3 3 2 2 2]

C = A (PB==3,:)
D = mean(C)
SD = size(C,1)

Results:
A =

   10   11
   20   21
   30   31
   40   41
   50   51
   60   61
   70   71

PB =

   1   1   3   3   2   2   2

C =

   30   31
   40   41

D =

   35   36

SD =  2

Simplified code:

for i=1:K
    centroids(i,:) = mean( X(idx==i,:) );
endfor

Array indexing in Octave

A=[10 11; 20 21; 30 31; 40 41; 60 61; 60 61; 70 71]
PB = [1 3 5]
B = [1 2 3 4 7]
C = A (B(PB),:)
D = mean(C)

A =

   10   11
   20   21
   30   31
   40   41
   60   61
   60   61
   70   71

PB =

   1   3   5

B =

   1   2   3   4   7

C =

   10   11
   30   31
   70   71

D =

   36.667   37.667

WPF update user interface in multithreading mode

   public partial class Window1 : Window  
   {  
     public Class1 c;  
     public Window1()  
     {  
       InitializeComponent();  
       c = new Class1();  
       c.Class1Event += C_Class1Event;  
      }  
     private void C_Class1Event(object sender, Class1EventArgs e)  
     {//Triggered from a different thread  

       this.Dispatcher.Invoke((Action)(() =>  
       {//this refer to form in WPF application   
         imgShirt.Source = new BitmapImage(new Uri(System.AppDomain.CurrentDomain.BaseDirectory + @"\images2.jpg", UriKind.RelativeOrAbsolute));  
       }));  

     }  
     private void Change_Click(object sender, RoutedEventArgs e)  
     {  
       c.Start();  
     }  
     private void Change2_Click(object sender, RoutedEventArgs e)  
     {//Called from the same thread  
       Uri fileUri = new Uri(System.AppDomain.CurrentDomain.BaseDirectory + @"\images.jpg", UriKind.RelativeOrAbsolute);  
       imgShirt.Source = new BitmapImage(fileUri);  
     }  
   }  

   public class Class1  
   {  
     public event EventHandler<Class1EventArgs> Class1Event;  
     public Class1()  
     {  
     }  
     public void Start()  
     {  
       Task.Run(() => {  
         Class1EventArgs e = new Class1EventArgs();  
         Class1Event(this, e);  
       });  
     }  
   }  
   public class Class1EventArgs : EventArgs  
   {  
   }  

How to deserialize Xml with different namespaces / prefixes

Specify the namespace in the child element

 [System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.8.3928.0")]  
 [System.SerializableAttribute()]  
 [System.Diagnostics.DebuggerStepThroughAttribute()]  
 [System.ComponentModel.DesignerCategoryAttribute("code")]  
 [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]  
 [System.Xml.Serialization.XmlRootAttribute(Namespace= "http://search.yahoo.com/mrss/", IsNullable=false)]  
 public partial class group {  
   private groupContent[] contentField;  
   /// <remarks/>  
   [System.Xml.Serialization.XmlElementAttribute("content")]  
   public groupContent[] content {  
     get {  
       return this.contentField;  
     }  
     set {  
       this.contentField = value;  
     }  
   }  
 }  

Use the XmlElement tag and specify the namespace in the parent node

   /// <remarks/>  
   public string pubDate {  
     get {  
       return this.pubDateField;  
     }  
     set {  
       this.pubDateField = value;  
     }  
   }  
   [XmlElement("group", Namespace = "http://search.yahoo.com/mrss/")]  
   public group group  
   {  
     get  
     {  
       return this.groupField;  
     }  
     set  
     {  
       this.groupField = value;  
     }  
   }  
 }  

Note: If you want to use the Visual Studio xsd.exe to generate the C# class, you need to strip off the elements with different namespace for xsd.exe to work. You can add the separate elements manually after.