Display context using C

Hello,

I must find a color code in an image. Either it is an image file, or is directly addressed from the screen. It must be very fast, then the solution proposed in memory lowest'm particularly. I'm looking for this afternoon tutorials on google but I hope I can find nothing. If someone has a complete, I am taker.

Code:

---

# include <stdio.h>
  # include <stdlib.h>
  # include <windows.h>
 
 
  int main (void)
  {
      / / Move the window
      HWND handle = FindWindow ( "MSPaintApp", NULL);
      SetForegroundWindow (handle);
      HDC hDC = GetDC (0);
      FILE * save = fopen ( "save.txt", "w");
 
      / / Retrieve the screen resolution
   
      int ResX = GetSystemMetrics (SM_CXSCREEN);
      int ResY = GetSystemMetrics (SM_CYSCREEN); 
   
      / / Image Processing
      int i = ResX;
      int j = ResY;
   
      int counter = 0;
      int nbr_loop = i * j;
      int progress;
      printf ( "loops:% d", nbr_loop);
      getchar ();
      for (i = 1; i <= ResX i + +)
          {
                for (j = 1; j <= ResY j + +)
                    {
                            increase = ((counter * 100) / nbr_loop);
                            COLORREF code_color;
                            code_couleur = GetPixel (hDC, i, j);
                            fprintf (save, "color code:% ld | loop:% d | progression:% d \ n", code_color, counter, progression);
                            printf ( "color code:% ld | loop:% d | progression:% d \ n", code_color, counter, progression);
                            counter + +;
                    }
          }
       
      getchar ();
  }

  }

---

It works with GetDC (0) is to handle the office but when I choose another handle the function that returns me -1 and I do not understand why? While walking, processing time is too long. Are you a quicker way please?

Thank you in advance

Hello,

At speed, it is possible to go faster by avoiding write to a file after each pixel read.

So, I do not understand why GetDC (handle) does not work as expected ... Perhaps he should try GetWindowDC.

I look in more detail when I have a windows on hand.

Yes indeed, by not displaying the calculations in the console, but it is still far too slow. Should be treated the image in the second. Are even faster?

Already, you do a GetDC (), but I see no ReleaseDC () in your code. Not good!

Indeed, I copied the wrong code but there is! No function faster to process the image please?

BitBlt () to copy a CD directly in another.
Then you can use functions slower, or directly to work in a DIB (Device-Independent Bitmap) ...

Thank you but really I looked I can not find a tutorial that explains how it works.

Anyways Thank you