DEGRADÉ DE COULEUR

//***********************************************
#include <windows.h>
#include "resource.h"

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
//***********************************************

int WINAPI WinMain(
                  HINSTANCE hInstance,
                  HINSTANCE hPrevInstance,
                  PSTR szCmdLine,
                  int iCmdShow
                  )
{
static char   szAppName[] = "Couleur";
HWND          hwnd;
MSG           msg;
WNDCLASSEX    wndclass;

wndclass.cbSize        = sizeof (wndclass);
wndclass.style         = 0;
wndclass.lpfnWndProc   = WndProc;
wndclass.cbClsExtra    = 0;
wndclass.cbWndExtra    = 0;
wndclass.hInstance     = hInstance;
wndclass.hIcon         = LoadIcon(NULL,IDI_APPLICATION);
wndclass.hCursor       = LoadCursor(NULL, IDC_ARROW);
wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.lpszMenuName  = NULL;
wndclass.lpszClassName = szAppName;
wndclass.hIconSm       = LoadIcon(NULL,IDI_APPLICATION);

RegisterClassEx(&wndclass);

hwnd = CreateWindow(
                  szAppName,               // nom de la classe
                  szAppName,               // titre de la fenetre
                  WS_OVERLAPPED | WS_SYSMENU,     // style de la fenetre
                  CW_USEDEFAULT,           // position initiale en x
                  CW_USEDEFAULT,           // position initiale en y
                  512,                     // largeur initiale
                  512,                     // hauteur initiale
                  NULL,                    // handle de la fenetre mere
                  NULL,                    // handle du menu de la fenetre
                  hInstance,               // handle de l'instance
                  NULL);                   // parametres de creation

ShowWindow(hwnd,iCmdShow);
UpdateWindow(hwnd);

while(GetMessage(&msg,NULL,0,0))
	{
	TranslateMessage(&msg);
	DispatchMessage(&msg);
	}
return msg.wParam;
}

LRESULT CALLBACK WndProc(
                        HWND hwnd,
                        UINT iMsg,
                        WPARAM wParam,
                        LPARAM lParam
                        )
{

switch (iMsg)
  {
  case WM_CREATE:
    {
	  return 0;
    }
  case WM_PAINT:
    {
    HDC		        hdc;
    PAINTSTRUCT   ps;
    RECT		      rect;
    int           x,y;

	  hdc = BeginPaint(hwnd,&ps);
	  GetClientRect(hwnd,&rect);
// les carres sont disposes comme ci-dessous
//  1 2
//  3 4
// 
    // 1    
    for(x=rect.left;x<256;x++)
      {
      for(y=rect.top;y<256;y++)
        {
        SetPixel(hdc,x,y,RGB(x & 255,0,y & 255));
        }
      }
    // 2
    for(x=max(rect.left,256);x<512;x++)
      {
      for(y=rect.top;y<256;y++)
        {
        SetPixel(hdc,x,y,RGB(~(x & 255),0,y & 255));
        }
      }
    // 3
    for(x=rect.left;x<256;x++)
      {
      for(y=max(rect.top,256);y<512;y++)
        {
        SetPixel(hdc,x,y,RGB(x & 255,0,~(y & 255)));
        }
      }
    // 4
   for(x=max(rect.left,256);x<512;x++)
      {
      for(y=max(rect.top,256);y<512;y++)
        {
        SetPixel(hdc,x,y,RGB(~(x & 255),0,~(y & 255)));
        }
      }

	  EndPaint(hwnd,&ps);
    return 0;
    }
  case WM_COMMAND:
    {
    break;
    }
  case WM_DESTROY:
    {
	  PostQuitMessage (0);
	  return 0;
    }
  }

return DefWindowProc(hwnd,iMsg,wParam,lParam);
}