Le code source est le suivant:
#include <windows.h>
#define MAXPOINTS 1000
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
RECT rect;
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("Connect");
HWND hwnd;
MSG msg;
WNDCLASS wndclass;
wndclass.style = CS_HREDRAW | CS_VREDRAW;
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;
if(!RegisterClass (&wndclass))
{
MessageBox (NULL, TEXT("This program requires Window NT!"), szAppName, MB_ICONERROR);
return 0;
}
hwnd = CreateWindow (szAppName, TEXT("Connect-the-Points Mouse Demo"),
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL
);
ShowWindow (hwnd, iCmdShow);
UpdateWindow (hwnd);
while (GetMessage (&msg, NULL, 0, 0))
{
TranslateMessage (&msg);
DispatchMessage (&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static POINT pt[MAXPOINTS];
static int iCount;
HDC hdc;
int i, j;
PAINTSTRUCT ps;
switch (message)
{
case WM_LBUTTONDOWN:
iCount = 0;
InvalidateRect(hwnd, NULL, TRUE);
return 0;
case WM_MOUSEMOVE:
if(wParam & MK_LBUTTON && iCount < 1000)
{
pt[iCount].x = LOWORD(lParam);
pt[iCount++].y = HIWORD(lParam);
hdc = GetDC(hwnd);
SetPixel(hdc, LOWORD(lParam), HIWORD(lParam), 0);
ReleaseDC(hwnd, hdc);
}
return 0;
case WM_LBUTTONUP:
InvalidateRect(hwnd, NULL, FALSE);
return 0;
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);
SetCursor(LoadCursor(NULL, IDC_WAIT));
ShowCursor(TRUE);
for(i = 0; i < iCount - 1; i++)
for(j = i + 1; j < iCount; j++)
{
MoveToEx(hdc, pt[i].x, pt[i].y, NULL);
LineTo(hdc, pt[j].x, pt[j].y);
}
ShowCursor(FALSE);
SetCursor(LoadCursor(NULL, IDC_ARROW));
EndPaint(hwnd, &ps);
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc (hwnd, message, wParam, lParam);
}Les résultats sont indiqués sur la figure:
Déplacez le pointeur de la souris vers la zone cliente, appuyez sur le bouton gauche, déplacez légèrement la souris, puis relâchez le bouton gauche. Appuyez sur le bouton gauche et déplacez rapidement la souris pour obtenir une courbe qui passe par plusieurs points.
