Experiment description:
Design a program to realize the bouncing ball.
The source code is as follows:
#include <windows.h>
#define ID_TIMER 1
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("Bounce");
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("Bouncing Ball"),
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 HBITMAP hBitmap;
static int cxClient, cyClient, xCenter, yCenter, cxTotal, cyTotal,
cxRadius, cyRadius, cxMove, cyMove, xPixel, yPixel;
HDC hdc, hdcMem;
HBRUSH hBrush;
int iScale;
switch (message)
{
case WM_CREATE:
hdc = GetDC(hwnd);
xPixel = GetDeviceCaps(hdc, ASPECTX);
yPixel = GetDeviceCaps(hdc, ASPECTY);
ReleaseDC(hwnd, hdc);
SetTimer(hwnd, ID_TIMER, 50, NULL);
return 0;
case WM_SIZE:
xCenter = (cxClient = LOWORD (lParam)) / 2;
yCenter = (cyClient = HIWORD (lParam)) / 2;
iScale = min(cxClient * xPixel, cyClient * yPixel) / 16;
cxRadius = iScale / xPixel;
cyRadius = iScale / yPixel;
cxMove = max (1, cxRadius / 4);
cyMove = max (1, cyRadius / 4);
cxTotal = 2 * (cxRadius + cxMove);
cyTotal = 2 * (cyRadius + cyMove);
if(hBitmap)
DeleteObject(hBitmap);
hdc = GetDC(hwnd);
hdcMem = CreateCompatibleDC(hdc);
hBitmap = CreateCompatibleBitmap(hdc, cxTotal, cyTotal);
ReleaseDC(hwnd, hdc);
SelectObject(hdcMem, hBitmap);
Rectangle(hdcMem, -1, -1, cxTotal + 1, cyTotal + 1);
hBrush = CreateHatchBrush(HS_DIAGCROSS, 0L);
SelectObject(hdcMem, hBrush);
SetBkColor(hdcMem, RGB(255, 0, 0));
Ellipse(hdcMem, cxMove, cyMove, cxTotal - cxMove, cyTotal - cyMove);
DeleteDC(hdcMem);
DeleteObject(hBrush);
return 0;
case WM_TIMER:
if(!hBitmap)
break;
hdc = GetDC(hwnd);
hdcMem = CreateCompatibleDC(hdc);
SelectObject(hdcMem, hBitmap);
BitBlt(hdc, xCenter - cxTotal / 2,
yCenter - cyTotal / 2, cxTotal, cyTotal,
hdcMem, 0, 0, SRCCOPY
);
ReleaseDC(hwnd, hdc);
DeleteDC(hdcMem);
xCenter += cxMove;
yCenter += cyMove;
if((xCenter + cxRadius >= cxClient) || (xCenter - cxRadius <= 0))
cxMove = -cxMove;
if((yCenter + cyRadius >= cyClient) || (yCenter - cyRadius <= 0))
cyMove = -cyMove;
return 0;
case WM_CLOSE:
if (IDOK == MessageBox(hwnd, TEXT("Exit？"), TEXT("Dialog"), MB_OKCANCEL | MB_DEFBUTTON1 | MB_ICONQUESTION))
DestroyWindow(hwnd);
return 0;
case WM_DESTROY:
if(hBitmap)
DeleteObject(hBitmap);
KillTimer(hwnd, ID_TIMER);
PostQuitMessage (0);
return 0;
}
return DefWindowProc (hwnd, message, wParam, lParam);
}The result is as follows: You get a bouncing ball (the color of the ball can be defined
by yourself), click on the upper right corner × (exit), and a dialog box will pop up:
