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lucamarcus 0 Newbie Poster

Am a new c++ programmer.

I refer to the code " Bouncing Ball" which is a GUI, now there is a rectangle created, i managed to change the color the rectangle in the main window and what my may problem is how to make the rectangle fixed and not only increase to be a full rectangle after the ball has hit both ends, how do i achieve that?

Secondly, i would love to then after making a 'fixed' rectangle, i would like to make the ball change color as it hits one side of the rectangle and change back to the original color as its starts coming back and approaches the other side and again change color as it hits the other side and change back again as it approaches the other side and keep repeating this cycle...

Basically I need the rectangle to be fully drawn or fixed EVEN before the ball starts moving and then the change of colors issue.

I have attached the code and the changes i made!

<snipped email>

#include <windows.h>

LRESULT CALLBACK WindProcedure(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam);

INT WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASSEX  WndCls;
    static char szAppName[] = "ExoBrush";
    MSG         Msg;

    WndCls.cbSize        = sizeof(WndCls);
    WndCls.style         = CS_OWNDC | CS_VREDRAW | CS_HREDRAW;
    WndCls.lpfnWndProc   = WindProcedure;
    WndCls.cbClsExtra    = 0;
    WndCls.cbWndExtra    = 0;
    WndCls.hInstance     = hInstance;
    WndCls.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    WndCls.hCursor       = LoadCursor(NULL, IDC_ARROW);
    WndCls.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    WndCls.lpszMenuName  = NULL;
    WndCls.lpszClassName = szAppName;
    WndCls.hIconSm       = LoadIcon(hInstance, IDI_APPLICATION);
    RegisterClassEx(&WndCls);

    CreateWindowEx(WS_EX_OVERLAPPEDWINDOW,
                   szAppName, "GDI Brushes Fundamentals",
                   WS_OVERLAPPEDWINDOW | WS_VISIBLE,
                   CW_USEDEFAULT, CW_USEDEFAULT, 420, 220,
                   NULL, NULL, hInstance, NULL);

    while( GetMessage(&Msg, NULL, 0, 0) )
    {
        TranslateMessage(&Msg);
        DispatchMessage( &Msg);
    }

    return static_cast<int>(Msg.wParam);
}

LRESULT CALLBACK WindProcedure(HWND hWnd, UINT Msg,
                               WPARAM wParam, LPARAM lParam)
{
	HDC         hDC;
    PAINTSTRUCT Ps;
	HBRUSH      NewBrush;


	switch(Msg)
	{
	case WM_PAINT:
		hDC = BeginPaint(hWnd, &Ps);

        NewBrush = CreateSolidBrush(RGB(250, 25, 5));

        SelectObject(hDC, NewBrush);
        Rectangle(hDC, 20, 20, 250, 120);
        DeleteObject(NewBrush);

		EndPaint(hWnd, &Ps);
		break;
	case WM_DESTROY:
		PostQuitMessage(WM_QUIT);
		break;
	default:
		return DefWindowProc(hWnd, Msg, wParam, lParam);
	}
	return 0;
}

 // draw the ball
    if (Msg == WM_SIZE)
    {
		xCenter = (cxClient=LOWORD(lParam))/2;
		yCenter = (cyClient=HIWORD(lParam))/2;
		nScale = (int)MIN(cxClient*xPixel,cyClient*yPixel)/8;
		cxRadius = nScale/xPixel;
		cyRadius = nScale/yPixel;
		cxMove = (int)MAX(1,cxRadius/4);
		cyMove = (int)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);

		rBrush = CreateSolidBrush(RGB(95,158,160));
		SelectObject(hdcMem,rBrush);


		Rectangle (hdcMem, -100, -100, 250, 250);
		DeleteObject(rBrush);
		
		hBrush = CreateSolidBrush(RGB(255, 255, 0));
		SelectObject(hdcMem,hBrush);
		SetBkColor(hdcMem,RGB(255,255,255));
		Ellipse(hdcMem,cxMove,cyMove,cxTotal-cxMove,cyTotal-cyMove);
		DeleteDC(hdcMem);
		DeleteObject(hBrush);
		return 0;
		break;
    }
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