Styjun

I am trying to create a Windows window and a graphic inside it using MFC, but after minimizing or maximizing the window the graphic is gone. Is there a way so that the graphic will still be up after minimizing or maximizing?

This is the code i wrote.

#include"Header.h"
#include <iostream>
using namespace std;
int APIENTRY WinMain(HINSTANCE hinstance, HINSTANCE,
LPSTR lpstr, int ncmdshow)
 CS_VREDRAW;
RegisterClassEx(&wnd);

HWND hwnd = CreateWindow(TEXT("mywn"),
 TEXT("mywn2"),
 WS_OVERLAPPEDWINDOW,
 50, 50, 300, 500,
 NULL,
 NULL,
 hinstance,
 0);

ShowWindow(hwnd, SW_SHOWNORMAL);

UpdateWindow(hwnd);

MSG msg;
while (GetMessage(&msg, NULL, 0, 0))

 TranslateMessage(&msg);
 DispatchMessage(&msg);



return 0;

LRESULT CALLBACK Mywndproc(HWND hwnd, UINT imessage, WPARAM
wparam, LPARAM lparam)

HDC hdc;
int x = LOWORD(lparam);
int y = HIWORD(lparam);
int cmd = LOWORD(wparam);


HBRUSH hbrush = CreateSolidBrush(RGB(125, 60, 250));
HBRUSH hbrush1 = CreateSolidBrush(RGB(255, 0, 0));
HPEN hpen = CreatePen(PS_DASH, 30, RGB(0, 50, 256));
PAINTSTRUCT ps;
switch (imessage)

case WM_DESTROY:
 PostQuitMessage(0);
 break;
case WM_LBUTTONDOWN:
 hdc = GetDC(hwnd);
 TextOut(hdc, x, y, TEXT("Name"), strlen("Name"));


 DeleteDC(hdc);
 break;
case WM_MOUSEMOVE:
 hdc = GetDC(hwnd);
 if (cmd == MK_LBUTTON) 
 SelectObject(hdc, hbrush1);

 Ellipse(hdc, x, y, x + 100, y + 120);

 
 else if (cmd == MK_RBUTTON) 
 TextOut(hdc, x, y, TEXT("Erevan"), strlen("Erevan"));

 


 DeleteDC(hdc);
 break;
case WM_PAINT:
 hdc = BeginPaint(hwnd, &ps);

 TextOut(hdc, 100, 100, TEXT("Text"), strlen("Text"));


 EndPaint(hwnd, &ps);


 break;


case WM_RBUTTONDOWN:

 hdc = GetDC(hwnd);
 SelectObject(hdc, hbrush1);

 Ellipse(hdc, x, y, x + 100, y + 120);

 EndPaint(hwnd, &ps);


 DeleteDC(hdc);
 break;
default:
 return DefWindowProc(hwnd, imessage, wparam, lparam);


return 0;

Drawing outside of processing of the WM_PAINT message is absolutely OK:

Painting and Drawing

You should call ReleaseDC() rather than DeleteDC() to return a HDC you got by calling GetDC().

Also, resources you select into a HDC must be selected out before releasing or destroying it.

However, a WM_PAINT message may indeed be received as a result of "invalidating" a part or all of the client area, due to moving, resizing, unhiding etc the window. So in response to a WM_PAINT message you should perform a full repaint, ie all the items you want to be displayed.

Do all your drawing in WM_PAINT, not WM_LBUTTONDOWN, WM_MOUSEMOVE, and WM_RBUTTONDOWN. Save what you want to draw in WM_LBUTTONDOWN, WM_MOUSEMOVE, and WM_RBUTTONDOWN and call Invalidate() to send a WM_PAINT message to draw them. Your drawing will be up all the time.