this code does not show a bitmap!

[abdul]

Please look at the following source code. I have a bimap in my resource file and I want to first load that bitmap into the memory DC and then I want to copy it on to the screen
But the following code just shows me an error message:
The message is my own. I call it whenver i cannot load the image from the resource file:

#include <windows.h>
#include "resource.h"
#define TheClass "myclass"

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
	switch(msg)
	{
	case WM_CREATE:
	HBITMAP hbball;
	hbball = LoadBitmap(NULL,  "BALLBMP");
	if(!hbball)
	{
     MessageBox(hwnd, "Load of resource BALLBMP failed.", "Error",
         MB_OK | MB_ICONEXCLAMATION);
	}
	 return 0;
	case WM_PAINT:
	if(hbball)
		{
		HDC winhdc, memhdc;
		PAINTSTRUCT ps;
		BITMAP bm;
		winhdc =  BeginPaint(hwnd, &ps);
		memhdc = CreateCompatibleDC(winhdc);
		SelectObject(memhdc, hbball);
		GetObject(hbball, sizeof(bm), &bm);
		BitBlt(winhdc,0,0,bm.bmWidth, bm.bmHeight, memhdc, 0,0,SRCCOPY);
		DeleteDC(memhdc);
		EndPaint(hwnd, &ps);
		}
		return 0;
	case WM_CLOSE:
		DestroyWindow(hwnd);
		return 0;
	case WM_DESTROY:
		DeleteObject(hbball);
		PostQuitMessage(0);
		return 0;
	}

	return DefWindowProc(hwnd, msg, wparam, lparam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE HPrevInstance, LPSTR lpCmdLine, int ShowCmd)
{
	WNDCLASSEX wc;
	HWND hwnd;
	MSG msg;

	//Creates the window class

	wc.cbClsExtra = 0;
	wc.cbSize = sizeof(wc);
	wc.cbWndExtra = 0;
	wc.hbrBackground = (HBRUSH)GetStockObject(LTGRAY_BRUSH);
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
	wc.hInstance = hInstance;
	wc.lpfnWndProc = WndProc;
	wc.lpszClassName = TheClass;
	wc.lpszMenuName = MAKEINTRESOURCE(MYMENU);
	wc.style = CS_VREDRAW | CS_HREDRAW;

	//Registers the Window Class -- if it does not succeed then it
	//shows an error message.

	if(!RegisterClassEx(&wc))
	{
		MessageBox(NULL, "Error occurred while \
		Registering the Main Class", "Error!", MB_OK);
		return 0;
	}

	//Creates the main window hwnd

	hwnd = CreateWindow(TheClass,
					"The Ball Example",
					WS_OVERLAPPEDWINDOW,
					0,
					0,
					500,
					500,
					NULL,
					NULL,
					hInstance,
					NULL);

	//Check if there is any error when we make our windows' Hwnd

	if(hwnd == NULL)
	{
		MessageBox(NULL, "Error making the Hwnd for our window","Error",MB_OK);
	return 0;
	}

	ShowWindow(hwnd, SW_SHOW);
	UpdateWindow(hwnd);

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

	return msg.wParam;
}

Do you know what is rong with that?

[denniswrenn]

Try this if you are using Visual C++:

LoadBitmap(NULL,  MAKEINTRESOURCE(BALLBMP));

[abdul]

I have tried that but it still does not load the bitmap

[denniswrenn]

Try this then:

//global(at the top)
HINSTANCE hInst; 

//somewhere in winmain
hInst = hInstance;

//WM_PAINT
LoadBitmap(hInstance,  MAKEINTRESOURCE(BALLBMP));

[parksie]

LoadBitmap(GetModuleHandle(NULL),  MAKEINTRESOURCE(BALLBMP));

[abdul]

Now it does does not show the error message but now it does show anything on my winodw.

[parksie]

SelectObject(memhdc, hbball);

Change that memhdc to winhdc and see what happens.

[Technocrat]

Here:

#include <windows.h>
#include "resource.h"
#define TheClass "myclass"

HBITMAP hbball;      //<-----HERE
HINSTANCE hInst;   //<-----HERE

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
    switch(msg)
    {
    case WM_CREATE:
    hbball = LoadBitmap(hInst,  MAKEINTRESOURCE(BALLBMP));   //<-----HERE
    if(!hbball)
    {
     MessageBox(hwnd, "Load of resource BALLBMP failed.", "Error",
         MB_OK | MB_ICONEXCLAMATION);
    }
     return 0;
    case WM_PAINT:
    if(hbball)
        {
        HDC winhdc, memhdc;
        PAINTSTRUCT ps;
        BITMAP bm;
        winhdc =  BeginPaint(hwnd, &ps);
        memhdc = CreateCompatibleDC(winhdc);
        SelectObject(memhdc, hbball);
        GetObject(hbball, sizeof(bm), &bm);
        BitBlt(winhdc,0,0,bm.bmWidth, bm.bmHeight, memhdc, 0,0,SRCCOPY);
        DeleteDC(memhdc);
        EndPaint(hwnd, &ps);
        }
        return 0;
    case WM_CLOSE:
        DestroyWindow(hwnd);
        return 0;
    case WM_DESTROY:
        DeleteObject(hbball);
        PostQuitMessage(0);
        return 0;
    }

    return DefWindowProc(hwnd, msg, wparam, lparam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE HPrevInstance, LPSTR lpCmdLine, int ShowCmd)
{
    WNDCLASSEX wc;
    HWND hwnd;
    MSG msg;

    //Creates the window class

    wc.cbClsExtra = 0;
    wc.cbSize = sizeof(wc);
    wc.cbWndExtra = 0;
    wc.hbrBackground = (HBRUSH)GetStockObject(LTGRAY_BRUSH);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    wc.hInstance = hInstance;
    wc.lpfnWndProc = WndProc;
    wc.lpszClassName = TheClass;
    wc.lpszMenuName = MAKEINTRESOURCE(MYMENU);
    wc.style = CS_VREDRAW | CS_HREDRAW;

    hInst = hInstance;  //<-----HERE

    //Registers the Window Class -- if it does not succeed then it
    //shows an error message.

    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Error occurred while \
        Registering the Main Class", "Error!", MB_OK);
        return 0;
    }

    //Creates the main window hwnd

    hwnd = CreateWindow(TheClass,
                    "The Ball Example",
                    WS_OVERLAPPEDWINDOW,
                    0,
                    0,
                    500,
                    500,
                    NULL,
                    NULL,
                    hInstance,
                    NULL);

    //Check if there is any error when we make our windows' Hwnd

    if(hwnd == NULL)
    {
        MessageBox(NULL, "Error making the Hwnd for our window","Error",MB_OK);
    return 0;
    }

    ShowWindow(hwnd, SW_SHOW);
    UpdateWindow(hwnd);

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

    return msg.wParam;
} 

Since you had your Bitmap as a local it was getting destroyed everytime it left create

[Technocrat]

Oh and you got 2 memory leaks, you need to add:

DeleteDC(memhdc);

//And

WM_CLOSE:
DeleteObject hbball;
return DefWindowProc(hwnd, msg, wparam, lparam);
break; 

Plus if when you get farther along your graphics seem a bit slow on the refresh, make your HDCs global and use select object only once to get them. That way it will not have to recreate them everytime you BitBlt.

[abdul]

It is working now.
So the only problem was that I was not declaring my "HBITMAP hbball"as global?

[Technocrat]

If you got it to work using a global then yeah, except for those pesky memory leaks you got