Bitmap change on button press..

I wrote this as a lead up to something I need to develop further down the track..
All I want to do at the moment is change the bitmap image when the button is pressed!

It is not working this way, and I am stuck for ideas ATM!
Can anyone tell me why it is not working correctly..

Cheers

Code:

---

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <commctrl.h>
#include <iostream>
#include "Resource.h"

using namespace std;

#pragma comment(lib, "comctl32.lib")


INT_PTR CALLBACK DlgProc( HWND hwnd , UINT msg , WPARAM wparam , LPARAM lparam)
{
        HWND Pic  = GetDlgItem(hwnd, IDC_GREEN);
        HWND Button = GetDlgItem(hwnd, IDC_BUTTON1);
       
        switch(msg)
        {
        case WM_INITDIALOG:
                {
                        static HBITMAP hbmp;
       
                        hbmp = (HBITMAP)LoadImage(0, MAKEINTRESOURCE(IDB_GREEN), IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
                        SendMessage(Pic, BM_SETIMAGE, IDC_GREEN, (LPARAM)hbmp);
                        SendMessage(hwnd, WM_SETICON, ICON_SMALL, (LPARAM)LoadIcon(GetModuleHandle(0), MAKEINTRESOURCE(0)));
                }
        break;

        case WM_COMMAND:
                switch(HIWORD(wparam))
                {
                        case BN_CLICKED:
                                        if(LOWORD(wparam) == IDC_BUTTON1)
                                        {
                                                //MessageBox(hwnd, "check for Message", 0 ,0);
                                                static HBITMAP hbmp = (HBITMAP)LoadImage(0, MAKEINTRESOURCE(IDB_RED), IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE | LR_LOADTRANSPARENT);       
                                                SendMessage(Pic, BM_SETIMAGE, IDC_GREEN, (LPARAM)hbmp);
                                        }
                        break;
                }
        break;
               
        case WM_CLOSE:
                {
                        PostQuitMessage(0);
                }
        break;               
                       
        }
        return false;
}

INT WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hprevinstance,
    LPSTR lpcmdline, int ncmdshow)
{
       
        InitCommonControls();
       
        DialogBox(hinstance, MAKEINTRESOURCE(IDD_MAIN), 0, DlgProc);
       
    return 0;
}

---

On first look I think your SendMessage function isn't good, exactly 3rd parameter is IMAGE_BITMAP (WPARAM), not IDC_GREEN.

I always thought IMAGE_BITMAP is of UINT type??

If I put IMAGE_BITMAP in it still does not function correctly?

Quote:

---

Originally Posted by Code_Nerd

I always thought IMAGE_BITMAP is of UINT type??

---

And how is that related to the fact you are passing the wrong ID? :confused:

Quote:

---

If I put IMAGE_BITMAP in it still does not function correctly?

---

Did you set the SS_BITMAP style to your pic control?

Cheers

I am very new to WIN32 programming..

I am not sure where I am meant to set SS_BITMAP?

Thankyou :)

• Go to the resource editor
• Right click on the image ( static ) control
• Choose properties
• In the type combo box choose Bitmap

Cheers

Also, if IDB_RED and IDB_GREEN are resources, you should:

1. Pass a valid hInstance as a first parameter to LoadImage
2. Do not specify LR_LOADFROMFILE flag

OK I think I have passed the correct hInstance to LoadImage() and now it seems as if the bitmap is loading correctly and getting put into hbmp..

@ golanshahar the picture control was already set as Bitmap type in the resource editor.. Thankyou :)

My code now looks like this:

Code:

---

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <commctrl.h>
#include <iostream>
#include <stdlib.h>
#include "Resource.h"

using namespace std;

#pragma comment(lib, "comctl32.lib")


INT_PTR CALLBACK DlgProc( HWND hwnd , UINT msg , WPARAM wparam , LPARAM lparam)
{
        HWND Pic  = GetDlgItem(hwnd, IDC_GREEN);
        HWND Button = GetDlgItem(hwnd, IDC_BUTTON1);
       
        switch(msg)
        {
        case WM_INITDIALOG:
                {
                        static HBITMAP hbmp;
       
                        hbmp = (HBITMAP)LoadImage(GetModuleHandle(0), MAKEINTRESOURCE(IDB_GREEN), IMAGE_BITMAP, 0, 0, 0);
                        if(!hbmp)
                        {
                                MessageBox(hwnd, "Test if no bitmap loaded", 0 ,0);
                        }
                        DWORD dw = GetLastError();
                        char poop[123]; itoa(dw, poop, 100);
                        MessageBox(hwnd, poop, 0 ,0);
                        SendMessage(Pic, BM_SETIMAGE, IDC_GREEN, (LPARAM)hbmp);
                        SendMessage(hwnd, WM_SETICON, ICON_SMALL, (LPARAM)LoadIcon(GetModuleHandle(0), MAKEINTRESOURCE(0)));
                }
        break;

        case WM_COMMAND:
                switch(HIWORD(wparam))
                {
                        case BN_CLICKED:
                                        if(LOWORD(wparam) == IDC_BUTTON1)
                                        {
                                               
                                                static HBITMAP hbmp = (HBITMAP)LoadImage(GetModuleHandle(0), MAKEINTRESOURCE(IDB_RED), IMAGE_BITMAP, 0, 0, 0);       
                                                if(!hbmp)
                                                        MessageBox(hwnd, "check for Message", 0 ,0);
                                                else
                                                        SendMessage(Pic, BM_SETIMAGE, IDC_GREEN, (LPARAM)hbmp);
                                                DWORD dw = GetLastError();
                                                char poop[123]; itoa(dw, poop, 100);
                                                MessageBox(hwnd, poop, 0 ,0);
                                        }
                        break;
                }
        break;
               
        case WM_CLOSE:
                {
                        PostQuitMessage(0);
                }
        break;               
                       
        }
        return false;
}

INT WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hprevinstance,
    LPSTR lpcmdline, int ncmdshow)
{
       
        InitCommonControls();
       
        DialogBox(hinstance, MAKEINTRESOURCE(IDD_MAIN), 0, DlgProc);
       
    return 0;
}

---

Your code still incorrect, instead of:

Code:

---

::SendMessage(Pic, BM_SETIMAGE, IDC_GREEN, (LPARAM)hbmp);

---

It should be:

Code:

---

::SendMessage(Pic, BM_SETIMAGE, IMAGE_BITMAP, (LPARAM)hbmp);

---

Read the documentation of BM_SETIMAGE.

Cheers

Thankyou for your reply...
I understand where I went wrong now, however the image is still not changing with the button press?

What else could it possibly be? Do I have to create a special type of bitmap (8bit etc etc) I am trying to use 24 bit .bmps...

Thanks again..

Look at this thread for sample.

Cheers