Loading an image into a dialog picture control during runtime - c++

Question

I recently acquired a laptop with a high dpi screen and have been adapting one of my programs to take advantage of the higher resolution. In one of my Win32 dialog boxes I display a bitmap picture. Normally I have that assigned to a picture control via the resource editor and don't have to deal with it. Now I need to display one of two images depending on the screen resolution. I know how to load a bitmap and get its handle, but how do I assign it to the picture control during the dialog's initiation so that the built in dialog routine will display it? I'm thinking I should put a static picture control in the dialog, but I can't find a win32 example of how I assign the image to that picture control at run time. Seems like it should be simple, but I can't seem to find a windows function that's appropriate. I'm not using MFC.
--Terry

Answer 1

Here's an example. Basically, you need to send the STM_SETIMAGE message to the picture control, along with the handle of the image you'd like to display.
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include "resource.h"
HINSTANCE hInst;
BOOL CALLBACK DialogProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
static HBITMAP bmp1, bmp2;
static bool isImg1 = true;
switch(uMsg)
{
case WM_INITDIALOG:
bmp1 = (HBITMAP)SendDlgItemMessage(hwndDlg, IDC_STATIC1, STM_GETIMAGE, IMAGE_BITMAP, 0);
bmp2 = (HBITMAP)LoadImage(NULL, "bitmap2.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
return TRUE;
case WM_DESTROY:
DeleteObject(bmp1);
DeleteObject(bmp2);
return true;
case WM_CLOSE:
EndDialog(hwndDlg, 0);
return TRUE;
case WM_COMMAND:
switch(LOWORD(wParam))
{
case IDC_BTN_QUIT:
EndDialog(hwndDlg, 0);
return TRUE;
case IDC_BTN_TEST:
if (isImg1)
SendDlgItemMessage(hwndDlg, IDC_STATIC1, STM_SETIMAGE, IMAGE_BITMAP, (LPARAM)bmp2);
else
SendDlgItemMessage(hwndDlg, IDC_STATIC1, STM_SETIMAGE, IMAGE_BITMAP, (LPARAM)bmp1);
isImg1 = !isImg1;
return TRUE;
}
}
return FALSE;
}
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
hInst = hInstance;
// The user interface is a modal dialog box
return DialogBox(hInstance, MAKEINTRESOURCE(DLG_MAIN), NULL, (DLGPROC)DialogProc);
}

Answer 2

Load a bitmap from resource
Send a message to Picture Control
case IDC_BUTTON_RELOAD:
hbitmap = (HBITMAP)LoadBitmap(GetModuleHandle(NULL),MAKEINTRESOURCE(IDB_BITMAP_FULL));
hbitmap2 = (HBITMAP)LoadBitmap(GetModuleHandle(NULL),MAKEINTRESOURCE(IDB_BITMAP_EMPTY));
/*hdc = GetDC(hDlg);
image_dc = CreateCompatibleDC(hdc);
old_hbitmap = (HBITMAP)SelectObject(image_dc,hbitmap);
BitBlt(hdc,1,0,530,450,image_dc,0,0,SRCCOPY);*/
SendMessage(GetDlgItem(hDlg,IDC_STATIC_PICTURE2), STM_SETIMAGE, (WPARAM)IMAGE_BITMAP, (LPARAM)hbitmap);
SendMessage(GetDlgItem(hDlg,IDC_STATIC_PICTURE), STM_SETIMAGE, (WPARAM)IMAGE_BITMAP, (LPARAM)hbitmap2);
return TRUE;
case IDC_BUTTON_EXIT:
MessageBox(hDlg,_T("Thank you"),_T("Close"),MB_ICONINFORMATION|MB_OK);
DeleteObject(hbitmap);
DeleteObject(hbitmap2);
DestroyWindow(hDlg);
return TRUE;