C++, GDI+, Load Bitmap and use UpdateLayeredWindow to show Bitmap - c++

Question

Community, I have a small problem and I need help.
I want to load a bitmap and want to show this with UpdatelayerdWindow. I have written the following source code. But nothing appears.
When I use the BitBlt function, the picture appears.
Where do I have here the error in my source code?
ATOM SplashRegisterClass(HINSTANCE hInstance) {
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = NULL;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassEx(&wcex);
}
void ShowBitMap(HWND hwnd, HINSTANCE hInstance) {
int nuXPos = 0;
int nuYPos = 0;
int width = 0;
int height = 0;
BITMAP bm;
hbmpSplash = (HBITMAP)::LoadImage(hInstance, L"software.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
if (hbmpSplash == NULL)
{
::MessageBox(NULL, __T("Image not Found"), __T("Error"), MB_OK);
}
GetObject(hbmpSplash, sizeof(bm), &bm);
SIZE size = { bm.bmHeight, bm.bmWidth };
width = bm.bmWidth;
height = bm.bmHeight;
POINT ptZero = { 0 };
HMONITOR hmonPrimary = MonitorFromPoint(ptZero, MONITOR_DEFAULTTOPRIMARY);
MONITORINFO monitorinfo = { 0 };
monitorinfo.cbSize = sizeof(monitorinfo);
GetMonitorInfo(hmonPrimary, &monitorinfo);
const RECT & rcWork = monitorinfo.rcWork;
nuXPos = rcWork.left + (rcWork.right - rcWork.left) / 2;
nuYPos = rcWork.top + (rcWork.bottom - rcWork.top) / 2;
nuXPos = nuXPos - (175 / 2);
nuYPos = nuYPos - (170 / 2);
HDC hdcScreen = GetDC(NULL);
HDC hdcneu = CreateCompatibleDC(hdcScreen);
HDC hdcMem = CreateCompatibleDC(hdcScreen);
HBITMAP hbmpOld = (HBITMAP)SelectObject(hdcMem, hbmpSplash);
POINT position = { nuXPos, nuYPos };
BLENDFUNCTION blend = { 0 };
blend.BlendOp = AC_SRC_OVER;
blend.SourceConstantAlpha = 255;
blend.AlphaFormat = AC_SRC_ALPHA;
//Next line only for test!
//::BitBlt(hdcScreen, nuXPos, nuYPos, width, height, hdcMem, 0, 0, SRCCOPY);
//Show the Bitmap
if (!UpdateLayeredWindow(splashOwner, hdcScreen, &position, &size, hdcMem, NULL, RGB(0, 0, 0), &blend, ULW_ALPHA))
{
//int LastError = GetLastError();
}
SelectObject(hdcMem, hbmpOld);
DeleteDC(hdcMem);
ReleaseDC(NULL, hdcScreen);
}
HWND CreateSplashWindow(HINSTANCE hInstance, int nCmdShow) {
SplashRegisterClass(hInstance);
splashOwner = CreateWindow(szWindowClass, NULL, WS_POPUP, 0, 0, 100, 100, NULL, NULL, hInstance, NULL);
if (!splashOwner)
{
::MessageBox(NULL, __T("Error"), __T("Error"), MB_OK);
}
ShowBitMap(splashOwner, hInstance);
return CreateWindowEx(WS_EX_LAYERED, szWindowClass, 0, WS_POPUP, 0, 0, 100, 100, splashOwner, NULL, hInstance, NULL);
}
I want delete everything when the main programme is running. Can I make with this function?
void DeleteSplashWindow(){
ReleaseDC(splashOwner, 0);
}
Thanks for help!

Answer 1

hbmpSplash = (HBITMAP)::LoadImage(hInstance, L"software.bmp",
IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
This function fails, it should give an error. Change it to
hbmpSplash = (HBITMAP)::LoadImage(0, L"software.bmp",
IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
When creating layered window you must call SetLayeredWindowAttributes. Example
HWND CreateSplashWindow(HINSTANCE hInstance, int nCmdShow) {
...
HWND hwnd = CreateWindowEx(WS_EX_LAYERED, szWindowClass,
0, WS_POPUP, 0, 0, 100, 100,
splashOwner, NULL, hInstance, NULL);
SetLayeredWindowAttributes(hwnd, transparentColor, alpha, LWA_COLORKEY | LWA_ALPHA);
return hwnd;
}

Answer 2

Thanks for the help, I arrive myself to the solution. 1. I forgot ShowWindow(hwnd,SW_SHOW); and
2.void DeleteSplashWindow(){
ReleaseDC(splashOwner, NULL);
ShowWindow(splashOwner, NULL);
}