Transparent

[nath2099]

Hi there,

I've been experimenting with this for a few days now and can't get it to work.

I am trying to get a transparent background text child label/button/window over a child button:


This is as close as I've got:


Using this code:

#include <windows.h>
#include <tchar.h>
#include <objidl.h>
#include "stdafx.h"
#include "gdiplus.h"
#include <iostream>
#include <string>

Gdiplus::Bitmap* m_pBitmap;

#define ID_BTNHI 0
const char windowClassName[] = "myWindowClass";

HWND button;


class inputButton {
	HWND hWnd;
	int xpos, ypos;
public:
	void createButton(HWND,int, int, int);
};

void inputButton::createButton(HWND hWnd, int xpos, int ypos, int nCmdShow) {

	// Create button    
	//HWND hButton1 = CreateWindow(_T("BUTTON"), _T("Test button"), BS_ICON | WS_VISIBLE | WS_CHILD, xpos, ypos, 100, 100, hWnd, (HMENU)1, NULL, NULL);


	HWND hButton1;
	hButton1 = CreateWindowEx(
		0,										// _In_     DWORD     dwExStyle											
		_T("BUTTON"),							// _In_opt_ LPCTSTR   lpClassName
		_T("Test button"),						// _In_opt_ LPCTSTR   lpWindowName
		BS_ICON | WS_VISIBLE | WS_CHILD,		// _In_     DWORD     dwStyle
		xpos,									// _In_     int       x
		ypos,									// _In_     int       y
		100,									// _In_     int       nWidth
		100,									// _In_     int       nHeight
		hWnd,									// _In_opt_ HWND      hWndParent
		NULL,									// _In_opt_ HMENU     hMenu
		NULL,									// _In_opt_ HINSTANCE hInstance
		NULL									// _In_opt_ LPVOID    lpParam
	);




	ShowWindow(hButton1, nCmdShow);
	UpdateWindow(hButton1);


	// Assign image to button
	Gdiplus::Bitmap* m_pBitmap;
	HICON hicon;
	m_pBitmap = Gdiplus::Bitmap::FromFile(L"greySwitch.png");
	m_pBitmap->GetHICON(&hicon);


	LRESULT lr = SendMessage(hButton1, BM_SETIMAGE, IMAGE_ICON, (LPARAM)hicon);


	DWORD Flags1 = WS_EX_COMPOSITED | WS_EX_LAYERED | WS_EX_NOACTIVATE | WS_EX_TOPMOST | WS_EX_TRANSPARENT;
	//DWORD Flags1 =  WS_EX_TRANSPARENT;
	DWORD Flags2 = WS_POPUP;


	HWND hStatic;


	hStatic = CreateWindowEx(
		WS_EX_TRANSPARENT,					// _In_     DWORD     dwExStyle	
		TEXT("Static"),						// _In_opt_ LPCTSTR   lpClassName
		TEXT("text"),						// _In_opt_ LPCTSTR   lpWindowName
		WS_CHILD | WS_VISIBLE,				// _In_     DWORD     dwStyle
		10,									// _In_     int       x
		40,									// _In_     int       y
		80,									// _In_     int       nWidth
		20,									// _In_     int       nHeight
		hButton1,							// _In_opt_ HWND      hWndParent
		NULL,								// _In_opt_ HMENU     hMenu
		NULL,								// _In_opt_ HINSTANCE hInstance
		NULL								// _In_opt_ LPVOID    lpParam
	);

	
	/*
	HRGN GGG = CreateRectRgn(0, 0, 50, 50);
	InvertRgn(GetDC(hStatic), GGG);
	SetWindowRgn(hStatic, GGG, false);

	COLORREF RRR = RGB(255, 0, 0);
	SetLayeredWindowAttributes(hStatic, RRR, (BYTE)0, LWA_COLORKEY);


	ShowWindow(hStatic, nCmdShow);
	UpdateWindow(hStatic);

	DeleteObject(GGG);

	*/

	ShowWindow(hStatic, nCmdShow);
	UpdateWindow(hStatic);

}

LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) {

	int wmId, wmEvent;
	PAINTSTRUCT ps;
	HDC hdc;
	RECT rect;

	switch (msg) {

		case WM_CLOSE:
			DestroyWindow(hWnd);
			break;
		case WM_DESTROY:
			PostQuitMessage(0);
			break;
		case WM_CTLCOLORSTATIC: {
			::MessageBox(NULL, "WM_CTLCOLORSTATIC", "", MB_OK); 

			}
			break;
		case WM_CREATE: {

			}
			break;
		case WM_ERASEBKGND: {
			/*
			GetClientRect(hWnd, &rect);
			FillRect((HDC)wParam, &rect, CreateSolidBrush(RGB(255, 0, 0)));
			*/
		}
		break;
  
		default:
			return DefWindowProc(hWnd, msg, wParam, lParam);
	}
	return 0;
}


int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
	FreeConsole(); //Hides console


				   // Initialize GDI+
	Gdiplus::GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

	

	WNDCLASSEX wc;
	HWND hWnd;
	MSG Msg;

	// Register window class for main window    
	wc.cbSize = sizeof(WNDCLASSEX);
	wc.style = 0;
	wc.lpfnWndProc = WndProc;
	wc.cbClsExtra = 0;
	wc.cbWndExtra = 0;
	wc.hInstance = hInstance;
	wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
	wc.lpszMenuName = NULL;
	wc.lpszClassName = windowClassName;
	

	if (!RegisterClassEx(&wc)) {
		::MessageBox(NULL, "Window Registration Failed!", "", MB_OK);
		return 0;
	}

	// Create main window    
	hWnd = CreateWindowEx(
		WS_EX_CLIENTEDGE,
		windowClassName,
		"C++ Win32 Window",
		WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT, CW_USEDEFAULT,
		600, 450,
		NULL, NULL, hInstance, NULL
	);

	if (hWnd == NULL) {
		::MessageBox(NULL, "Window Creation Failed!", "", MB_OK);
	}

	ShowWindow(hWnd, nCmdShow);
	UpdateWindow(hWnd);


	inputButton button1;
	button1.createButton(hWnd, 50, 50,1);
	inputButton button2;
	button2.createButton(hWnd, 150, 50, 1);
	inputButton button3;
	button3.createButton(hWnd, 250, 50, 1);
	inputButton button4;
	button3.createButton(hWnd, 350, 50, 1);





	while (GetMessage(&Msg, NULL, 0, 0) > 0) {
		TranslateMessage(&Msg);
		DispatchMessage(&Msg);
	}
	return Msg.wParam;
}

As you can no doubt see I'm a beginner to both C++ and WinAPI so don't really know much about what I'm doing. There are quite a few results for exactly this but they all seem to assume some prior knowledge, with only coding 'concepts' as opposed to an example that actually works...



Any help appreciated!

[TubularX]

Is there any reason why you need it to be a child window?

It would be much easier to just draw the text on top of the button image with Gdiplus::Graphics:: DrawString.

That would have the same visual appearance as your first image (demo.jpg).

[Marc G]

As TabularX said, I don't understand why you are making it a child control.
You can either just draw the entire button, or use custom drawing.
See https://msdn.microsoft.com/en-us/lib...(v=vs.85).aspx and https://msdn.microsoft.com/en-us/lib...(v=vs.85).aspx