使用WinAPI使用透明背景创建文本标签 [英] Creating a text label with a transparent background using WinAPI

问题描述

是否可以使用WinAPI命令在窗口中创建带有透明背景的标签？

我试图将图像添加到对话框窗口用作背景图像，然后在该图像上显示文本。

这是我迄今为止我的代码的一个例子（显示了一个例子）对话框的整个消息处理程序）：

  INT_PTR CALLBACK OfferWindowProc（HWND hDlg，UINT message，WPARAM wParam，LPARAM lParam）
 {
 HWND hWndBackground; 
 HWND hWndLabel; 
 HBRUSH hLabelBackColour = NULL; 
 HFONT hfFont; 
 HWND hWndTitleLabel; 
 HDC hdcStatic = NULL; 
 
 UNREFERENCED_PARAMETER（lParam）; 
 switch（message）
 {
 case WM_INITDIALOG：
 
 //加载背景图片
 HANDLE hBitmap; 
 hBitmap = LoadImage（NULL，LC：\\Users\\DavidHall\\Documents\\bg.bmp，IMAGE_BITMAP，0，0，LR_LOADFROMFILE）; 
 if（hBitmap！= NULL）
 {
 hWndBackground = CreateWindow（LSTATIC，Limage box，WS_CHILD | WS_VISIBLE | SS_BITMAP，0，0，100，100，hDlg ，（HMENU）2000，NULL，NULL）; 
 SendMessage（hWndBackground，STM_SETIMAGE，IMAGE_BITMAP，LPARAM（hBitmap））; 
} 
 
 //使用CreateWindowEx创建标签
 hfFont = CreateFont（20，0，0，0，fontWeight，FALSE，FALSE，FALSE，DEFAULT_CHARSET，OUT_DEFAULT_PRECIS，CLIP_DEFAULT_PRECIS， ANTIALIASED_QUALITY，
 DEFAULT_PITCH，LVerdana）; 
 
 hWndTitleLabel = CreateWindowEx（WS_EX_TRANSPARENT，LSTATIC，L，WS_CHILD | WS_VISIBLE | SS_LEFT | WS_SYSMENU，xPos，yPos，width，height，hwnd，（HMENU）id，hInst，NULL） ; 
 
 SendMessage（hWndTitleLabel，WM_SETTEXT，NULL，（LPARAM）labelText.c_str（））; 
 
 SendMessage（hWndTitleLabel，WM_SETFONT，（WPARAM）hfFont，NULL）; 
 
 return（INT_PTR）TRUE; 
 
 case WM_CLOSE：
 EndDialog（hDlg，LOWORD（wParam））; 
 
 //删除画笔 - 是正确的吗？ 
 DeleteObject（hLabelBackColour）; 
 return（INT_PTR）TRUE; 
 
 case WM_COMMAND：
 if（LOWORD（wParam）== IDCANCEL）
 {
 EndDialog（hDlg，LOWORD（wParam） 
 return（INT_PTR）TRUE; 
} 
 break; 
默认值：
 break; 
} 
 return（INT_PTR）FALSE; 
} 
  

我尝试过各种组合，包括：

• SetLayeredWindowAttributes


• SetBkMode ，TRANSPARENT）


• 处理 WM_CTLCOLORSTATIC 讯息

解决方案

我发现一些似乎是工作，虽然由于我是新的编程在纯WinAPI这可能是非常糟糕的做法

 
我正在处理WM_CTLCOLORSTATIC消息，如下所示：
 code> case WM_CTLCOLORSTATIC：
 
 hdcStatic =（HDC）wParam; 
 SetTextColor（hdcStatic，RGB（0,0,0））; 
 SetBkMode（hdcStatic，TRANSPARENT）; 
 
 return（LRESULT）GetStockObject（NULL_BRUSH）; 
  

这使我的标签出现在我的图像顶部，背景。

Is it possible to create a label with a transparent background within a window using only WinAPI commands?

I am trying to add an image to a Dialog window that will serve as a background image and then display text upon that image. Everything I have tried so far shows the text label on top of the background image with a grey rectangle drawn around it.

This is an example of my code so far (showing the entire message handler for the dialog):

INT_PTR CALLBACK OfferWindowProc(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{       
    HWND hWndBackground;
    HWND hWndLabel;
    HBRUSH hLabelBackColour = NULL;
      HFONT hfFont;
      HWND hWndTitleLabel;
    HDC hdcStatic = NULL;

    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:             

        //Load the background image
        HANDLE hBitmap;
        hBitmap = LoadImage(NULL, L"C:\\Users\\DavidHall\\Documents\\bg.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
        if (hBitmap != NULL)
        {
            hWndBackground = CreateWindow(L"STATIC", L"image box", WS_CHILD | WS_VISIBLE | SS_BITMAP, 0, 0, 100, 100, hDlg, (HMENU) 2000, NULL, NULL);          
            SendMessage(hWndBackground, STM_SETIMAGE, IMAGE_BITMAP, LPARAM(hBitmap));
        }           

        // Create the label using CreateWindowEx
        hfFont = CreateFont(20, 0, 0, 0, fontWeight, FALSE, FALSE, FALSE, DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS, ANTIALIASED_QUALITY,
            DEFAULT_PITCH, L"Verdana");

        hWndTitleLabel = CreateWindowEx( WS_EX_TRANSPARENT, L"STATIC", L"", WS_CHILD | WS_VISIBLE | SS_LEFT | WS_SYSMENU , xPos, yPos, width, height, hwnd, (HMENU) id, hInst, NULL);           

        SendMessage(hWndTitleLabel, WM_SETTEXT, NULL, (LPARAM) labelText.c_str());

        SendMessage(hWndTitleLabel, WM_SETFONT, (WPARAM)hfFont, NULL);  

        return (INT_PTR)TRUE;   

    case WM_CLOSE:
        EndDialog(hDlg, LOWORD(wParam));    

        // Delete the brush - is that correct?
        DeleteObject(hLabelBackColour);
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    default:
        break;
    }
    return (INT_PTR)FALSE;
}

I've tried various combinations of things including:

• SetLayeredWindowAttributes
• SetBkMode(hdc, TRANSPARENT)
• Handling the WM_CTLCOLORSTATIC message

解决方案

I've found something that appears to be working, though since I am very new to programming in pure WinAPI this could well be very bad practice and I would have no idea!

I am handling the WM_CTLCOLORSTATIC message as shown:

case WM_CTLCOLORSTATIC:

    hdcStatic = (HDC) wParam; 
    SetTextColor(hdcStatic, RGB(0,0,0));    
    SetBkMode (hdcStatic, TRANSPARENT);

    return (LRESULT)GetStockObject(NULL_BRUSH);

This gives the effect that I'm after of my label appearing on top of my image with a transparent background.

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