使用 Win32 的带有主题的透明单选按钮控件

2022-01-21 00:00:00 winapi radio-button c++ visual-styles

我正在尝试在启用主题时仅使用 Win32 制作具有透明背景的单选按钮控件.这样做的原因是允许将单选按钮放置在图像上并显示图像(而不是灰色的默认控件背景).

I am trying to make a radio button control with a transparent background using only Win32 when themes are enabled. The reason for doing this is to allow a radio button to be placed over an image and have the image show (rather than the grey default control background).

开箱即用的是控件将具有灰色的默认控件背景以及通过处理 WM_CTLCOLORSTATICWM_CTLCOLORBTN 来更改它的标准方法,如下所示不起作用:

What happens out of the box is that the control will have the grey default control background and the standard method of changing this by handling either WM_CTLCOLORSTATIC or WM_CTLCOLORBTN as shown below does not work:

case WM_CTLCOLORSTATIC:
    hdcStatic = (HDC)wParam;

    SetTextColor(hdcStatic, RGB(0,0,0)); 
    SetBkMode(hdcStatic,TRANSPARENT);

    return (LRESULT)GetStockObject(NULL_BRUSH);
    break;  

到目前为止,我的研究表明 Owner Draw 是实现这一目标的唯一方法.我已经设法通过 Owner Draw 单选按钮获得了大部分方法 - 使用下面的代码,我有一个单选按钮和一个透明背景(背景在 WM_CTLCOLORBTN 中设置).然而,无线电检查的边缘使用这种方法被切断了――我可以通过取消对函数 DrawThemeParentBackgroundEx 的调用来取回它们,但这会破坏透明度.

My research so far indicates that Owner Draw is the only way to achieve this. I've managed to get most of the way with an Owner Draw radio button - with the code below I have a radio button and a transparent background (the background is set in WM_CTLCOLORBTN). However, the edges of the radio check are cut off using this method - I can get them back by uncommenting the call to the function DrawThemeParentBackgroundEx but this breaks the transparency.

void DrawRadioControl(HWND hwnd, HTHEME hTheme, HDC dc, bool checked, RECT rcItem)
{
    if (hTheme)
    {
      static const int cb_size = 13;

      RECT bgRect, textRect;
      HFONT font = (HFONT)SendMessageW(hwnd, WM_GETFONT, 0, 0);
      WCHAR *text = L"Experiment";

      DWORD state = ((checked) ? RBS_CHECKEDNORMAL : RBS_UNCHECKEDNORMAL) | ((bMouseOverButton) ? RBS_HOT : 0); 

      GetClientRect(hwnd, &bgRect);
      GetThemeBackgroundContentRect(hTheme, dc, BP_RADIOBUTTON, state, &bgRect, &textRect);

      DWORD dtFlags = DT_VCENTER | DT_SINGLELINE;

      if (dtFlags & DT_SINGLELINE) /* Center the checkbox / radio button to the text. */
         bgRect.top = bgRect.top + (textRect.bottom - textRect.top - cb_size) / 2;

      /* adjust for the check/radio marker */
      bgRect.bottom = bgRect.top + cb_size;
      bgRect.right = bgRect.left + cb_size;
      textRect.left = bgRect.right + 6;

      //Uncommenting this line will fix the button corners but breaks transparency
      //DrawThemeParentBackgroundEx(hwnd, dc, DTPB_USECTLCOLORSTATIC, NULL);

      DrawThemeBackground(hTheme, dc, BP_RADIOBUTTON, state, &bgRect, NULL);
      if (text)
      {
          DrawThemeText(hTheme, dc, BP_RADIOBUTTON, state, text, lstrlenW(text), dtFlags, 0, &textRect);

      }

   }
   else
   {
       // Code for rendering the radio when themes are not present
   }

}

上面的方法是从WM_DRAWITEM调用的,如下所示:

The method above is called from WM_DRAWITEM as shown below:

case WM_DRAWITEM:
{
    LPDRAWITEMSTRUCT pDIS = (LPDRAWITEMSTRUCT)lParam;
    hTheme = OpenThemeData(hDlg, L"BUTTON");    

    HDC dc = pDIS->hDC;

    wchar_t sCaption[100];
    GetWindowText(GetDlgItem(hDlg, pDIS->CtlID), sCaption, 100);
    std::wstring staticText(sCaption);

    DrawRadioControl(pDIS->hwndItem, hTheme, dc, radio_group.IsButtonChecked(pDIS->CtlID), pDIS->rcItem, staticText);                               

    SetBkMode(dc, TRANSPARENT);
    SetTextColor(hdcStatic, RGB(0,0,0));                                
    return TRUE;

}                           

所以我的问题是我想的两个部分:

So my question is two parts I suppose:

  1. 我是否错过了其他方法来达到我想要的结果?
  2. 是否可以用我的代码修复被剪裁的按钮角问题并且仍然具有透明背景

推荐答案

断断续续地看了近三个月后,我终于找到了一个令我满意的解决方案.我最终发现单选按钮边缘由于某种原因没有被 WM_DRAWITEM 中的例程绘制,但是如果我在控件周围的矩形中使单选按钮控件的父级无效,它们就会出现.

After looking at this on and off for nearly three months I've finally found a solution that I'm pleased with. What I eventually found was that the radio button edges were for some reason not being drawn by the routine within WM_DRAWITEM but that if I invalidated the radio button control's parent in a rectangle around the control, they appeared.

由于我找不到一个好的示例,因此我提供了完整的代码(在我自己的解决方案中,我已将所有者绘制的控件封装到他们自己的类中,因此您需要提供一些详细信息,例如是否按钮是否被选中)

Since I could not find a single good example of this I'm providing the full code (in my own solution I have encapsulated my owner drawn controls into their own class, so you will need to provide some details such as whether the button is checked or not)

这是单选按钮的创建(将其添加到父窗口),同时设置 GWL_UserData 和子类化单选按钮:

This is the creation of the radiobutton (adding it to the parent window) also setting GWL_UserData and subclassing the radiobutton:

HWND hWndControl = CreateWindow( _T("BUTTON"), caption, WS_CHILD | WS_VISIBLE | BS_OWNERDRAW, 
    xPos, yPos, width, height, parentHwnd, (HMENU) id, NULL, NULL);

// Using SetWindowLong and GWL_USERDATA I pass in the this reference, allowing my 
// window proc toknow about the control state such as if it is selected
SetWindowLong( hWndControl, GWL_USERDATA, (LONG)this);

// And subclass the control - the WndProc is shown later
SetWindowSubclass(hWndControl, OwnerDrawControl::WndProc, 0, 0);

由于是所有者绘制,我们需要在父窗口过程中处理 WM_DRAWITEM 消息.

Since it is owner draw we need to handle the WM_DRAWITEM message in the parent window proc.

case WM_DRAWITEM:      
{      
    LPDRAWITEMSTRUCT pDIS = (LPDRAWITEMSTRUCT)lParam;      
    hTheme = OpenThemeData(hDlg, L"BUTTON");          

    HDC dc = pDIS->hDC;      

    wchar_t sCaption[100];      
    GetWindowText(GetDlgItem(hDlg, pDIS->CtlID), sCaption, 100);      
    std::wstring staticText(sCaption);      

    // Controller here passes to a class that holds a map of all controls 
    // which then passes on to the correct instance of my owner draw class
    // which has the drawing code I show below
    controller->DrawControl(pDIS->hwndItem, hTheme, dc, pDIS->rcItem, 
        staticText, pDIS->CtlID, pDIS->itemState, pDIS->itemAction);    

    SetBkMode(dc, TRANSPARENT);      
    SetTextColor(hdcStatic, RGB(0,0,0));     

    CloseThemeData(hTheme);                                 
    return TRUE;      

}    

这里是 DrawControl 方法 - 它可以访问类级别的变量以允许管理状态,因为所有者绘制不会自动处理.

Here is the DrawControl method - it has access to class level variables to allow state to be managed since with owner draw this is not handled automatically.

void OwnerDrawControl::DrawControl(HWND hwnd, HTHEME hTheme, HDC dc, bool checked, RECT rcItem, std::wstring caption, int ctrlId, UINT item_state, UINT item_action)
{   
    // Check if we need to draw themed data    
    if (hTheme)
    {   
        HWND parent = GetParent(hwnd);      

        static const int cb_size = 13;                      

        RECT bgRect, textRect;
        HFONT font = (HFONT)SendMessageW(hwnd, WM_GETFONT, 0, 0);

        DWORD state;

        // This method handles both radio buttons and checkboxes - the enums here
        // are part of my own code, not Windows enums.
        // We also have hot tracking - this is shown in the window subclass later
        if (Type() == RADIO_BUTTON) 
            state = ((checked) ? RBS_CHECKEDNORMAL : RBS_UNCHECKEDNORMAL) | ((is_hot_) ? RBS_HOT : 0);      
        else if (Type() == CHECK_BOX)
            state = ((checked) ? CBS_CHECKEDNORMAL : CBS_UNCHECKEDNORMAL) | ((is_hot_) ? RBS_HOT : 0);      

        GetClientRect(hwnd, &bgRect);

        // the theme type is either BP_RADIOBUTTON or BP_CHECKBOX where these are Windows enums
        DWORD theme_type = ThemeType(); 

        GetThemeBackgroundContentRect(hTheme, dc, theme_type, state, &bgRect, &textRect);

        DWORD dtFlags = DT_VCENTER | DT_SINGLELINE;

        if (dtFlags & DT_SINGLELINE) /* Center the checkbox / radio button to the text. */
            bgRect.top = bgRect.top + (textRect.bottom - textRect.top - cb_size) / 2;

        /* adjust for the check/radio marker */
        // The +3 and +6 are a slight fudge to allow the focus rectangle to show correctly
        bgRect.bottom = bgRect.top + cb_size;
        bgRect.left += 3;
        bgRect.right = bgRect.left + cb_size;       

        textRect.left = bgRect.right + 6;       

        DrawThemeBackground(hTheme, dc, theme_type, state, &bgRect, NULL);          
        DrawThemeText(hTheme, dc, theme_type, state, caption.c_str(), lstrlenW(caption.c_str()), dtFlags, 0, &textRect);                    

        // Draw Focus Rectangle - I still don't really like this, it draw on the parent
        // mainly to work around the way DrawFocus toggles the focus rect on and off.
        // That coupled with some of my other drawing meant this was the only way I found
        // to get a reliable focus effect.
        BOOL bODAEntire = (item_action & ODA_DRAWENTIRE);
        BOOL bIsFocused  = (item_state & ODS_FOCUS);        
        BOOL bDrawFocusRect = !(item_state & ODS_NOFOCUSRECT);

        if (bIsFocused && bDrawFocusRect)
        {
            if ((!bODAEntire))
            {               
                HDC pdc = GetDC(parent);
                RECT prc = GetMappedRectanglePos(hwnd, parent);
                DrawFocus(pdc, prc);                
            }
        }   

    }
      // This handles drawing when we don't have themes
    else
    {
          TEXTMETRIC tm;
          GetTextMetrics(dc, &tm);      

          RECT rect = { rcItem.left , 
              rcItem.top , 
              rcItem.left + tm.tmHeight - 1, 
              rcItem.top + tm.tmHeight - 1};    

          DWORD state = ((checked) ? DFCS_CHECKED : 0 ); 

          if (Type() == RADIO_BUTTON) 
              DrawFrameControl(dc, &rect, DFC_BUTTON, DFCS_BUTTONRADIO | state);
          else if (Type() == CHECK_BOX)
              DrawFrameControl(dc, &rect, DFC_BUTTON, DFCS_BUTTONCHECK | state);

          RECT textRect = rcItem;
          textRect.left = rcItem.left + 19;

          SetTextColor(dc, ::GetSysColor(COLOR_BTNTEXT));
          SetBkColor(dc, ::GetSysColor(COLOR_BTNFACE));
          DrawText(dc, caption.c_str(), -1, &textRect, DT_WORDBREAK | DT_TOP);
    }           
}

接下来是用于子类化单选按钮控件的窗口过程 - 这个使用所有 Windows 消息调用并处理几个,然后传递未处理那些在默认的proc上.

Next is the window proc that is used to subclass the radio button control - this is called with all windows messages and handles several before then passing unhandled ones on to the default proc.

LRESULT OwnerDrawControl::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam,
                               LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
    // Get the button parent window
    HWND parent = GetParent(hWnd);  

    // The page controller and the OwnerDrawControl hold some information we need to draw
    // correctly, such as if the control is already set hot.
    st_mini::IPageController * controller = GetWinLong<st_mini::IPageController *> (parent);

    // Get the control
    OwnerDrawControl *ctrl = (OwnerDrawControl*)GetWindowLong(hWnd, GWL_USERDATA);

    switch (uMsg)
    {       
        case WM_LBUTTONDOWN:
        if (controller)
        {
            int ctrlId = GetDlgCtrlID(hWnd);

            // OnCommand is where the logic for things like selecting a radiobutton
            // and deselecting the rest of the group lives.
            // We also call our Invalidate method there, which redraws the radio when
            // it is selected. The Invalidate method will be shown last.
            controller->OnCommand(parent, ctrlId, 0);       

            return (0);
        }
        break;
        case WM_LBUTTONDBLCLK:
            // We just treat doubleclicks as clicks
            PostMessage(hWnd, WM_LBUTTONDOWN, wParam, lParam);
            break;
        case WM_MOUSEMOVE:
        {
            if (controller)                 
            {
                // This is our hot tracking allowing us to paint the control
                // correctly when the mouse is over it - it sets flags that get
                // used by the above DrawControl method
                if(!ctrl->IsHot())
                {
                    ctrl->SetHot(true);
                    // We invalidate to repaint
                    ctrl->InvalidateControl();

                    // Track the mouse event - without this the mouse leave message is not sent
                    TRACKMOUSEEVENT tme;
                    tme.cbSize = sizeof(TRACKMOUSEEVENT);
                    tme.dwFlags = TME_LEAVE;
                    tme.hwndTrack = hWnd;

                    TrackMouseEvent(&tme);
                }
            }    
            return (0);
        }
        break;
    case WM_MOUSELEAVE:
    {
        if (controller)
        {
            // Turn off the hot display on the radio
            if(ctrl->IsHot())
            {
                ctrl->SetHot(false);        
                ctrl->InvalidateControl();
            }
        }

        return (0);
    }
    case WM_SETFOCUS:
    {
        ctrl->InvalidateControl();
    }
    case WM_KILLFOCUS:
    {
        RECT rcItem;
        GetClientRect(hWnd, &rcItem);
        HDC dc = GetDC(parent);
        RECT prc = GetMappedRectanglePos(hWnd, parent);
        DrawFocus(dc, prc);

        return (0);
    }
    case WM_ERASEBKGND:
        return 1;
    }
    // Any messages we don't process must be passed onto the original window function
    return DefSubclassProc(hWnd, uMsg, wParam, lParam); 

}

最后一个难题是您需要在正确的时间使控件无效(重绘它).我最终发现,使父级无效可以让绘图 100% 正确工作.这导致了闪烁,直到我意识到我可以通过仅使与单选检查一样大的矩形无效来摆脱困境,而不是像我以前那样大到包括文本在内的整个控件.

Finally the last little piece of the puzzle is that you need to invalidate the control (redraw it) at the right times. I eventually found that invalidating the parent allowed the drawing to work 100% correctly. This was causing flicker until I realised that I could get away by only invalidating a rectangle as big as the radio check, rather than as big as the whole control including text as I had been.

void InvalidateControl()
{
    // GetMappedRectanglePos is my own helper that uses MapWindowPoints 
    // to take a child control and map it to its parent
    RECT rc = GetMappedRectanglePos(ctrl_, parent_);

    // This was my first go, that caused flicker
    // InvalidateRect(parent_, &rc_, FALSE);    

    // Now I invalidate a smaller rectangle
    rc.right = rc.left + 13;
    InvalidateRect(parent_, &rc, FALSE);                
}

为了简单的事情需要大量的代码和努力 - 在背景图像上绘制一个主题单选按钮.希望答案能减轻别人的痛苦!

A lot of code and effort for something that should be simple - drawing a themed radio button over a background image. Hopefully the answer will save someone else some pain!

* 一个重要的警告是,它仅适用于背景上的所有者控件(例如填充矩形或图像)100% 正确.不过没关系,因为只有在背景上绘制无线电控件时才需要它.

* One big caveat with this is it only works 100% correctly for owner controls that are over a background (such as a fill rectangle or an image). That is ok though, since it is only needed when drawing the radio control over a background.

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