我找到了一种可用的解决方法,通过在图标上混合带有复选标记的绿色圆圈进行 alpha 混合来检查大图标——与 Windows 用于在控制面板中标记默认音频设备或打印机的解决方案相同:
这是我的 CMFCRibbonButtonEx 类声明:
class CMFCRibbonButtonEx : public CMFCRibbonButton
{
// Construction
public:
CMFCRibbonButtonEx();
CMFCRibbonButtonEx(UINT nID, LPCTSTR lpszText, int nSmallImageIndex = -1, int nLargeImageIndex = -1, BOOL bAlwaysShowDescription = FALSE);
CMFCRibbonButtonEx(UINT nID, LPCTSTR lpszText, HICON hIcon, BOOL bAlwaysShowDescription = FALSE, HICON hIconSmall = NULL, BOOL bAutoDestroyIcon = FALSE, BOOL bAlphaBlendIcon = FALSE);
// Overridden
void SetCheck(BOOL bCheck = TRUE);
void DrawImage(CDC* pDC, RibbonImageType type, CRect rectImage);
// Attributes
private:
BOOL m_bChecked;
// Helper
private:
void DrawCheckmark(CDC* pDC, int CheckmarkResourceBitmapID, RECT *r);
void PremultiplyBitmapAlpha(HDC hDC, HBITMAP hBmp);
};
以下是类函数定义:
CMFCRibbonButtonEx::CMFCRibbonButtonEx() : CMFCRibbonButton() { }
CMFCRibbonButtonEx::CMFCRibbonButtonEx(UINT nID, LPCTSTR lpszText, int nSmallImageIndex, int nLargeImageIndex, BOOL bAlwaysShowDescription)
: CMFCRibbonButton(nID, lpszText, nSmallImageIndex, nLargeImageIndex, bAlwaysShowDescription) { }
CMFCRibbonButtonEx::CMFCRibbonButtonEx(UINT nID, LPCTSTR lpszText, HICON hIcon, BOOL bAlwaysShowDescription, HICON hIconSmall, BOOL bAutoDestroyIcon, BOOL bAlphaBlendIcon)
: CMFCRibbonButton(nID, lpszText, hIcon, bAlwaysShowDescription , hIconSmall, bAutoDestroyIcon, bAlphaBlendIcon) { }
void CMFCRibbonButtonEx::SetCheck(BOOL bCheck)
{
m_bChecked = bCheck;
}
void CMFCRibbonButtonEx::DrawImage(CDC* pDC, RibbonImageType type, CRect rectImage)
{
CMFCRibbonButton::DrawImage(pDC, type, rectImage);
if (type == RibbonImageLarge && m_bChecked)
DrawCheckmark(pDC, IDB_BIG_ICON_CHECKMARK, &rectImage);
}
void CMFCRibbonButtonEx::DrawCheckmark(CDC* pDC, int CheckmarkResourceBitmapID, RECT *r)
{
HDC hdc;
CDC *dc;
CDC dcMem;
CBitmap cbm;
VERIFY(hdc = pDC->m_hDC);
VERIFY(dc = pDC);
dcMem.CreateCompatibleDC(dc);
cbm.LoadBitmap(CheckmarkResourceBitmapID);
PremultiplyBitmapAlpha(dcMem.m_hDC, cbm);
SelectObject(dcMem.m_hDC, cbm.m_hObject);
BLENDFUNCTION bf;
bf.BlendOp = AC_SRC_OVER;
bf.BlendFlags = 0;
bf.SourceConstantAlpha = 255;
bf.AlphaFormat = AC_SRC_ALPHA;
::AlphaBlend(hdc, r->left, r->top, r->right-r->left, r->bottom-r->top, dcMem, 0, 0, 32, 32, bf);
VERIFY(dcMem.DeleteDC());
}
void CMFCRibbonButtonEx::PremultiplyBitmapAlpha(HDC hDC, HBITMAP hBmp)
{
BITMAP bm = { 0 };
GetObject(hBmp, sizeof(bm), &bm);
BITMAPINFO* bmi = (BITMAPINFO*) _alloca(sizeof(BITMAPINFOHEADER) + (256 * sizeof(RGBQUAD)));
::ZeroMemory(bmi, sizeof(BITMAPINFOHEADER) + (256 * sizeof(RGBQUAD)));
bmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
BOOL bRes = ::GetDIBits(hDC, hBmp, 0, bm.bmHeight, NULL, bmi, DIB_RGB_COLORS);
if( !bRes || bmi->bmiHeader.biBitCount != 32 ) return;
LPBYTE pBitData = (LPBYTE) ::LocalAlloc(LPTR, bm.bmWidth * bm.bmHeight * sizeof(DWORD));
if( pBitData == NULL ) return;
LPBYTE pData = pBitData;
::GetDIBits(hDC, hBmp, 0, bm.bmHeight, pData, bmi, DIB_RGB_COLORS);
for( int y = 0; y < bm.bmHeight; y++ ) {
for( int x = 0; x < bm.bmWidth; x++ ) {
pData[0] = (BYTE)((DWORD)pData[0] * pData[3] / 255);
pData[1] = (BYTE)((DWORD)pData[1] * pData[3] / 255);
pData[2] = (BYTE)((DWORD)pData[2] * pData[3] / 255);
pData += 4;
}
}
::SetDIBits(hDC, hBmp, 0, bm.bmHeight, pBitData, bmi, DIB_RGB_COLORS);
::LocalFree(pBitData);
}
IDB_BIG_ICON_CHECKMARK 是一个带有 alpha 通道的 32 位 bmp:Download here
遗憾的是,在 OnCmdMsg 中仅维护由功能区框架创建的假 CMFCRibbonButton,因此 SetCheck() 对 DrawImage() 中的 IsChecked() 调用没有任何影响。您只需要在菜单的子项中找到真正的CMFCRibbonButtonEx,如下所示:
BOOL CEasyCashView::OnCmdMsg(UINT nID, int nCode, void* pExtra, AFX_CMDHANDLERINFO* pHandlerInfo)
{
...
else if (nID >= ID_MY_ITEMS_BASE && nID < ID_ITEMS_BASE+MAX_MY_ITEMS)
{
if (nCode == CN_COMMAND)
{
OnMyItemsCommand(nID);
}
else if (nCode == CN_UPDATE_COMMAND_UI)
{
((CCmdUI*)pExtra)->SetCheck(myItemsCheckedArray[nID-ID_MY_ITEMS_BASE] == TRUE);
// this won't have any effect, use code below
CMFCRibbonButton* pMyMainMenuButton;
if (pMyMainMenuButton = ((CMainFrame*)AfxGetMainWnd())->m_pMyMainMenuButton)
{
int i;
for (i = 0; i < pMyMainMenuButton->GetSubItems().GetCount(); i++)
if (pMyMainMenuButton->GetSubItems()[i]->GetID() == nID)
{
((CMFCRibbonButtonEx*)pMyMainMenuButton->GetSubItems()[i])->SetCheck(myItemsCheckedArray[nID-ID_MY_ITEMS_BASE] == TRUE);
break;
}
}
return TRUE;
}
}
如果有人知道如何将CCmdUI维护的假CMFCRibbonButton(或CMFCRibbonBaseElement)连接到最初创建的CMFCRibbonButtonEx,请给我留言。