我正在尝试add bitmaps to a popup menu。
我遇到的问题是我动态地从ICON创建我的位图,而24位彩色图标与24 + alpha(32位)彩色图标有问题。
似乎位图只有在32bpp(包括alpha通道)时才能正确绘制。
这是我的(测试)代码:
void ConvertIconToBitmap(CBitmap& bmpObj, HICON hIcon, int cx, int cy, BOOL useDIB) {
CClientDC screenDC(NULL);
CBitmap bmpTmp;
HANDLE_API_FAILURE( bmpTmp.CreateCompatibleBitmap(&screenDC, cx, cy) );
CDC memDC;
HANDLE_API_FAILURE( memDC.CreateCompatibleDC(&screenDC) );
CBitmap* pOldBmp = memDC.SelectObject(&bmpTmp);
HANDLE_API_FAILURE( ::DrawIconEx( memDC.GetSafeHdc(), 0, 0, hIcon, cx, cy, 0, NULL, DI_NORMAL) );
memDC.SelectObject( pOldBmp );
HBITMAP hDibBmp = (HBITMAP)::CopyImage((HANDLE)(HBITMAP)bmpTmp, IMAGE_BITMAP, 0, 0, LR_DEFAULTSIZE | LR_CREATEDIBSECTION);
HANDLE_API_FAILURE( hDibBmp );
if (useDIB) {
HANDLE_API_FAILURE( bmpObj.Attach(hDibBmp) ); // works for 32bit/transparanecy
} else {
HANDLE_API_FAILURE( bmpObj.Attach(bmpTmp.Detach()) ); // works for 24bit
}
}
...
CMenu menu;
menu.LoadMenu(IDR_POPUPMENU);
CMenu* pMenu = menu.GetSubMenu(0);
int cx, cy;
cx = cy = GetSystemMetrics(SM_CYMENU);
MENUITEMINFO mii;
mii.cbSize = sizeof mii;
mii.fMask = MIIM_BITMAP;
HICON pwdIco = ExtractIcon(NULL/*=current instance*/, L"path/to/file.exe", 0);
// If icon is 32bit-alpha this works, but doesn't work with 24bit icon
CBitmap bmpTop;
ConvertIconToBitmap(bmpTop, pwdIco, cx, cy, TRUE);
mii.hbmpItem = bmpTop;
pMenu->SetMenuItemInfo(ID_MENU_TOP, &mii, FALSE);
// If icon is 32bit-alpha transparent areas are shown in black, but 24bit icon is also displayed correctly
CBitmap bmpApp;
ConvertIconToBitmap(bmpApp, pwdIco, cx, cy, FALSE);
HBITMAP bmpTransp = bmpApp;
mii.hbmpItem = bmpTransp;
pMenu->SetMenuItemInfo(ID_MENU_TEST, &mii, FALSE);
this->ClientToScreen(&point);
pMenu->TrackPopupMenu(nFlags, point.x, point.y, this);
由于我需要从现有文件的图标中动态填充菜单条目图像,我不能只是静态地调整位图并使用这些图标而不是图标。
传递给MENUITEMINFO的SetMenuItemInfo结构的HBITMAP
成员传递的hbmpItem
有什么要求???
如何确保DrawIconEx
“创建”的位图确实符合这些要求?
哦,我很高兴我刚刚了解到32位alpha混合菜单项位图在Windows XP下无法正常工作(透明=黑色),所以我必须以某种方式自己映射透明度。 (可能用GetSysColor(COLOR_MENU)
替换某些颜色。)