CODEWITHSUNDEEP
cwinapibitmapmenutransparency
Tim Thaller
Tim Thaller

Reputation: 21

Win32 menu bitmap transparency after selecting item

I am trying to add icon image to context menu of my win32 application

Here is my code 

hMenu = LoadMenuIndirect( LoadResourceLang( RT_MENU, resID ) );

hMenu = ::GetSubMenu( hMenu, 0 );

HBITMAP hBitmap = (HBITMAP)LoadImage((HMODULE)g_hInst,MAKEINTRESOURCE(IDB_BM_PAUSE), IMAGE_BITMAP, 16, 16, LR_CREATEDIBSECTION );

SetMenuItemBitmaps( hMenu, 2, MF_BITMAP|MF_BYPOSITION, hBitmap, hBitmap );

::TrackPopupMenu( hMenu, TPM_LEFTALIGN | TPM_LEFTBUTTON | TPM_RIGHTBUTTON, point.x, point.y, 0, m_hWnd, 0 );

Everything works fine when menu first shown.

But when the cursor hovers over menu item and selection rectangle is drawn, the bitmap is redrawn incorrectly, the transparency is ignored.

Here are the screenshots:

enter image description here

enter image description here

Any suggestion how to fix this?

Upvotes: 2

Views: 914

Answers (1)

Anders
Anders

Reputation: 101569

These bitmaps are only supposed to be used for simple checkmarks etc. and must be monochrome bitmaps. Your usage seems fine as long as you only need one color.

The selected and clear bitmaps should be monochrome. The system uses the Boolean AND operator to combine bitmaps with the menu so that the white part becomes transparent and the black part becomes the menu-item color. If you use color bitmaps, the results may be undesirable.

Ideally you should generate the bitmap on the fly so it matches CYMENUCHECK.

On Windows Vista and later it is also possible to assign a 32bpp image to a menu item without doing owner-draw...

Upvotes: 3

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