Drawing a system-like cursor, top-most, anywhere

Question

I need to draw a system-like cursor that I simply can control the position of. In other words, I need to draw a transparent image that looks just like the system cursor and I need it to be rendered on top of all other windows. I've tried multiple approaches, but they all seem to have some downside.

I've figured out that I can load the cursor image by using LoadImage() and passing the resource OCR_NORMAL and casting it into a HBITMAP.

HICON NormalCursor = (HICON)LoadImage(NULL, MAKEINTRESOURCE(OCR_NORMAL), IMAGE_CURSOR, 0, 0, LR_DEFAULTSIZE | LR_SHARED);

Then getting the "desktop" HDC

hDC = GetDC(NULL);

Then I can try to draw it using DrawIconEx()

DrawIconEx(hDC, (int)x, 0, NormalCursor, 0, 0, NULL, NULL, DI_DEFAULTSIZE | DI_NORMAL);

The DI_NORMAL flag is supposed to combine the DI_IMAGE & DI_MASK flags giving me a transparent image/icon/cursor, but this is my result on the desktop:

Not to mention that if it moves it creates trails.

By making a transparent window using SetLayeredWindowAttributes like this:

SetLayeredWindowAttributes(hWnd, RGB(0, 0, 0), 50, LWA_COLORKEY);

And having the background color of my window to be black, I can remove the background from the window. But due to doing alpha based on a color I get ugly black pixels around my cursor icon.

Can I make the background of a window transparent in some other way than using a color mask?

How do I draw a transparent cursor on top of all windows properly?

I find it sad that it has to be this hard. Who the hell thought of hardware cursors and why does it still live in Windows today? — sippeangelo
Can I ask why you are not able just to use the system cursor itself? — Ian Goldby

Reinderien Reinderien · Accepted Answer · 2010-09-17T17:49:15

I would recommend that you do make your own window, and do something like what's described at http://www.codeproject.com/KB/GDI-plus/CsTranspTutorial3.aspx . It's in C#, but most of it is just win32 calls. It does a nice job of variable transparency, too, not just 0%/100%.

Drawing a system-like cursor, top-most, anywhere

2 Answers