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I tried to build a scrollable container with Direct2D, I know how to do that. I need to handle mouse scroll, as far as I know, the easiest way is to handle the WM_MOUSESCROLL message.
Here is my try:
UINT direction = HIWORD(wparam);
I used a debugger to see if it works, but its not. the variable direction always have a value 224, which is weird, even If I scroll both up and down.
What I want to achieve is:
You can see the sample I had posted in this thread : Win32 C++; How to use mouse wheel to zoom in and zoom out of picture in the client area of the application window?
In your example, why you need to check if (abs(nDelta) >= WHEEL_DELTA)? Sorry, I didn't know much about delta-thing, etc. Can you please explain me what it is?
It is to check if the user rotated sufficiently the wheel (at least 1 WHEEL_DELTA)
There is in MSDN :
The high-order word indicates the distance the wheel is rotated, expressed in multiples or divisions of WHEEL_DELTA, which is 120. A positive value indicates that the wheel was rotated forward, away from the user; a negative value indicates that the wheel was rotated backward, toward the user.
Yea, I have read that too before asking this questions, but I still have no idea what does it means.
It should measure the distance/speed of the rotation.
Although with my (old) mouse, I always get -480 or +480
(+/- WHEEL_DELTA * 4)