mouse scroll wheel zooming instead scrolling windows 10

The second and third pieces can come from GetCursorPos. The helper program can get the first piece of essential information because it came from the mouse. And the shift key states are essential because that tells the application what action it should take. The mouse coordinates are essential in order for the application to know which object to scroll. The scroll amount is essential because that’s sort of the point of the message. You have four pieces of information that are essential: Let’s start with “What do you put in the message payload?” When it detected that the wheel scrolled, it delivered a custom wheel scroll message: MSH_MOUSEWHEEL.¹

Wheel support operated by having a dedicated helper program that listened to the mouse hardware. Since the hardware team had to invent something and couldn’t rely on help from the window manager team, they had to make do with what they could. It’s also apparent in the header file name: The z represents the third coordinate, emphasizing that the wheel is supposed to move you closer to or further away from the document. The fact that the wheel was intended for zooming rather than scrolling is also evident in the names of the parameters in the header file: The parameter that receives a boolean that tells you whether a wheel mouse is installed is named pf 3DSupport. This is a header file from 1996 that nobody wants to delete because doing so might break somebody. You can see the result of this in the zmouse.h header file buried in your SDK. Therefore, the hardware team had to invent their own mechanism for mouse wheel messages, with the understanding that operating system support for it wouldn’t arrive until the next major release of Windows (which turned out to be Windows 98 and Windows NT 4.0). This was not synchronized with an operating system release, and Windows Update wasn’t a thing yet, not that anybody cared because Internet access was not widespread, and those who did were using mostly dial-up. The historical context is that the mouse wheel in Windows was introduced by the Microsoft Hardware team in 1996. (Or is it the other way? I can never remember.) In practice, though, people preferred to use the mouse wheel to scroll, and zooming got relegated to a secondary feature activated by holding the Ctrl key while turning the wheel.Īnd it’s the Ctrl key that is the key that unlocks the puzzle. Spin the wheel forward to zoom in spin it backward to zoom out. The original intent of the mouse wheel was to control zooming. The mouse wheel turned into one of those features whose primary use is not the original intended use. I don’t know if there’s a good reason, but there’s a reason. Douglas asks, “Is there a good reason that mouse wheel messages are sent to the focused window instead of the window under the mouse?”

Mouse scroll wheel zooming instead scrolling windows 10