Pixel-based scrolling mystery
We have a NEWS entry that says:
** Pixel-based scrolling has been implemented.
By default this will attempt to scroll in increments equal to the
height of the default face. Set `window-pixel-scroll-increment' to
modify this behaviour.
"Wow," says I, "we have pixel-based scrolling, and I wasn't even aware
of it." But no matter how hard I try, I cannot get it to work.
Dragging the scrollbar scrolls by lines. Changing the value of
window-pixel-scroll-increment doesn't seem to help. Its documentation
says:
`window-pixel-scroll-increment' is a simple built-in variable.
Value: t
Documentation:
*Number of pixels to scroll by per requested line.
If nil then normal line scrolling occurs regardless of line height.
If t then scrolling is done in increments equal to the height of the default face.
I'd expect that setting window-pixel-scroll-increment to 1 effectively
enables pixel-based scrolling. Why doesn't it? How is one to
interpret the above NEWS entry?