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Improve velocity calculation in momentum scrolling

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* lisp/pixel-scroll.el
(pixel-scroll-precision-momentum-factor): Remove option.
(pixel-scroll-precision-initial-velocity-factor)
(pixel-scroll-precision-momentum-min-velocity): New user
options.
(pixel-scroll-accumulate-velocity): Clear velocity ring
if sign is different.
(pixel-scroll-calculate-velocity): Use current time.
(pixel-scroll-start-momentum): Use better algorithm.
This commit is contained in:
Po Lu 2021-12-03 13:55:39 +08:00
parent c66eb52453
commit 1afa295aed
1 changed files with 49 additions and 25 deletions
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74
lisp/pixel-scroll.el
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@ -121,8 +121,14 @@ This is only effective if supported by your mouse or touchpad."
:type 'float
:version "29.1")
(defcustom pixel-scroll-precision-momentum-factor 0.95
"Factor by which to reduce scroll velocity on each momentum scroll"
(defcustom pixel-scroll-precision-momentum-min-velocity 10.0
"The minimum scrolled pixels per second before momentum scrolling starts."
:group 'mouse
:type 'float
:version "29.1")
(defcustom pixel-scroll-precision-initial-velocity-factor 0.25
"Factor applied to the initial velocity before momentum scrolling begins."
:group 'mouse
:type 'float
:version "29.1")
@ -524,8 +530,13 @@ It is a vector of the form [ VELOCITY TIME ]."
(defun pixel-scroll-accumulate-velocity (delta)
"Accumulate DELTA into the current window's kinetic scroll state."
(let* ((state (pixel-scroll-kinetic-state))
(ring (aref state 0))
(time (aref state 1)))
(when (and time (> (- (float-time) time) 0.5))
(when (or (and time (> (- (float-time) time) 0.5))
(and (not (ring-empty-p ring))
(not (eq (< delta 0)
(< (cdr (ring-ref ring 0))
0)))))
(aset state 0 (make-ring 10)))
(ring-insert (aref state 0)
(cons (aset state 1 (float-time))
@ -538,8 +549,7 @@ It is a vector of the form [ VELOCITY TIME ]."
(total 0))
(dolist (tem elts)
(setq total (+ total (cdr tem))))
(/ total (* (- (caar elts)
(caar (last elts)))
(/ total (* (- (float-time) (caar elts))
100))))
(defun pixel-scroll-start-momentum (event)
@ -555,26 +565,40 @@ It is a vector of the form [ VELOCITY TIME ]."
(while-no-input
(unwind-protect (progn
(aset state 0 (pixel-scroll-calculate-velocity state))
(let ((velocity (/ (aref state 0) 3))
(time-spent 0))
(if (> velocity 0)
(while (and (> velocity 0.2)
(<= time-spent pixel-scroll-precision-momentum-seconds))
(pixel-scroll-precision-scroll-up (ceiling velocity))
(setq velocity (* velocity pixel-scroll-precision-momentum-factor))
(redisplay t)
(sit-for pixel-scroll-precision-momentum-tick)
(setq time-spent (+ time-spent
pixel-scroll-precision-momentum-tick))))
(while (and (< velocity -0.4)
(<= time-spent
pixel-scroll-precision-momentum-seconds))
(pixel-scroll-precision-scroll-down (floor (abs velocity)))
(setq velocity (* velocity pixel-scroll-precision-momentum-factor))
(redisplay t)
(sit-for pixel-scroll-precision-momentum-tick)
(setq time-spent (+ time-spent
pixel-scroll-precision-momentum-tick)))))
(when (> (abs (aref state 0))
pixel-scroll-precision-momentum-min-velocity)
(let* ((velocity (* (aref state 0)
pixel-scroll-precision-initial-velocity-factor))
(original-velocity velocity)
(time-spent 0))
(if (> velocity 0)
(while (and (> velocity 0)
(<= time-spent
pixel-scroll-precision-momentum-seconds))
(when (> (round velocity) 0)
(pixel-scroll-precision-scroll-up (round velocity)))
(setq velocity (- velocity
(/ original-velocity
(/ pixel-scroll-precision-momentum-seconds
pixel-scroll-precision-momentum-tick))))
(redisplay t)
(sit-for pixel-scroll-precision-momentum-tick)
(setq time-spent (+ time-spent
pixel-scroll-precision-momentum-tick))))
(while (and (< velocity 0)
(<= time-spent
pixel-scroll-precision-momentum-seconds))
(when (> (round (abs velocity)) 0)
(pixel-scroll-precision-scroll-down (round
(abs velocity))))
(setq velocity (+ velocity
(/ (abs original-velocity)
(/ pixel-scroll-precision-momentum-seconds
pixel-scroll-precision-momentum-tick))))
(redisplay t)
(sit-for pixel-scroll-precision-momentum-tick)
(setq time-spent (+ time-spent
pixel-scroll-precision-momentum-tick))))))
(aset state 0 (make-ring 10))
(aset state 1 nil))))))))