ScrollMomentum
Applies "momentum" to scroll bars. Works with:
- most standard windows scrollbars
- Internet Explorer's scroll bars (tested on IE7.)
Thanks to Sean for his help and excellent COM scripts, and FireGirl for the idea and insisting that I add IE support.
Requires Standard Library COM.ahkKnown Issues:- Doesn't work in Explorer (i.e. the file browser; at least on Vista; let me know if this is not the case for your version of Windows.)
- Doesn't work in Microsoft Document Explorer's Index.
- There is a delay when grabbing Internet Explorer scroll bars before the script starts working. This is usually around 100-140 ms for the initial "grab," and 30-60 ms for subsequent "grabs."
Code:
;
; AutoHotkey Version: 1.0.47 (MINIMUM), tested on 1.0.47.06.L
; Language: English
; Platform: Windows 98 and later? (REQUIRED), tested on Windows Vista (IE7).
; Author: Lexikos
;
; Momentum-related code and ideas were developed for a different script by various users at:
; http://www.autohotkey.com/forum/viewtopic.php?t=19773
;
; Script Function:
; Apply momentum to scroll bars.
;
; Idea by FireGirl:
; http://www.autohotkey.com/forum/viewtopic.php?t=21790
#NoEnv
CoordMode, Mouse, Screen
;
; CONFIGURATION
;
UPDATE_RATE = 10 ; milliseconds
SENSITIVITY = 0.5
INERTIA = 0.95
;
; WIN32 DEFINES
;
; SetWinEventHook Flags
WINEVENT_OUTOFCONTEXT = 0x0000
; Events
EVENT_SYSTEM_SCROLLINGSTART = 0x0012
EVENT_SYSTEM_SCROLLINGEND = 0x0013
; Scrollbar Constants
SB_HORZ = 0
SB_VERT = 1
;
; INITIALIZATION
;
SpeedA := 1 - SENSITIVITY
; Register callback proc.
cbOnScrollEvent := RegisterCallback("OnScrollEvent")
; Set scrolling start/end hook to call OnScrollEvent().
hScrollHook := DllCall("SetWinEventHook"
, "uint", EVENT_SYSTEM_SCROLLINGSTART ; eventMin
, "uint", EVENT_SYSTEM_SCROLLINGEND ; eventMax
, "uint", 0 ; hmodWinEventProc (only for in-context hooks)
, "uint", cbOnScrollEvent ; lpfnWinEventProc
, "uint", 0 ; idProcess (0 = all processes)
, "uint", 0 ; idThread (0 = all threads)
, "uint", WINEVENT_OUTOFCONTEXT) ; dwflags
if (!hScrollHook)
MsgBox, 48, Error, SetWinEventHook failed. Standard Windows scrollbars will not have momentum applied.
; IE support init.
WM_HTML_GETOBJECT := DllCall("RegisterWindowMessage", "str", "WM_HTML_GETOBJECT")
COM_CoInitialize()
OnExit, CleanupAndExit
return
CleanupAndExit:
; May not be necessary; but for good measure...
if hScrollHook
DllCall("UnhookWinEvent", "uint", hScrollHook)
ExitApp
ContinueScroll:
Scroll_Speed *= INERTIA
; Continue until
; the scroll bar slows to a stop,
; the window is closed,
; or something else moves the scroll bar.
if (Abs(Scroll_Speed)>0.01
&& GetAbstractScrollInfo(Scroll_Container, Scroll_Type, Scroll_Pos_Int)
&& Scroll_Pos_Int = Last_Pos)
{
; Apply momentum.
Scroll_Pos += Scroll_Speed
; Check if it hit the end.
if (Scroll_Pos < Scroll_Min)
Scroll_Pos := Scroll_Min
if (Scroll_Pos > Scroll_Max)
Scroll_Pos := Scroll_Max
; If it has come to a stop, stop the timer.
if (Scroll_Pos = Last_Pos) {
Scroll_Speed = 0
SetTimer, ContinueScroll, Off
return
}
; Move scroll bar.
if SetAbstractScrollPos(Scroll_Container, Scroll_Type, Round(Scroll_Pos))
{ ; Update position (to detect if something else moves the bar.)
GetAbstractScrollInfo(Scroll_Container, Scroll_Type, Last_Pos)
return
}
}
Scroll_Speed = 0
SetTimer, ContinueScroll, Off
gosub ReleaseScrollContainerIfNecessary
return
TrackScrollBar:
; Update scroll position.
if GetAbstractScrollInfo(Scroll_Container, Scroll_Type, Scroll_Pos)
{ ; Recalculate velocity.
Scroll_Speed := Scroll_Speed*SpeedA + (Scroll_Pos-Last_Pos)*SENSITIVITY
Last_Pos := Scroll_Pos
}
else
{ ; Error: maybe the window closed?
SetTimer, TrackScrollBar, Off
gosub ReleaseScrollContainerIfNecessary
}
return
ReleaseScrollContainerIfNecessary:
if Scroll_Type in scrollbarHThumb,scrollbarVThumb
COM_Release(Scroll_Container)
Scroll_Container = 0
return
~LButton::
gosub GetIEDocumentAtMouse
if !pDoc
return
pWin := COM_Invoke(pDoc, "parentWindow"), COM_Release(pDoc), pDoc := 0
if !pWin
return
; Currently only one scroll bar can be moving at a time.
SetTimer, ContinueScroll, Off
gosub ReleaseScrollContainerIfNecessary
MouseGetPos, x, y
if (GetDeepestScrollElement(pWin, x, y, Scroll_Container, pElementWin))
{ ; Hit-test for scrollbarHThumb or scrollbarVThumb.
cx:=COM_Invoke(pElementWin,"screenLeft"), cy:=COM_Invoke(pElementWin,"screenTop"), pWin!=pElementWin ? (cx-=2, cy-=2) : ""
Scroll_Type := COM_Invoke(Scroll_Container,"componentFromPoint",x-cx,y-cy)
if Scroll_Type not in scrollbarHThumb,scrollbarVThumb
COM_Release(Scroll_Container),Scroll_Container:=0, Scroll_Type:=""
pElementWin!=pWin ? COM_Release(pElementWin) . pElementWin:=0 : ""
}
COM_Release(pWin), pWin:=0
if !Scroll_Container
return
GetAbstractScrollInfo(Scroll_Container, Scroll_Type, Scroll_Pos, Scroll_Min, Scroll_Max)
Last_Pos := Scroll_Pos
Scroll_Speed := 0
; Set the tracking timer.
SetTimer, TrackScrollBar, %UPDATE_RATE%
KeyWait, LButton
; Scrolling has stopped, so stop tracking the scroll position.
SetTimer, TrackScrollBar, Off
if Scroll_Container
{ ; Apply momentum.
SetTimer, ContinueScroll, %UPDATE_RATE%
; Update Last_Pos in case it has changed since the last TrackScrollBar iteration.
GetAbstractScrollInfo(Scroll_Container, Scroll_Type, Last_Pos)
}
return
;
; CALLBACK - Standard Windows Scrollbars
;
OnScrollEvent(hWinEventHook, event, hwnd, idObject, idChild, dwEventThread, dwmsEventTime)
{
global
local trackpos
static lbutton_state
static OBJID_VSCROLL = 0xFFFFFFFB, OBJID_HSCROLL = 0xFFFFFFFA
if (event = EVENT_SYSTEM_SCROLLINGSTART) && (lbutton_state:=GetKeyState("LButton"))
{
gosub ReleaseScrollContainerIfNecessary
Scroll_Container := hwnd
Scroll_Type := (idObject=OBJID_HSCROLL) ? SB_HORZ : SB_VERT
; Get this scroll bar's parameters.
GetScrollInfo(Scroll_Container, Scroll_Type, Scroll_Pos, trackpos, Scroll_Min, Scroll_Max, Scroll_Page)
Last_Pos := Scroll_Pos
; Set the tracking timer.
SetTimer, TrackScrollBar, %UPDATE_RATE%
; Currently only one scroll bar can be moving at a time.
SetTimer, ContinueScroll, Off
}
else if (event = EVENT_SYSTEM_SCROLLINGEND) && lbutton_state
{
; Scrolling has stopped, so stop tracking the scroll position.
SetTimer, TrackScrollBar, Off
; Apply momentum.
SetTimer, ContinueScroll, %UPDATE_RATE%
; Update Last_Pos in case it has changed since the last TrackScrollBar iteration.
GetScrollInfo(Scroll_Container, Scroll_Type, Last_Pos)
}
}
;
; FUNCTIONS - Standard Windows Scrollbars
;
GetScrollInfo(hwnd, fnBar, ByRef nPos=0, ByRef nTrackPos=0, ByRef nMin=0, ByRef nMax=0, ByRef nPage=0)
{
WinGet, Style, Style, ahk_id %hwnd%
if !(Style & (fnBar ? 0x200000 : 0x100000))
return false ; Fix for some controls which report {min:0,max:100} even though scroll bar doesn't exist.
VarSetCapacity(si, 28, 0) ; SCROLLINFO si
NumPut(28 , si, 0) ; si.cbSize := sizeof(SCROLLINFO)
NumPut(0x17, si, 4) ; si.fMask := SIF_ALL
if ! DllCall("GetScrollInfo", "uint", hwnd, "int", fnBar, "uint", &si)
return false
nPos := NumGet(si, 20)
nTrackPos := NumGet(si, 24)
nMin := NumGet(si, 8)
nMax := NumGet(si, 12)
nPage := NumGet(si, 16)
return true
}
SetScrollPos(hwnd, fnBar, nPos)
{
VarSetCapacity(si, 28, 0) ; SCROLLINFO si
NumPut(28 , si, 0) ; si.cbSize := sizeof(SCROLLINFO)
NumPut(0x4 , si, 4) ; si.fMask := SIF_POS
NumPut(nPos, si, 20) ; si.nPos := nPos
; Use SetScrollInfo first because it supports 32-bit positions.
; If an application supports positions < 0 or > 65535, it most likely
; ignores WM_#SCROLL's wParam and uses GetScrollPos or GetScrollInfo
; to get the actual scroll position.
DllCall("SetScrollInfo", "uint", hwnd, "int", fnBar, "uint", &si, "int", 0)
; WM_HSCROLL or WM_VSCROLL must be sent for the window to update it's contents.
msg := (fnBar=0) ? 0x114 : 0x115
wParam := 4 ; SB_THUMBPOSITION
| ((nPos&0xFFFF)<<16)
SendMessage, msg, wParam,,, ahk_id %hwnd%
return (ErrorLevel != "FAIL")
}
;
; ABSTRACT FUNCTIONS - for both standard Windows scrollbar and IE scrollbar support.
;
GetAbstractScrollInfo(Container, Type, ByRef Pos=0, ByRef Min=0, ByRef Max=0)
{
if !Container
return false
if Type in 0,1 ; SB_HORZ,SB_VERT
return GetScrollInfo(Container, Type, Pos, track_pos, Min, Max)
if Type = scrollbarHThumb
Pos:=COM_Invoke(Container,"scrollLeft"), Max:=COM_Invoke(Container,"scrollWidth"), Min:=0
else if Type = scrollbarVThumb
Pos:=COM_Invoke(Container,"scrollTop"), Max:=COM_Invoke(Container,"scrollHeight"), Min:=0
return Pos!=""
}
SetAbstractScrollPos(Container, Type, Pos)
{
if !Container
return false
if Type in 0,1 ; SB_HORZ,SB_VERT
return SetScrollPos(Container, Type, Pos)
; TODO: determine success or failure for assignment.
if Type = scrollbarHThumb
return true, COM_Invoke(Container,"scrollLeft=",Pos)
else if Type = scrollbarVThumb
return true, COM_Invoke(Container,"scrollTop=",Pos)
return false
}
;
; IE FUNCTIONS & SUBROUTINES
;
GetDeepestScrollElement(pWin, x, y, ByRef pElement, ByRef pElementWin)
{
; AddRef so we don't release pWin below. (Caller may still need it.)
COM_AddRef(win:=pWin)
Loop {
if (!win)
break ; Error
if !(doc:=COM_Invoke(win,"document"))
break ; Error
if !(element:=COM_Invoke(doc,"elementFromPoint",x-COM_Invoke(win,"screenLeft"),y-COM_Invoke(win,"screenTop")))
break ; Error
if (tag:=COM_Invoke(element,"tagName")) != "FRAME"
{ ; return element.isScrollable ? element : frame.body
scrollHeight:=COM_Invoke(element,"scrollHeight"), clientHeight:=COM_Invoke(element,"clientHeight")
if !(clientHeight && clientHeight < scrollHeight)
COM_Release(element), element:=COM_Invoke(doc,"body")
break
}
COM_Release(doc), doc:=0, COM_Release(win), win:=0
if !(win:=COM_Invoke(element,"contentWindow"))
{
COM_Release(element), element:=0
break ; Error
}
}
if doc
COM_Release(doc), doc:=0
if (win && !element)
COM_Release(win), win:=0
pElement := element
pElementWin := win
return pElement
}
GetIEDocumentAtMouse:
MouseGetPos,,,, hIESvr, 2
WinGetClass, class, ahk_id %hIESvr%
if (!hIESvr or class != "Internet Explorer_Server")
{ ; Try again with alternate method (for "Microsoft Document Explorer" support.)
MouseGetPos,,,, hIESvr, 3
WinGetClass, class, ahk_id %hIESvr%
if (!hIESvr or class != "Internet Explorer_Server")
return
}
SendMessage, WM_HTML_GETOBJECT,,,, ahk_id %hIESvr%
lResult := ErrorLevel
DllCall("oleacc\ObjectFromLresult", "uint", lResult
, "uint", COM_GUID4String(IID_IHTMLDocument2,"{332C4425-26CB-11D0-B483-00C04FD90119}")
, "int", 0, "uint*", pDoc)
return
!Up::
Scroll_Type = 1
Scroll_Speed_Boost = -2
goto KickActiveScrollBar
!Down::
Scroll_Type = 1
Scroll_Speed_Boost = +2
goto KickActiveScrollBar
!Left::
Scroll_Type = 0
Scroll_Speed_Boost = -10
goto KickActiveScrollBar
!Right::
Scroll_Type = 0
Scroll_Speed_Boost = +10
goto KickActiveScrollBar
; Scroll_Type should be set to 0 (horz) or 1 (vert) before calling this subroutine.
; Scroll_Speed should be set to:
; a scalar value with decimal point (it is multiplied by (Scroll_Max-Scroll_Min))
; or
; an absolute value with no decimal point.
KickActiveScrollBar:
ControlGetFocus, ctl, A
ControlGet, hCtl, Hwnd,, %ctl%, A
SetTimer, ContinueScroll, Off
gosub ReleaseScrollContainerIfNecessary
; Internet Explorer scrollbars.
if InStr(ctl,"Internet Explorer_Server")
{ ; Get the document object of this IE control.
SendMessage, WM_HTML_GETOBJECT,,,, ahk_id %hCtl%
lResult := ErrorLevel ; necessary because COM_GUID4String() changes ErrorLevel.
DllCall("oleacc\ObjectFromLresult", "uint",lResult
, "uint",COM_GUID4String(IID_IHTMLDocument2,"{332C4425-26CB-11D0-B483-00C04FD90119}")
, "int",0, "uint*",pDoc)
if (pDoc && (pWin:=COM_Invoke(pDoc,"parentWindow"), COM_Release(pDoc),pDoc:=0))
if (pElement:=GetActiveScrollElement(pWin)), COM_Release(pWin),pWin:=0
{
Scroll_Container := pElement
Scroll_Type := Scroll_Type ? "scrollbarVThumb" : "scrollbarHThumb"
GetAbstractScrollInfo(Scroll_Container, Scroll_Type, Scroll_Pos, Scroll_Min, Scroll_Max)
}
}
; Standard Windows scrollbars.
if !Scroll_Container
{
Scroll_Container := hCtl
Loop
if GetScrollInfo(Scroll_Container, Scroll_Type, Scroll_Pos, trackpos, Scroll_Min, Scroll_Max, Scroll_Page)
&& Scroll_Min != Scroll_Max
break
else
Scroll_Container := DllCall("GetParent","uint",Scroll_Container)
}
Last_Pos := Scroll_Pos
; if InStr(Scroll_Speed,".")
; Scroll_Speed *= Scroll_Max-Scroll_Min
if Abs(Scroll_Speed_Boost) < 1
Scroll_Speed_Boost *= Scroll_Max-Scroll_Min
if Abs(Scroll_Speed) < 1
Scroll_Speed = 0
Scroll_Speed += Scroll_Speed_Boost
; Apply momentum.
SetTimer, ContinueScroll, %UPDATE_RATE%
return
GetActiveScrollElement(win)
{
if !win
return 0
COM_AddRef(win) ; caller is responsible for releasing win
Loop {
if (!win)
break ; Error
if !(doc:=COM_Invoke(win,"document")), COM_Release(win),win:=0
break ; Error
if !(element:=COM_Invoke(doc,"activeElement"))
break ; Error
if (tag:=COM_Invoke(element,"tagName")) != "FRAME"
{ ; return element.isScrollable ? element : frame.body
scrollHeight:=COM_Invoke(element,"scrollHeight"), clientHeight:=COM_Invoke(element,"clientHeight")
if !(clientHeight && clientHeight < scrollHeight)
COM_Release(element), element:=COM_Invoke(doc,"body")
break
}
COM_Release(doc),doc:=0
if !(win:=COM_Invoke(element,"contentWindow"))
{
COM_Release(element), element:=0
break ; Error
}
}
doc ? COM_Release(doc) . doc:=0 : ""
return element
}
2007-10-12
Made a few misc changes. Scrolling now halts "glide" of standard Windows scrollbars.
2007-10-13
Fixed a couple potential "reference leaks."
2007-10-14
Fixed GetDeepestScrollElement() attempting to release an invalid object when the script fails to retrieve the contentWindow of a frame.
Fixed potential "reference leak" in ~LButton hotkey.
2008-12-30
Released script under
Lexikos' default copyright license.
2009-01-01
Added Alt+Arrow "kicker" hotkeys which I had posted elsewhere. Also fixed them to "cascade" properly - i.e. scroll the active control if possible, otherwise its parent, its grandparent, etc.
Changed GetScrollInfo to return false if WS_VSCROLL or WS_HSCROLL style (as applicable) is not set. This fixes kicker cascading for
some applications.
Other misc changes.
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