Short answer
For horizontal scrolling in Adobe Reader X, send scroll messages to the parent of the scrollbar, as in sendscrolltoscrollbarparent in the code. Many other ways would not work properly. This method somehow gives very fast scrolling, even better than my original mouse driver.
Long answer
I had found my own answers, but had forgotten about this question. Basically I used an idiosyncratic method for each and every crazy application. Since there are too many, I've created a separate question and answer for the whole lot (AutoHotkey scrolling & middle click & mouse acceleration), and only give the parts relevant to Adobe Reader here.
The process should go like this. First you call gettarget, which assumes the mouse position is stored in mx,my and finds the correct target for the scroll events based on what is currently under the mouse. Then you repeatedly call scroll after adding the amount to scroll to sx,sy.
For Adobe Reader, even vertical scrolling depends on sending wheel messages to the right place, which is not consistent and hence I ended up hard-coding for the two main cases, which are scrolling the document display area and scrolling the bookmarks area. To find out which case it is, I check whether the parent of the control under the mouse has a descendant called AVL_AVView4 or not. If it does, then that's the right one to send vertical wheel messages to, performed by sendwheel. But for horizontal scrolling, it turns out that sending scroll messages to the parent control of the correct scrollbar works in both places, performed by sendscrolltoscrollbarparent. The correct scrollbar is the one called scrollbar1 that is the descendent of the parent of the control under the mouse.
Code
#commentflag // ; Change to C++ comment style
global mx,my
global sx:=0
global sy:=0
global ctrl,window,parent
global methodx
global methody
global scrollbarx
global scrollbary
global max16bit:=32767
gettarget()
{
ctrl:=getctrlat(mx,my)
window:=getwindow(ctrl)
class:=getclass(window)
parent:=getparent(ctrl)
parentname:=getnameatroot(parent)
if( class=="AcrobatSDIWindow" )
{
if( regexmatch(parentname,"AVL_AVView")==1 )
{
ctrl:=getdescendant(parent,"AVL_AVView4")
if( ctrl=="" )
{
ctrl:=getdescendant(parent,"AVL_AVView1")
}
methodx:="scrolltoscrollbarparent"
scrollbarx:="scrollbar1"
methody:="wheel"
}
}
}
scroll:
critical on
tx:=sx
ty:=sy
sx-=tx
sy-=ty
rx:=0
ry:=0
if( tx!=0 )
{
txi:=rtoz(tx)
rx:=tx-txi
if( txi!=0 )
{
if( methodx=="scrolltoscrollbarparent" )
{
sendscrolltoscrollbarparent(scrollbarx,"h",txi)
}
}
}
if( ty!=0 )
{
if( methody=="wheel" )
{
sendwheel("v",-ty)
}
}
sx:=rx
sy:=ry
return
sendwheel(dir,amount)
{
t:=a_tickcount
msg:=( dir=="v" ? 0x20a : 0x20e )
flags:=getkeystate("Ctrl")<<3|getkeystate("Shift")<<2
amount*=120
while( amount>max16bit )
{
sendmessage msg,max16bit<<16|flags,mx|my<<16,,ahk_id %ctrl%,,,,timelimit
amount-=max16bit
if( a_tickcount-t>=timelimit )
{
return
}
}
while( amount<-max16bit )
{
sendmessage msg,-max16bit<<16|flags,mx|my<<16,,ahk_id %ctrl%,,,,timelimit
amount+=max16bit
if( a_tickcount-t>=timelimit )
{
return
}
}
sendmessage msg,round(amount)<<16|flags,mx|my<<16,,ahk_id %ctrl%,,,,timelimit
}
sendscrolltoscrollbarparent(name,dir,amount)
{
sb:=getdescendant(parent,name)
sbp:=getparent(sb)
t:=a_tickcount
msg:=( dir=="v" ? 0x115 : 0x114 )
flag:=( amount<0 ? 0 : 1 )
loop % abs(amount)
{
sendmessage msg,flag,sb,,ahk_id %sbp%,,,,timelimit
if( a_tickcount-t>=timelimit )
{
return
}
}
}
rtoz(r)
{
return ( r>0 ? floor(r) : ceil(r) )
}
getparent(handle)
{
return dllcall("GetParent","uint",handle)
}
getname(root,handle)
{
local CH,CN,S,P
WinGet, CH, ControlListHwnd, ahk_id %root%
WinGet, CN, ControlList, ahk_id %root%
setformat integerfast,h
handle+=0
handle.=""
setformat integerfast,d
LF:= "`n", CH:= LF CH LF, CN:= LF CN LF, S:= SubStr( CH, 1, InStr( CH, LF handle LF ) )
StringReplace, S, S,`n,`n, UseErrorLevel
StringGetPos, P, CN, `n, L%ErrorLevel%
Return SubStr( CN, P+2, InStr( CN, LF, 0, P+2 ) -P-2 )
}
getdescendant(handle,name)
{
local CH,CN,S,P
WinGet, CH, ControlListHwnd, ahk_id %handle%
WinGet, CN, ControlList, ahk_id %handle%
setformat integerfast,h
handle+=0
handle.=""
setformat integerfast,d
LF:= "`n", CH:= LF CH LF, CN:= LF CN LF, S:= SubStr( CN, 1, InStr( CN, LF name LF ) )
StringReplace, S, S,`n,`n, UseErrorLevel
StringGetPos, P, CH, `n, L%ErrorLevel%
Return SubStr( CH, P+2, InStr( CH, LF, 0, P+2 ) -P-2 )*1
}
getnameatroot(handle)
{
return getname(dllcall("GetAncestor","uint",handle,"uint",2),handle)
}
getnameaschild(handle)
{
return getname(getparent(handle),handle)
}
getclass(handle)
{
local class
wingetclass class,ahk_id %handle%
return class
}
getwindow(handle)
{
return dllcall("GetAncestor","uint",handle,"uint",2)
}
getctrlat2(x,y,first,current)
{
/*
Pushes the following invisible container controls to the back because they are in front of their contents for no reason
SysTabControl32 : The usual class that contains tabbed panes ( Mouse properties , ... )
Static : A class occasionally used to contain tabbed panes ( Programmer's Notepad Options > Fonts and Colours > Advanced , ... )
Button : A typical class used to contain a List Box ( Outlook Contact > Properties > General > Members , ... )
Executes WindowFromPoint again to access the contents of such container controls
*/
local handle,class,style
class:=getclass(current)
winget style,style,ahk_id %current%
if( class=="SysTabControl32" or class=="Static" or ( class=="Button" and (style&0x7)==0x7 ) )
{
dllcall("SetWindowPos","uint",current,"uint",1,"int",0,"int",0,"int",0,"int",0,"uint",0x3) // push it to the back where it belongs
handle:=dllcall("WindowFromPoint","int",x,"int",y)
//handle:=DllCall( "WindowFromPoint", "int64", (my << 32) | (mx & 0xFFFFFFFF), "Ptr") // for negative 64-bit
if( handle==first )
{
return first
}
return getctrlat2(x,y,first,handle)
}
return current
}
getctrlat(x,y)
{
local handle
handle:=dllcall("WindowFromPoint","int",x,"int",y)
//handle:=DllCall( "WindowFromPoint", "int64", (my << 32) | (mx & 0xFFFFFFFF), "Ptr") // for negative 64-bit
return getctrlat2(x,y,handle,handle)
}
