--[[ 

written by: Bartos P. - info[at]talmai[dot]de
created:	August 2009
version:	1.1

install: 	Fusion 5: Fusion:/Scripts/Comp
			Fusion 6: "Shared Documents"/eyeon/Fusion/Scripts/Comp

usage: 		select tracking node an execute the script. use the "Track forward" or "Track reverse" button to
			track only one frame forward or reverse relative to your current time

changelog:	1.1 - "always on top" fixed

]]--

toollist = comp:GetToolList(true)
compattrs = comp:GetAttrs()

-- iup button setup
btn_fwd = iup.button{title = ">> Track forward ", size="100x20", fgcolor = "200 200 200", bgcolor = "64 64 64"}
btn_rev = iup.button{title = "Track reverse <<", size="100x20", fgcolor = "200 200 200", bgcolor = "64 64 64"}

-- iup button function
function btn_fwd:action()
	comp:Lock()													-- lock comp, this will stop the "render complete" msg.
	local from_orig = compattrs.COMPN_RenderStart				-- get the original render range
	local to_orig = compattrs.COMPN_RenderEnd
	local current = CurrentTime
	local to_new = current + 1
	comp:SetAttrs({COMPN_RenderStart = current})				-- set new render range relative to current time
	comp:SetAttrs({COMPN_RenderEnd = to_new})
	toollist[1].TrackForwardFromCurrentTime[current] = 1		-- track
	while comp:IsRendering() == true do							-- wait for tracker to complete
		wait(0.5)
	end
	comp:SetAttrs({COMPN_CurrentTime = to_new})	
	local intrack = toollist[1].TrackerList[1] + 1				-- pattern center won't update while comp is locked
	pcenter = "PatternCenter"..intrack .."[1]"					-- fixing here ...
	tcenter = "TrackedCenter"..intrack .."[1]"					-- ... here ...
	toollist[1].pcenter = toollist[1].tcenter					-- ... and here
	comp:SetAttrs({COMPN_RenderStart = from_orig})				-- set render range back to original state
	comp:SetAttrs({COMPN_RenderEnd = to_orig})
	comp:Unlock()												-- unlock comp
end	

function btn_rev:action()										-- same as fwd, only rev :-)
	comp:Lock()
	local from_orig = compattrs.COMPN_RenderStart
	local to_orig = compattrs.COMPN_RenderEnd
	local current = CurrentTime
	local to_new = current - 1
	comp:SetAttrs({COMPN_RenderStart = current})
	comp:SetAttrs({COMPN_RenderEnd = to_new})
	toollist[1].TrackReverseFromCurrentTime[current] = 1
	while comp:IsRendering() == true do
		wait(0.5)
	end
	comp:SetAttrs({COMPN_CurrentTime = to_new})
	local intrack = toollist[1].TrackerList[1] + 1
	pcenter = "PatternCenter"..intrack .."[1]"
	tcenter = "TrackedCenter"..intrack .."[1]"
	toollist[1].pcenter = toollist[1].tcenter
	comp:SetAttrs({COMPN_RenderStart = from_orig})
	comp:SetAttrs({COMPN_RenderEnd = to_orig})
	comp:Unlock()
end

-- checking some req.
if toollist[1] ~= nil then
	if toollist[1]:GetAttrs().TOOLS_RegID == "Tracker" then
	
	-- iup msg box setup
	buttons = iup.hbox{btn_rev, btn_fwd; gap=20}
	dlg = iup.dialog{
		iup.vbox{
			buttons
		};
		title = "track one frame", margin = "20x20", topmost = "yes", resize = "no", fgcolor = "200 200 200", bgcolor = "64 64 64"
	}
	dlg:showxy(iup.CENTER, iup.CENTER)
	if (not iup.MainLoopLevel or iup.MainLoopLevel()==0) then
		iup.MainLoop()
	end
	
	-- checking more req.
	else
		d = {"Msg", Name = "Warning", "Text", ReadOnly = true, Lines = 5, Wrap = true, Default = msg} 
		comp:AskUser("This is not a Tracker", d)
	end
else
	d = {"Msg", Name = "Warning", "Text", ReadOnly = true, Lines = 5, Wrap = true, Default = msg} 
	comp:AskUser("Plese select a Tracker", d)
end