Release Scroll TCP to track currently edited in active MIDI editor v0…

….5 (#1453)

MIDI Editor/talagan_Scroll TCP to track currently edited in active MIDI editor.lua

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+--[[
+@description Scroll TCP to track currently edited in active MIDI editor
+@version 0.5.0
+@author Ben 'Talagan' Babut
+@donation https://www.paypal.com/donate/?business=3YEZMY9D6U8NC&no_recurring=1&currency_code=EUR
+@license MIT
+@provides
+  [main=main,midi_editor] .
+@changelog
+  Initial release.
+@about
+  It may happen that you are working in the MIDI editor and want to access the edited track TCP's but unfortunately, it's not on screen, you
+  don't want to scroll by yourself, and you don't want to break your track selection.
+
+  This action can be used to scroll the TCP to have the currently edited MIDI take's track at the top, so you can interract with the track
+  controls and keep your track selection and the rest of your current screen layout intact.
+
+  There's a good chance that if you need this, you'll use it as a small brick in custom actions in conjunction with other ones
+  (scroll, resize, fit, etc).
+--]]
+
+local function CheckReapack(func_name, api_name, search_string)
+  if not reaper.APIExists(func_name) then
+    local answer = reaper.MB( api_name .. " is required and you need to install it.\z
+      Right-click the entry in the next window and choose to install.",
+      api_name .. " not installed", 0 )
+    reaper.ReaPack_BrowsePackages( search_string )
+    return false
+  end
+  return true
+end
+
+if not CheckReapack("JS_ReaScriptAPI_Version",   "JS_ReaScriptAPI",  "js_ReaScriptAPI")     then return end
+
+
+-- Using X-Raym's X-Raym_Scroll vertically to first selected track.lua
+-- Thanks Raymond !
+function ScrollTrackToTop( track )
+  reaper.PreventUIRefresh( 1 )
+
+  local track_tcpy = reaper.GetMediaTrackInfo_Value( track, "I_TCPY" )
+
+  local mainHWND    = reaper.GetMainHwnd()
+  local windowHWND  = reaper.JS_Window_FindChildByID(mainHWND, 1000)
+  local scroll_retval, scroll_position, scroll_pageSize, scroll_min, scroll_max, scroll_trackPos = reaper.JS_Window_GetScrollInfo( windowHWND, "v" )
+  reaper.JS_Window_SetScrollPos( windowHWND, "v", track_tcpy + scroll_position )
+
+  reaper.PreventUIRefresh( -1 )
+end
+
+local function proceed()
+
+  local me    = reaper.MIDIEditor_GetActive()
+  if not me then return end
+
+  local take  = reaper.MIDIEditor_GetTake(me);
+  if not take then return end
+
+  local track = reaper.GetMediaItemTake_Track(take);
+  if not track then return end
+
+  ScrollTrackToTop(track);
+
+end
+
+proceed();
+