Create amagalma_Smooth scroll arrange view 1 measure left.lua

Author: amagalma

View/amagalma_Smooth scroll arrange view 1 measure left.lua

@@ -0,0 +1,60 @@
+-- @description Smooth scroll arrange view 1 measure left
+-- @author amagalma
+-- @version 1.00
+-- @provides
+--   .
+--   [main] . > amagalma_Smooth scroll arrange view 2 measures left.lua
+--   [main] . > amagalma_Smooth scroll arrange view 4 measures left.lua
+--   [main] . > amagalma_Smooth scroll arrange view 8 measures left.lua
+-- @donation https://www.paypal.me/amagalma
+
+reaper.set_action_options( 1|2 )
+
+local Set, floor, log = reaper.GetSet_ArrangeView2, math.floor, math.log
+local measures = tonumber((({reaper.get_action_context()})[2]):match(".-(%d+).-$"))
+local a0, b0 = Set( 0, 0, 0, 0, 0, 0 )
+if a0 == 0 then return reaper.defer(function() end) end
+
+local qn_current = floor(reaper.TimeMap_timeToQN( a0 ))
+local measure_start = reaper.TimeMap_QNToMeasures(0, qn_current )
+local measure_time, qn_start, qn_end = reaper.TimeMap_GetMeasureInfo( 0, measure_start-1 )
+local first_visible_measure = measure_start
+local first_visible_measure_time = measure_time
+if measure_time + 0.00001 < a0 then
+  first_visible_measure = measure_start + 1
+  first_visible_measure_time = reaper.TimeMap_GetMeasureInfo( 0, first_visible_measure-1 )
+end
+local wanted_time = reaper.TimeMap_GetMeasureInfo( 0, first_visible_measure-1-measures )
+if wanted_time < 0 then wanted_time = 0 end
+local total_shift = a0 - wanted_time
+
+local ret = tonumber(reaper.GetExtState("amagalma_Smooth Scroll", "max_duration"))
+local max_duration = ret and ret or 400
+local max_max_duration = max_duration*1.25
+local hzoom = reaper.GetHZoomLevel()
+if hzoom > 200 then
+  max_duration = max_duration*0.25
+else
+  max_duration = max_duration * log(hzoom) / 4
+end
+  if max_duration < 40 then max_duration = 40 end
+  if max_duration > max_max_duration then max_duration = max_max_duration end
+local total_frames = floor(max_duration / 31 + 0.5)
+local delta = total_shift / total_frames
+
+local frame = 0
+
+local function scroll_left()
+  frame = frame + 1
+  local a = a0 - delta * frame
+  local b = b0 - delta * frame
+  Set( 0, 1, 0, 0, a, b )
+
+  if frame ~= total_frames then
+    reaper.defer(scroll_left)
+  else
+    return reaper.defer(function() end)
+  end
+end
+
+scroll_left()