Create string_harmonics.lua

Create diamond noteheads on the top note of dyads identified as viable string harmonics. I use this script __a lot__ and just noticed that its exact functionality is not available in the Repo. It is only provided in the full commercial version of TGTools, not the inbuilt version.

Author: cv-on-hub

src/string_harmonics.lua

@@ -0,0 +1,40 @@
+function plugindef()
+    finaleplugin.RequireSelection = true
+    finaleplugin.Author = "Carl Vine"
+    finaleplugin.AuthorURL = "https://carlvine.com/lua/"
+    finaleplugin.Copyright = "https://creativecommons.org/licenses/by/4.0/"
+    finaleplugin.Version = "0.62"
+    finaleplugin.Date = "2024/06/02"
+    finaleplugin.Notes = [[
+        Create diamond noteheads on the top note of dyads identified as viable string harmonics. 
+        Note that this uses MIDI note values to identify acceptable intervals to 
+        avoid the complications of key signatures and transposing instruments. 
+        This is inelegant but simple and should work in most situations! 
+    ]]
+    return "String Harmonics", "String Harmonics",
+        "Create diamond noteheads on the top note of dyads identified as viable string harmonics"
+end
+
+local notehead = require("library.notehead")
+
+function string_harmonics()
+    -- allowable intervals for string harmonics, measured in interval STEPS
+    local allowed = { 3, 4, 5, 7, 9, 12, 16, 19, 24, 28, 31 }
+    local allowable = {}
+    for _, v in ipairs(allowed) do allowable[v] = true end
+
+    for entry in eachentrysaved(finenv.Region()) do
+        if entry:IsNote() and (entry.Count == 2) then -- only treat 2-note chords
+            local highest = entry:CalcHighestNote(nil)
+            local lowest = entry:CalcLowestNote(nil)
+            local midi_diff = highest:CalcMIDIKey() - lowest:CalcMIDIKey()
+
+            if allowable[midi_diff] then -- only permissible intervals
+                finale.FCNoteheadMod():EraseAt(lowest)
+                notehead.change_shape(highest, "diamond")
+            end
+        end
+    end
+end
+
+string_harmonics()