smallpond

commit e3fd305a9a698eeaf77f1966b7b7f55f6d0f632a
parent 34958ac65f6d2e35f294ded5434afdd84b5af3e6
Author: Nihal Jere <nihal@nihaljere.xyz>
Date:   Mon, 22 Aug 2022 21:30:04 -0500

basic note placement for treble and bass clefs

Diffstat:
M
smallpond.lua
 | 
46
+++++++++++++++++++++++++++++++++-------------

1 file changed, 33 insertions(+), 13 deletions(-)
diff --git a/smallpond.lua b/smallpond.lua
@@ -1,12 +1,26 @@
 -- parse
 local em = 8
 
-function placement(char)
-	assert(char)
-	local NOTES = "abcdefg"
-	local s, _ = string.find(NOTES, char)
-	return s
-end
+local noteheadBlock = 0xE0A4
+local gClef = 0xE050
+local fClef = 0xE062
+local treble = {
+	glyph = gClef,
+	place = function(char)
+		local NOTES = "abcdefg"
+		local s, _ = string.find(NOTES, char)
+		return 6 - s
+	end
+}
+
+local bass = {
+	glyph = fClef,
+	place = function(char)
+		local NOTES = "abcdefg"
+		local s, _ = string.find(NOTES, char)
+		return 8 - s
+	end
+}
 
 commands = {
 	clef = {
@@ -15,8 +29,10 @@ commands = {
 			start = start + 6
 			if string.match(text, "^treble", start) then
 				return #"\\clef treble", {command="changeclef", kind="treble"}
+			elseif string.match(text, "^bass", start) then
+				return #"\\clef bass", {command="changeclef", kind="bass"}
 			else
-				error(string.format("unknown clef at offset %s", string.sub(text, start)))
+				error(string.format("unknown clef %s", string.sub(text, start)))
 			end
 		end
 	}
@@ -49,12 +65,18 @@ local x = 10
 staff = {}
 command_dispatch = {
 	newnote = function(data)
-		local i = placement(data.note)
+		local i = staff.clef.place(data.note)
 		table.insert(staff, {kind="notehead", x=x, y=(em*i) / 2})
 		x = x + 20
 	end,
 	changeclef = function(data)
-		table.insert(staff, {kind="clef", x=x, y=4*em})
+		if data.kind == "treble" then
+			staff.clef = treble
+			table.insert(staff, {kind="clef", class=treble, x=x, y=3*em})
+		elseif data.kind == "bass" then
+			staff.clef = bass
+			table.insert(staff, {kind="clef", class=bass, x=x, y=em})
+		end
 		x = x + 40
 	end
 }
@@ -70,16 +92,14 @@ local yoffset = 20
 local xoffset = 20
 
 -- draw staff
-for y=0,em*5,em do
+for y=0,em*4,em do
 	draw_line(xoffset, y + yoffset, staff_width + xoffset, y + yoffset)
 end
 
-local noteheadBlock = 0xE0A4
-local gClef = 0xE050
 for i, el in ipairs(staff) do
 	if el.kind == "notehead" then
 		draw_glyph(noteheadBlock, xoffset + el.x, yoffset + el.y)
 	elseif el.kind == "clef" then
-		draw_glyph(gClef, xoffset + el.x, yoffset + el.y)
+		draw_glyph(el.class.glyph, xoffset + el.x, yoffset + el.y)
 	end
 end