smallpond

commit 34958ac65f6d2e35f294ded5434afdd84b5af3e6
Author: Nihal Jere <nihal@nihaljere.xyz>
Date:   Mon, 22 Aug 2022 20:40:36 -0500

initial commit: set clef and draw notes

Diffstat:
A
Makefile
 | 
5
+++++
A
main.c
 | 
100
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
smallpond.lua
 | 
85
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

3 files changed, 190 insertions(+), 0 deletions(-)
diff --git a/Makefile b/Makefile
@@ -0,0 +1,5 @@
+smallpond: main.c
+	gcc -o smallpond main.c $(shell pkg-config --cflags --libs lua) $(shell pkg-config --cflags --libs freetype2) $(shell pkg-config --cflags --libs cairo)
+
+clean:
+	rm -f smallpond
diff --git a/main.c b/main.c
@@ -0,0 +1,99 @@
+#include <stdio.h>
+
+#include <ft2build.h>
+#include FT_FREETYPE_H
+
+#include <cairo-ft.h>
+#include <cairo-pdf.h>
+#include <cairo.h>
+
+#include <lua.h>
+#include <lauxlib.h>
+#include <lualib.h>
+
+cairo_t *cr;
+FT_Face face;
+cairo_font_face_t *cface;
+
+int
+draw_line(lua_State *L)
+{
+	double x1 = lua_tonumber(L, -4);
+	double y1 = lua_tonumber(L, -3);
+	double x2 = lua_tonumber(L, -2);
+	double y2 = lua_tonumber(L, -1);
+
+	cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
+
+	cairo_move_to(cr, x1, y1);
+	cairo_line_to(cr, x2, y2);
+	cairo_set_line_width(cr, 1);
+	cairo_stroke(cr);
+
+	return 0;
+}
+
+int
+draw_glyph(lua_State *L)
+{
+	unsigned int glyph = lua_tonumber(L, -3);
+	double x = lua_tonumber(L, -2);
+	double y = lua_tonumber(L, -1);
+
+	int index = FT_Get_Char_Index(face, glyph);
+	cairo_glyph_t treble_clef = {index, x, y};
+
+	cairo_text_extents_t extents;
+	cairo_glyph_extents(cr, &treble_clef, 1, &extents);
+
+	cairo_set_font_face(cr, cface);
+	cairo_set_font_size(cr, 32.0);
+
+	cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
+	cairo_show_glyphs(cr, &treble_clef, 1);
+
+	return 0;
+}
+
+int
+main(int argc, char *argv[])
+{
+	lua_State *L = luaL_newstate();
+	luaL_openlibs(L);
+	lua_pushcfunction(L, draw_glyph);
+	lua_setglobal(L, "draw_glyph");
+	lua_pushcfunction(L, draw_line);
+	lua_setglobal(L, "draw_line");
+	FT_Library library;
+	int error = FT_Init_FreeType(&library);
+
+	// TODO: print the actual error
+	if (error) {
+		fprintf(stderr, "freetype init error");
+		return 1;
+	}
+
+	error = FT_New_Face(library, "/usr/share/fonts/OTF/Bravura.otf", 0, &face);
+	if (error) {
+		fprintf(stderr, "freetype font load error");
+		return 1;
+	}
+
+	cface = cairo_ft_font_face_create_for_ft_face(face, 0);
+	if (!cface) {
+		fprintf(stderr, "cairo font face load error");
+		return 1;
+	}
+
+	cairo_surface_t *surface = cairo_pdf_surface_create("out.pdf", 648, 864);
+	cr = cairo_create(surface);
+
+	if (luaL_dofile(L, "smallpond.lua")) {
+		fprintf(stderr, "lua error: %s\n", lua_tostring(L, -1));
+		return 1;
+	}
+
+	cairo_destroy(cr);
+	cairo_surface_destroy(surface);
+	lua_close(L);
+}
+\ No newline at end of file
diff --git a/smallpond.lua b/smallpond.lua
@@ -0,0 +1,85 @@
+-- parse
+local em = 8
+
+function placement(char)
+	assert(char)
+	local NOTES = "abcdefg"
+	local s, _ = string.find(NOTES, char)
+	return s
+end
+
+commands = {
+	clef = {
+		parse = function(text, start)
+			-- move past "\clef "
+			start = start + 6
+			if string.match(text, "^treble", start) then
+				return #"\\clef treble", {command="changeclef", kind="treble"}
+			else
+				error(string.format("unknown clef at offset %s", string.sub(text, start)))
+			end
+		end
+	}
+}
+
+function parse(text)
+	local i = 1
+	return function()
+		if i >= #text then return nil end
+		local cmd = string.match(text, "^\\(%a+)", i)
+		if cmd then
+			local size, data = commands[cmd].parse(text, i)
+			i = i + size
+			return data
+		end
+
+		local s, e, note = string.find(text, "^%s*([abcdefg])", i)
+		if note then
+			i = i + e - s + 1
+			return {command="newnote", note=note}
+		end
+
+		error("unknown token")
+	end
+end
+
+f = assert(io.open("score.sp"))
+
+local x = 10
+staff = {}
+command_dispatch = {
+	newnote = function(data)
+		local i = placement(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})
+		x = x + 40
+	end
+}
+
+for tok in parse(f:read("*a")) do
+	local func = assert(command_dispatch[tok.command])
+	func(tok)
+end
+
+-- determine staff width, the +20 is a hack, should be determined from notehead width + some padding
+local staff_width = staff[#staff].x + 20
+local yoffset = 20
+local xoffset = 20
+
+-- draw staff
+for y=0,em*5,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)
+	end
+end