REF remove submodule for core and move all lua files to common subdir

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "core"]
-	path = core
-	url = gitolite:conky/core.git

config/schema.yml

@@ -49,6 +49,9 @@ properties:
         required: [show_temp, show_clock, show_gpu_util, show_mem_util, show_vid_util]
         additionalProperties: false
         properties:
+          dev_power:
+            description: the sysfs path to the graphics card power indicator
+            type: string
           show_temp:
             description: show the GPU temp
             type: boolean

conky.conf

@@ -3,16 +3,14 @@
 
 local conky_dir = debug.getinfo(1).source:match("@?(.*/)")
 local subdirs = {
-   '?.lua',
-   'drawing/?.lua',
-   'schema/?.lua',
-   'core/?.lua',
-   'core/widget/?.lua',
-   'core/widget/arc/?.lua',
-   'core/widget/text/?.lua',
-   'core/widget/timeseries/?.lua',
-   'core/widget/rect/?.lua',
-   'core/widget/line/?.lua',
+   'src/?.lua',
+   'src/modules/?.lua',
+   'src/widget/?.lua',
+   'src/widget/arc/?.lua',
+   'src/widget/text/?.lua',
+   'src/widget/timeseries/?.lua',
+   'src/widget/rect/?.lua',
+   'src/widget/line/?.lua',
    'lib/share/lua/5.4/?.lua',
    'lib/share/lua/5.4/?/init.lua',
 }
@@ -41,7 +39,7 @@ if i_o.exe_exists('yajsv') then
    end
 else
    validate_config = function(_)
-      print('WARNING: could not validate config')
+      i_o.warnf('could not validate config')
       return true
    end
 end
@@ -52,16 +50,16 @@ local find_valid_config = function(paths)
       local r = i_o.read_file(path)
       if r ~= nil then
          if validate_config(path) then
-            i_o.printf('INFO: Using config at %s', path)
+            i_o.infof('Using config at %s', path)
             return path, yaml.load(r)
          else
-            i_o.printf('WARNING: %s did not pass; trying next', path)
+            i_o.warnf('%s did not pass; trying next', path)
          end
       else
-         i_o.printf('INFO: could not find %s; trying next', path)
+         i_o.infof('could not find %s; trying next', path)
       end
    end
-   assert(false, 'ERROR: could not load valid config')
+   i_o.assertf(false, 'ERROR: could not load valid config')
 end
 
 local get_config_dir = function()

core

@@ -1 +0,0 @@
-Subproject commit ac2604709f5344125519913849e9013e1dfea717

schema/geometry.lua

@@ -1,20 +0,0 @@
-local M = {}
-
-M.LEFT_X = 32
-M.SECTION_WIDTH	= 436
-M.CENTER_PAD = 20
-M.PANEL_HORZ_SPACING = 10
-M.PANEL_MARGIN_X = 20
-M.PANEL_MARGIN_Y = 10
-M.TOP_Y	= 21
-M.SIDE_HEIGHT = 1020
-M.CENTER_HEIGHT = 220
-
-local margin_width = M.PANEL_MARGIN_X * 2 + M.PANEL_HORZ_SPACING
-
-M.CENTER_LEFT_X = M.LEFT_X + M.SECTION_WIDTH + margin_width
-M.CENTER_RIGHT_X = M.CENTER_LEFT_X + M.SECTION_WIDTH + M.CENTER_PAD
-M.CENTER_WIDTH = M.SECTION_WIDTH * 2 + M.CENTER_PAD
-M.RIGHT_X = M.CENTER_LEFT_X + M.CENTER_WIDTH + margin_width
-
-return M

schema/theme.lua

@@ -1,64 +0,0 @@
-local M = {}
-
-local color = require 'color'
-
-M.FONT = 'Neuropolitical'
-
--- text colors
-M.HEADER_FG = color.rgb(0xefefef)
-
-M.PRIMARY_FG = color.rgb(0xbfe1ff)
-M.CRITICAL_FG = color.rgb(0xff8282)
-
-M.INACTIVE_TEXT_FG = color.rgb(0xc8c8c8)
-M.MID_GREY = color.rgb(0xd6d6d6)
-M.BORDER_FG = color.rgb(0x888888)
-M.PLOT_GRID_FG = color.rgb(0x666666)
-M.PLOT_OUTLINE_FG = color.rgb(0x777777)
-
-
--- arc bg colors
-local GREY2 = 0xbfbfbf
-local GREY5 = 0x565656
-M.INDICATOR_BG = color.gradient_rgb{
-   [0.0] = GREY5,
-   [0.5] = GREY2,
-   [1.0] = GREY5
-}
-
--- arc/bar fg colors
-local PRIMARY1 = 0x99CEFF
-local PRIMARY3 = 0x316BA6
-M.INDICATOR_FG_PRIMARY = color.gradient_rgb{
-   [0.0] = PRIMARY3,
-   [0.5] = PRIMARY1,
-   [1.0] = PRIMARY3
-}
-
-local CRITICAL1 = 0xFF3333
-local CRITICAL3 = 0xFFB8B8
-M.INDICATOR_FG_CRITICAL = color.gradient_rgb{
-   [0.0] = CRITICAL1,
-   [0.5] = CRITICAL3,
-   [1.0] = CRITICAL1
-}
-
--- plot colors
-local PLOT_PRIMARY1 = 0x003f7c
-local PLOT_PRIMARY2 = 0x1e90ff
-local PLOT_PRIMARY3 = 0x316ece
-local PLOT_PRIMARY4 = 0x8cc7ff
-M.PLOT_FILL_BORDER_PRIMARY = color.gradient_rgb{
-   [0.0] = PLOT_PRIMARY1,
-   [1.0] = PLOT_PRIMARY2
-}
-
-M.PLOT_FILL_BG_PRIMARY = color.gradient_rgba{
-   [0.2] = {PLOT_PRIMARY3, 0.5},
-   [1.0] = {PLOT_PRIMARY4, 1.0}
-}
-
--- panel pattern
-M.PANEL_BG = color.rgba(0x121212, 0.7)
-
-return M

src/color.lua

@@ -0,0 +1,87 @@
+local err = require 'err'
+
+--------------------------------------------------------------------------------
+-- colors
+--
+-- these are tables like {red :: Int, green :: Int, blue :: Int, alpha :: Int}
+
+local rgba = function(hex, alpha)
+   local obj = err.safe_table(
+      {
+         r = ((hex / 0x10000) % 0x100) / 255.,
+         g = ((hex / 0x100) % 0x100) / 255.,
+         b = (hex % 0x100) / 255.,
+         a = alpha,
+      }
+   )
+   return err.set_type(obj, "color")
+end
+
+local rgb = function(hex)
+   return rgba(hex, 1.0)
+end
+
+--------------------------------------------------------------------------------
+-- Gradients
+--
+-- these are tables like {[stop] :: color} where stop is a float between 0 and 1
+-- and color is a color as defined above
+
+local _make_gradient = function(colorstops, f)
+   local c = {}
+   for stop, spec in pairs(colorstops) do
+      assert(
+         stop <= 1 and stop >= 0,
+         "ERROR: color stop must be between 0 and 1; got " .. stop
+      )
+      c[stop] = f(spec)
+   end
+   return err.set_type(err.safe_table(c), "gradient")
+end
+
+-- {[stop] :: hex} -> Gradient
+local gradient_rgb = function(colorstops)
+   return _make_gradient(colorstops, rgb)
+end
+
+-- {[stop] :: {hex, alpha}} -> Gradient
+local gradient_rgba = function(colorstops)
+   return _make_gradient(
+      colorstops,
+      function(spec) return rgba(spec[1], spec[2]) end
+   )
+end
+
+local compile_patterns
+
+compile_patterns = function(patterns)
+   local r = {}
+   for k, v in pairs(patterns) do
+      if type(v) == "number" then
+         r[k] = rgb(v)
+      elseif v.color ~= nil then
+         r[k] = rgba(v.color, v.alpha)
+      elseif v.gradient ~= nil then
+         local p = {}
+         local g = v.gradient
+         for i = 1, #g do
+            local _g = g[i]
+            p[_g.stop] = _g.color
+         end
+         r[k] = gradient_rgb(p)
+      elseif v.gradient_alpha ~= nil then
+         local p = {}
+         local g = v.gradient_alpha
+         for i = 1, #g do
+            local _g = g[i]
+            p[_g.stop] = {_g.color, _g.alpha}
+         end
+         r[k] = gradient_rgba(p)
+      else
+         r[k] = compile_patterns(v)
+      end
+   end
+   return r
+end
+
+return compile_patterns

src/err.lua

@@ -0,0 +1,52 @@
+local M = {}
+
+local i_o = require 'i_o'
+
+M.assert_trace = function(test, msg)
+   if not test then
+      i_o.errorf(msg)
+      print(debug.traceback())
+      os.exit(1)
+   end
+end
+
+M.safe_table = function(tbl)
+   local ck_key = function(_, key)
+      local v = rawget(tbl, key)
+      M.assert_trace(v ~= nil, "key doesn't exist: "..key)
+      return v
+   end
+   return setmetatable(tbl, {__index = ck_key})
+end
+
+local TYPE_KEY = '__type'
+
+M.set_type = function(tbl, _type)
+   local mt = getmetatable(tbl)
+   mt[TYPE_KEY] = _type
+   return setmetatable(tbl, mt)
+end
+
+M.get_type = function(x)
+   local ltype = type(x)
+   if ltype == "table" then
+      local mt = getmetatable(x)
+      if mt == nil then
+         return ltype
+      else
+         return mt[TYPE_KEY]
+      end
+   else
+      return ltype
+   end
+end
+
+M.check_type = function(x, _type)
+   local xtype = nil
+   if x ~= nil then
+      xtype = M.get_type(x)
+   end
+   i_o.assertf(xtype == _type, "type must be '%s' got '%s' instead", _type, xtype)
+end
+
+return M

src/format.lua

@@ -0,0 +1,43 @@
+local M = {}
+
+local __tostring		= tostring
+local __math_floor 		= math.floor
+local __math_ceil 		= math.ceil
+local __string_format 	= string.format
+
+M.round = function(x, places)
+    local m = 10 ^ (places or 0)
+    if x >= 0 then
+		return __math_floor(x * m + 0.5) / m
+	else
+		return __math_ceil(x * m - 0.5) / m
+	end
+end
+
+M.round_to_string = function(x, places)
+	places = places or 0
+	if places >= 0 then
+       return __string_format('%.'..places..'f', x)
+    else
+       return __tostring(M.round(x, 0))
+    end
+end
+
+M.precision_round_to_string = function(x, sig_fig)
+	sig_fig = sig_fig or 4
+	if     x < 10   then return M.round_to_string(x, sig_fig - 1)
+	elseif x < 100  then return M.round_to_string(x, sig_fig - 2)
+	elseif x < 1000 then return M.round_to_string(x, sig_fig - 3)
+	else                 return M.round_to_string(x, sig_fig - 4)
+	end
+end
+
+M.convert_data_val = function(x)
+	if     	x < 1024       then	return '', x
+	elseif 	x < 1048576    then	return 'Ki', x / 1024
+	elseif 	x < 1073741824 then	return 'Mi', x / 1048576
+    else					    return 'Gi', x / 1073741824
+    end
+end
+
+return M

src/i_o.lua

@@ -0,0 +1,107 @@
+local M = {}
+
+local __string_format = string.format
+local __tonumber = tonumber
+local __os_execute = os.execute
+local __io_popen = io.popen
+local __io_open = io.open
+local __string_match = string.match
+local __conky_parse	= conky_parse
+
+--------------------------------------------------------------------------------
+-- logging/printing
+
+M.printf = function(fmt, ...)
+   print(__string_format(fmt, ...))
+end
+
+M.logf = function(level, fmt, ...)
+   M.printf(level..': '..fmt, ...)
+end
+
+M.errorf = function(fmt, ...)
+   M.logf('ERROR', fmt, ...)
+end
+
+M.warnf = function(fmt, ...)
+   M.logf('WARN', fmt, ...)
+end
+
+M.infof = function(fmt, ...)
+   M.logf('INFO', fmt, ...)
+end
+
+M.assertf = function(test, fmt, ...)
+   -- NOTE use exit here because the assert command will only break one loop
+   -- in the conky update cycle rather than quit the entire program
+   if not test then
+      M.errorf(fmt, ...)
+      print(debug.traceback())
+      os.exit(1)
+   end
+end
+
+--------------------------------------------------------------------------------
+-- reading files/command output
+
+--[[
+available modes per lua docs
+*n: number (actually returns a number)
+*a: entire file (default here)
+*l: reads one line and strips \n (default for read cmd)
+*L; reads one line and keeps \n
+N: reads number of lines (where N is a number)
+--]]
+local read_entire_file = function(file, regex, mode)
+	if not file then return end
+	local str = file:read(mode or '*a')
+	file:close()
+	if not str then return end
+	if regex then return __string_match(str, regex) or '' else return str end
+end
+
+M.read_file = function(path, regex, mode)
+	return read_entire_file(__io_open(path, 'rb'), regex, mode)
+end
+
+M.execute_cmd = function(cmd, regex, mode)
+	return read_entire_file(__io_popen(cmd), regex, mode)
+end
+
+--------------------------------------------------------------------------------
+-- boolean tests
+
+M.exit_code_cmd = function(cmd)
+   local _, _, rc = __os_execute(cmd)
+   return rc
+end
+
+M.exe_exists = function(exe)
+   return M.exit_code_cmd('command -v '..exe..' > /dev/null') == 0
+end
+
+M.assert_exe_exists = function(exe)
+   M.assertf(M.exe_exists(exe), 'executable %s not found', exe)
+end
+
+M.file_exists = function(path)
+   return M.exit_code_cmd('stat '..path..' > /dev/null 2>&1') == 0
+end
+
+M.assert_file_exists = function(path)
+   M.assertf(M.file_exists(path), '%s does not exist', path)
+end
+
+--------------------------------------------------------------------------------
+-- conky object execution
+
+M.conky = function(expr, regex)
+	local ans = __conky_parse(expr)
+	if regex then return __string_match(ans, regex) or '' else return ans end
+end
+
+M.conky_numeric = function(expr, regex)
+	return __tonumber(M.conky(expr, regex)) or 0
+end
+
+return M

src/impure.lua

@@ -0,0 +1,28 @@
+local M = {}
+
+M.sequence = function(...)
+   local fs = {...}
+   for i = 1, #fs do
+      fs[i]()
+   end
+end
+
+M.each = function(f, seq, ...)
+   for i = 1, #seq do
+      f(seq[i], ...)
+   end
+end
+
+M.ieach = function(f, seq, ...)
+   for i = 1, #seq do
+      f(i, seq[i], ...)
+   end
+end
+
+M.each2 = function(f, seq1, seq2, ...)
+   for i = 1, #seq1 do
+      f(seq1[i], seq2[i], ...)
+   end
+end
+
+return M

src/json.lua

@@ -0,0 +1,194 @@
+local M = {}
+
+local __string_gsub 	= string.gsub
+local __string_char 	= string.char
+local __string_find 	= string.find
+local __string_sub 		= string.sub
+local __table_concat 	= table.concat
+local __math_floor 		= math.floor
+local __pairs 			= pairs
+local __tonumber 		= tonumber
+
+local decode -- to ref this before definition
+
+local decode_scan_whitespace = function(s, start_pos)
+	local whitespace = " \n\r\t"
+	local string_len = #s
+	
+	while (__string_find(whitespace, __string_sub(s, start_pos, start_pos), 1, true) and
+	  start_pos <= string_len) do
+		start_pos = start_pos + 1
+	end
+	return start_pos
+end
+
+local decode_scan_array = function(s, start_pos)
+	local array = {}
+	local string_len = #s
+	
+	start_pos = start_pos + 1
+
+	repeat
+		start_pos = decode_scan_whitespace(s, start_pos)
+		
+		local cur_char = __string_sub(s,start_pos,start_pos)
+		
+		if (cur_char == ']') then
+			return array, start_pos + 1
+		end
+		
+		if (cur_char == ',') then
+			start_pos = decode_scan_whitespace(s, start_pos + 1)
+		end
+		
+		object, start_pos = decode(s, start_pos)
+		array[#array + 1] = object
+	until false
+end
+
+local decode_scan_comment = function(s, start_pos)
+	local end_pos = __string_find(s, '*/', start_pos + 2)
+	return end_pos + 2
+end
+
+local decode_scan_constant = function(s, start_pos)
+	local consts = {["true"] = true, ["false"] = false,	["null"] = nil}
+	local const_names = {"true", "false", "null"}
+	
+	for _, k in __pairs(const_names) do
+		if __string_sub(s, start_pos, start_pos + #k - 1 ) == k then
+			return consts[k], start_pos + #k
+		end
+	end
+end
+
+local decode_scan_number = function(s, start_pos)
+	local end_pos = start_pos + 1
+	local string_len = #s
+	local acceptable_chars = "+-0123456789.e"
+	
+	while (__string_find(acceptable_chars, __string_sub(s, end_pos, end_pos), 1, true)
+	  and end_pos <= string_len) do
+		end_pos = end_pos + 1
+	end
+
+	local number_string = __string_gsub(__string_sub(s, start_pos, end_pos - 1), '+', '')
+	return __tonumber(number_string), end_pos
+end
+
+local decode_scan_object = function(s, start_pos)
+	local object = {}
+	local string_len = #s
+	local key, value
+	
+	start_pos = start_pos + 1
+	
+	repeat
+		start_pos = decode_scan_whitespace(s, start_pos)
+		
+		local cur_char = __string_sub(s, start_pos, start_pos)
+		
+		if (cur_char == '}') then
+			return object, start_pos + 1
+		end
+		
+		if (cur_char == ',') then
+			start_pos = decode_scan_whitespace(s, start_pos + 1)
+		end
+		
+		-- Scan the key
+		key, start_pos = decode(s, start_pos)
+		
+		start_pos = decode_scan_whitespace(s, start_pos)
+		start_pos = decode_scan_whitespace(s, start_pos + 1)
+
+		value, start_pos = decode(s, start_pos)
+		
+		object[key] = value
+	until false
+end
+
+local escape_sequences = {
+	["\\t"] = "\t",
+	["\\f"] = "\f",
+	["\\r"] = "\r",
+	["\\n"] = "\n",
+	["\\b"] = "\b"
+}
+
+setmetatable(escape_sequences, {__index = function(t, k) return __string_sub(k, 2) end})--skip "\"
+
+local decode_scan_string = function (s, start_pos)
+	local start_char = __string_sub(s, start_pos, start_pos)
+	
+	local t = {}
+	local i, j = start_pos, start_pos
+	
+	while __string_find(s, start_char, j + 1) ~= j + 1 do
+		local oldj = j
+		local x, y = __string_find(s, start_char, oldj + 1)
+		
+		i, j = __string_find(s, "\\.", j + 1)
+		
+		if not i or x < i then i, j = x, y - 1 end
+
+		t[#t + 1] = __string_sub(s, oldj + 1, i - 1)
+		
+		if __string_sub(s, i, j) == "\\u" then
+			local a = __string_sub(s, j + 1, j + 4)
+			local n = __tonumber(a, 16)
+			local x
+			
+			j = j + 4
+			
+			if n < 0x80 then
+				x = __string_char(n % 0x80)
+			elseif n < 0x800 then
+				x = __string_char(0xC0 + (__math_floor(n / 64) % 0x20), 0x80 + (n % 0x40))
+			else
+				x = __string_char(0xE0 + (__math_floor(n / 4096) % 0x10), 0x80 +
+				  (__math_floor(n / 64) % 0x40), 0x80 + (n % 0x40))
+			end
+		
+			t[#t + 1] = x
+		else
+			t[#t + 1] = escape_sequences[__string_sub(s, i, j)]
+		end
+	end
+	t[#t + 1] = __string_sub(j, j + 1)
+	
+	return __table_concat(t, ""), j + 2
+end
+
+decode = function(s, start_pos)
+	start_pos = start_pos or 1
+	start_pos = decode_scan_whitespace(s, start_pos)
+	
+	local cur_char = __string_sub(s, start_pos, start_pos)
+	
+	if cur_char == '{' then
+		return decode_scan_object(s, start_pos)
+	end
+	
+	if cur_char == '[' then
+		return decode_scan_array(s, start_pos)
+	end
+
+	if __string_find("+-0123456789.e", cur_char, 1, true) then
+		return decode_scan_number(s, start_pos)
+	end
+
+	if cur_char == [["]] or cur_char == [[']] then
+		return decode_scan_string(s, start_pos)
+	end
+
+	if __string_sub(s, start_pos, start_pos + 1) == '/*' then
+		return decode(s, decode_scan_comment(s, start_pos))
+	end
+
+	return decode_scan_constant(s, start_pos)
+end
+
+M.decode = decode
+
+return M

src/modules/common.lua

@@ -19,43 +19,10 @@ local style = require 'style'
 local source = require 'source'
 local pure = require 'pure'
 
-local compile_patterns
-
--- TODO move to color module
-compile_patterns = function(patterns)
-   local r = {}
-   for k, v in pairs(patterns) do
-      if type(v) == "number" then
-         r[k] = color.rgb(v)
-      elseif v.color ~= nil then
-         r[k] = color.rgba(v.color, v.alpha)
-      elseif v.gradient ~= nil then
-         local p = {}
-         local g = v.gradient
-         for i = 1, #g do
-            local _g = g[i]
-            p[_g.stop] = _g.color
-         end
-         r[k] = color.gradient_rgb(p)
-      elseif v.gradient_alpha ~= nil then
-         local p = {}
-         local g = v.gradient_alpha
-         for i = 1, #g do
-            local _g = g[i]
-            p[_g.stop] = {_g.color, _g.alpha}
-         end
-         r[k] = color.gradient_rgba(p)
-      else
-         r[k] = compile_patterns(v)
-      end
-   end
-   return r
-end
-
 return function(config)
    local M = {}
 
-   local patterns = compile_patterns(config.theme.patterns)
+   local patterns = color(config.theme.patterns)
    local font = config.theme.font
    local font_sizes = font.sizes
    local font_family = font.family

src/modules/filesystem.lua

@@ -10,7 +10,7 @@ return function(config, main_state, common, width, point)
    -----------------------------------------------------------------------------
    -- smartd
 
-   i_o.exe_assert('pidof')
+   i_o.assert_exe_exists('pidof')
 
    local mk_smart = function(y)
       local obj = common.make_text_row(point.x, y, width, 'SMART Daemon')
@@ -35,6 +35,7 @@ return function(config, main_state, common, width, point)
    local mk_bars = function(y)
       local paths = pure.map_keys('path', config.fs_paths)
       local names = pure.map_keys('name', config.fs_paths)
+      impure.each(i_o.assert_file_exists, paths)
       local CONKY_CMDS = pure.map(
          pure.partial(string.format, '${fs_used_perc %s}', true),
          paths

src/modules/graphics.lua

@@ -14,7 +14,8 @@ return function(update_freq, config, common, width, point)
    -----------------------------------------------------------------------------
    -- nvidia state
 
-   i_o.exe_assert(NVIDIA_EXE)
+   i_o.assert_exe_exists(NVIDIA_EXE)
+   i_o.assert_file_exists(config.dev_power)
 
    -- vars to process the nv settings glob
    --
@@ -38,8 +39,6 @@ return function(update_freq, config, common, width, point)
       '(%d+),(%d+)\n'..
       'graphics=(%d+), memory=%d+, video=(%d+), PCIe=%d+\n'
 
-   local GPU_BUS_CTRL = '/sys/bus/pci/devices/0000:01:00.0/power/control'
-
    local mod_state = {
       error = false,
       used_memory = 0,
@@ -52,7 +51,7 @@ return function(update_freq, config, common, width, point)
    }
 
    local update_state = function()
-      if i_o.read_file(GPU_BUS_CTRL, nil, '*l') == 'on' then
+      if i_o.read_file(config.dev_power, nil, '*l') == 'on' then
          local nvidia_settings_glob = i_o.execute_cmd(NV_QUERY)
          if nvidia_settings_glob == '' then
             mod_state.error = 'Error'

src/modules/processor.lua

@@ -39,13 +39,11 @@ return function(update_freq, config, main_state, common, width, point)
       if math.fmod(ncores, config.core_rows) == 0 then
          show_cores = true
       else
-         print(
-            string.format(
-               'WARNING: could not evenly distribute %i cores over %i rows',
+         i_o.warnf(
+            'could not evenly distribute %i cores over %i rows; disabling',
             ncores,
             config.core_rows
          )
-         )
       end
    end
 

src/modules/readwrite.lua

@@ -1,6 +1,8 @@
 local format = require 'format'
 local pure = require 'pure'
 local sys = require 'sys'
+local i_o = require 'i_o'
+local impure = require 'impure'
 
 return function(update_freq, config, common, width, point)
    local PLOT_SEC_BREAK = 20
@@ -9,6 +11,8 @@ return function(update_freq, config, common, width, point)
    local mod_state = {read = 0, write = 0}
    local device_paths = sys.get_disk_paths(config.devices)
 
+   impure.each(i_o.assert_file_exists, device_paths)
+
    local update_state = function()
       mod_state.read, mod_state.write = sys.get_total_disk_io(device_paths)
    end

src/pure.lua

@@ -0,0 +1,259 @@
+local M = {}
+
+local err = require 'err'
+
+local __math_floor = math.floor
+
+--------------------------------------------------------------------------------
+-- zippy functions
+
+-- TODO generalize to arbitrary number of sequences
+M.zip_with = function(f, seq1, seq2)
+   local r = {}
+   for i = 1, #seq1 do
+      r[i] = f(seq1[i], seq2[i])
+   end
+   return r
+end
+
+M.zip = function(...)
+   local seqs = {...}
+   local imax = math.min(table.unpack(M.map(function(t) return #t end, seqs)))
+   local jmax = #seqs
+   local r = {}
+   for i = 1, imax do
+      r[i] = {}
+      for j = 1, jmax do
+         r[i][j] = seqs[j][i]
+      end
+   end
+   return r
+end
+
+M.unzip = function(seqs)
+   return M.zip(table.unpack(seqs))
+end
+
+--------------------------------------------------------------------------------
+-- reductions
+
+M.reduce = function(f, init, seq)
+   if seq == nil then
+      return init
+   else
+      local r = init
+      for i = 1, #seq do
+         r = f(r, seq[i])
+      end
+      return r
+   end
+end
+
+--------------------------------------------------------------------------------
+-- mappy functions
+
+M.map = function(f, seq, ...)
+   local r = {}
+   for i = 1, #seq do
+      r[i] = f(seq[i], ...)
+   end
+   return r
+end
+
+M.map_n = function(f, n, ...)
+   local r = {}
+   for i = 1, n do
+      r[i] = f(i, ...)
+   end
+   return r
+end
+
+M.imap = function(f, seq)
+   local r = {}
+   for i = 1, #seq do
+      r[i] = f(i, seq[i])
+   end
+   return r
+end
+
+M.map_keys = function(key, tbls)
+   local r = {}
+   for i = 1, #tbls do
+      r[i] = tbls[i][key]
+   end
+   return r
+end
+
+M.map_at = function(key, f, tbl)
+   local r = {}
+   for k, v in pairs(tbl) do
+      if k == key then
+         r[k] = f(v)
+      else
+         r[k] = v
+      end
+   end
+   return r
+end
+
+--------------------------------------------------------------------------------
+-- generations
+
+M.seq = function(n, start)
+   start = start or 1
+   local r = {}
+   for i = 1, n do
+      r[i] = i + start - 1
+   end
+   return r
+end
+
+M.rep = function(n, x)
+   local r = {}
+   for i = 1, n do
+      r[i] = x
+   end
+   return r
+end
+
+--------------------------------------------------------------------------------
+-- random list things
+
+M.set = function(tbl, key, value)
+   local r = {}
+   for k, v in pairs(tbl) do
+      if k == key then
+         r[k] = value
+      else
+         r[k] = v
+      end
+   end
+   return r
+end
+
+M.reverse = function(xs)
+   local j = 1
+   local r = {}
+   for i = #xs, 1, -1 do
+      r[j] = xs[i]
+      j = j + 1
+   end
+   return r
+end
+
+M.filter = function(f, seq)
+   local r = {}
+   local j = 1
+   for i = 1, #seq do
+      if f(seq[i]) == true then
+         r[j] = seq[i]
+         j = j + 1
+      end
+   end
+   return r
+end
+
+M.flatten = function(xs)
+   local r = {}
+   for i = 1, #xs do
+      for j = 1, #xs[i] do
+         table.insert(r, xs[i][j])
+      end
+   end
+   return r
+end
+
+M.concat = function(...)
+   return M.flatten({...})
+end
+
+M.table_array = function(tbl)
+   local r = {}
+   for i = 1, #tbl do
+      r[i] = tbl[i]
+   end
+   return r
+end
+
+--------------------------------------------------------------------------------
+-- functional functions
+
+local get_arity = function(f, args)
+   local i = #args
+   while args[i] == true do
+      i = i - 1
+   end
+   if i < #args then
+      return table.move(args, 1, #args - i, 1, {}), #args
+   else
+      local arity = debug.getinfo(f, "u")["nparams"]
+      err.assert_trace(arity > #args, 'too many arguments for partial')
+      return args, arity
+   end
+end
+
+-- poor man's Lisp macro :)
+M.partial = function(f, ...)
+   local args, arity = get_arity(f, {...})
+   local format_args = function(fmt, n, start)
+      return table.concat(
+         M.map(function(i) return string.format(fmt, i) end, M.seq(n, start)),
+         ','
+      )
+   end
+   local partial_args = format_args('args[%i]', #args, 1)
+   local rem_args = format_args('x%i', arity - #args, #args + 1)
+   local src = string.format(
+      'return function(%s) return f(%s,%s) end',
+      rem_args,
+      partial_args,
+      rem_args
+   )
+   return load(src, 'partial_apply', 't', {f = f, args = args})()
+end
+
+M.compose = function(f, ...)
+   if #{...} == 0 then
+      return f
+   else
+      local g = M.compose(...)
+      return function(x) return f(g(x)) end
+   end
+end
+
+-- TODO is there a way to do this without nesting a zillion function calls?
+M.sequence = function(...)
+   local fs = {...}
+   return function(x)
+      for i = 1, #fs do
+         fs[i](x)
+      end
+   end
+end
+
+M.memoize = function(f)
+   local mem = {} -- memoizing table
+   setmetatable(mem, {__mode = "kv"}) -- make it weak
+   return function (x, ...)
+      local r = mem[x]
+      if not r then
+         r = f(x, ...)
+         mem[x] = r
+      end
+      return r
+   end
+end
+
+M.maybe = function(def, f, x)
+   if x == nil then
+      return def
+   else
+      return f(x)
+   end
+end
+
+-- round to whole numbers since I don't need more granularity and extra values
+-- will lead to cache misses
+M.round_percent = __math_floor
+
+return M

src/sys.lua

@@ -0,0 +1,332 @@
+local M = {}
+
+local i_o = require 'i_o'
+local pure = require 'pure'
+
+local __string_match = string.match
+local __string_gmatch = string.gmatch
+local __string_format = string.format
+local __tonumber = tonumber
+
+local dirname = function(s)
+   return __string_match(s, '(.*)/name')
+end
+
+local read_micro = function(path)
+   return i_o.read_file(path, nil, '*n') * 0.000001
+end
+
+--------------------------------------------------------------------------------
+-- memory
+
+local MEMINFO_PATH = '/proc/meminfo'
+
+local fmt_mem_field = function(field)
+   return field..':%s+(%d+)'
+end
+
+local meminfo_regex = function(read_swap)
+   -- ASSUME the order of the meminfo file will never change, but some options
+   -- (like swap) might not exist
+   local free_fields = {
+         'MemFree',
+         'Buffers',
+         'Cached'
+   }
+   local swap_field = 'SwapFree'
+   local slab_fields = {
+      'Shmem',
+      'SReclaimable'
+   }
+   local all_fields = read_swap == true
+      and {free_fields, {swap_field}, slab_fields}
+      or {free_fields, slab_fields}
+   local patterns = pure.map(fmt_mem_field, pure.flatten(all_fields))
+   return table.concat(patterns, '.+\n')
+end
+
+M.meminfo_updater_swap = function(mem_state, swap_state)
+   local regex = meminfo_regex(true)
+   return function()
+      mem_state.memfree,
+         mem_state.buffers,
+         mem_state.cached,
+         swap_state.free,
+         mem_state.shmem,
+         mem_state.sreclaimable
+         = __string_match(i_o.read_file(MEMINFO_PATH), regex)
+   end
+end
+
+M.meminfo_updater_noswap = function(mem_state)
+   local regex = meminfo_regex(false)
+   return function()
+      mem_state.memfree,
+         mem_state.buffers,
+         mem_state.cached,
+         mem_state.shmem,
+         mem_state.sreclaimable
+         = __string_match(i_o.read_file(MEMINFO_PATH), regex)
+   end
+end
+
+M.meminfo_field_reader = function(field)
+   local pattern = fmt_mem_field(field)
+   return function()
+      return tonumber(i_o.read_file(MEMINFO_PATH, pattern))
+   end
+end
+
+--------------------------------------------------------------------------------
+-- intel powercap
+
+local SYSFS_RAPL = '/sys/class/powercap'
+
+M.intel_powercap_reader = function(dev)
+   local uj = __string_format('%s/%s/energy_uj', SYSFS_RAPL, dev)
+   i_o.assert_file_exists(uj)
+   return function()
+      return read_micro(uj)
+   end
+end
+
+--------------------------------------------------------------------------------
+-- battery
+
+local SYSFS_POWER = '/sys/class/power_supply'
+
+local format_power_path = function(battery, property)
+   local p = __string_format('%s/%s/%s', SYSFS_POWER, battery, property)
+   i_o.assert_file_exists(p)
+   return p
+end
+
+M.battery_power_reader = function(battery)
+   local current = format_power_path(battery, 'current_now')
+   local voltage = format_power_path(battery, 'voltage_now')
+   return function()
+      return read_micro(current) * read_micro(voltage)
+   end
+end
+
+M.battery_status_reader = function(battery)
+   local status = format_power_path(battery, 'status')
+   return function()
+      return i_o.read_file(status, nil, '*l') ~= 'Discharging'
+   end
+end
+
+--------------------------------------------------------------------------------
+-- disk io
+
+M.get_disk_paths = function(devs)
+   return pure.map(pure.partial(string.format, '/sys/block/%s/stat', true), devs)
+end
+
+-- fields 3 and 7 (sectors read and written)
+local RW_REGEX = '%s+%d+%s+%d+%s+(%d+)%s+%d+%s+%d+%s+%d+%s+(%d+)'
+
+-- the sector size of any block device in linux is 512 bytes
+-- see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/types.h?id=v4.4-rc6#n121
+local BLOCK_SIZE_BYTES = 512
+
+M.get_disk_io = function(path)
+   local r, w = __string_match(i_o.read_file(path), RW_REGEX)
+   return __tonumber(r) * BLOCK_SIZE_BYTES, __tonumber(w) * BLOCK_SIZE_BYTES
+end
+
+M.get_total_disk_io = function(paths)
+   local r = 0
+   local w = 0
+   for i = 1, #paths do
+      local _r, _w = M.get_disk_io(paths[i])
+      r = r + _r
+      w = w + _w
+   end
+   return r, w
+end
+
+--------------------------------------------------------------------------------
+-- network
+
+-- ASSUME realpath exists (part of coreutils)
+
+local get_interfaces = function()
+   local s = i_o.execute_cmd('realpath /sys/class/net/* | grep -v virtual')
+   local interfaces = {}
+   for iface in __string_gmatch(s, '/([^/\n]+)\n') do
+      interfaces[#interfaces + 1] = iface
+   end
+   return interfaces
+end
+
+M.get_net_interface_paths = function()
+   local is = get_interfaces()
+   return pure.map(
+      function(s)
+         local dir = string.format('/sys/class/net/%s/statistics/', s)
+         return {rx = dir..'rx_bytes', tx = dir..'tx_bytes'}
+      end,
+      is
+   )
+end
+
+--------------------------------------------------------------------------------
+-- cpu
+
+-- ASSUME nproc and lscpu will always be available
+
+M.get_core_number = function()
+   return tonumber(i_o.read_file('/proc/cpuinfo', 'cpu cores%s+:%s(%d+)'))
+end
+
+M.get_cpu_number = function()
+   return tonumber(i_o.execute_cmd('nproc', nil, '*n'))
+end
+
+-- TODO what if this fails?
+local get_coretemp_dir = function()
+   i_o.assert_exe_exists('grep')
+   local s = i_o.execute_cmd('grep -l \'^coretemp$\' /sys/class/hwmon/*/name')
+   return dirname(s)
+end
+
+-- map cores to integer values starting at 1; this is necessary since some cpus
+-- don't report their core id's as a sequence of integers starting at 0
+local get_core_id_mapper = function()
+   local s = i_o.execute_cmd('lscpu -p=CORE | tail -n+5 | sort | uniq')
+   local m = {}
+   local i = 1
+   for core_id in string.gmatch(s, '(%d+)') do
+      m[tonumber(core_id)] = i
+      i = i + 1
+   end
+   return m
+end
+
+local get_core_mappings = function()
+   local ncpus = M.get_cpu_number()
+   local ncores = M.get_core_number()
+   local nthreads = ncpus / ncores
+   local core_id_mapper = get_core_id_mapper()
+   local conky_thread_ids = pure.rep(ncores, nthreads)
+   local core_mappings = {}
+   local s = i_o.execute_cmd('lscpu -p=cpu,CORE | tail -n+5')
+   for cpu_id, core_id in string.gmatch(s, '(%d+),(%d+)') do
+      local conky_core_id = core_id_mapper[tonumber(core_id)]
+      local conky_cpu_id = tonumber(cpu_id) + 1
+      core_mappings[conky_cpu_id] = {
+         conky_core_id = conky_core_id,
+         conky_thread_id = conky_thread_ids[conky_core_id],
+      }
+      conky_thread_ids[conky_core_id] = conky_thread_ids[conky_core_id] - 1
+   end
+   return core_mappings
+end
+
+M.get_coretemp_paths = function()
+   local d = get_coretemp_dir()
+   i_o.assert_exe_exists('grep')
+   local s = i_o.execute_cmd(string.format('grep Core %s/temp*_label', d))
+   local ps = {}
+   local core_id_mapper = get_core_id_mapper()
+   for temp_name, core_id in string.gmatch(s, '/([^/\n]+)_label:Core (%d+)\n') do
+      ps[core_id_mapper[tonumber(core_id)]] = string.format('%s/%s_input', d, temp_name)
+   end
+   return ps
+end
+
+M.read_freq = function()
+   -- NOTE: Using the builtin conky functions for getting cpu freq seems to make
+   -- the entire loop jittery due to high variance latency. Querying
+   -- scaling_cur_freq in sysfs seems to do the same thing. It appears lscpu
+   -- (which queries /proc/cpuinfo) is much faster and doesn't have this jittery
+   -- problem.
+   local c = i_o.execute_cmd('lscpu -p=MHZ')
+   local f = 0
+   local n = 0
+   for s in __string_gmatch(c, '(%d+%.%d+)') do
+      f = f + __tonumber(s)
+      n = n + 1
+   end
+   return __string_format('%.0f Mhz', f / n)
+end
+
+M.get_hwp_paths = function()
+   return pure.map_n(
+      function(i)
+         return '/sys/devices/system/cpu/cpu'
+            .. (i - 1)
+            .. '/cpufreq/energy_performance_preference'
+      end,
+      M.get_cpu_number()
+   )
+end
+
+M.read_hwp = function(hwp_paths)
+   -- read HWP of first cpu, then test all others to see if they match
+   local hwp_pref = i_o.read_file(hwp_paths[1], nil, "*l")
+   local mixed = false
+   local i = 2
+
+   while not mixed and i <= #hwp_paths do
+      if hwp_pref ~= i_o.read_file(hwp_paths[i], nil, '*l') then
+         mixed = true
+      end
+      i = i + 1
+   end
+
+   if mixed then
+      return 'Mixed'
+   elseif hwp_pref == 'power' then
+      return 'Power'
+   elseif hwp_pref == 'balance_power' then
+      return 'Bal. Power'
+   elseif hwp_pref == 'balance_performance' then
+      return 'Bal. Performance'
+   elseif hwp_pref == 'performance' then
+      return 'Performance'
+   elseif hwp_pref == 'default' then
+      return 'Default'
+   else
+      return 'Unknown'
+   end
+end
+
+M.init_cpu_loads = function()
+   local m = get_core_mappings()
+   local cpu_loads = {}
+   for cpu_id, core in pairs(m) do
+      cpu_loads[cpu_id] = {
+         active_prev = 0,
+         total_prev = 0,
+         percent_active = 0,
+         conky_core_id = core.conky_core_id,
+         conky_thread_id = core.conky_thread_id,
+      }
+   end
+   return cpu_loads
+end
+
+M.read_cpu_loads = function(cpu_loads)
+   local ncpus = #cpu_loads
+   local i = 1
+   local iter = io.lines('/proc/stat')
+   iter() -- ignore first line
+   for ln in iter do
+      if i > ncpus then break end
+      local user, system, idle = __string_match(ln, '(%d+) %d+ (%d+) (%d+)', 5)
+      local active = user + system
+      local total = active + idle
+      local c = cpu_loads[i]
+      if total > c.total_prev then -- guard against 1/0 errors
+         c.percent_active = (active - c.active_prev) / (total - c.total_prev)
+         c.active_prev = active
+         c.total_prev = total
+      end
+      i = i + 1
+   end
+   return cpu_loads
+end
+
+return M

src/widget/arc/arc.lua

@@ -0,0 +1,29 @@
+local M = {}
+
+local geom = require 'geom'
+local circle = require 'circle'
+local path = require 'path'
+local shape = require 'shape'
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.make_shape = function(arc, thickness, pattern)
+   return shape.shape(
+      path.create_arc_from_geom(geom.CR_DUMMY, arc),
+      circle.make_source(pattern, arc.center, arc.radius, thickness)
+   )
+end
+
+M.make = function(arc, config)
+   return circle._make(arc, config, M.make_shape)
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.config = circle.config
+
+M.draw = circle.draw
+
+return M

src/widget/arc/circle.lua

@@ -0,0 +1,55 @@
+local M = {}
+
+local geom = require 'geom'
+local err = require 'err'
+local source = require 'source'
+local style = require 'style'
+local path = require 'path'
+local shape = require 'shape'
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.make_pattern_radii = function(r, t)
+   return r - t * 0.5, r + t * 0.5
+end
+
+M.make_source = function(pattern, center, radius, thickness)
+   local r1, r2 = M.make_pattern_radii(radius, thickness)
+   return source.radial_pattern(pattern, center, r1, r2)
+end
+
+M.make_shape = function(circle, thickness, pattern)
+   return shape.shape(
+      path.create_circle_from_geom(geom.CR_DUMMY, circle),
+      M.make_source(pattern, circle.center, circle.radius, thickness)
+   )
+end
+
+M._make = function(_geom, config, make_shape_fun)
+   return shape.styled_shape(
+      config.style,
+      make_shape_fun,
+      _geom,
+      config.style.thickness,
+      config.pattern
+   )
+end
+
+M.make = function(circle, config)
+   return M._make(circle, config, M.make_shape)
+end
+
+M.config = function(_style, pattern)
+   return err.safe_table({style = _style, pattern = pattern})
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.draw = function(obj, cr)
+   style.set_line_style(obj.style, cr)
+   shape.draw_shape(obj.shape, cr)
+end
+
+return M

src/widget/arc/compound_dial.lua

@@ -0,0 +1,60 @@
+local M = {}
+
+local arc = require 'arc'
+local dial = require 'dial'
+local pure = require 'pure'
+local impure = require 'impure'
+local style = require 'style'
+local shape = require 'shape'
+local dynamic = require 'dynamic'
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.make = function(_arc, bg_config, fg_threshold_config, inner_radius, num_dials)
+   local t = bg_config.style.thickness
+
+   local spacing = (t * num_dials - _arc.radius + inner_radius)
+      / (1 - num_dials)
+   assert(spacing >= 0, "ERROR: compound dial spacing is negative")
+   local arcs = pure.map_n(
+      function(i)
+         return pure.set(
+            _arc,
+            "radius",
+            inner_radius + t * 0.5 + (i - 1) * (spacing + t)
+         )
+      end,
+      num_dials
+   )
+   local setters = pure.map(dial.make_setter, arcs, t, fg_threshold_config)
+
+   return dynamic.compound(
+      {
+         shapes = pure.map(arc.make_shape, arcs, t, bg_config.pattern),
+         style = bg_config.style,
+      },
+      setters,
+      0
+   )
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.set = function(obj, i, percent)
+   obj.var[i] = obj.setters[i](percent)
+end
+
+M.draw_static = function(obj, cr)
+   local static = obj.static
+   style.set_line_style(static.style, cr)
+   impure.each(shape.draw_shape, static.shapes, cr)
+end
+
+M.draw_dynamic = function(obj, cr)
+   style.set_line_style(obj.static.style, cr)
+   impure.each(shape.draw_shape, obj.var, cr)
+end
+
+return M

src/widget/arc/dial.lua

@@ -0,0 +1,75 @@
+local M = {}
+
+local geom = require 'geom'
+local pure = require 'pure'
+local arc = require 'arc'
+local circle = require 'circle'
+local source = require 'source'
+local style = require 'style'
+local path = require 'path'
+local shape = require 'shape'
+local dynamic = require 'dynamic'
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.make_setter = function(_arc, thickness, threshold_config)
+   local c = _arc.center
+   local r = _arc.radius
+   local t1 = _arc.theta0
+   local t2 = _arc.theta1
+   local r1, r2 = circle.make_pattern_radii(r, thickness)
+   local source_chooser = source.radial_pattern_chooser(
+      threshold_config.low_pattern,
+      threshold_config.high_pattern,
+      threshold_config.threshold,
+      c,
+      r1,
+      r2
+   )
+   local f = pure.memoize(
+      function(percent)
+         return shape.shape(
+            path.create_arc(
+               geom.CR_DUMMY,
+               c.x,
+               c.y,
+               r,
+               t1,
+               t1 + (percent / 100) * (t2 - t1)
+            ),
+            source_chooser(percent)
+         )
+      end
+   )
+   return function(percent)
+      return f(pure.round_percent(percent))
+   end
+end
+
+M.make = function(_arc, bg_config, fg_threshold_config)
+   local setter = M.make_setter(
+      _arc,
+      bg_config.style.thickness,
+      fg_threshold_config
+   )
+   return dynamic.single(arc.make(_arc, bg_config), setter, 0)
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.set = function(obj, percent)
+   obj.var = obj.setter(percent)
+end
+
+M.draw_static = function(obj, cr)
+   arc.draw(obj.static, cr)
+end
+
+M.draw_dynamic = function(obj, cr)
+   style.set_line_style(obj.static.style, cr)
+   shape.draw_shape(obj.var, cr)
+end
+
+return M

src/widget/dynamic.lua

@@ -0,0 +1,45 @@
+local M = {}
+
+local err = require 'err'
+local pure = require 'pure'
+
+-- TODO generalize these
+-- types of dynamic mappers
+-- 1 -> 1
+-- 1 -> 1 with recursion
+-- 1 -> many
+-- 1 -> many (nested in many)
+-- many -> many
+
+M.single = function(static, setter, init)
+   return err.safe_table(
+      {
+         static = static,
+         setter = setter,
+         var = setter(init)
+      }
+   )
+end
+
+-- TODO think of a better more mathy name
+M.multi = function(static, setter, inits)
+   return err.safe_table(
+      {
+         static = static,
+         setter = setter,
+         var = pure.map(setter, inits)
+      }
+   )
+end
+
+M.compound = function(static, setters, init)
+   return err.safe_table(
+      {
+         static = static,
+         setters = setters,
+         var = pure.map(function(setter) return setter(init) end, setters),
+      }
+   )
+end
+
+return M

src/widget/geom.lua

@@ -0,0 +1,60 @@
+local M = {}
+
+local err = require 'err'
+
+-- TODO this is weird to have here
+-- dummy drawing surface
+local cs = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1366, 768)
+M.CR_DUMMY = cairo_create(cs)
+cairo_surface_destroy(cs)
+cs = nil
+
+M.make_point = function(x, y)
+   return err.safe_table({x = x, y = y})
+end
+
+M.make_box_at_point = function(p, w, h)
+   return err.safe_table(
+      {
+         corner = p,
+         width = w,
+         height = h,
+         -- TODO these might be unnecessary
+         right_x = w + p.x,
+         bottom_y = h + p.y
+      }
+   )
+end
+
+M.make_box = function(x, y, w, h)
+   return M.make_box_at_point(M.make_point(x, y), w, h)
+end
+
+M.make_arc_at_point = function(p, r, t1, t2)
+   return err.safe_table(
+      {
+         center = p,
+         radius = r,
+         theta0 = t1,
+         theta1 = t2,
+      }
+   )
+end
+
+M.make_arc = function(x, y, r, t0, t1)
+   return M.make_arc_at_point(M.make_point(x, y), r, t0, t1)
+end
+
+M.make_circle_at_point = function(p, r)
+   return err.safe_table({center = p, radius = r})
+end
+
+M.make_circle = function(x, y, r)
+   return M.make_circle_at_point(M.make_point(x, y), r)
+end
+
+M.make_line = function(p1, p2)
+   return err.safe_table({p1 = p1, p2 = p2})
+end
+
+return M

src/widget/image/Image.lua

@@ -0,0 +1,31 @@
+local M = {}
+
+local __imlib_load_image    			= imlib_load_image
+local __imlib_context_set_image 		= imlib_context_set_image
+local __imlib_render_image_on_drawable  = imlib_render_image_on_drawable
+local __imlib_free_image    			= imlib_free_image
+local __imlib_image_get_width			= imlib_image_get_width
+local __imlib_image_get_height			= imlib_image_get_height
+
+local set = function(obj, path)
+	local img = __imlib_load_image(path)
+	__imlib_context_set_image(img)
+
+	obj.width = __imlib_image_get_width()
+	obj.height = __imlib_image_get_height()
+	obj.path = path
+
+	__imlib_free_image()
+end
+
+local draw = function(obj)
+	local img = __imlib_load_image(obj.path)
+	__imlib_context_set_image(img)
+	__imlib_render_image_on_drawable(obj.x, obj.y)
+	__imlib_free_image()
+end
+
+M.set = set
+M.draw = draw
+
+return M

src/widget/image/ScaledImage.lua

@@ -0,0 +1,31 @@
+local M = {}
+
+local __imlib_load_image    					= imlib_load_image
+local __imlib_context_set_image 				= imlib_context_set_image
+local __imlib_render_image_on_drawable_at_size  = imlib_render_image_on_drawable_at_size
+local __imlib_free_image    					= imlib_free_image
+local __imlib_image_get_width					= imlib_image_get_width
+local __imlib_image_get_height					= imlib_image_get_height
+
+local set = function(obj, path)
+	local img = __imlib_load_image(path)
+	__imlib_context_set_image(img)
+
+	obj.img_width = __imlib_image_get_width()
+	obj.img_height = __imlib_image_get_height()
+	obj.path = path
+
+	__imlib_free_image()
+end
+
+local draw = function(obj)
+	local img = __imlib_load_image(obj.path)
+	__imlib_context_set_image(img)
+	__imlib_render_image_on_drawable_at_size(obj.x, obj.y, obj.width, obj.height)
+	__imlib_free_image()
+end
+
+M.set = set
+M.draw = draw
+
+return M

src/widget/line/bar.lua

@@ -0,0 +1,61 @@
+local M = {}
+
+local geom = require 'geom'
+local line = require 'line'
+local source = require 'source'
+local pure = require 'pure'
+local path = require 'path'
+local shape = require 'shape'
+local dynamic = require 'dynamic'
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.make_setter = function(_line, config, threshold_config)
+   local p1 = _line.p1
+   local p2 = _line.p2
+   local _p1, _p2 = line.get_wide_pattern_points(_line, config.style.thickness, config.is_wide_pattern)
+
+   local source_chooser = source.linear_pattern_chooser(
+      threshold_config.low_pattern,
+      threshold_config.high_pattern,
+      threshold_config.threshold,
+      _p1,
+      _p2
+   )
+   local f = pure.memoize(
+      function(percent)
+         local frac = percent / 100
+         local mp = geom.make_point(
+            (p2.x - p1.x) * frac + p1.x,
+            (p2.y - p1.y) * frac + p1.y
+         )
+         return shape.shape(
+            path.create_line(geom.CR_DUMMY, p1, mp),
+            source_chooser(percent)
+         )
+      end
+   )
+   return function(percent)
+      return f(pure.round_percent(percent))
+   end
+end
+
+M.make = function(p1, p2, bg_config, fg_threshold_config)
+   local setter = M.make_setter(geom.make_line(p1, p2), bg_config, fg_threshold_config)
+   return dynamic.single(line.make(p1, p2, bg_config), setter, 0)
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.set = function(obj, percent)
+   obj.var = obj.setter(percent)
+end
+
+M.draw = function(obj, cr)
+   line.draw(obj.static, cr)
+   shape.draw_shape(obj.var, cr)
+end
+
+return M

src/widget/line/compound_bar.lua

@@ -0,0 +1,67 @@
+local M = {}
+
+local geom = require 'geom'
+local bar = require 'bar'
+local dynamic = require 'dynamic'
+local line = require 'line'
+local style = require 'style'
+local pure = require 'pure'
+local impure = require 'impure'
+local shape = require 'shape'
+
+--------------------------------------------------------------------------------
+-- pure
+
+-- TODO make this handle vertical bars
+M.make = function(point, length, bg_config, fg_threshold_config, spacing,
+                   num_bars, is_vertical)
+   local lines = pure.map_n(
+      function(i)
+         local y = (i - 1) * spacing + point.y
+         local p1 = geom.make_point(point.x, y)
+         local p2 = geom.make_point(point.x + length, y)
+         return geom.make_line(p1, p2)
+      end,
+      num_bars
+   )
+
+   local setters = pure.map(
+      bar.make_setter,
+      lines,
+      bg_config,
+      fg_threshold_config
+   )
+
+   local bs = bg_config.style
+   local static = {
+      shapes = pure.map(
+         line.make_shape,
+         lines,
+         bg_config.pattern,
+         bs.thickness,
+         bg_config.is_wide_pattern
+      ),
+      style = bs,
+   }
+   return dynamic.compound(static, setters, 0)
+end
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.set = function(obj, i, percent)
+   obj.var[i] = obj.setters[i](percent)
+end
+
+M.draw_static = function(obj, cr)
+   local static = obj.static
+   style.set_line_style(static.style, cr)
+   impure.each(shape.draw_shape, static.shapes, cr)
+end
+
+M.draw_dynamic = function(obj, cr)
+   style.set_line_style(obj.static.style, cr)
+   impure.each(shape.draw_shape, obj.var, cr)
+end
+
+return M

src/widget/line/line.lua

@@ -0,0 +1,74 @@
+local M = {}
+
+local geom = require 'geom'
+local err = require 'err'
+local source = require 'source'
+local style = require 'style'
+local path = require 'path'
+local shape = require 'shape'
+
+local __math_atan2	= math.atan2
+local __math_sin	= math.sin
+local __math_cos	= math.cos
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.config = function(_style, pattern, is_wide_pattern)
+   return err.safe_table(
+      {
+         style = _style,
+         pattern = pattern,
+         is_wide_pattern = is_wide_pattern or false,
+      }
+   )
+end
+
+M.get_wide_pattern_points = function(line, thickness, is_wide)
+   local p1 = line.p1
+   local p2 = line.p2
+   if is_wide then
+      local theta = __math_atan2(p2.y - p1.y, p2.x - p1.x)
+      local delta_x = 0.5 * thickness * __math_sin(theta) --and yes, these are actually flipped
+      local delta_y = 0.5 * thickness * __math_cos(theta)
+      local _p1 = geom.make_point(p1.x + delta_x, p1.y + delta_y)
+      local _p2 = geom.make_point(p1.x - delta_x, p1.y - delta_y)
+      return _p1, _p2
+   else
+      return p1, p2
+   end
+end
+
+M.make_source = function(line, thickness, pattern, is_wide)
+   local p1, p2 = M.get_wide_pattern_points(line, thickness, is_wide)
+   return source.linear_pattern(pattern, p1, p2)
+end
+
+M.make_shape = function(line, pattern, thickness, is_wide)
+   return shape.shape(
+      path.create_line_from_geom(geom.CR_DUMMY, line),
+      M.make_source(line, thickness, pattern, is_wide)
+   )
+end
+
+M.make = function(line, config)
+   local _style = config.style
+   return shape.styled_shape(
+      _style,
+      M.make_shape,
+      line,
+      config.pattern,
+      _style.thickness,
+      config.is_wide_pattern
+   )
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.draw = function(obj, cr)
+   style.set_line_style(obj.style, cr)
+   shape.draw_shape(obj.shape, cr)
+end
+
+return M

src/widget/path.lua

@@ -0,0 +1,73 @@
+local M = {}
+
+local impure = require 'impure'
+
+local __cairo_new_path = cairo_new_path
+local __cairo_line_to = cairo_line_to
+local __cairo_copy_path	= cairo_copy_path
+local __cairo_close_path = cairo_close_path
+local __cairo_arc = cairo_arc
+local __cairo_rectangle = cairo_rectangle
+local __math_rad = math.rad
+
+local line_to = function(p, cr)
+   __cairo_line_to(cr, p.x, p.y)
+end
+
+local create_poly = function(cr, points)
+   __cairo_new_path(cr)
+   impure.each(line_to, points, cr)
+end
+
+local copy_path = function(cr)
+   local path = __cairo_copy_path(cr)
+   __cairo_new_path(cr) -- clear path to keep it from reappearing
+   return path
+end
+
+M.create_open_poly = function(cr, points)
+   create_poly(cr, points)
+   return copy_path(cr)
+end
+
+M.create_closed_poly = function(cr, points)
+   create_poly(cr, points)
+   __cairo_close_path(cr)
+   return copy_path(cr)
+end
+
+M.create_line = function(cr, p1, p2)
+   return M.create_open_poly(cr, {p1, p2})
+end
+
+M.create_line_from_geom = function(cr, line)
+   return M.create_line(cr, line.p1, line.p2)
+end
+
+M.create_arc = function(cr, x, y, radius, theta1, theta2)
+   __cairo_new_path(cr)
+   __cairo_arc(cr, x, y, radius, __math_rad(theta1), __math_rad(theta2))
+   return copy_path(cr)
+end
+
+M.create_arc_from_geom = function(cr, arc)
+   local c = arc.center
+   return M.create_arc(cr, c.x, c.y, arc.radius, arc.theta0, arc.theta1)
+end
+
+M.create_circle = function(cr, x, y, radius)
+   return M.create_arc(cr, x, y, radius, 0, 360)
+end
+
+M.create_circle_from_geom = function(cr, circle)
+   local c = circle.center
+   return M.create_circle(cr, c.x, c.y, circle.radius)
+end
+
+M.create_rect = function(cr, x, y, w, h)
+   __cairo_new_path(cr)
+   __cairo_rectangle(cr, x, y, w, h)
+   return copy_path(cr)
+end
+
+return M

src/widget/rect/fill_rect.lua

@@ -0,0 +1,34 @@
+local M = {}
+
+local geom = require 'geom'
+local source = require 'source'
+local path = require 'path'
+local style = require 'style'
+local shape = require 'shape'
+
+--------------------------------------------------------------------------------
+-- pure
+
+local make_shape = function(box, line_pattern, fill_pattern)
+   local p1 = box.corner
+   local p2 = geom.make_point(p1.x, p1.y + box.height)
+   return shape.filled_shape(
+      path.create_rect(geom.CR_DUMMY, p1.x, p1.y, box.width, box.height),
+      source.linear_pattern(line_pattern, p1, p2),
+      source.linear_pattern(fill_pattern, p1, p2)
+   )
+end
+
+M.make = function(box, config, fill_pattern)
+   return shape.styled_shape(config.style, make_shape, box, config.pattern, fill_pattern)
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.draw = function(obj, cr)
+   style.set_closed_poly_style(obj.style, cr)
+   shape.draw_filled_shape(obj.shape, cr)
+end
+
+return M

src/widget/rect/rect.lua

@@ -0,0 +1,40 @@
+local M = {}
+
+local geom = require 'geom'
+local err = require 'err'
+local source = require 'source'
+local style = require 'style'
+local path = require 'path'
+local shape = require 'shape'
+
+M.config = function(closed_poly_style, pattern)
+   return err.safe_table(
+      {
+         style = closed_poly_style,
+         pattern = pattern,
+      }
+   )
+end
+
+local make_shape = function(box, pattern)
+   local p = box.corner
+   return shape.shape(
+      path.create_rect(geom.CR_DUMMY, p.x, p.y, box.width, box.height),
+      source.linear_pattern(
+         pattern,
+         p,
+         geom.make_point(p.x, p.y + box.height)
+      )
+   )
+end
+
+M.make = function(box, config)
+   return shape.styled_shape(config.style, make_shape, box, config.pattern)
+end
+
+M.draw = function(obj, cr)
+   style.set_closed_poly_style(obj.style, cr)
+   shape.draw_shape(obj.shape, cr)
+end
+
+return M

src/widget/shape.lua

@@ -0,0 +1,70 @@
+local M = {}
+
+local impure = require 'impure'
+local err = require 'err'
+
+local __cairo_append_path = cairo_append_path
+local __cairo_fill_preserve = cairo_fill_preserve
+local __cairo_set_source = cairo_set_source
+local __cairo_stroke = cairo_stroke
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.shape = function(path, source)
+   return {path = path, source = source}
+end
+
+M.filled_shape = function(path, line_source, fill_source)
+   return {path = path, line_source = line_source, fill_source = fill_source}
+end
+
+M.shapes = function(paths, source)
+   return {paths = paths, source = source}
+end
+
+M.styled_shape = function(style, make_shape_fun, geom, ...)
+   return err.safe_table(
+      {
+         style = style,
+         shape = make_shape_fun(geom, ...),
+      }
+   )
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.draw_path_with_source = function(path, cr, source)
+   __cairo_append_path(cr, path)
+   __cairo_set_source(cr, source)
+   __cairo_stroke(cr)
+end
+
+M.draw_shape = function(shape, cr)
+   M.draw_path_with_source(shape.path, cr, shape.source)
+end
+
+M.draw_filled_shape = function(shape, cr)
+   __cairo_append_path(cr, shape.path)
+   __cairo_set_source(cr, shape.fill_source)
+   __cairo_fill_preserve(cr)
+   __cairo_set_source(cr, shape.line_source)
+   __cairo_stroke(cr)
+end
+
+local append_path = function(p, cr)
+   __cairo_append_path(cr, p)
+end
+
+M.draw_paths_with_source = function(paths, cr, source)
+   impure.each(append_path, paths, cr)
+   __cairo_set_source(cr, source)
+   __cairo_stroke(cr)
+end
+
+M.draw_shapes = function(shapes, cr)
+   M.draw_paths_with_source(shapes.paths, cr, shapes.source)
+end
+
+return M

src/widget/source.lua

@@ -0,0 +1,117 @@
+local M = {}
+
+local err		= require 'err'
+
+local __cairo_pattern_create_rgba = cairo_pattern_create_rgba
+local __cairo_pattern_create_radial	= cairo_pattern_create_radial
+local __cairo_pattern_create_linear	= cairo_pattern_create_linear
+local __cairo_pattern_add_color_stop_rgba = cairo_pattern_add_color_stop_rgba
+
+M.threshold_config = function(low_pattern, high_pattern, threshold)
+   return err.safe_table(
+      {
+         low_pattern = low_pattern,
+         high_pattern = high_pattern,
+         threshold = threshold,
+      }
+   )
+end
+
+local set_color_stops = function(pattern, colorstops)
+   for stop, color in pairs(colorstops) do
+      __cairo_pattern_add_color_stop_rgba(
+         pattern,
+         stop,
+         color.r,
+         color.g,
+         color.b,
+         color.a
+      )
+   end
+end
+
+local _solid_color = function(color)
+   return __cairo_pattern_create_rgba(color.r, color.g, color.b, color.a)
+end
+
+local _linear_gradient = function(gradient, p1, p2)
+   local pattern = __cairo_pattern_create_linear(p1.x, p1.y, p2.x, p2.y)
+   set_color_stops(pattern, gradient)
+   return pattern
+end
+
+local _radial_gradient = function(gradient, p, r1, r2)
+   local pattern = __cairo_pattern_create_radial(p.x, p.y, r1, p.x, p.y, r2)
+   set_color_stops(pattern, gradient)
+   return pattern
+end
+
+local _is_gradient = function(spec)
+   return err.get_type(spec) == "gradient"
+end
+
+local _create_critical_function = function(limit)
+   if limit then
+      return function(n) return (n > limit) end
+   else
+      return function(_) return nil end
+   end
+end
+
+M.solid_color = function(spec)
+   err.check_type(spec, "color")
+   return _solid_color(spec)
+end
+
+M.linear_pattern = function(spec, p1, p2)
+   if _is_gradient(spec) then
+      return _linear_gradient(spec, p1, p2)
+   else
+      return _solid_color(spec)
+   end
+end
+
+M.radial_pattern = function(spec, p, r1, r2)
+   if _is_gradient(spec) then
+      return _radial_gradient(spec, p, r1, r2)
+   else
+      return _solid_color(spec)
+   end
+end
+
+local source_chooser = function(low_source, high_source, limit)
+   local f = _create_critical_function(limit)
+   return function(value)
+      if f(value) then
+         return high_source
+      else
+         return low_source
+      end
+   end
+end
+
+M.solid_color_chooser = function(low_color, high_color, limit)
+   return source_chooser(
+      M.solid_color(low_color),
+      M.solid_color(high_color),
+      limit
+   )
+end
+
+M.linear_pattern_chooser = function(low_pattern, high_pattern, limit, p1, p2)
+   return source_chooser(
+      M.linear_pattern(low_pattern, p1, p2),
+      M.linear_pattern(high_pattern, p1, p2),
+      limit
+   )
+end
+
+M.radial_pattern_chooser = function(low_pattern, high_pattern, limit, p, r1, r2)
+   return source_chooser(
+      M.radial_pattern(low_pattern, p, r1, r2),
+      M.radial_pattern(high_pattern, p, r1, r2),
+      limit
+   )
+end
+
+return M

src/widget/style.lua

@@ -0,0 +1,55 @@
+local M = {}
+
+local err = require 'err'
+
+local __cairo_set_line_width = cairo_set_line_width
+local __cairo_set_line_cap = cairo_set_line_cap
+local __cairo_set_line_join = cairo_set_line_join
+
+--------------------------------------------------------------------------------
+-- pure
+
+-- circle: a closed path with no corners
+M.circle = function(thickness)
+   return err.safe_table({thickness = thickness})
+end
+
+-- line: an open path with no corners
+M.line = function(thickness, cap)
+   return err.safe_table({thickness = thickness, cap = cap})
+end
+
+-- open poly: an open path with corners
+M.open_poly = function(thickness, cap, join)
+   return err.safe_table({thickness = thickness, cap = cap, join = join})
+end
+
+-- closed poly: an closed path with corners
+M.closed_poly = function(thickness, join)
+   return err.safe_table({thickness = thickness, join = join})
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.set_circle_style = function(style, cr)
+   __cairo_set_line_width(cr, style.thickness)
+end
+
+M.set_line_style = function(style, cr)
+   __cairo_set_line_width(cr, style.thickness)
+   __cairo_set_line_cap(cr, style.cap)
+end
+
+M.set_open_poly_style = function(style, cr)
+   __cairo_set_line_width(cr, style.thickness)
+   __cairo_set_line_cap(cr, style.cap)
+   __cairo_set_line_join(cr, style.join)
+end
+
+M.set_closed_poly_style = function(style, cr)
+   __cairo_set_line_width(cr, style.thickness)
+   __cairo_set_line_join(cr, style.join)
+end
+
+return M

src/widget/text/text.lua

@@ -0,0 +1,58 @@
+local M = {}
+
+local err = require 'err'
+local dynamic = require 'dynamic'
+local ti = require 'text_internal'
+local source = require 'source'
+local pure = require 'pure'
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.config = function(font_spec, color, x_align, y_align)
+   return err.safe_table(
+      {
+         font_spec = font_spec,
+         color = color,
+         x_align = x_align,
+         y_align = y_align,
+      }
+   )
+end
+
+local _make = function(point, chars, config, format)
+   local font = ti.make_font(config.font_spec)
+   local get_delta_x = ti.x_align_function(config.x_align, font)
+   local format_chars = ti.make_format_function(format)
+   local make_vtext = pure.partial(ti.make_vtext, point.x, get_delta_x)
+   local setter = pure.memoize(pure.compose(make_vtext, format_chars))
+   local static = {
+      y = point.y + ti.get_delta_y(config.y_align, font),
+      font = font,
+      source = source.solid_color(config.color),
+   }
+   return dynamic.single(static, setter, chars)
+end
+
+M.make_formatted = function(point, text, config, format)
+   return _make(point, (text or ti.NULL_TEXT_STRING), config, format)
+end
+
+M.make_plain = function(point, text, config)
+   return M.make_formatted(point, text, config, nil)
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.set = function(obj, text)
+   obj.var = obj.setter(text)
+end
+
+M.draw = function(obj, cr)
+   local st = obj.static
+   ti.set_font_spec(cr, st.font, st.source)
+   ti.draw_vtext_at_y(obj.var, st.y, cr)
+end
+
+return M

src/widget/text/text_column.lua

@@ -0,0 +1,49 @@
+local M = {}
+
+local source = require 'source'
+local ti = require 'text_internal'
+local pure = require 'pure'
+local impure = require 'impure'
+local dynamic = require 'dynamic'
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.make = function(point, texts, config, format, spacing)
+   local font = ti.make_font(config.font_spec)
+   local get_delta_x = ti.x_align_function(config.x_align, font)
+   local format_chars = ti.make_format_function(format)
+   local delta_y = ti.get_delta_y(config.y_align, font)
+   local ys = pure.map_n(
+      function(i) return point.y + spacing * (i - 1) + delta_y end,
+      #texts
+   )
+   local make_vtext = pure.partial(ti.make_vtext, point.x, get_delta_x)
+   local setter = pure.memoize(pure.compose(make_vtext, format_chars))
+   local static = {
+      y_positions = ys,
+      font = font,
+      source = source.solid_color(config.color),
+   }
+   return dynamic.multi(static, setter, texts)
+end
+
+M.make_n = function(point, num_rows, config, format, spacing, init_text)
+   local dummy = pure.rep(num_rows, init_text or ti.NULL_TEXT_STRING)
+   return M.make(point, dummy, config, format, spacing)
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.set = function(obj, row_num, text)
+   obj.var[row_num] = obj.setter(text)
+end
+
+M.draw = function(obj, cr)
+   local static = obj.static
+   ti.set_font_spec(cr, static.font, static.source)
+   impure.each2(ti.draw_vtext_at_y, obj.var, static.y_positions, cr)
+end
+
+return M

src/widget/text/text_internal.lua

@@ -0,0 +1,165 @@
+local M = {}
+
+local err = require 'err'
+local geom = require 'geom'
+
+local __string_sub = string.sub
+local __cairo_toy_font_face_create = cairo_toy_font_face_create
+local __cairo_font_extents = cairo_font_extents
+local __cairo_set_font_face = cairo_set_font_face
+local __cairo_set_font_size = cairo_set_font_size
+local __cairo_text_extents = cairo_text_extents
+local __cairo_set_source = cairo_set_source
+local __cairo_move_to = cairo_move_to
+local __cairo_show_text = cairo_show_text
+
+M.NULL_TEXT_STRING = '<null>'
+
+--------------------------------------------------------------------------------
+-- pure
+
+local trim_to_length = function(text, len)
+   if #text > len then
+      return __string_sub(text, 1, len)..'...'
+   else
+      return text
+   end
+end
+
+M.make_format_function = function(format)
+   if type(format) == "function" then
+      return format
+   elseif type(format) == "number" and format > 0 then
+      return function(_text) return trim_to_length(_text, format) end
+   elseif type(format) == "string" then
+      return function(_text) return string.format(format, _text) end
+   elseif format == nil or format == false then
+      return function(_text) return _text end
+   else
+      local msg = "format must be a printf string, positive int, or function: got "
+      local t = type(format)
+      if t == "number" or t == "string" then
+         msg = msg..format
+      else
+         msg = msg.."a "..t
+      end
+      err.assert_trace(nil, msg)
+   end
+end
+
+M.make_font_face = function(font_spec)
+   return __cairo_toy_font_face_create(
+      font_spec.family,
+      font_spec.slant,
+      font_spec.weight
+   )
+end
+
+M.make_font = function(font_spec)
+   return {
+      face = M.make_font_face(font_spec),
+      size = font_spec.size,
+   }
+end
+
+M.make_text = function(x, y, chars)
+   return err.safe_table({x = x, y = y, chars = chars})
+end
+
+M.make_htext = function(y, delta_x, chars)
+   return err.safe_table({y = y, delta_x = delta_x, chars = chars})
+end
+
+M.make_vtext = function(x, delta_x_fun, chars)
+   return err.safe_table({x = x + delta_x_fun(chars), chars = chars})
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+local dummy_text_extents = cairo_text_extents_t:create()
+tolua.takeownership(dummy_text_extents)
+
+local dummy_font_extents = cairo_font_extents_t:create()
+tolua.takeownership(dummy_font_extents)
+
+local set_font_extents = function(font)
+   __cairo_set_font_size(geom.CR_DUMMY, font.size)
+   __cairo_set_font_face(geom.CR_DUMMY, font.face)
+   __cairo_font_extents(geom.CR_DUMMY, dummy_font_extents)
+   return dummy_font_extents
+end
+
+local set_text_extents = function(chars, font)
+   __cairo_set_font_size(geom.CR_DUMMY, font.size)
+   __cairo_set_font_face(geom.CR_DUMMY, font.face)
+   __cairo_text_extents(geom.CR_DUMMY, chars, dummy_text_extents)
+   return dummy_text_extents
+end
+
+M.get_width = function(chars, font)
+   return set_text_extents(chars, font).width
+end
+
+M.font_height = function(font)
+   return set_font_extents(font).height
+end
+
+M.x_align_function = function(x_align, font)
+   if x_align == 'left' then
+      return function(text)
+         local te = set_text_extents(text, font)
+         return -te.x_bearing
+      end
+   elseif x_align == 'center' then
+      return function(text)
+         local te = set_text_extents(text, font)
+         return -(te.x_bearing + te.width * 0.5)
+      end
+   elseif x_align == 'right' then
+      return function(text)
+         local te = set_text_extents(text, font)
+         return -(te.x_bearing + te.width)
+      end
+   else
+      err.assert_trace(nil, "invalid x_align")
+   end
+end
+
+M.get_delta_y = function(y_align, font)
+   local fe = set_font_extents(font)
+   if y_align == 'bottom' then
+      return -fe.descent
+   elseif y_align == 'top'	then
+      return fe.height
+   elseif y_align == 'center' then
+      return 0.92 * fe.height * 0.5 - fe.descent
+   else
+      err.assert_trace(nil, "invalid y_align")
+   end
+end
+
+M.set_font_spec = function(cr, font, source)
+   __cairo_set_font_face(cr, font.face)
+   __cairo_set_font_size(cr, font.size)
+   __cairo_set_source(cr, source)
+end
+
+local draw_text_at = function(cr, x, y, chars)
+   __cairo_move_to(cr, x, y)
+   __cairo_show_text(cr, chars)
+end
+
+M.draw_text = function(obj, cr)
+   draw_text_at(cr, obj.x, obj.y, obj.chars)
+end
+
+M.draw_htext_at_x = function(obj, x, cr)
+   draw_text_at(cr, obj.delta_x + x, obj.y, obj.chars)
+end
+
+M.draw_vtext_at_y = function(obj, y, cr)
+   draw_text_at(cr, obj.x, y, obj.chars)
+end
+
+return M

src/widget/text/text_table.lua

@@ -0,0 +1,183 @@
+local M = {}
+
+local source = require 'source'
+local rect = require 'rect'
+local err = require 'err'
+local ti = require 'text_internal'
+local geom = require 'geom'
+local pure = require 'pure'
+local impure = require 'impure'
+local style = require 'style'
+local path = require 'path'
+local shape = require 'shape'
+
+--------------------------------------------------------------------------------
+-- pure
+
+M.config = function(border_config, sep_config, header_config, body_config, padding)
+   return err.safe_table(
+      {
+         border_config = border_config,
+         sep_config = sep_config,
+         header_config = header_config,
+         body_config = body_config,
+         padding = padding,
+      }
+   )
+end
+
+M.body_config = function(font_spec, color, columns)
+   return err.safe_table(
+      {
+         font_spec = font_spec,
+         color = color,
+         columns = columns,
+      }
+   )
+end
+
+M.column_config = function(header, format)
+   return err.safe_table({header = header, format = format})
+end
+
+M.header_config = function(font_spec, color, bottom_padding)
+   return err.safe_table(
+      {
+         font_spec = font_spec,
+         color = color,
+         bottom_padding = bottom_padding,
+      }
+   )
+end
+
+M.padding = function(l, t, r, b)
+   return err.safe_table(
+      {
+         left = l,
+         right = r,
+         top = t,
+         bottom = b,
+      }
+   )
+end
+
+-- TODO this is basically the same as that from ylabels
+local make_header_text = function(x, y, chars, font)
+   return ti.make_text(
+      x + ti.x_align_function('center', font)(chars),
+      y + ti.get_delta_y('center', font),
+      chars
+   )
+end
+
+-- M.make = function(box, num_rows, columns, table_config)
+M.make = function(box, num_rows, table_config)
+   local bc = table_config.body_config
+   local hs = table_config.header_config
+   local columns = bc.columns
+   local header_font = ti.make_font(hs.font_spec)
+   local body_font = ti.make_font(bc.font_spec)
+   local p = table_config.padding
+   local tbl_width = box.width - p.left - p.right
+   local tbl_height = box.height - p.top - p.bottom
+   local tbl_x = box.corner.x + p.left
+   local tbl_y = box.corner.y + p.top
+   local body_delta_y = ti.get_delta_y('center', body_font)
+   local body_y = tbl_y + hs.bottom_padding + body_delta_y
+   local column_width = tbl_width / #columns
+   local spacing = (tbl_height - hs.bottom_padding) / (num_rows - 1)
+   local headers = pure.imap(
+      function (i, conf)
+         local x = tbl_x + column_width * (i - 0.5)
+         return make_header_text(x, tbl_y, conf.header, header_font)
+      end,
+      columns
+   )
+   local sep_paths = pure.map_n(
+      function(i)
+         local x = tbl_x + column_width * i
+         return path.create_line(
+            geom.CR_DUMMY,
+            geom.make_point(x, tbl_y),
+            geom.make_point(x, tbl_y + tbl_height)
+         )
+      end,
+      #columns - 1
+   )
+
+   local get_delta_x = ti.x_align_function('center', body_font)
+   local make_setter = function(i, conf)
+      local column_x = tbl_x + column_width * (i - 0.5)
+      return pure.memoize(
+         pure.compose(
+            pure.partial(ti.make_vtext, column_x, get_delta_x),
+            ti.make_format_function(conf.format)
+         )
+      )
+   end
+   local setters = pure.imap(make_setter, columns)
+
+   return {
+      static = {
+         header = {
+            font = header_font,
+            source = source.solid_color(hs.color),
+            texts = headers,
+         },
+         body = {
+            font = body_font,
+            source = source.solid_color(bc.color),
+            y_positions = pure.map_n(
+               function(i) return body_y + spacing * (i - 1) end,
+               num_rows
+            ),
+         },
+         separators = {
+            style = table_config.sep_config.style,
+            shapes = {
+               source = source.solid_color(table_config.sep_config.pattern),
+               paths = sep_paths,
+            },
+         },
+         border = rect.make(box, table_config.border_config),
+      },
+      setters = setters,
+      var = pure.map_n(
+         function(c) return pure.rep(num_rows, setters[c]("NULL")) end,
+         #columns
+      )
+   }
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.set = function(obj, col_num, row_num, text)
+   obj.var[col_num][row_num] = obj.setters[col_num](text)
+end
+
+M.draw_static = function(obj, cr)
+   local static = obj.static
+   local seps = static.separators
+   local header = static.header
+
+   rect.draw(static.border, cr)
+
+   style.set_line_style(seps.style, cr)
+   shape.draw_shapes(seps.shapes, cr)
+
+   ti.set_font_spec(cr, header.font, header.source)
+   impure.each(ti.draw_text, header.texts, cr)
+end
+
+local draw_column = function(rows, ys, cr)
+   impure.each2(ti.draw_vtext_at_y, rows, ys, cr)
+end
+
+M.draw_dynamic = function(obj, cr)
+   local body = obj.static.body
+   ti.set_font_spec(cr, body.font, body.source)
+   impure.each(draw_column, obj.var, body.y_positions, cr)
+end
+
+return M

src/widget/text/text_threshold.lua

@@ -0,0 +1,79 @@
+local M = {}
+
+local err = require 'err'
+local pure = require 'pure'
+local source = require 'source'
+local ti = require 'text_internal'
+local dynamic = require 'dynamic'
+
+local __tonumber = tonumber
+
+--------------------------------------------------------------------------------
+-- pure
+
+local _make = function(point, chars, config, threshold_config, format)
+   local font = ti.make_font(config.font_spec)
+   local get_delta_x = ti.x_align_function(config.x_align, font)
+   local make_vtext = pure.partial(ti.make_vtext, point.x, get_delta_x)
+   local format_chars = ti.make_format_function(format)
+   local source_chooser = source.solid_color_chooser(
+      config.color,
+      threshold_config.high_color,
+      threshold_config.threshold
+   )
+   local _setter = pure.memoize(
+      function(cs)
+         local _cs = cs or 0
+         return {
+            text = make_vtext(format_chars(_cs)),
+            source = source_chooser(_cs),
+         }
+      end
+   )
+   local f = threshold_config.pre_function
+   local setter
+   if f then
+      setter = function(x) return _setter(f(x)) end
+   else
+      setter = _setter
+   end
+   local static = {
+      y = point.y + ti.get_delta_y(config.y_align, font),
+      font = font,
+   }
+   return dynamic.single(static, setter, chars or 0)
+end
+
+M.config = function(high_color, threshold, pre_function)
+   return err.safe_table(
+      {
+         high_color = high_color,
+         threshold = threshold,
+         pre_function = pre_function,
+      }
+   )
+end
+
+M.make_formatted = function(point, text, config, format, threshold_config)
+   return _make(point, text, config, threshold_config, format)
+end
+
+M.make_plain = function(point, text, config, threshold_config)
+   return M.make_formatted(point, text, config, threshold_config, nil)
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.set = function(obj, x)
+   obj.var = obj.setter(x)
+end
+
+M.draw = function(obj, cr)
+   local st = obj.static
+   local var = obj.var
+   ti.set_font_spec(cr, st.font, var.source)
+   ti.draw_vtext_at_y(var.text, st.y, cr)
+end
+
+return M

src/widget/timeseries/scaled_timeseries.lua

@@ -0,0 +1,269 @@
+local M = {}
+
+local timeseries = require 'timeseries'
+local tsi = require 'timeseries_internal'
+local ti = require 'text_internal'
+local err = require 'err'
+local ylabels = require 'ylabels'
+local xlabels = require 'xlabels'
+local geom = require 'geom'
+local source = require 'source'
+local pure = require 'pure'
+local impure = require 'impure'
+
+local __table_remove = table.remove
+local __math_ceil = math.ceil
+local __math_log = math.log
+
+--------------------------------------------------------------------------------
+-- pure
+
+local choose_scale_factor = function(timers, new_sf)
+   if #timers == 0 then
+      return new_sf
+   else
+      local cur_sf = timers[1].factor
+      if new_sf < cur_sf then
+         return new_sf
+      else
+         return cur_sf
+      end
+   end
+end
+
+M.scaling_parameters = function(base, min_domain, threshold)
+   return err.safe_table(
+      {
+         base = base,
+         min_domain = min_domain,
+         threshold = threshold,
+      }
+   )
+end
+
+local tick_timer = function(timer)
+   timer.remaining = timer.remaining - 1
+end
+
+-- ASSUME
+-- 1. this is a FIFO queue
+-- 2. timers will be sorted from highest scale to lowest scale going from
+--    back to front
+-- 3. no timers will share a time slot
+-- 4. no timers will have the same scale factor
+-- 5. the table will always be a sequence
+-- NOTE: scale factor is inversely related to scale, so higher scale -> lower
+-- factor (hence the inequalities)
+local update_timers = function(timers, prev_sf, new_sf, init_timer)
+   if timers[1] and timers[1].remaining == 0 then
+      __table_remove(timers, 1)
+   end
+
+   impure.each(tick_timer, timers)
+   local n = #timers
+
+   if new_sf < prev_sf then
+      while n > 0 and timers[n].factor >= new_sf do
+         timers[n] = nil
+         n = n - 1
+      end
+   elseif new_sf > prev_sf and (n == 0 or prev_sf > timers[1].factor) then
+      timers[n + 1] = init_timer(prev_sf)
+   end
+   return timers
+end
+
+local scale_point = function(value, y, h, new_factor, old_factor)
+   return y + h * (1 - (1 - (value - y) / h) * (new_factor / old_factor))
+end
+
+-- local debug_timers = function(timers, sf, value)
+--    print('----------------------------------------------------------------------')
+--    print('value', value, 'scale_factor', sf)
+--    for i, v in pairs(timers) do
+--       print('timers', 'i', i, 't', v.remaining, 'f', v.factor)
+--    end
+--    print('length', #timers)
+-- end
+
+M.make = function(box, samplefreq, plot_config, label_config, scaling_params)
+   local t = scaling_params.threshold
+   local m = scaling_params.min_domain
+   local b = scaling_params.base
+
+   local get_scale_factor = function(x)
+      local domain = m
+      if x > 0 then
+         domain = __math_ceil(__math_log(x / t) / __math_log(b))
+      end
+      if domain < m then domain = m end
+      return b ^ -domain
+   end
+
+   local x = box.corner.x
+   local gconf = plot_config.grid_config
+   local x_label_format = timeseries.make_format_timecourse_x_label(plot_config.num_points, samplefreq)
+   local label_font = ti.make_font(label_config.font_spec)
+   local x_label_data = xlabels.make(box.bottom_y, gconf.num_x + 1, x_label_format, label_font)
+   local axis_x = box.corner.x
+   local right_x = axis_x + box.width
+   local plot_y = box.corner.y
+   local total_width = box.width
+   local n_y_labels = gconf.num_y + 1
+
+   local plot_height = box.height - xlabels.get_x_axis_height(label_font)
+
+   local make_y_labels = pure.memoize(
+      function(scale_factor)
+         return ylabels.make(
+            box.corner,
+            plot_height,
+            n_y_labels,
+            label_font,
+            label_config.y_format,
+            scale_factor
+         )
+      end
+   )
+
+   local make_grid_paths = pure.memoize(
+      function(y_axis_width)
+         return tsi.make_plotarea_paths(
+            geom.CR_DUMMY,
+            right_x,
+            plot_y,
+            total_width - y_axis_width,
+            plot_height,
+            gconf.num_x,
+            gconf.num_y
+         )
+      end
+   )
+
+   local get_x_label_positions = pure.memoize(
+      function(y_axis_width)
+         local w = total_width - y_axis_width
+         return xlabels.get_x_label_positions(right_x, w, x_label_data)
+      end
+   )
+
+   local init_timer = function(scale_factor)
+      return {
+         factor = scale_factor,
+         remaining = plot_config.num_points
+      }
+   end
+
+   local scale_data_points = function(series, old_factor, new_factor)
+      if old_factor == new_factor then
+         return series
+      else
+         return pure.map(scale_point, series, plot_y, plot_height, new_factor, old_factor)
+      end
+   end
+
+   local insert_data_point = function(series, value, scale_factor)
+      return tsi.insert_data_point(plot_y, plot_height, plot_config.num_points, series, value * scale_factor)
+   end
+
+   local inner_setter = function(value, series, cur_sf, prev_sf, timers)
+      local new_sf = get_scale_factor(value)
+      local new_timers = update_timers(timers, prev_sf, new_sf, init_timer)
+      local new_cur_sf = choose_scale_factor(new_timers, new_sf)
+      local y_labels = make_y_labels(1 / new_cur_sf)
+      local width = total_width - y_labels.width
+      -- debug_timers(new_timers, new_sf, value)
+      return {
+         axis = {
+            x = {
+               positions = get_x_label_positions(y_labels.width),
+            },
+            y = {
+               labels = y_labels,
+            }
+         },
+         current_scale_factor = new_cur_sf,
+         prev_scale_factor = new_sf,
+         plotarea = {
+            dx = width / plot_config.num_points,
+            paths = make_grid_paths(y_labels.width)
+         },
+         timers = new_timers,
+         series = insert_data_point(
+            scale_data_points(series, cur_sf, new_cur_sf),
+            value,
+            new_cur_sf
+         )
+      }
+   end
+
+   local setter = function(value, var)
+      return inner_setter(
+         value,
+         var.series,
+         var.current_scale_factor,
+         var.prev_scale_factor,
+         var.timers
+      )
+   end
+
+   return err.safe_table(
+      {
+         static = {
+            box = box,
+            axis = {
+               font = label_font,
+               source = source.solid_color(label_config.color),
+               x = {
+                  label_data = x_label_data,
+               }
+            },
+            plotarea = {
+               bottom_y = plot_height + plot_y,
+               sources = tsi.make_sources(x, plot_y, total_width, plot_config),
+            },
+         },
+         setter = setter,
+         var = inner_setter(0, {}, 1, 1, {}),
+      }
+   )
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.update = function(obj, value)
+   obj.var = obj.setter(value, obj.var)
+end
+
+-- nothing here is "static" because we cannot assume that
+-- any object will remain the same shape (can shift in both x and y)
+M.draw_static = function(_, _)
+   -- stub
+end
+
+M.draw_dynamic = function(obj, cr)
+   local var = obj.var
+   local static = obj.static
+   local box = static.box
+   local saxis = static.axis
+   local vaxis = var.axis
+   local vplotarea = var.plotarea
+   local splotarea = static.plotarea
+   local sources = splotarea.sources
+   local paths = vplotarea.paths
+   local right_x = box.right_x
+   timeseries.draw_labels(
+      cr,
+      saxis.font,
+      saxis.source,
+      vaxis.x.positions,
+      saxis.x.label_data,
+      vaxis.y.labels
+   )
+   tsi.draw_grid(cr, paths.grid, sources.grid)
+   tsi.draw_series(cr, right_x, splotarea.bottom_y, vplotarea.dx, var.series, sources.series)
+   tsi.draw_outline(cr, paths.outline, sources.outline)
+end
+
+return M

src/widget/timeseries/timeseries.lua

@@ -0,0 +1,163 @@
+local M = {}
+
+local err = require 'err'
+local xlabels = require 'xlabels'
+local ylabels = require 'ylabels'
+local source = require 'source'
+local ti = require 'text_internal'
+local tsi = require 'timeseries_internal'
+local geom = require 'geom'
+local impure = require 'impure'
+
+local __string_format = string.format
+
+--------------------------------------------------------------------------------
+-- pure
+
+-- TODO group these better
+M.config = function(num_points, outline_color, data_line_pattern,
+                   data_fill_pattern, grid_config)
+   return err.safe_table(
+      {
+         num_points = num_points,
+         outline_color = outline_color,
+         data_line_pattern = data_line_pattern,
+         data_fill_pattern = data_fill_pattern,
+         grid_config = grid_config,
+      }
+   )
+end
+
+M.grid_config = function(num_x, num_y, color)
+   return err.safe_table(
+      {
+         num_x = num_x,
+         num_y = num_y,
+         pattern = color,
+      }
+   )
+end
+
+M.label_config = function(color, font_spec, y_format)
+   return err.safe_table(
+      {
+         color = color,
+         font_spec = font_spec,
+         y_format = y_format
+      }
+   )
+end
+
+M.make_format_timecourse_x_label = function(n, freq)
+   return function(x) return __string_format('%.0fs', (1 - x) * n / freq) end
+end
+
+M.make = function(box, samplefreq, config, label_config)
+   local x = box.corner.x
+   local y = box.corner.y
+   local w = box.width
+   local h = box.height
+   local right_x = x + w
+   local bottom_y = y + h
+   local gconf = config.grid_config
+   local label_font = ti.make_font(label_config.font_spec)
+
+   local plot_height = box.height - xlabels.get_x_axis_height(label_font)
+   local y_labels = ylabels.make(
+      box.corner,
+      plot_height,
+      gconf.num_y + 1,
+      label_font,
+      label_config.y_format,
+      1
+   )
+
+   local plot_width = w - y_labels.width
+
+   local x_label_format = M.make_format_timecourse_x_label(config.num_points, samplefreq)
+
+   local x_labels = xlabels.make(bottom_y, gconf.num_x + 1, x_label_format, label_font)
+
+   local setter = function(value, series)
+      return tsi.insert_data_point(y, plot_height, config.num_points, series, value)
+   end
+
+   return err.safe_table(
+      {
+         static = {
+            box = box,
+            axis = {
+               font = label_font,
+               source = source.solid_color(label_config.color),
+               x = {
+                  label_data = x_labels,
+                  positions = xlabels.get_x_label_positions(right_x, plot_width, x_labels),
+               },
+               y = {
+                  labels = y_labels,
+               }
+            },
+            plotarea = {
+               dx = plot_width / config.num_points,
+               bottom_y = y + plot_height,
+               paths = tsi.make_plotarea_paths(
+                  geom.CR_DUMMY,
+                  right_x,
+                  y,
+                  plot_width,
+                  plot_height,
+                  gconf.num_x,
+                  gconf.num_y
+               ),
+               sources = tsi.make_sources(x, y, w, config),
+            },
+         },
+         setter = setter,
+         var = setter(0, {}),
+      }
+   )
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.update = function(obj, value)
+   obj.var = obj.setter(value, obj.var)
+end
+
+M.draw_labels = function(cr, font, _source, x_positions, x_label_data, y_labels)
+   ti.set_font_spec(cr, font, _source)
+   impure.each2(ti.draw_htext_at_x, x_label_data, x_positions, cr)
+   impure.each(ti.draw_text, y_labels, cr)
+end
+
+
+M.draw_static = function(obj, cr)
+   local static = obj.static
+   local axis = static.axis
+   local ax = axis.x
+   local plotarea = static.plotarea
+   local paths = plotarea.paths
+   local sources = plotarea.sources
+   M.draw_labels(
+      cr,
+      axis.font,
+      axis.source,
+      ax.positions,
+      ax.label_data,
+      axis.y.labels
+   )
+   tsi.draw_grid(cr, paths.grid, sources.grid)
+end
+
+M.draw_dynamic = function(obj, cr)
+   local static = obj.static
+   local box = static.box
+   local plotarea = static.plotarea
+   local right_x = box.right_x
+   local sources = plotarea.sources
+   tsi.draw_series(cr, right_x, plotarea.bottom_y, plotarea.dx, obj.var, sources.series)
+   tsi.draw_outline(cr, plotarea.paths.outline, sources.outline)
+end
+
+return M

src/widget/timeseries/timeseries_internal.lua

@@ -0,0 +1,132 @@
+local M = {}
+
+local source = require 'source'
+local geom = require 'geom'
+local pure = require 'pure'
+local style = require 'style'
+local path = require 'path'
+local shape = require 'shape'
+
+local __cairo_move_to = cairo_move_to
+local __cairo_line_to = cairo_line_to
+local __cairo_set_source = cairo_set_source
+local __cairo_fill_preserve = cairo_fill_preserve
+local __cairo_stroke = cairo_stroke
+local __table_insert = table.insert
+
+local DATA_STYLE = style.open_poly(1, CAIRO_LINE_CAP_BUTT, CAIRO_LINE_JOIN_MITER)
+local GRID_CONFIG = style.line(1, CAIRO_LINE_CAP_BUTT)
+local OUTLINE_STYLE = style.open_poly(2, CAIRO_LINE_CAP_BUTT, CAIRO_LINE_JOIN_MITER)
+
+--------------------------------------------------------------------------------
+-- pure
+
+local make_x_grid = function(cr, x, y, w, h, n)
+   local y1 = y - 0.5
+   local y2 = y1 + h + 0.5
+   local grid_line_spacing = w / n
+   local f = function(i)
+      local x1 = x - w + grid_line_spacing * i - 0.5
+      local p1 = geom.make_point(x1, y1)
+      local p2 = geom.make_point(x1, y2)
+      return path.create_line(cr, p1, p2)
+   end
+   return pure.map_n(f, n)
+end
+
+local make_y_grid = function(cr, x, y, w, h, n)
+   local x1 = x
+   local x2 = x - w
+   local grid_line_spacing = h / n
+   local f = function(i)
+      local y1 = y + (i - 1) * grid_line_spacing - 0.5
+      local p1 = geom.make_point(x1, y1)
+      local p2 = geom.make_point(x2, y1)
+      return path.create_line(cr, p1, p2)
+   end
+   return pure.map_n(f, n)
+end
+
+local make_grid_paths = function(cr, x, y, w, h, nx, ny)
+   return {
+      x = make_x_grid(cr, x, y, w, h, nx),
+      y = make_y_grid(cr, x, y, w, h, ny),
+   }
+end
+
+local make_outline = function(cr, right_x, y, w, h)
+	local x1 = right_x - w
+	local y1 = y - 0.5
+	local x2 = right_x + 0.5
+	local y2 = y + h + 1.0
+	local p1 = geom.make_point(x1, y1)
+	local p2 = geom.make_point(x1, y2)
+	local p3 = geom.make_point(x2, y2)
+	return path.create_open_poly(cr, {p1, p2, p3})
+end
+
+M.make_plotarea_paths = function(cr, right_x, y, w, h, num_x, num_y)
+   return {
+      grid = make_grid_paths(cr, right_x, y, w, h, num_x, num_y),
+      outline = make_outline(cr, right_x, y, w, h),
+   }
+end
+
+M.make_sources = function(x, y, width, config)
+   local p1 = geom.make_point(x, y)
+   local p2 = geom.make_point(x + width, y)
+   return {
+      grid = source.solid_color(config.grid_config.pattern),
+      outline = source.solid_color(config.outline_color),
+      series = {
+         line = source.linear_pattern(config.data_line_pattern, p1, p2),
+         fill = source.linear_pattern(config.data_fill_pattern, p1, p2),
+      }
+   }
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.insert_data_point = function(y, h, n, series, value)
+   __table_insert(series, 1, y + h * (1 - value))
+   if #series == n + 2 then
+      series[#series] = nil
+   end
+   return series
+end
+
+M.draw_grid = function(cr, grid, _source)
+   style.set_line_style(GRID_CONFIG, cr)
+   -- TODO this sets the same source twice and strokes twice
+   shape.draw_paths_with_source(grid.x, cr, _source)
+   shape.draw_paths_with_source(grid.y, cr, _source)
+end
+
+M.draw_outline = function(cr, _path, _source)
+   style.set_open_poly_style(OUTLINE_STYLE, cr)
+   shape.draw_path_with_source(_path, cr, _source)
+end
+
+M.draw_series = function(cr, right_x, bottom_y, dx, series, sources)
+   style.set_open_poly_style(DATA_STYLE, cr)
+   local n = #series
+
+   -- TODO this accounts for up to 20% of the execution time once the series
+   -- reaches its max length
+   __cairo_move_to(cr, right_x, series[1])
+
+   for j = 2, n do
+      __cairo_line_to(cr, right_x - (j - 1) * dx, series[j])
+   end
+
+   __cairo_line_to(cr, right_x - (n - 1) * dx, bottom_y)
+   __cairo_line_to(cr, right_x, bottom_y)
+   __cairo_set_source(cr, sources.fill)
+   __cairo_fill_preserve(cr)
+
+   __cairo_set_source(cr, sources.line)
+   __cairo_stroke(cr)
+end
+
+return M

src/widget/timeseries/xlabels.lua

@@ -0,0 +1,46 @@
+local M = {}
+
+local ti = require 'text_internal'
+local pure = require 'pure'
+
+--------------------------------------------------------------------------------
+-- pure
+
+local make_x_label_text = function(y, chars, font)
+   return ti.make_htext(
+      y + ti.get_delta_y('bottom', font),
+      ti.x_align_function('center', font)(chars),
+      chars
+   )
+end
+
+local X_LABEL_PAD = 8
+
+M.get_x_axis_height = function(font)
+   return ti.font_height(font) + X_LABEL_PAD
+end
+
+M.make = function(y, n, format_fun, font)
+   local f = function(i)
+      return make_x_label_text(y, format_fun((i - 1) / (n - 1)), font)
+   end
+   return pure.map_n(f, n)
+end
+
+M.get_x_label_positions = function(right_x, w, x_labels)
+   local n = #x_labels
+   local f = function(i)
+      return right_x - w * (1 - (i - 1) / (n - 1))
+   end
+   return pure.map_n(f, n)
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.draw = function(obj, cr, positions)
+   ti.set_font_spec(cr, obj.font, obj.source)
+   pure.each2(ti.draw_htext_at, obj.labels, positions, cr)
+end
+
+return M

src/widget/timeseries/ylabels.lua

@@ -0,0 +1,47 @@
+local M = {}
+
+local geom = require 'geom'
+local text = require 'text'
+local ti = require 'text_internal'
+
+local Y_LABEL_PAD = 5
+
+--------------------------------------------------------------------------------
+-- pure
+
+local make_y_label_text = function(point, chars, font)
+   return ti.make_text(
+      point.x,
+      point.y + ti.get_delta_y('center', font),
+      chars
+   )
+end
+
+
+-- TODO this function smells funny
+M.make = function(point, h, n, font, y_format, scale_factor)
+   local y_labels = {width = 0}
+   local f = y_format(scale_factor)
+   for i = 1, n do
+      local z = (i - 1) / (n - 1)
+      local l = make_y_label_text(
+         geom.make_point(point.x, point.y + z * h),
+         f((1 - z) * scale_factor),
+         font
+      )
+      local w = ti.get_width(l.chars, font)
+      if w > y_labels.width then
+         y_labels.width = w
+      end
+      y_labels[i] = l
+   end
+   y_labels.width = y_labels.width + Y_LABEL_PAD
+   return y_labels
+end
+
+--------------------------------------------------------------------------------
+-- impure
+
+M.draw = text.draw
+
+return M