simplify color picker script

client/script/color_picker.lua

@@ -15,23 +15,29 @@ local state = {
   rgb = {0, 0, 0, 1},
   saved = {},
   hex_string = "#000000FF",
-  hex_len = 8,
 }
 for i = 1, 12 do state.saved[i] = {0, 0, 0, 0} end
 
+local function clamp01(x) return math.max(0, math.min(1, x)) end
+
 local function update_hex_string()
   state.hex_string = string.format("#%02X%02X%02X%02X",
       math.floor(state.rgb[1]*255 + 0.5),
       math.floor(state.rgb[2]*255 + 0.5),
       math.floor(state.rgb[3]*255 + 0.5),
       math.floor(state.rgb[4]*255 + 0.5))
-  state.hex_len = 8
   ui.set_string(0, 0, state.hex_string)
 end
 
+local function sync_rgb_from_hsv()
+  state.rgb[1], state.rgb[2], state.rgb[3] =
+      ui.hsv_to_rgb(state.hsv[1], state.hsv[2], state.hsv[3])
+  update_hex_string()
+end
+
 local function sv_pick(s, v)
-  s = math.max(0, math.min(1, s))
-  v = math.max(0, math.min(1, v))
+  s = clamp01(s)
+  v = clamp01(v)
   state.hsv[2] = s
   state.hsv[3] = v
 
@@ -41,16 +47,13 @@ local function sv_pick(s, v)
   end
   ui.set_pos(0, 3, s*130 - 3, 130 - v*130 - 3)
 
-  state.rgb[1], state.rgb[2], state.rgb[3] =
-      ui.hsv_to_rgb(state.hsv[1], state.hsv[2], state.hsv[3])
-  update_hex_string()
+  sync_rgb_from_hsv()
 end
 
 local function hue_set(h)
-  h = math.max(0, math.min(1, h))
+  h = clamp01(h)
   state.hsv[1] = h
 
-  -- sv square and sv select keep their per-corner s/v, only hue changes
   for _, drawable in ipairs({1, 4}) do
     for corner = 0, 3 do
       local _, s, v, a = ui.get_corner_color(0, drawable, corner)
@@ -59,9 +62,7 @@ local function hue_set(h)
   end
   ui.set_pos(0, 6, 134, 2 + h*130)
 
-  state.rgb[1], state.rgb[2], state.rgb[3] =
-      ui.hsv_to_rgb(state.hsv[1], state.hsv[2], state.hsv[3])
-  update_hex_string()
+  sync_rgb_from_hsv()
 end
 
 local function hex_string_highlight(value)
@@ -80,20 +81,24 @@ local function set_saved(index, color)
   end
 end
 
-function on_button(layer, element, x, y, button, action, mods)
-  if element == 1 then  -- sv square
-    if action == PRESS and button == MOUSE_LEFT then
-      ui.focus(layer, element)
-      sv_pick(x, 1 - y)
-    elseif action == RELEASE and button == MOUSE_LEFT then
-      ui.blur()
-    end
-    return true
+-- Sync HSV+visuals from state.rgb; used after setting state.rgb directly.
+local function apply_state_rgb()
+  state.hsv[1], state.hsv[2], state.hsv[3] =
+      ui.rgb_to_hsv(state.rgb[1], state.rgb[2], state.rgb[3])
+  hue_set(state.hsv[1])
+  sv_pick(state.hsv[2], state.hsv[3])
+end
 
-  elseif element == 2 then  -- hue bar
+local drag = {
+  [1] = function(x, y) sv_pick(x, 1 - y) end,
+  [2] = function(x, y) hue_set(y) end,
+}
+
+function on_button(layer, element, x, y, button, action, mods)
+  if drag[element] then
     if action == PRESS and button == MOUSE_LEFT then
       ui.focus(layer, element)
-      hue_set(y)
+      drag[element](x, y)
     elseif action == RELEASE and button == MOUSE_LEFT then
       ui.blur()
     end
@@ -112,10 +117,7 @@ function on_button(layer, element, x, y, button, action, mods)
       if button == MOUSE_LEFT then
         local saved = state.saved[index]
         state.rgb = {saved[1], saved[2], saved[3], saved[4]}
-        state.hsv[1], state.hsv[2], state.hsv[3] =
-            ui.rgb_to_hsv(state.rgb[1], state.rgb[2], state.rgb[3])
-        hue_set(state.hsv[1])
-        sv_pick(state.hsv[2], state.hsv[3])
+        apply_state_rgb()
       elseif button == MOUSE_RIGHT then
         set_saved(index, state.rgb)
       elseif button == MOUSE_MIDDLE then
@@ -129,12 +131,11 @@ function on_button(layer, element, x, y, button, action, mods)
 end
 
 function on_cursor(layer, element, x, y)
-  if ui.is_focused(0, 1) then      -- dragging the sv square
-    sv_pick(x, 1 - y)
-    return true
-  elseif ui.is_focused(0, 2) then  -- dragging the hue bar
-    hue_set(y)
-    return true
+  for el, fn in pairs(drag) do
+    if ui.is_focused(0, el) then
+      fn(x, y)
+      return true
+    end
   end
   return false
 end
@@ -152,31 +153,23 @@ function on_key(layer, element, key, action, mods)
 
   if action == PRESS then
     if key == KEY_ESCAPE then
-      state.rgb[1], state.rgb[2], state.rgb[3] =
-          ui.hsv_to_rgb(state.hsv[1], state.hsv[2], state.hsv[3])
-      update_hex_string()
+      sync_rgb_from_hsv()
       ui.blur()
     elseif key == KEY_ENTER then
       local s = state.hex_string
-      state.rgb[1] = (tonumber(s:sub(2, 3), 16) or 0) / 255
-      state.rgb[2] = (tonumber(s:sub(4, 5), 16) or 0) / 255
-      state.rgb[3] = (tonumber(s:sub(6, 7), 16) or 0) / 255
-      state.rgb[4] = (tonumber(s:sub(8, 9), 16) or 0) / 255
-      state.hsv[1], state.hsv[2], state.hsv[3] =
-          ui.rgb_to_hsv(state.rgb[1], state.rgb[2], state.rgb[3])
-      hue_set(state.hsv[1])
-      sv_pick(state.hsv[2], state.hsv[3])
+      for i = 1, 4 do
+        state.rgb[i] = (tonumber(s:sub(2*i, 2*i + 1), 16) or 0) / 255
+      end
+      apply_state_rgb()
       ui.blur()
     elseif key == KEY_BACKSPACE then
-      if state.hex_len > 0 then
-        state.hex_string = state.hex_string:sub(1, state.hex_len)
-        state.hex_len = state.hex_len - 1
+      if #state.hex_string > 1 then
+        state.hex_string = state.hex_string:sub(1, -2)
         ui.set_string(0, 0, state.hex_string)
       end
     end
   end
 
-  -- consume all keys while the hex input is focused
   return true
 end
 
@@ -185,9 +178,8 @@ function on_text(layer, element, codepoint)
 
   if codepoint < 128 then
     local ch = string.char(codepoint):upper()
-    if ch:match("[0-9A-F]") and state.hex_len < 8 then
+    if ch:match("[0-9A-F]") and #state.hex_string < 9 then
       state.hex_string = state.hex_string .. ch
-      state.hex_len = state.hex_len + 1
       ui.set_string(0, 0, state.hex_string)
     end
   end