feat(palette): add palette API

Usage: lvgl.palette.main(lvgl.palette.BLUE_GREY)
Fix #35

Signed-off-by: Neo Xu <neo.xu1990@gmail.com>

examples/examples.lua

@@ -11,6 +11,9 @@ local container = lvgl.Object {
     }
 }
 
+-- change color directly using property
+container.bg_color = lvgl.palette.main(lvgl.palette.BLUE_GREY)
+
 print("created container", container)
 
 local function createBtn(parent, name)

src/luavgl.c

@@ -9,6 +9,7 @@
 #include "group.c"
 #include "indev.c"
 #include "obj.c"
+#include "palette.c"
 #include "timer.c"
 #include "util.c"
 
@@ -137,7 +138,7 @@ LUALIB_API int luaopen_lvgl(lua_State *L)
   luavgl_indev_init(L);
   luavgl_group_init(L);
   luavgl_disp_init(L);
-
+  luavgl_palette_init(L);
   luavgl_constants_init(L);
 
   /* Methods to create widget locate in widgets table, check `luavgl_obj_init`

src/luavgl.h

@@ -232,6 +232,11 @@ LUALIB_API lv_property_t luavgl_toproperty(lua_State *L, int idx,
  */
 LUALIB_API int luavgl_pushproperty(lua_State *L, const lv_property_t *prop);
 
+/**
+ * @brief Push lvgl color to stack
+ */
+LUALIB_API int luavgl_pushcolor(lua_State *L, lv_color_t color);
+
 /**
  * @brief Helper function to iterate through table
  *

src/palette.c

@@ -0,0 +1,68 @@
+#include "luavgl.h"
+#include "private.h"
+#include "rotable.h"
+
+static int luavgl_palette_main(lua_State *L)
+{
+  lv_palette_t p = luaL_checkinteger(L, 1);
+
+  lv_color_t c = lv_palette_main(p);
+  luavgl_pushcolor(L, c);
+  return 1;
+}
+
+static int luavgl_palette_lighten(lua_State *L)
+{
+  lv_palette_t p = luaL_checkinteger(L, 1);
+  uint8_t lvl = luaL_checkinteger(L, 2);
+
+  lv_color_t c = lv_palette_lighten(p, lvl);
+  luavgl_pushcolor(L, c);
+  return 1;
+}
+
+static int luavgl_palette_darken(lua_State *L)
+{
+  lv_palette_t p = luaL_checkinteger(L, 1);
+  uint8_t lvl = luaL_checkinteger(L, 2);
+
+  lv_color_t c = lv_palette_darken(p, lvl);
+  luavgl_pushcolor(L, c);
+  return 1;
+}
+
+static const rotable_Reg palette_constants[] = {
+    {"RED",         0,             {.integer = LV_PALETTE_RED}        },
+    {"PINK",        0,             {.integer = LV_PALETTE_PINK}       },
+    {"PURPLE",      0,             {.integer = LV_PALETTE_PURPLE}     },
+    {"DEEP_PURPLE", 0,             {.integer = LV_PALETTE_DEEP_PURPLE}},
+    {"INDIGO",      0,             {.integer = LV_PALETTE_INDIGO}     },
+    {"BLUE",        0,             {.integer = LV_PALETTE_BLUE}       },
+    {"LIGHT_BLUE",  0,             {.integer = LV_PALETTE_LIGHT_BLUE} },
+    {"CYAN",        0,             {.integer = LV_PALETTE_CYAN}       },
+    {"TEAL",        0,             {.integer = LV_PALETTE_TEAL}       },
+    {"GREEN",       0,             {.integer = LV_PALETTE_GREEN}      },
+    {"LIGHT_GREEN", 0,             {.integer = LV_PALETTE_LIGHT_GREEN}},
+    {"LIME",        0,             {.integer = LV_PALETTE_LIME}       },
+    {"YELLOW",      0,             {.integer = LV_PALETTE_YELLOW}     },
+    {"AMBER",       0,             {.integer = LV_PALETTE_AMBER}      },
+    {"ORANGE",      0,             {.integer = LV_PALETTE_ORANGE}     },
+    {"DEEP_ORANGE", 0,             {.integer = LV_PALETTE_DEEP_ORANGE}},
+    {"BROWN",       0,             {.integer = LV_PALETTE_BROWN}      },
+    {"BLUE_GREY",   0,             {.integer = LV_PALETTE_BLUE_GREY}  },
+    {"GREY",        0,             {.integer = LV_PALETTE_GREY}       },
+    {"LAST",        0,             {.integer = LV_PALETTE_LAST}       },
+    {"NONE",        0,             {.integer = LV_PALETTE_NONE}       },
+
+    {"main",        LUA_TFUNCTION, {luavgl_palette_main}              },
+    {"lighten",     LUA_TFUNCTION, {luavgl_palette_lighten}           },
+    {"darken",      LUA_TFUNCTION, {luavgl_palette_darken}            },
+
+    {0,             0,             {0}                                },
+};
+
+static void luavgl_palette_init(lua_State *L)
+{
+  rotable_newlib(L, palette_constants);
+  lua_setfield(L, -2, "palette");
+}

src/util.c

@@ -431,6 +431,12 @@ LUALIB_API lv_property_t luavgl_toproperty(lua_State *L, int idx,
   return prop;
 }
 
+LUALIB_API int luavgl_pushcolor(lua_State *L, lv_color_t color)
+{
+  lua_pushinteger(L, lv_color_to_int(color));
+  return 1;
+}
+
 LUALIB_API int luavgl_pushproperty(lua_State *L, const lv_property_t *prop)
 {
   lv_prop_id_t id = prop->id;
@@ -444,7 +450,7 @@ LUALIB_API int luavgl_pushproperty(lua_State *L, const lv_property_t *prop)
     lua_pushnumber(L, prop->precise);
     return 1;
   case LV_PROPERTY_TYPE_COLOR:
-    lua_pushinteger(L, lv_color_to_int(prop->color));
+    luavgl_pushcolor(L, prop->color);
     return 1;
   case LV_PROPERTY_TYPE_POINT:
     /* table of {x, y} */