Support pinning decoded images to RAM

lib/luavgl/src/imgdata.c

@@ -0,0 +1,38 @@
+#include "draw/lv_img_buf.h"
+#include "draw/lv_img_decoder.h"
+#include "lauxlib.h"
+#include "lua.h"
+#include "luavgl.h"
+#include "misc/lv_color.h"
+#include "misc/lv_mem.h"
+#include "misc/lv_types.h"
+#include "private.h"
+#include <stdint.h>
+#include <string.h>
+
+static int luavgl_imgdata_create(lua_State *L)
+{
+  if (!lua_isstring(L, 1)) {
+    return luaL_argerror(L, 1, "expect string");
+  }
+
+  lv_img_decoder_dsc_t descriptor;
+  lv_res_t res =
+      lv_img_decoder_open(&descriptor, lua_tostring(L, 1), lv_color_black(), 0);
+  if (res != LV_RES_OK) {
+    return luaL_error(L, "failed to decode image.");
+  }
+
+  lv_img_dsc_t *data = lv_mem_alloc(sizeof(lv_img_dsc_t));
+  data->header = descriptor.header;
+  data->data_size = data->header.w * data->header.h * sizeof(uint32_t); // ???
+
+  uint8_t *data_copy = lv_mem_alloc(data->data_size);
+  memcpy(data_copy, descriptor.img_data, data->data_size);
+  data->data = data_copy;
+
+  lv_img_decoder_close(&descriptor);
+
+  lua_pushlightuserdata(L, data);
+  return 1;
+}

lib/luavgl/src/luavgl.c

@@ -7,6 +7,7 @@
 #include "font.c"
 #include "fs.c"
 #include "group.c"
+#include "imgdata.c"
 #include "indev.c"
 #include "obj.c"
 #include "timer.c"
@@ -17,6 +18,7 @@ static const struct luaL_Reg luavgl_methods[] = {
     {"Font",  luavgl_font_create }, /* font.c */
     {"Style", luavgl_style_create}, /* style.c */
     {"Anim",  luavgl_anim_create }, /* anim.c */
+    {"ImgData",  luavgl_imgdata_create}, /* imgdata.c */
 
     {NULL,    NULL               },
 };