[lua] Add Image.id and Image.version getters

src/app/script/image_class.cpp

@@ -532,6 +532,20 @@ int Image_shrinkBounds(lua_State* L)
   return 1;
 }
 
+int Image_get_id(lua_State* L)
+{
+  const auto obj = get_obj<ImageObj>(L, 1);
+  lua_pushinteger(L, obj->imageId);
+  return 1;
+}
+
+int Image_get_version(lua_State* L)
+{
+  const auto obj = get_obj<ImageObj>(L, 1);
+  lua_pushinteger(L, obj->image(L)->version());
+  return 1;
+}
+
 int Image_get_rowStride(lua_State* L)
 {
   const auto obj = get_obj<ImageObj>(L, 1);
@@ -625,6 +639,8 @@ const luaL_Reg Image_methods[] = {
 };
 
 const Property Image_properties[] = {
+  { "id", Image_get_id, nullptr },
+  { "version", Image_get_version, nullptr },
   { "rowStride", Image_get_rowStride, nullptr },
   { "bytes", Image_get_bytes, Image_set_bytes },
   { "width", Image_get_width, nullptr },

tests/scripts/image.lua

@@ -9,6 +9,7 @@ dofile('./test_utils.lua')
 local rgba = app.pixelColor.rgba
 
 local a = Image(32, 64)
+assert(a.id > 0)
 assert(a.width == 32)
 assert(a.height == 64)
 assert(a.colorMode == ColorMode.RGB) -- RGB by default
@@ -50,6 +51,7 @@ do
   assert(c.width == d.width)
   assert(c.height == d.height)
   assert(c.colorMode == d.colorMode)
+  assert(c.id ~= d.id) -- The clone must have different ID
 
   -- Get RGB pixels
   for y=0,c.height-1 do
@@ -75,6 +77,9 @@ end
 do
   local spr = Sprite(256, 256)
   local image = app.site.image
+  local imageID = image.id
+  assert(image.id > 0)
+  assert(image.version == 0)
   local copy = image:clone()
   assert(image:getPixel(0, 0) == 0)
   for y=0,copy.height-1 do
@@ -83,9 +88,12 @@ do
     end
   end
   image:putImage(copy)
+  assert(image.version == 1)
   assert(image:getPixel(0, 0) == rgba(255, 255, 0, 255))
   assert(image:getPixel(255, 255) == rgba(0, 0, 0, 255))
   app.undo()
+  assert(image.version == 2)
+  assert(image.id == imageID) -- the ID doesn't change
   assert(image:getPixel(0, 0) == rgba(0, 0, 0, 0))
   assert(image:getPixel(255, 255) == rgba(0, 0, 0, 0))
 end