Added WidgetText. Fixed some things. Updated README

sdl_helpers.cpp

@@ -11,6 +11,7 @@ using namespace std;
 using nlohmann::json;
 
 map<pair<string, int>, TTF_Font*> font_map;
+string default_font_name = "font.ttf";
 
 bool init_sdl()
 {
@@ -75,6 +76,49 @@ TTF_Font* get_font(int size, const string& filename)
 	}
 }
 
+SDL_Rect surface_align(const SDL_Surface* base, const SDL_Surface* applied,
+	HorizontalAlign halign, VerticalAlign valign)
+{
+	SDL_Rect align = {.x = 0, .y = 0, .w = 0, .h = 0};
+
+	if ((nullptr == base) || (nullptr == applied))
+	{
+		return align;
+	}
+
+	switch (halign)
+	{
+	case HALIGN_LEFT:
+		align.x = 0;
+		break;
+
+	case HALIGN_CENTER:
+		align.x = base->w / 2 - applied->w / 2;
+		break;
+
+	case HALIGN_RIGHT:
+		align.x = base->w - applied->w;
+		break;
+	}
+
+	switch (valign)
+	{
+	case VALIGN_TOP:
+		align.y = 0;
+		break;
+
+	case VALIGN_CENTER:
+		align.y = base->h / 2 - applied->h / 2;
+		break;
+
+	case VALIGN_BOTTOM:
+		align.y = base->h - applied->h;
+		break;
+	}
+
+	return align;
+}
+
 bool read_config_json(json& cfg, const string& filename, ostream* log)
 {
 	ifstream cfg_file(filename);
@@ -120,3 +164,74 @@ void json_extract(const nlohmann::json& j, const string& key, int& out)
 		out = j[key];
 	}
 }
+
+void json_extract(const nlohmann::json& j, const string& key, bool& out)
+{
+	if (j.contains(key) && j[key].is_boolean())
+	{
+		out = j[key];
+	}
+}
+
+void json_extract(const json& j, const string& key, HorizontalAlign& out)
+{
+	if (j.contains(key))
+	{
+		try
+		{
+			out = j[key].get<HorizontalAlign>();
+		}
+		catch(const std::exception& e)
+		{
+		}
+	}
+}
+
+void json_extract(const json& j, const string& key, VerticalAlign& out)
+{
+	if (j.contains(key))
+	{
+		try
+		{
+			out = j[key].get<VerticalAlign>();
+		}
+		catch(const std::exception& e)
+		{
+		}
+	}
+}
+
+void json_extract(const json& j, const string& key, TextFit& out)
+{
+	if (j.contains(key))
+	{
+		try
+		{
+			out = j[key].get<TextFit>();
+		}
+		catch(const std::exception& e)
+		{
+		}
+	}
+}
+
+void json_extract(const json& j, const string& key, SDL_Color& out)
+{
+	if (j.contains(key) && j[key].is_object())
+	{
+		const json& j2 = j[key];
+
+		json_extract(j2, "r", out.r);
+		json_extract(j2, "g", out.g);
+		json_extract(j2, "b", out.b);
+		json_extract(j2, "a", out.a);
+	}
+}
+
+void json_extract(const nlohmann::json& j, const string& key, Uint8& out)
+{
+	if (j.contains(key) && j[key].is_number_unsigned())
+	{
+		out = j[key];
+	}
+}