Display: add compactMode: null; improve json schema

Author: CarterLi

doc/json_schema.json

@@ -2067,12 +2067,25 @@
                                     },
                                     "order": {
                                         "description": "Set the order should be used when printing",
-                                        "enum": [
-                                            "none",
-                                            "asc",
-                                            "desc"
+                                        "oneOf": [
+                                            {
+                                                "const": null,
+                                                "description": "Use the default order"
+                                            },
+                                            {
+                                                "const": "none",
+                                                "description": "Use the detected order (kept for compatibility)"
+                                            },
+                                            {
+                                                "const": "asc",
+                                                "description": "Sort by display name in ascending order"
+                                            },
+                                            {
+                                                "const": "desc",
+                                                "description": "Sort by display name in descending order"
+                                            }
                                         ],
-                                        "default": "none"
+                                        "default": null
                                     },
                                     "key": {
                                         "$ref": "#/$defs/key"

src/modules/display/display.c

@@ -257,17 +257,22 @@ void ffParseDisplayJsonObject(FFDisplayOptions* options, yyjson_val* module)
 
         if (unsafe_yyjson_equals_str(key, "order"))
         {
-            int value;
-            const char* error = ffJsonConfigParseEnum(val, &value, (FFKeyValuePair[]) {
-                { "asc", FF_DISPLAY_ORDER_ASC },
-                { "desc", FF_DISPLAY_ORDER_DESC },
-                { "none", FF_DISPLAY_ORDER_NONE },
-                {},
-            });
-            if (error)
-                ffPrintError(FF_DISPLAY_MODULE_NAME, 0, &options->moduleArgs, FF_PRINT_TYPE_DEFAULT, "Invalid %s value: %s", unsafe_yyjson_get_str(key), error);
+            if (yyjson_is_null(val))
+                options->order = FF_DISPLAY_ORDER_NONE;
             else
-                options->order = (FFDisplayOrder) value;
+            {
+                int value;
+                const char* error = ffJsonConfigParseEnum(val, &value, (FFKeyValuePair[]) {
+                    { "asc", FF_DISPLAY_ORDER_ASC },
+                    { "desc", FF_DISPLAY_ORDER_DESC },
+                    { "none", FF_DISPLAY_ORDER_NONE },
+                    {},
+                });
+                if (error)
+                    ffPrintError(FF_DISPLAY_MODULE_NAME, 0, &options->moduleArgs, FF_PRINT_TYPE_DEFAULT, "Invalid %s value: %s", unsafe_yyjson_get_str(key), error);
+                else
+                    options->order = (FFDisplayOrder) value;
+            }
             continue;
         }