feat: add configurable image input preprocessing (#2028)

examples/common/common.h

@@ -200,18 +200,17 @@ struct SDGenerationParams {
     std::string ad_prompt;
     std::string ad_negative_prompt;
     std::string extra_ad_args;
-    int clip_skip              = -1;  // <= 0 represents unspecified
-    int width                  = -1;
-    int height                 = -1;
-    int batch_count            = 1;
-    int qwen_image_layers      = 3;
-    int64_t seed               = 42;
-    float strength             = 0.75f;
-    float control_strength     = 0.9f;
-    float ip_adapter_strength  = 1.0f;
-    bool auto_resize_ref_image = true;
-    bool increase_ref_index    = false;
-    bool embed_image_metadata  = true;
+    int clip_skip             = -1;  // <= 0 represents unspecified
+    int width                 = -1;
+    int height                = -1;
+    int batch_count           = 1;
+    int qwen_image_layers     = 3;
+    int64_t seed              = 42;
+    float strength            = 0.75f;
+    float control_strength    = 0.9f;
+    float ip_adapter_strength = 1.0f;
+    bool increase_ref_index   = false;
+    bool embed_image_metadata = true;
 
     std::string init_image_path;
     std::string end_image_path;
@@ -247,6 +246,7 @@ struct SDGenerationParams {
     std::string extra_tiling_args;
 
     std::string ref_image_args;
+    std::string image_preprocess;
 
     std::string pm_id_images_dir;
     std::string pm_id_embed_path;
@@ -310,6 +310,7 @@ struct SDGenerationParams {
     ArgOptions get_options();
     bool from_json_str(const std::string& json_str,
                        const std::function<std::string(const std::string&)>& lora_path_resolver = {});
+    bool parse_image_preprocess_json(const std::string& json_str);
     bool initialize_cache_params();
     void extract_and_remove_lora(const std::string& lora_model_dir);
     bool width_and_height_are_set() const;