clip : refactor graph builder (#13321)

* mtmd : refactor graph builder

* fix qwen2vl

* clean up siglip cgraph

* pixtral migrated

* move minicpmv to a dedicated build function

* move max_feature_layer to build_llava

* use build_attn for minicpm resampler

* fix windows build

* add comment for batch_size

* also support tinygemma3 test model

* qwen2vl does not use RMS norm

* fix qwen2vl norm (2)

convert_hf_to_gguf.py

@@ -3915,6 +3915,16 @@ class Gemma3VisionModel(VisionModel):
         # default values below are taken from HF tranformers code
         self.gguf_writer.add_vision_attention_layernorm_eps(hparams.get("layer_norm_eps", 1e-6))
         self.gguf_writer.add_vision_use_gelu(True)
+        # calculate proj_scale_factor (used by tinygemma3 test model)
+        image_seq_length = self.preprocessor_config.get("image_seq_length", 256)
+        n_per_side = int(image_seq_length ** 0.5)
+        image_size = self.hparams["image_size"]
+        patch_size = self.hparams["patch_size"]
+        proj_scale_factor = (image_size // patch_size) // n_per_side
+        if proj_scale_factor > 0 and proj_scale_factor != 4:
+            # we only need to write this if it's not the default value
+            # in this case, we are converting a test model
+            self.gguf_writer.add_vision_projector_scale_factor(proj_scale_factor)
 
     def tensor_force_quant(self, name, new_name, bid, n_dims):
         del bid, new_name, n_dims  # unused
@@ -3928,6 +3938,9 @@ class Gemma3VisionModel(VisionModel):
     def modify_tensors(self, data_torch: Tensor, name: str, bid: int | None) -> Iterable[tuple[str, Tensor]]:
         del bid  # unused
 
+        if "vision_model.head." in name:
+            return [] # skip redundant tensors for tinygemma3
+
         if name.startswith("multi_modal_projector.") or name.startswith("vision_tower.") \
                 or name.startswith("multimodal_projector.") or name.startswith("vision_model."):
             # process vision tensors