add save line as img

backend/nodes/save.py

@@ -46,7 +46,7 @@ class Save:
                         "DATA_FIELD": ["TIFF", "PNG", "NPZ"],
                         "IMAGE": ["PNG", "TIFF", "NPZ"],
                         "ANNOTATION_SOURCE": ["PNG", "TIFF", "NPZ"],
-                        "LINE": ["CSV", "NPZ", "JSON"],
+                        "LINE": ["PNG", "TIFF", "CSV", "NPZ", "JSON"],
                         "RECORD_TABLE": ["CSV", "JSON"],
                         "DATA_TABLE": ["CSV", "JSON"],
                         "FLOAT": ["TXT", "JSON"],
@@ -57,6 +57,11 @@ class Save:
             },
             "optional": {
                 "directory": ("DIRECTORY", {"label": "directory"}),
+                "plot_title": ("STRING", {
+                    "default": "",
+                    "placeholder": "plot title (optional)",
+                    "label": "title",
+                }),
             },
         }
 
@@ -79,6 +84,7 @@ class Save:
         format: str,
         value,
         directory: str | None = None,
+        plot_title: str = "",
     ):
         path = self._resolve_save_path(filename, format, directory, directory_path)
 
@@ -88,11 +94,11 @@ class Save:
             self._save_datafield(path, value, format)
         elif isinstance(value, np.ndarray):
             if value.ndim == 1:
-                self._save_line(path, LineData(data=value), format)
+                self._save_line(path, LineData(data=value), format, title=plot_title)
             else:
                 self._save_image_or_array(path, value, format)
         elif isinstance(value, LineData):
-            self._save_line(path, value, format)
+            self._save_line(path, value, format, title=plot_title)
         elif isinstance(value, list):
             self._save_table(path, value, format)
         elif isinstance(value, (int, float, np.floating, np.integer)):
@@ -176,9 +182,12 @@ class Save:
             return
         raise ValueError(f"Format {format_name} is not supported for IMAGE.")
 
-    def _save_line(self, path: Path, line: LineData, format_name: str):
+    def _save_line(self, path: Path, line: LineData, format_name: str, title: str = ""):
         y = np.asarray(line.data, dtype=np.float64).ravel()
         x = np.asarray(line.x_axis, dtype=np.float64).ravel()[: len(y)] if line.x_axis is not None else np.arange(len(y), dtype=np.float64)
+        if format_name in ("PNG", "TIFF"):
+            self._save_line_plot(path, x, y, line.x_unit, line.y_unit, title, format_name)
+            return
         if format_name == "CSV":
             with path.open("w", newline="", encoding="utf-8") as fh:
                 writer = csv.writer(fh)
@@ -199,6 +208,33 @@ class Save:
             return
         raise ValueError(f"Format {format_name} is not supported for LINE.")
 
+    def _save_line_plot(
+        self,
+        path: Path,
+        x: np.ndarray,
+        y: np.ndarray,
+        x_unit: str,
+        y_unit: str,
+        title: str,
+        format_name: str,
+    ):
+        import matplotlib
+        matplotlib.use("Agg")
+        import matplotlib.pyplot as plt
+
+        fig, ax = plt.subplots(figsize=(8, 5), dpi=150)
+        ax.plot(x, y, linewidth=1.2, color="#4f8ef7")
+        ax.set_xlabel(x_unit if x_unit else "x")
+        ax.set_ylabel(y_unit if y_unit else "y")
+        if title and title.strip():
+            ax.set_title(title.strip())
+        ax.grid(True, linestyle="--", linewidth=0.5, alpha=0.5)
+        fig.tight_layout()
+
+        ext = ".png" if format_name == "PNG" else ".tiff"
+        fig.savefig(str(path.with_suffix(ext)), format=format_name.lower(), dpi=150)
+        plt.close(fig)
+
     def _save_table(self, path: Path, rows: list, format_name: str):
         if format_name == "JSON":
             path.write_text(json.dumps(rows, indent=2), encoding="utf-8")