Default travel width to 1/4 of filament width, travel opacity to 0.2

Travel tubes now default to a quarter of the filament width (which
tracks the layer height) and 20% opacity, so traverse moves recede
behind the printed path. The layer-height sync keeps the 1/4 ratio.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app.py

@@ -1024,12 +1024,12 @@ def render_toolpath(
     shape1_path: str | None,
     shape2_path: str | None,
     shape3_path: str | None,
-    travel_opacity: float = 0.25,
+    travel_opacity: float = 0.2,
     print_opacity: float = 1.0,
     travel_color: str = "#969696",
     print_color: str = "#ff7f0e",
     print_width: float = 0.8,
-    travel_width: float = 0.8,
+    travel_width: float = 0.2,
     tube: bool = True,
 ) -> tuple[Any, str, dict]:
     if source == GCODE_SOURCE_UPLOAD:
@@ -1721,7 +1721,7 @@ def build_demo() -> gr.Blocks:
                             label="Travel (G0) opacity",
                             minimum=0.0,
                             maximum=1.0,
-                            value=0.25,
+                            value=0.2,
                             step=0.05,
                             min_width=150,
                         )
@@ -1751,9 +1751,9 @@ def build_demo() -> gr.Blocks:
                     with gr.Row(visible=False) as width_row:
                         travel_width_slider = gr.Slider(
                             label="Travel width (mm)",
-                            minimum=0.1,
+                            minimum=0.05,
                             maximum=1.2,
-                            value=0.8,
+                            value=0.2,
                             step=0.05,
                             min_width=150,
                         )
@@ -1803,18 +1803,20 @@ def build_demo() -> gr.Blocks:
                 inputs=[render_mode] + render_inputs,
                 outputs=[toolpath_plot, toolpath_status, parsed_state],
             )
-            # Keep the filament and travel width sliders in sync with the
-            # Layer Height chosen on the slicing tab: default value equals the
-            # layer height, maximum is 50% above it.
+            # Keep the filament and travel width sliders in sync with the Layer
+            # Height chosen on the slicing tab: filament width equals the layer
+            # height, travel width is a quarter of it, both capped 50% above the
+            # layer height.
             def sync_width_sliders(v: float):
                 height = float(v or 0.8)
-                def width_update():
-                    return gr.update(
-                        value=height,
-                        minimum=min(0.1, height),
-                        maximum=height * 1.5,
-                    )
-                return width_update(), width_update()
+                travel = height / 4
+                print_update = gr.update(
+                    value=height, minimum=min(0.1, height), maximum=height * 1.5
+                )
+                travel_update = gr.update(
+                    value=travel, minimum=min(0.05, travel), maximum=height * 1.5
+                )
+                return print_update, travel_update
 
             layer_height.change(
                 fn=sync_width_sliders,

gcode_viewer.py

@@ -383,12 +383,12 @@ def _segments_to_xyz(
 
 def build_toolpath_figure(
     parsed: dict,
-    travel_opacity: float = 0.25,
+    travel_opacity: float = 0.2,
     print_opacity: float = 1.0,
     travel_color: str = "#969696",
     print_color: str = "#1f77b4",
     print_width: float = 0.8,
-    travel_width: float = 0.8,
+    travel_width: float = 0.2,
     tube: bool = True,
 ) -> go.Figure:
     moves = parsed.get("moves") or []