Refine footprint raster starts and lead-in UI

app.py

@@ -2641,6 +2641,10 @@ def update_nozzle_spacing_mode(layout_mode: str | None) -> tuple[dict[str, Any],
     return gr.update(visible=not custom_selected), gr.update(visible=custom_selected)
 
 
+def update_lead_in_options_visibility(enabled: bool | None) -> dict[str, Any]:
+    return gr.update(visible=bool(enabled))
+
+
 def _dropdown_update(records: list[dict], selected: str | None = None) -> dict[str, Any]:
     choices = [_shape_choice(record) for record in records]
     value = selected if selected in choices else (choices[0] if choices else None)
@@ -3685,10 +3689,11 @@ def build_dynamic_demo() -> gr.Blocks:
                 allow_custom_value=False,
             )
             gcode_lead_in_enabled = gr.Checkbox(label="Lead In", value=False)
-            with gr.Row():
-                gcode_lead_in_length = gr.Number(label="Lead In Length (mm)", value=5.0, minimum=0.1, step=0.1)
-                gcode_lead_in_clearance = gr.Number(label="Lead In Clearance (mm)", value=5.0, minimum=0.0, step=0.1)
-                gcode_lead_in_lines = gr.Number(label="Lead In Raster Lines", value=3, minimum=1, step=1)
+            with gr.Group(visible=False) as gcode_lead_in_options_group:
+                with gr.Row():
+                    gcode_lead_in_length = gr.Number(label="Lead In Length (mm)", value=5.0, minimum=0.1, step=0.1)
+                    gcode_lead_in_clearance = gr.Number(label="Lead In Clearance (mm)", value=5.0, minimum=0.0, step=0.1)
+                    gcode_lead_in_lines = gr.Number(label="Lead In Raster Lines", value=3, minimum=1, step=1)
             gcode_button = gr.Button("Generate G-Code", variant="primary")
             gcode_downloads = gr.File(label="Download G-Code Files", file_count="multiple", interactive=False, elem_classes=["gcode-download"])
             gcode_status = gr.Markdown("")
@@ -4022,6 +4027,12 @@ def build_dynamic_demo() -> gr.Blocks:
             inputs=[shape_records, gcode_text_source],
             outputs=[gcode_text],
         )
+        gcode_lead_in_enabled.change(
+            fn=update_lead_in_options_visibility,
+            inputs=[gcode_lead_in_enabled],
+            outputs=[gcode_lead_in_options_group],
+            queue=False,
+        )
         gcode_text_source.change(fn=load_selected_gcode_text, inputs=[shape_records, gcode_text_source], outputs=[gcode_text])
         refresh_gcode_text_button.click(fn=load_selected_gcode_text, inputs=[shape_records, gcode_text_source], outputs=[gcode_text])
         nozzle_layout_mode.change(

tests/test_tiff_to_gcode.py

@@ -673,15 +673,17 @@ def test_woodpile_raster_switches_print_axis_between_layers(tmp_path) -> None:
         raster_pattern=RASTER_PATTERN_WOODPILE,
     )
 
+    gcode_text = gcode_path.read_text()
     move_lines = [
         line.strip()
-        for line in gcode_path.read_text().splitlines()
+        for line in gcode_text.splitlines()
         if line.startswith(("G0", "G1"))
     ]
     z_move_index = next(i for i, line in enumerate(move_lines) if " Z" in line)
     first_layer_prints = [line for line in move_lines[:z_move_index] if line.startswith("G1") and "; Color 255" in line]
     second_layer_prints = [line for line in move_lines[z_move_index + 1 :] if line.startswith("G1") and "; Color 255" in line]
 
+    assert move_lines[0] == "G0 X1.0 Y0.0 ; Color 0"
     assert any("X" in line and "Y0" in line for line in first_layer_prints)
     assert any("X0" in line and "Y" in line for line in second_layer_prints)
 
@@ -696,10 +698,28 @@ def test_woodpile_raster_switches_print_axis_between_layers(tmp_path) -> None:
                 y += float(token[1:])
         x_positions.append(x)
         y_positions.append(y)
-    assert min(x_positions) == -1.0
-    assert max(x_positions) == 4.0
-    assert min(y_positions) == -1.0
-    assert max(y_positions) == 3.0
+    assert min(x_positions) == 0.0
+    assert max(x_positions) == 5.0
+    assert min(y_positions) == -1.5
+    assert max(y_positions) == 2.5
+
+    moves = _moves_with_colors(gcode_text)
+    first_layer_change = next(
+        move for move in moves if move["end"][2] > move["start"][2]
+    )
+    previous_xy = first_layer_change["start"][:2]
+    actual_restart_xy = first_layer_change["end"][:2]
+    old_restart_xy = (1.5, -1.5)
+    actual_restart_distance = (
+        (previous_xy[0] - actual_restart_xy[0]) ** 2
+        + (previous_xy[1] - actual_restart_xy[1]) ** 2
+    )
+    old_restart_distance = (
+        (previous_xy[0] - old_restart_xy[0]) ** 2
+        + (previous_xy[1] - old_restart_xy[1]) ** 2
+    )
+    assert actual_restart_xy != old_restart_xy
+    assert actual_restart_distance < old_restart_distance
 
 
 def test_y_direction_raster_prints_each_layer_along_y_axis(tmp_path) -> None:
@@ -724,9 +744,10 @@ def test_y_direction_raster_prints_each_layer_along_y_axis(tmp_path) -> None:
         raster_pattern=RASTER_PATTERN_Y_DIRECTION,
     )
 
+    gcode_text = gcode_path.read_text()
     move_lines = [
         line.strip()
-        for line in gcode_path.read_text().splitlines()
+        for line in gcode_text.splitlines()
         if line.startswith(("G0", "G1"))
     ]
     print_lines = [
@@ -735,6 +756,7 @@ def test_y_direction_raster_prints_each_layer_along_y_axis(tmp_path) -> None:
         if line.startswith("G1") and "; Color 255" in line
     ]
     assert print_lines
+    assert move_lines[0] == "G0 X0.0 Y1.0 ; Color 0"
     assert all("X0" in line and "Y0" not in line for line in print_lines)
 
     x = y = 0.0
@@ -748,10 +770,16 @@ def test_y_direction_raster_prints_each_layer_along_y_axis(tmp_path) -> None:
                 y += float(token[1:])
         x_positions.append(x)
         y_positions.append(y)
-    assert min(x_positions) >= 0.0
-    assert max(x_positions) <= 3.0
-    assert min(y_positions) == -1.0
-    assert max(y_positions) == 3.0
+    assert min(x_positions) == 0.0
+    assert max(x_positions) == 2.0
+    assert min(y_positions) == 0.0
+    assert max(y_positions) == 4.0
+
+    moves = _moves_with_colors(gcode_text)
+    first_layer_change = next(
+        move for move in moves if move["end"][2] > move["start"][2]
+    )
+    assert first_layer_change["start"][:2] == first_layer_change["end"][:2]
 
 
 def test_contour_tracing_skips_inactive_nozzle_outline(tmp_path) -> None:

tiff_to_gcode.py

@@ -829,6 +829,8 @@ def _woodpile_layer_segments(
     color_img: np.ndarray,
     pixel_size: float,
     raster_axis: str,
+    reverse_order: bool = False,
+    start_forward: bool = True,
 ) -> list[tuple[float, float, float, float, int]]:
     mask = path_img > 0
     segments: list[tuple[float, float, float, float, int]] = []
@@ -840,11 +842,14 @@ def _woodpile_layer_segments(
             mask.shape[0] - 1 - np.flipud(mask).argmax(axis=0),
             -1,
         )
-        for col_number, col in enumerate(np.where(first_nonblank != -1)[0]):
+        columns = list(np.where(first_nonblank != -1)[0])
+        if reverse_order:
+            columns.reverse()
+        for col_number, col in enumerate(columns):
             f_idx, l_idx = int(first_nonblank[col]), int(last_nonblank[col])
             if f_idx == -1:
                 continue
-            forward = col_number % 2 == 0
+            forward = (col_number % 2 == 0) == start_forward
             row_values = list(range(f_idx, l_idx + 1)) if forward else list(range(l_idx, f_idx - 1, -1))
             run_start = row_values[0]
             prev_row = row_values[0]
@@ -893,11 +898,14 @@ def _woodpile_layer_segments(
         mask.shape[1] - 1 - np.fliplr(mask).argmax(axis=1),
         -1,
     )
-    for row_number, row in enumerate(np.where(first_nonblank != -1)[0]):
+    rows = list(np.where(first_nonblank != -1)[0])
+    if reverse_order:
+        rows.reverse()
+    for row_number, row in enumerate(rows):
         f_idx, l_idx = int(first_nonblank[row]), int(last_nonblank[row])
         if f_idx == -1:
             continue
-        forward = row_number % 2 == 0
+        forward = (row_number % 2 == 0) == start_forward
         col_values = list(range(f_idx, l_idx + 1)) if forward else list(range(l_idx, f_idx - 1, -1))
         run_start = col_values[0]
         prev_col = col_values[0]
@@ -945,6 +953,49 @@ def _raster_axis_for_pattern(pattern: str, layer_number: int) -> str:
     return "X"
 
 
+def _oriented_woodpile_layer_segments(
+    path_img: np.ndarray,
+    color_img: np.ndarray,
+    pixel_size: float,
+    raster_axis: str,
+    current_x: float,
+    current_y: float,
+    prefer_default: bool = False,
+) -> list[tuple[float, float, float, float, int]]:
+    default_segments = _woodpile_layer_segments(
+        path_img,
+        color_img,
+        pixel_size,
+        raster_axis,
+    )
+    if prefer_default or not default_segments:
+        return default_segments
+
+    candidates: list[list[tuple[float, float, float, float, int]]] = [default_segments]
+    for reverse_order in (False, True):
+        for start_forward in (False, True):
+            segments = _woodpile_layer_segments(
+                path_img,
+                color_img,
+                pixel_size,
+                raster_axis,
+                reverse_order=reverse_order,
+                start_forward=start_forward,
+            )
+            if segments and segments not in candidates:
+                candidates.append(segments)
+
+    return min(
+        candidates,
+        key=lambda segments: _point_distance_sq(
+            current_x,
+            current_y,
+            segments[0][0],
+            segments[0][1],
+        ),
+    )
+
+
 def _build_footprint_raster_gcode_list(
     path_ref_list: list[np.ndarray],
     color_ref_list: list[np.ndarray],
@@ -957,11 +1008,20 @@ def _build_footprint_raster_gcode_list(
     gcode_list: list[dict] = []
     current_x = 0.0
     current_y = 0.0
+    raster_origin_initialized = False
     contour_layers = contour_layers or []
 
     for layer_number, (path_img, color_img) in enumerate(zip(path_ref_list, color_ref_list)):
         raster_axis = _raster_axis_for_pattern(raster_pattern, layer_number)
-        segments = _woodpile_layer_segments(path_img, color_img, pixel_size, raster_axis)
+        segments = _oriented_woodpile_layer_segments(
+            path_img,
+            color_img,
+            pixel_size,
+            raster_axis,
+            current_x,
+            current_y,
+            prefer_default=not raster_origin_initialized,
+        )
         if not segments:
             if layer_number > 0:
                 gcode_list.append({"X": 0.0, "Y": 0.0, "Z": layer_height, "Color": 0})
@@ -985,7 +1045,20 @@ def _build_footprint_raster_gcode_list(
             continue
 
         first_x, first_y = segments[0][0], segments[0][1]
-        if layer_number > 0:
+        if not raster_origin_initialized:
+            if layer_number > 0:
+                current_x, current_y = _append_relative_move(
+                    gcode_list,
+                    current_x,
+                    current_y,
+                    current_x,
+                    current_y,
+                    0,
+                    z_step=layer_height,
+                )
+            current_x, current_y = first_x, first_y
+            raster_origin_initialized = True
+        elif layer_number > 0:
             current_x, current_y = _append_relative_move(
                 gcode_list,
                 current_x,