Add Y-direction raster option

README.md

@@ -82,7 +82,7 @@ When you click **Generate Reference TIFF Stack**, the app combines available TIF
 - Pressure increases by `0.1` psi per layer by default.
 - **Use G1 for all moves**: when enabled, every movement line is emitted as `G1` (no `G0` rapid travel); the WAGO valve still marks where material is dispensed. Applies to all shapes.
 - **Use Reference Stack for motion**: when enabled, every shape's snake-path *motion* is taken from the combined Reference TIFF Stack while each shape's *valve/dispensing* comes from its own slices — so parallel print heads share one synchronized nozzle path and each deposits only its own geometry. Requires generating the Reference TIFF Stack on the first tab first; shapes are skipped with a message if it is missing.
-- **Raster Pattern**: `Same-direction raster` keeps the existing back-and-forth raster direction on every layer. `Woodpile raster` alternates the raster axis by layer, switching between X-direction and Y-direction sweeps.
+- **Raster Pattern**: `X-direction raster` keeps the existing X-direction back-and-forth raster on every layer. `Y-direction raster` rasters every layer in Y. `Woodpile raster` alternates the raster axis by layer, switching between X-direction and Y-direction sweeps.
 
 ### Print vs Travel Classification
 

tests/test_tiff_to_gcode.py

@@ -4,7 +4,11 @@ import zipfile
 
 from PIL import Image
 
-from tiff_to_gcode import RASTER_PATTERN_WOODPILE, generate_snake_path_gcode
+from tiff_to_gcode import (
+    RASTER_PATTERN_WOODPILE,
+    RASTER_PATTERN_Y_DIRECTION,
+    generate_snake_path_gcode,
+)
 
 
 def test_gcode_header_writes_presets_before_initial_aux_commands(tmp_path) -> None:
@@ -111,3 +115,54 @@ def test_woodpile_raster_switches_print_axis_between_layers(tmp_path) -> None:
     assert max(x_positions) <= 3.0
     assert min(y_positions) >= 0.0
     assert max(y_positions) <= 2.0
+
+
+def test_y_direction_raster_prints_each_layer_along_y_axis(tmp_path) -> None:
+    tiff_paths = []
+    for index in range(2):
+        tiff_path = tmp_path / f"slice_{index:04d}.tif"
+        Image.new("L", (3, 2), 0).save(tiff_path)
+        tiff_paths.append(tiff_path)
+
+    zip_path = tmp_path / "slices.zip"
+    with zipfile.ZipFile(zip_path, mode="w") as archive:
+        for tiff_path in tiff_paths:
+            archive.write(tiff_path, arcname=tiff_path.name)
+
+    gcode_path = generate_snake_path_gcode(
+        zip_path,
+        shape_name="y_direction",
+        pressure=25,
+        valve=7,
+        port=3,
+        raster_pattern=RASTER_PATTERN_Y_DIRECTION,
+    )
+
+    move_lines = [
+        line.strip()
+        for line in gcode_path.read_text().splitlines()
+        if line.startswith(("G0", "G1"))
+    ]
+    print_lines = [
+        line
+        for line in move_lines
+        if line.startswith("G1") and "; Color 255" in line
+    ]
+    assert print_lines
+    assert all("X0" in line and "Y0" not in line for line in print_lines)
+
+    x = y = 0.0
+    x_positions = [x]
+    y_positions = [y]
+    for line in move_lines:
+        for token in line.split():
+            if token.startswith("X"):
+                x += float(token[1:])
+            if token.startswith("Y"):
+                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) >= 0.0
+    assert max(y_positions) <= 2.0

tiff_to_gcode.py

@@ -11,14 +11,21 @@ import numpy as np
 from PIL import Image
 
 
-RASTER_PATTERN_SAME_DIRECTION = "Same-direction raster"
+RASTER_PATTERN_SAME_DIRECTION = "X-direction raster"
+RASTER_PATTERN_Y_DIRECTION = "Y-direction raster"
 RASTER_PATTERN_WOODPILE = "Woodpile raster"
-RASTER_PATTERN_CHOICES = (RASTER_PATTERN_SAME_DIRECTION, RASTER_PATTERN_WOODPILE)
+RASTER_PATTERN_CHOICES = (
+    RASTER_PATTERN_SAME_DIRECTION,
+    RASTER_PATTERN_Y_DIRECTION,
+    RASTER_PATTERN_WOODPILE,
+)
 
 
 def _normalize_raster_pattern(pattern: str | None) -> str:
     if pattern == RASTER_PATTERN_WOODPILE:
         return RASTER_PATTERN_WOODPILE
+    if pattern == RASTER_PATTERN_Y_DIRECTION:
+        return RASTER_PATTERN_Y_DIRECTION
     return RASTER_PATTERN_SAME_DIRECTION
 
 
@@ -299,18 +306,27 @@ def _woodpile_layer_segments(
     return segments
 
 
-def _build_woodpile_gcode_list(
+def _raster_axis_for_pattern(pattern: str, layer_number: int) -> str:
+    if pattern == RASTER_PATTERN_Y_DIRECTION:
+        return "Y"
+    if pattern == RASTER_PATTERN_WOODPILE and layer_number % 2 == 1:
+        return "Y"
+    return "X"
+
+
+def _build_footprint_raster_gcode_list(
     path_ref_list: list[np.ndarray],
     color_ref_list: list[np.ndarray],
     pixel_size: float,
     layer_height: float,
+    raster_pattern: str,
 ) -> list[dict]:
     gcode_list: list[dict] = []
     current_x = 0.0
     current_y = 0.0
 
     for layer_number, (path_img, color_img) in enumerate(zip(path_ref_list, color_ref_list)):
-        raster_axis = "X" if layer_number % 2 == 0 else "Y"
+        raster_axis = _raster_axis_for_pattern(raster_pattern, layer_number)
         segments = _woodpile_layer_segments(path_img, color_img, pixel_size, raster_axis)
         if not segments:
             if layer_number > 0:
@@ -423,12 +439,13 @@ def generate_snake_path_gcode(
     pressure_on_lines = [_toggle_cmd(com_port, start=True)]
     pressure_off_lines = [_toggle_cmd(com_port, start=False)]
 
-    if raster_pattern == RASTER_PATTERN_WOODPILE:
-        gcode_list = _build_woodpile_gcode_list(
+    if raster_pattern in (RASTER_PATTERN_Y_DIRECTION, RASTER_PATTERN_WOODPILE):
+        gcode_list = _build_footprint_raster_gcode_list(
             path_ref_list,
             color_ref_list,
             fil_width,
             layer_height,
+            raster_pattern,
         )
     else:
         gcode_list: list[dict] = []