new grayscale output for testing laser, not working, will change to new design

blender/scripts/random_patch_dd02c.py

@@ -681,9 +681,21 @@ def _clipped_shapes(shapes, width, height):
 
 def write_svg_vector(
     output_path, texture_width, texture_height, width_mm, height_mm,
-    mesh_polygons, patch_shapes, cross_rects, cross_color, uv_map
+    mesh_polygons, patch_shapes, cross_rects, cross_color, uv_map,
+    background=None,
 ):
-    """Write editable grouped SVG geometry; no raster data is embedded."""
+    """Write editable grouped SVG geometry; no raster data is embedded.
+
+    ``background`` is the page fill. Left as ``None`` it is the black production ground; the
+    laser-engraving variant passes white, because a laser cuts what is dark and an
+    unengraved sheet must be light.
+    """
+    if background is None:
+        background_fill = "#000000"
+    else:
+        background_fill = "#" + "".join(
+            f"{round(_clamp_channel(channel) * 255):02x}" for channel in background[:3]
+        )
     lines = [
         '<?xml version="1.0" encoding="UTF-8"?>',
         (
@@ -705,7 +717,7 @@ def write_svg_vector(
         (
             f'      <rect id="background-fill" x="0" y="0" '
             f'width="{texture_width}" height="{texture_height}" '
-            f'fill="#000000" stroke="none"/>'
+            f'fill="{background_fill}" stroke="none"/>'
         ),
         "    </g>",
         '    <g id="mesh">',
@@ -785,15 +797,26 @@ def _build_pdf(objects):
 
 def write_pdf_vector(
     output_path, texture_width, texture_height, width_mm, height_mm,
-    mesh_polygons, patch_shapes, cross_rects, cross_color
+    mesh_polygons, patch_shapes, cross_rects, cross_color,
+    background=None,
 ):
-    """Write native vector PDF paths at the configured physical page size."""
+    """Write native vector PDF paths at the configured physical page size.
+
+    ``background`` as for `write_svg_vector`. The default emits the original literal command
+    so existing documents stay byte-identical.
+    """
     page_width_pt = float(width_mm) * 72.0 / 25.4
     page_height_pt = float(height_mm) * 72.0 / 25.4
     scale_x = page_width_pt / float(texture_width)
     scale_y = page_height_pt / float(texture_height)
 
-    content = ["q", "% background", "0 0 0 rg"]
+    if background is None:
+        background_command = "0 0 0 rg"
+    else:
+        background_command = _pdf_set_fill(
+            (background[0], background[1], background[2], 1.0)
+        )
+    content = ["q", "% background", background_command]
     content.append(
         f"0 0 {_format_number(page_width_pt)} {_format_number(page_height_pt)} re f"
     )