diff --git a/README.md b/README.md
index a186369..6cc8488 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,9 @@ directories and Python command can be overridden, for example:
 
 **There is a brute force path optimisator algorithm. Very slow for large files, can be disabled in config.py**
 
+Travel-distance measurements preserve all drawing shapes. Single-shape drawings
+have zero inter-shape travel; SVGs with no drawable shapes are rejected.
+
 Conversion raises Python's recursion limit to at least 100,000 as a temporary
 workaround for long SVG paths. Larger paths may still exceed this limit, and
 deep recursion can exhaust the stack on some Python versions and platforms.
@@ -32,6 +35,16 @@ deep recursion can exhaust the stack on some Python versions and platforms.
 **Illustrator exports in points, not mm** regardless of your document settings.  
 If units are set to points in the config file, we convert to mm on the fly.
 
+With `auto_scale = True` (the default), drawings outside
+`0 <= X <= bed_max_x` or `0 <= Y <= bed_max_y` are automatically fitted using
+their actual coordinate bounds after unit conversion and SVG transformations.
+Fitting preserves aspect ratio, never enlarges drawings, and shifts fitted
+drawings to start at X0/Y0. Drawings already in range remain unchanged.
+Set `auto_scale = False` to reject out-of-range drawings instead. The error
+reports the offending coordinate and bed limits; no output is created or
+overwritten on a size-check failure.
+These are work-coordinate limits, not a check of controller offsets or Z travel.
+
 There are various settings you can change in config.py. Most notably, you must set an upper and lower position for the z axis.
 
 The `preamble` is emitted after the header and before the feed rate and drawing
diff --git a/config.py b/config.py
index 581ebd4..5d640b7 100644
--- a/config.py
+++ b/config.py
@@ -33,15 +33,15 @@ zTravel = 2
 """ height that the z axis will use to draw """
 zDraw = 0
 
-""" feed rate """
-feed_rate = 80000
+""" drawing feed rate in mm/min """
+feed_rate = 1600
 
 """ decimal precision of gcode"""
 precision = 2
 
 
-""" scale gcode to fit bed size"""
-auto_scale = False
+""" shrink and shift out-of-bed drawings to fit, preserving aspect ratio"""
+auto_scale = True
 
 """ optimize path - slow for large files"""
 optimise = True
diff --git a/optimise.py b/optimise.py
index cdb829e..4382f9c 100644
--- a/optimise.py
+++ b/optimise.py
@@ -19,10 +19,8 @@ def get_distance(a, b, sq=False):
 def get_total_distance(shapes):
 
     total_distance = 0
-    last = shapes.pop(0)[-1]
-
-    for i in shapes:
-        total_distance += get_distance(i[0], last, sq=True)
+    for previous, current in zip(shapes, shapes[1:]):
+        total_distance += get_distance(current[0], previous[-1], sq=True)
 
     return total_distance
 
@@ -61,4 +59,3 @@ def optimise_path(shapes, sq=False):
 
     timer(t1, "optimizing       ")
     return new_order
-
diff --git a/svg2gcode.py b/svg2gcode.py
index fdb543a..2cae5c8 100755
--- a/svg2gcode.py
+++ b/svg2gcode.py
@@ -6,6 +6,7 @@ import shapes as shapes_pkg
 from shapes import point_generator
 from config import *
 import re
+from math import isfinite
 from datetime import datetime as dt
 from optimise import optimise_path, get_total_distance
 from utils import *
@@ -51,18 +52,6 @@ def get_shapes(path, auto_scale=True):
         width *= pointRatio
         height *= pointRatio
 
-    if auto_scale:
-        print("\nauto scaling")
-
-        scale_x = bed_max_x / max(width, height)
-        scale_y = bed_max_y / max(width, height)
-        scale_x = min(scale_x, scale_y)
-        scale_y = scale_x
-
-        print("width / height        ", width, height)
-        print("scale factor          ", scale_x, "\n")
-
-
     for elem in root.iter():
 
         try:
@@ -94,11 +83,6 @@ def get_shapes(path, auto_scale=True):
 
                     y = -y + height
 
-                    if auto_scale:
-
-                        x *= scale_x
-                        y *= scale_y
-
                     if first:
                         #coords.append((x, -y + height))
                         coords.append((x, y))
@@ -112,7 +96,41 @@ def get_shapes(path, auto_scale=True):
                     if first:
                         first = False
 
-            shapes.append(coords)
+            if coords:
+                shapes.append(coords)
+
+    if not (isfinite(bed_max_x) and isfinite(bed_max_y)
+            and bed_max_x > 0 and bed_max_y > 0):
+        raise ValueError("Bed dimensions must be finite and greater than zero")
+
+    points = [point for shape in shapes for point in shape]
+    if any(not (isfinite(x) and isfinite(y)) for x, y in points):
+        raise ValueError(f"{path}: drawing coordinates must be finite")
+
+    if auto_scale and points:
+        min_x = min(x for x, y in points)
+        max_x = max(x for x, y in points)
+        min_y = min(y for x, y in points)
+        max_y = max(y for x, y in points)
+        if min_x < 0 or max_x > bed_max_x or min_y < 0 or max_y > bed_max_y:
+            span_x = max_x - min_x
+            span_y = max_y - min_y
+            scale = min(1.0, bed_max_x / span_x if span_x else 1.0,
+                        bed_max_y / span_y if span_y else 1.0)
+            print("auto fitting: scale", scale, "origin", (min_x, min_y))
+            # Bound floating-point roundoff at the fitted upper edges.
+            shapes = [[(min(bed_max_x, (x - min_x) * scale),
+                        min(bed_max_y, (y - min_y) * scale))
+                       for x, y in shape] for shape in shapes]
+
+    for shape in shapes:
+        for x, y in shape:
+            if not (0 <= x <= bed_max_x and 0 <= y <= bed_max_y):
+                raise ValueError(
+                    f"{path}: drawing coordinate X{x:.6f} Y{y:.6f} mm "
+                    f"is outside bed limits X[0, {bed_max_x}] "
+                    f"Y[0, {bed_max_y}] mm"
+                )
 
     timer(t1, "parsing gcode    ")
 
@@ -168,21 +186,23 @@ def main(file_path, output):
     sys.setrecursionlimit(max(sys.getrecursionlimit(), 100000))
     shapes = get_shapes(file_path, auto_scale)
 
-
+    if not shapes:
+        raise ValueError(f"{file_path}: no drawable SVG shapes found")
 
     if optimise:
 
         pre_distance = get_total_distance(shapes)
 
-        print("unoptimised distance: ", get_total_distance(shapes))
-
         new_order = optimise_path(shapes)
 
         post_distance = get_total_distance(new_order)
 
         print("unoptimised distance: ", pre_distance)
         print("optimised distance    ", post_distance)
-        print("factor:               ", post_distance / pre_distance)
+        if pre_distance:
+            print("factor:               ", post_distance / pre_distance)
+        else:
+            print("factor:                not applicable (no travel between shapes)")
 
         commands = shapes_2_gcode(new_order)
 
diff --git a/test_bounds.py b/test_bounds.py
new file mode 100644
index 0000000..b2ca443
--- /dev/null
+++ b/test_bounds.py
@@ -0,0 +1,122 @@
+import tempfile
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+import svg2gcode
+
+
+class DrawingBoundsTests(unittest.TestCase):
+    def setUp(self):
+        self.directory = tempfile.TemporaryDirectory()
+        self.addCleanup(self.directory.cleanup)
+        self.source = Path(self.directory.name) / "drawing.svg"
+        self.output = Path(self.directory.name) / "drawing.gcode"
+        for name, value in (
+            ("bed_max_x", 200),
+            ("bed_max_y", 280),
+            ("units", "mm"),
+            ("auto_scale", False),
+        ):
+            patcher = patch.object(svg2gcode, name, value)
+            patcher.start()
+            self.addCleanup(patcher.stop)
+
+    def write_line(self, x1, y1, x2, y2, width=200, height=280, transform=""):
+        self.source.write_text(
+            f'<svg xmlns="http://www.w3.org/2000/svg" '
+            f'width="{width}" height="{height}">'
+            f'<line x1="{x1}" y1="{y1}" x2="{x2}" y2="{y2}" '
+            f'transform="{transform}"/></svg>'
+        )
+
+    def test_exact_boundaries_are_allowed(self):
+        self.write_line(0, 0, 200, 280)
+        shapes = svg2gcode.get_shapes(self.source, False)
+        self.assertIn((0, 280), shapes[0])
+        self.assertIn((200, 0), shapes[0])
+
+    def test_each_boundary_is_enforced(self):
+        for x, y in ((-0.0001, 100), (200.0001, 100),
+                     (100, -0.0001), (100, 280.0001)):
+            with self.subTest(x=x, y=y):
+                self.write_line(10, 10, x, y)
+                with self.assertRaisesRegex(ValueError, "outside bed limits"):
+                    svg2gcode.get_shapes(self.source, False)
+
+    def test_transformed_coordinates_are_checked(self):
+        self.write_line(10, 10, 20, 20, transform="translate(200, 0)")
+        with self.assertRaisesRegex(ValueError, "outside bed limits"):
+            svg2gcode.get_shapes(self.source, False)
+
+    def test_points_are_converted_before_checking(self):
+        self.write_line(0, 0, 500, 500, width=500, height=500)
+        with patch.object(svg2gcode, "units", "points"):
+            shapes = svg2gcode.get_shapes(self.source, False)
+        self.assertAlmostEqual(shapes[0][-1][0], 500 * 0.352778)
+
+    def test_auto_scaling_is_applied_before_checking(self):
+        self.write_line(0, 0, 400, 560, width=400, height=560)
+        shapes = svg2gcode.get_shapes(self.source, True)
+        self.assertTrue(all(0 <= x <= 200 and 0 <= y <= 280
+                            for shape in shapes for x, y in shape))
+        self.assertEqual(shapes[0], [(0, 280), (200, 0)])
+
+    def test_fitting_preserves_in_bounds_coordinates(self):
+        self.write_line(10, 10, 20, 20)
+        self.assertEqual(svg2gcode.get_shapes(self.source, True),
+                         svg2gcode.get_shapes(self.source, False))
+
+    def test_negative_coordinates_are_shifted_and_scaled(self):
+        self.write_line(-100, -100, 300, 300, height=200)
+        shapes = svg2gcode.get_shapes(self.source, True)
+        self.assertEqual(shapes[0], [(0, 200), (200, 0)])
+
+    def test_horizontal_vertical_and_single_point_drawings(self):
+        for coords, expected in (
+            ((-100, 100, 300, 100), [(0, 0), (200, 0)]),
+            ((100, -100, 100, 300), [(0, 280), (0, 0)]),
+            ((300, 100, 300, 100), [(0, 0)]),
+        ):
+            with self.subTest(coords=coords):
+                self.write_line(*coords)
+                self.assertEqual(svg2gcode.get_shapes(self.source, True)[0],
+                                 expected)
+
+    def test_fitting_uses_drawing_not_canvas_dimensions(self):
+        self.write_line(10, 300, 20, 350, width=500, height=500)
+        self.assertEqual(svg2gcode.get_shapes(self.source, True)[0],
+                         [(10, 200), (20, 150)])
+
+    def test_fitting_transformed_coordinates(self):
+        self.write_line(10, 10, 20, 20, transform="translate(200, 0)")
+        shapes = svg2gcode.get_shapes(self.source, True)
+        self.assertTrue(all(0 <= x <= 200 and 0 <= y <= 280
+                            for shape in shapes for x, y in shape))
+
+    def test_invalid_bed_dimensions_are_rejected(self):
+        self.write_line(10, 10, 20, 20)
+        for dimension in (0, -1, float("inf")):
+            with patch.object(svg2gcode, "bed_max_x", dimension):
+                with self.assertRaisesRegex(ValueError, "Bed dimensions"):
+                    svg2gcode.get_shapes(self.source, True)
+
+    def test_canvas_size_alone_does_not_reject_in_bounds_drawing(self):
+        self.write_line(10, 300, 20, 350, width=500, height=500)
+        self.assertTrue(svg2gcode.get_shapes(self.source, False))
+
+    def test_failure_does_not_create_or_overwrite_output(self):
+        self.write_line(10, 10, 201, 20)
+        with patch.object(svg2gcode, "optimise_path") as optimise_path:
+            with self.assertRaisesRegex(ValueError, "X201.000000"):
+                svg2gcode.main(self.source, self.output)
+            self.assertFalse(self.output.exists())
+            self.output.write_text("existing output")
+            with self.assertRaises(ValueError):
+                svg2gcode.main(self.source, self.output)
+            self.assertEqual(self.output.read_text(), "existing output")
+            optimise_path.assert_not_called()
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/test_optimise.py b/test_optimise.py
new file mode 100644
index 0000000..3ae48c7
--- /dev/null
+++ b/test_optimise.py
@@ -0,0 +1,45 @@
+import copy
+import tempfile
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+import svg2gcode
+from optimise import get_total_distance
+
+
+class OptimisationTests(unittest.TestCase):
+    def test_distance_does_not_remove_shapes(self):
+        shapes = [[(0, 0), (1, 0)], [(4, 0), (5, 0)], [(5, 4)]]
+        original = copy.deepcopy(shapes)
+        self.assertEqual(get_total_distance(shapes), 7)
+        self.assertEqual(get_total_distance(shapes), 7)
+        self.assertEqual(shapes, original)
+
+    def test_empty_and_single_shape_distance(self):
+        self.assertEqual(get_total_distance([]), 0)
+        self.assertEqual(get_total_distance([[(0, 0), (1, 1)]]), 0)
+
+    def test_single_shape_conversion_retains_all_moves(self):
+        with tempfile.TemporaryDirectory() as directory:
+            output = Path(directory) / "drawing.gcode"
+            shapes = [[(10, 20), (11, 21), (12, 22)]]
+            with patch.object(svg2gcode, "get_shapes", return_value=shapes), \
+                    patch.object(svg2gcode, "optimise", True):
+                svg2gcode.main("drawing.svg", output)
+            text = output.read_text()
+            for x, y in ((10, 20), (11, 21), (12, 22)):
+                self.assertIn(f"G1 X{x:.3f} Y{y:.3f}", text)
+            self.assertTrue(text.endswith("G0 Z2\nG0 X0 Y0\n"))
+
+    def test_no_shapes_is_an_explicit_error_without_output(self):
+        with tempfile.TemporaryDirectory() as directory:
+            output = Path(directory) / "drawing.gcode"
+            with patch.object(svg2gcode, "get_shapes", return_value=[]):
+                with self.assertRaisesRegex(ValueError, "no drawable SVG shapes"):
+                    svg2gcode.main("empty.svg", output)
+            self.assertFalse(output.exists())
+
+
+if __name__ == "__main__":
+    unittest.main()