diff --git a/src/spatialdata_plot/pl/utils.py b/src/spatialdata_plot/pl/utils.py
index ae55a9c8..6c5aaddf 100644
--- a/src/spatialdata_plot/pl/utils.py
+++ b/src/spatialdata_plot/pl/utils.py
@@ -2895,13 +2895,16 @@ def _get_extent_and_range_for_datashader_canvas(
             ]
         )
 
-    # compute canvas size in pixels close to the actual image size to speed up computation
+    # Compute canvas size in pixels, capped at the figure's display resolution.
+    # Using np.max ensures the canvas never exceeds display pixels on either axis,
+    # preventing pixel-based operations (spread, line_width) from being downscaled
+    # to sub-pixel size when the data aspect ratio differs from the figure's.
     plot_width = x_ext[1] - x_ext[0]
     plot_height = y_ext[1] - y_ext[0]
     plot_width_px = int(round(fig_params.fig.get_size_inches()[0] * fig_params.fig.dpi))
     plot_height_px = int(round(fig_params.fig.get_size_inches()[1] * fig_params.fig.dpi))
     factor: float
-    factor = np.min([plot_width / plot_width_px, plot_height / plot_height_px])
+    factor = np.max([plot_width / plot_width_px, plot_height / plot_height_px])
     plot_width = int(np.round(plot_width / factor))
     plot_height = int(np.round(plot_height / factor))
 
diff --git a/tests/_images/Points_datashader_can_transform_points.png b/tests/_images/Points_datashader_can_transform_points.png
index 6bd5506f..51813e64 100644
Binary files a/tests/_images/Points_datashader_can_transform_points.png and b/tests/_images/Points_datashader_can_transform_points.png differ
diff --git a/tests/_images/Shapes_datashader_can_render_shapes_with_colored_double_outline.png b/tests/_images/Shapes_datashader_can_render_shapes_with_colored_double_outline.png
index 8614e760..d5468723 100644
Binary files a/tests/_images/Shapes_datashader_can_render_shapes_with_colored_double_outline.png and b/tests/_images/Shapes_datashader_can_render_shapes_with_colored_double_outline.png differ
diff --git a/tests/_images/Shapes_datashader_can_render_shapes_with_double_outline.png b/tests/_images/Shapes_datashader_can_render_shapes_with_double_outline.png
index 5475f24f..6bb56592 100644
Binary files a/tests/_images/Shapes_datashader_can_render_shapes_with_double_outline.png and b/tests/_images/Shapes_datashader_can_render_shapes_with_double_outline.png differ
diff --git a/tests/_images/Shapes_datashader_can_render_with_diff_width_outline.png b/tests/_images/Shapes_datashader_can_render_with_diff_width_outline.png
index b638716a..e39c24f1 100644
Binary files a/tests/_images/Shapes_datashader_can_render_with_diff_width_outline.png and b/tests/_images/Shapes_datashader_can_render_with_diff_width_outline.png differ
diff --git a/tests/pl/test_render_points.py b/tests/pl/test_render_points.py
index e0574137..32e0b973 100644
--- a/tests/pl/test_render_points.py
+++ b/tests/pl/test_render_points.py
@@ -606,3 +606,14 @@ def test_plot_datashader_single_category_points(sdata_blobs: SpatialData):
         method="datashader",
         size=5,
     ).pl.show()
+
+
+def test_datashader_points_visible_with_nonuniform_scale(sdata_blobs: SpatialData):
+    """Datashader points must remain visible when data has a non-square aspect ratio.
+
+    Regression test for https://github.com/scverse/spatialdata-plot/issues/445.
+    Before the fix, the datashader canvas was oversized on the longer axis, causing
+    spread(px) to be downscaled to sub-pixel size on display.
+    """
+    _set_transformations(sdata_blobs["blobs_points"], {"global": Scale([1, 5], axes=("x", "y"))})
+    sdata_blobs.pl.render_points("blobs_points", method="datashader", color="black").pl.show()