plotly · emilykl · Jun 3, 2025 · May 27, 2025 · Jun 2, 2025 · Jun 2, 2025
diff --git a/plotly/io/_defaults.py b/plotly/io/_defaults.py
@@ -13,6 +13,7 @@ def __init__(self):
         self.default_scale = 1
         self.mathjax = None
         self.topojson = None
+        self.plotlyjs = None
 
 
 defaults = _Defaults()
diff --git a/plotly/io/_kaleido.py b/plotly/io/_kaleido.py
@@ -369,6 +369,12 @@ def to_image(
         from kaleido.errors import ChromeNotFoundError
 
         try:
+            kopts = {}
+            if defaults.plotlyjs:
+                kopts["plotlyjs"] = defaults.plotlyjs
+            if defaults.mathjax:
+                kopts["mathjax"] = defaults.mathjax
+
             # TODO: Refactor to make it possible to use a shared Kaleido instance here
             img_bytes = kaleido.calc_fig_sync(
                 fig_dict,
@@ -379,13 +385,7 @@ def to_image(
                     scale=scale or defaults.default_scale,
                 ),
                 topojson=defaults.topojson,
-                kopts=(
-                    dict(
-                        mathjax=defaults.mathjax,
-                    )
-                    if defaults.mathjax
-                    else None
-                ),
+                kopts=kopts,
             )
         except ChromeNotFoundError:
             raise RuntimeError(PLOTLY_GET_CHROME_ERROR_MSG)
@@ -692,15 +692,14 @@ def write_images(
     from kaleido.errors import ChromeNotFoundError
 
     try:
+        kopts = {}
+        if defaults.plotlyjs:
+            kopts["plotlyjs"] = defaults.plotlyjs
+        if defaults.mathjax:
+            kopts["mathjax"] = defaults.mathjax
         kaleido.write_fig_from_object_sync(
             kaleido_specs,
-            kopts=(
-                dict(
-                    mathjax=defaults.mathjax,
-                )
-                if defaults.mathjax
-                else None
-            ),
+            kopts=kopts,
         )
     except ChromeNotFoundError:
         raise RuntimeError(PLOTLY_GET_CHROME_ERROR_MSG)

diff --git a/pyproject.toml b/pyproject.toml
@@ -46,7 +46,7 @@ dependencies = [
 
 [project.optional-dependencies]
 express = ["numpy"]
-kaleido = ["kaleido==1.0.0rc13"]
+kaleido = ["kaleido==1.0.0rc15"]
 dev = ["black==25.1.0"]
 
 [project.scripts]

diff --git a/test_requirements/requirements_optional.txt b/test_requirements/requirements_optional.txt
@@ -18,7 +18,7 @@ matplotlib
 scikit-image
 psutil
 # kaleido>=1.0.0  # Uncomment and delete line below once Kaleido v1 is released
-kaleido==1.0.0rc13
+kaleido==1.0.0rc15
 orjson
 polars[timezone]
 pyarrow

diff --git a/tests/test_optional/test_kaleido/test_kaleido.py b/tests/test_optional/test_kaleido/test_kaleido.py
@@ -154,15 +154,105 @@ def test_bytesio():
 
 def test_defaults():
     """Test that image output defaults can be set using pio.defaults.*"""
+    test_fig = go.Figure(fig)
+    test_image_bytes = b"mock image data"
+
+    # Check initial defaults
+    assert pio.defaults.default_format == "png"
+    assert pio.defaults.default_width == 700
+    assert pio.defaults.default_height == 500
+    assert pio.defaults.default_scale == 1
+    assert pio.defaults.mathjax is None
+    assert pio.defaults.topojson is None
+    assert pio.defaults.plotlyjs is None
+
     try:
-        assert pio.defaults.default_format == "png"
+        # Set new defaults
         pio.defaults.default_format = "svg"
+        pio.defaults.default_width = 701
+        pio.defaults.default_height = 501
+        pio.defaults.default_scale = 2
+        pio.defaults.mathjax = (
+            "https://cdn.jsdelivr.net/npm/mathjax@3.1.2/es5/tex-svg.js"
+        )
+        pio.defaults.topojson = "path/to/topojson/files/"
+        pio.defaults.plotlyjs = "https://cdn.plot.ly/plotly-3.0.0.js"
+
+        # Check that new defaults are saved
         assert pio.defaults.default_format == "svg"
-        result = pio.to_image(fig, format="svg", validate=False)
+        assert pio.defaults.default_width == 701
+        assert pio.defaults.default_height == 501
+        assert pio.defaults.default_scale == 2
+        assert (
+            pio.defaults.mathjax
+            == "https://cdn.jsdelivr.net/npm/mathjax@3.1.2/es5/tex-svg.js"
+        )
+        assert pio.defaults.topojson == "path/to/topojson/files/"
+        assert pio.defaults.plotlyjs == "https://cdn.plot.ly/plotly-3.0.0.js"
+
+        if kaleido_major() > 0:
+            # Check that all the defaults values are passed through to the function call to calc_fig_sync
+            with patch(
+                "plotly.io._kaleido.kaleido.calc_fig_sync",
+                return_value=test_image_bytes,
+            ) as mock_calc_fig:
+                result = pio.to_image(test_fig, validate=False)
+
+                # Verify calc_fig_sync was called with correct args
+                # taken from pio.defaults
+                mock_calc_fig.assert_called_once()
+                args, kwargs = mock_calc_fig.call_args
+                assert args[0] == test_fig.to_dict()
+                assert kwargs["opts"]["format"] == "svg"
+                assert kwargs["opts"]["width"] == 701
+                assert kwargs["opts"]["height"] == 501
+                assert kwargs["opts"]["scale"] == 2
+                assert kwargs["topojson"] == "path/to/topojson/files/"
+                # mathjax and plotlyjs are passed through in kopts
+                assert (
+                    kwargs["kopts"]["mathjax"]
+                    == "https://cdn.jsdelivr.net/npm/mathjax@3.1.2/es5/tex-svg.js"
+                )
+                assert (
+                    kwargs["kopts"]["plotlyjs"] == "https://cdn.plot.ly/plotly-3.0.0.js"
+                )
+
+        else:
+            # Check that all the default values have been set in pio._kaleido.scope
+            assert pio._kaleido.scope.default_format == "svg"
+            assert pio._kaleido.scope.default_width == 701
+            assert pio._kaleido.scope.default_height == 501
+            assert pio._kaleido.scope.default_scale == 2
+            assert (
+                pio._kaleido.scope.mathjax
+                == "https://cdn.jsdelivr.net/npm/mathjax@3.1.2/es5/tex-svg.js"
+            )
+            assert pio._kaleido.scope.topojson == "path/to/topojson/files/"
+            assert pio._kaleido.scope.plotlyjs == "https://cdn.plot.ly/plotly-3.0.0.js"
+
+        # Set topojson default back to None
+        # (otherwise image generation will fail)
+        pio.defaults.topojson = None
+        # Generate image for real and make sure it's an SVG
+        result = test_fig.to_image(format="svg", validate=False)
         assert result.startswith(b"<svg")
+
     finally:
+        # Reset defaults to original values and check that they are restored
         pio.defaults.default_format = "png"
+        pio.defaults.default_width = 700
+        pio.defaults.default_height = 500
+        pio.defaults.default_scale = 1
+        pio.defaults.mathjax = None
+        pio.defaults.topojson = None
+        pio.defaults.plotlyjs = None
         assert pio.defaults.default_format == "png"
+        assert pio.defaults.default_width == 700
+        assert pio.defaults.default_height == 500
+        assert pio.defaults.default_scale == 1
+        assert pio.defaults.mathjax is None
+        assert pio.defaults.topojson is None
+        assert pio.defaults.plotlyjs is None
 
 
 def test_fig_write_image():