#
# Authors: The MNE-Python contributors.
# License: BSD-3-Clause
# Copyright the MNE-Python contributors.

import os
import platform
from contextlib import nullcontext
from pathlib import Path
from shutil import copyfile

import numpy as np
import pytest
from matplotlib import image
from matplotlib.lines import Line2D
from numpy.testing import assert_allclose, assert_array_equal

from mne import (
    Dipole,
    MixedSourceEstimate,
    SourceEstimate,
    VolSourceEstimate,
    create_info,
    pick_types_forward,
    read_cov,
    read_evokeds,
    read_forward_solution,
    read_source_estimate,
    vertex_to_mni,
    write_surface,
)
from mne.channels import make_dig_montage
from mne.datasets import testing
from mne.io import read_info
from mne.label import read_label
from mne.minimum_norm import apply_inverse, make_inverse_operator
from mne.source_estimate import _BaseSourceEstimate
from mne.source_space import read_source_spaces, setup_volume_source_space
from mne.utils import check_version
from mne.viz import ui_events
from mne.viz._brain import Brain, _BrainScraper, _LayeredMesh, _LinkViewer
from mne.viz._brain.colormap import calculate_lut
from mne.viz.utils import _get_cmap

data_path = testing.data_path(download=False)
subject = "sample"
subjects_dir = data_path / "subjects"
sample_dir = data_path / "MEG" / "sample"
fname_raw_testing = sample_dir / "sample_audvis_trunc_raw.fif"
fname_trans = sample_dir / "sample_audvis_trunc-trans.fif"
fname_stc = sample_dir / "sample_audvis_trunc-meg"
fname_label = sample_dir / "labels" / "Vis-lh.label"
fname_cov = sample_dir / "sample_audvis_trunc-cov.fif"
fname_evoked = sample_dir / "sample_audvis_trunc-ave.fif"
fname_fwd = sample_dir / "sample_audvis_trunc-meg-eeg-oct-4-fwd.fif"
src_fname = subjects_dir / subject / "bem" / "sample-oct-6-src.fif"

pytest.importorskip("nibabel")


class _Collection:
    def __init__(self, actors):
        self._actors = actors

    def GetNumberOfItems(self):
        return len(self._actors)

    def GetItemAsObject(self, ii):
        return self._actors[ii]


class TstVTKPicker:
    """Class to test cell picking."""

    def __init__(self, mesh, cell_id, hemi, brain):
        self.mesh = mesh
        self.cell_id = cell_id
        self.point_id = None
        self.hemi = hemi
        self.brain = brain
        self._actors = ()

    def GetCellId(self):
        """Return the picked cell."""
        return self.cell_id

    def GetDataSet(self):
        """Return the picked mesh."""
        return self.mesh

    def GetPickPosition(self):
        """Return the picked position."""
        if self.hemi == "vol":
            self.point_id = self.cell_id
            return self.brain._data["vol"]["grid_coords"][self.cell_id]
        else:
            vtk_cell = self.mesh.GetCell(self.cell_id)
            cell = [
                vtk_cell.GetPointId(point_id)
                for point_id in range(vtk_cell.GetNumberOfPoints())
            ]
            self.point_id = cell[0]
            return self.mesh.points[self.point_id]

    def GetProp3Ds(self):
        """Return all picked Prop3Ds."""
        return _Collection(self._actors)

    def GetRenderer(self):
        """Return the "renderer"."""
        return self  # set this to also be the renderer and active camera

    GetActiveCamera = GetRenderer

    def GetPosition(self):
        """Return the position."""
        return np.array(self.GetPickPosition()) - (0, 0, 100)


# TODO: allow_unclosed for macOS here as the conda and M1 builds show some
# windows stay open afterward
@pytest.mark.allow_unclosed
def test_layered_mesh(renderer_interactive_pyvistaqt):
    """Test management of scalars/colormap overlay."""
    mesh = _LayeredMesh(
        renderer=renderer_interactive_pyvistaqt._get_renderer(size=(300, 300)),
        vertices=np.array([[0, 0, 0], [1, 0, 0], [0, 1, 0], [1, 1, 0]]),
        triangles=np.array([[0, 1, 2], [1, 2, 3]]),
        normals=np.array([[0, 0, 1]] * 4),
    )
    assert not mesh._is_mapped
    mesh.map()
    assert mesh._is_mapped
    assert mesh._current_colors is None
    assert mesh._cached_colors is None
    mesh.update()
    assert len(mesh._overlays) == 0
    mesh.add_overlay(
        scalars=np.array([0, 1, 1, 0]),
        colormap=np.array([(1, 1, 1, 1), (0, 0, 0, 0)]),
        rng=[0, 1],
        opacity=None,
        name="test1",
    )
    assert mesh._current_colors is not None
    assert mesh._cached_colors is None
    assert len(mesh._overlays) == 1
    assert "test1" in mesh._overlays
    mesh.add_overlay(
        scalars=np.array([1, 0, 0, 1]),
        colormap=np.array([(1, 1, 1, 1), (0, 0, 0, 0)]),
        rng=[0, 1],
        opacity=None,
        name="test2",
    )
    assert mesh._current_colors is not None
    assert mesh._cached_colors is not None
    assert len(mesh._overlays) == 2
    assert "test2" in mesh._overlays
    mesh.remove_overlay("test2")
    assert "test2" not in mesh._overlays
    mesh.update()
    assert len(mesh._overlays) == 1
    mesh._clean()


@testing.requires_testing_data
def test_brain_gc(renderer_pyvistaqt, brain_gc):
    """Test that a minimal version of Brain gets GC'ed."""
    brain = Brain("fsaverage", "both", "inflated", subjects_dir=subjects_dir)
    brain.close()


@testing.requires_testing_data
def test_brain_data_gc(renderer_interactive_pyvistaqt, brain_gc):
    """Test that a version of Brain with added data gets GC'ed."""
    brain = _create_testing_brain(hemi="both", show_traces="vertex")
    brain.close()


@testing.requires_testing_data
def test_brain_routines(renderer, brain_gc):
    """Test backend agnostic Brain routines."""
    brain_klass = renderer.get_brain_class()
    from mne.viz._brain import Brain

    assert brain_klass == Brain


@testing.requires_testing_data
def test_brain_init(renderer_pyvistaqt, tmp_path, pixel_ratio, brain_gc):
    """Test initialization of the Brain instance."""

    class FakeSTC(_BaseSourceEstimate):
        def __init__(self):
            pass

    hemi = "lh"
    surf = "inflated"
    cortex = "low_contrast"
    title = "test"
    size = (300, 300)

    kwargs = dict(subject=subject, subjects_dir=subjects_dir)
    with pytest.raises(ValueError, match='"size" parameter must be'):
        Brain(hemi=hemi, surf=surf, size=[1, 2, 3], **kwargs)
    with pytest.raises(ValueError, match=".*hemi.*Allowed values.*"):
        Brain(hemi="foo", surf=surf, **kwargs)
    with pytest.raises(ValueError, match=".*view.*Allowed values.*"):
        Brain(hemi="lh", surf=surf, views="foo", **kwargs)
    with pytest.raises(TypeError, match="figure"):
        Brain(hemi=hemi, surf=surf, figure="foo", **kwargs)
    with pytest.raises(TypeError, match="interaction"):
        Brain(hemi=hemi, surf=surf, interaction=0, **kwargs)
    with pytest.raises(ValueError, match="interaction"):
        Brain(hemi=hemi, surf=surf, interaction="foo", **kwargs)
    with pytest.raises(FileNotFoundError, match=r"lh\.whatever"):
        Brain(hemi="lh", surf="whatever", **kwargs)
    with pytest.raises(ValueError, match="`surf` cannot be seghead"):
        Brain(hemi="lh", surf="seghead", **kwargs)
    with pytest.raises(ValueError, match="RGB argument"):
        Brain("sample", cortex="badcolor")
    # test no surfaces
    with pytest.raises(TypeError, match="missing 1 required positional"):
        Brain()
    renderer_pyvistaqt.backend._close_all()

    brain = Brain(
        hemi=hemi,
        surf=surf,
        size=size,
        title=title,
        cortex=cortex,
        units="m",
        silhouette=dict(decimate=0.95),
        **kwargs,
    )
    assert "data" not in brain._actors
    with pytest.raises(TypeError, match="not supported"):
        brain._check_stc(hemi="lh", array=FakeSTC(), vertices=None)
    with pytest.raises(ValueError, match="add_data"):
        brain.setup_time_viewer(time_viewer=True)
    brain._hemi = "foo"  # for testing: hemis
    with pytest.raises(ValueError, match="not be None"):
        brain._check_hemi(hemi=None)
    with pytest.raises(ValueError, match="Invalid.*hemi.*Allowed"):
        brain._check_hemi(hemi="foo")
    brain._hemi = hemi  # end testing: hemis
    with pytest.raises(ValueError, match="bool or positive"):
        brain._to_borders(None, None, "foo")
    assert brain.interaction == "trackball"
    # add_data
    stc = read_source_estimate(fname_stc)
    fmin = stc.data.min()
    fmax = stc.data.max()
    for h in brain._hemis:
        if h == "lh":
            hi = 0
        else:
            hi = 1
        hemi_data = stc.data[: len(stc.vertices[hi]), 10]
        hemi_vertices = stc.vertices[hi]

        with pytest.raises(TypeError, match="scale_factor"):
            brain.add_data(hemi_data, hemi=h, scale_factor="foo")
        with pytest.raises(TypeError, match="vector_alpha"):
            brain.add_data(hemi_data, hemi=h, vector_alpha="foo")
        with pytest.raises(ValueError, match="thresh"):
            brain.add_data(hemi_data, hemi=h, thresh=-1)
        with pytest.raises(ValueError, match="remove_existing"):
            brain.add_data(hemi_data, hemi=h, remove_existing=-1)
        with pytest.raises(ValueError, match="time_label_size"):
            brain.add_data(
                hemi_data, hemi=h, time_label_size=-1, vertices=hemi_vertices
            )
        with pytest.raises(ValueError, match="is positive"):
            brain.add_data(
                hemi_data, hemi=h, smoothing_steps=-1, vertices=hemi_vertices
            )
        with pytest.raises(TypeError, match="int or NoneType"):
            brain.add_data(hemi_data, hemi=h, smoothing_steps="foo")
        with pytest.raises(ValueError, match="dimension mismatch"):
            brain.add_data(array=np.array([0, 1, 2]), hemi=h, vertices=hemi_vertices)
        with pytest.raises(ValueError, match="vertices parameter must not be"):
            brain.add_data(hemi_data, fmin=fmin, hemi=hemi, fmax=fmax, vertices=None)
        with pytest.raises(ValueError, match="has shape"):
            brain.add_data(
                hemi_data[:, np.newaxis],
                fmin=fmin,
                hemi=hemi,
                fmax=fmax,
                vertices=None,
                time=[0, 1],
            )

        brain.add_data(
            hemi_data,
            fmin=fmin,
            hemi=h,
            fmax=fmax,
            colormap="hot",
            vertices=hemi_vertices,
            smoothing_steps="nearest",
            colorbar=(0, 0),
            time=None,
        )
        with pytest.raises(ValueError, match="brain has no defined times"):
            brain.set_time(0.0)
        assert brain.data["lh"]["array"] is hemi_data
        assert brain.views == ["lateral"]
        assert brain.hemis == ("lh",)
        brain.add_data(
            hemi_data[:, np.newaxis],
            fmin=fmin,
            hemi=h,
            fmax=fmax,
            colormap="hot",
            vertices=hemi_vertices,
            smoothing_steps=1,
            initial_time=0.0,
            colorbar=False,
            time=[0],
        )
        with pytest.raises(ValueError, match="the range of available times"):
            brain.set_time(7.0)
        brain.set_time(0.0)
        brain.set_time_point(0)  # should hit _safe_interp1d

        with pytest.raises(ValueError, match="consistent with"):
            brain.add_data(
                hemi_data[:, np.newaxis],
                fmin=fmin,
                hemi=h,
                fmax=fmax,
                colormap="hot",
                vertices=hemi_vertices,
                smoothing_steps="nearest",
                colorbar=False,
                time=[1],
            )
        with pytest.raises(ValueError, match="different from"):
            brain.add_data(
                hemi_data[:, np.newaxis][:, [0, 0]],
                fmin=fmin,
                hemi=h,
                fmax=fmax,
                colormap="hot",
                vertices=hemi_vertices,
            )
        with pytest.raises(ValueError, match="need shape"):
            brain.add_data(
                hemi_data[:, np.newaxis],
                time=[0, 1],
                fmin=fmin,
                hemi=h,
                fmax=fmax,
                colormap="hot",
                vertices=hemi_vertices,
            )
        with pytest.raises(ValueError, match="If array has 3"):
            brain.add_data(
                hemi_data[:, np.newaxis, np.newaxis],
                fmin=fmin,
                hemi=h,
                fmax=fmax,
                colormap="hot",
                vertices=hemi_vertices,
            )
    assert len(brain._actors["data"]) == 4
    brain.remove_data()
    assert "data" not in brain._actors
    assert "time_change" not in ui_events._get_event_channel(brain)

    # add label
    label = read_label(fname_label)
    with pytest.raises(ValueError, match="not a filename"):
        brain.add_label(0)
    with pytest.raises(ValueError, match="does not exist"):
        brain.add_label("foo", subdir="bar")
    label.name = None  # test unnamed label
    brain.add_label(label, scalar_thresh=0.0, color="green")
    assert isinstance(brain.labels[label.hemi], list)
    overlays = brain._layered_meshes[label.hemi]._overlays
    assert "unnamed0" in overlays
    assert np.allclose(
        overlays["unnamed0"]._colormap[0], [0, 0, 0, 0]
    )  # first component is transparent
    assert np.allclose(
        overlays["unnamed0"]._colormap[1], [0, 128, 0, 255]
    )  # second is green
    brain.remove_labels()
    assert "unnamed0" not in overlays
    brain.add_label(str(fname_label))
    brain.add_label("V1", borders=True)
    brain.remove_labels()
    brain.remove_labels()

    # add foci
    brain.add_foci([0], coords_as_verts=True, hemi=hemi, color="blue")

    # add head and skull
    brain.add_head(color="red", alpha=0.1)
    brain.remove_head()
    brain.add_skull(outer=True, color="green", alpha=0.1)
    brain.remove_skull()

    # add volume labels
    plotargs = {
        "bcolor": (0.5, 0.5, 0.5),
        "border": False,
        "size": (0.2, 0.6),
        "loc": "upper left",
    }
    brain.add_volume_labels(
        aseg="aseg",
        labels=("Brain-Stem", "Left-Hippocampus", "Left-Amygdala"),
        legend=plotargs,
    )
    brain.remove_volume_labels()

    # add sensors
    info = read_info(fname_raw_testing)
    brain.add_sensors(info, trans=fname_trans)
    for kind in ("meg", "eeg", "fnirs", "ecog", "seeg", "dbs", "helmet"):
        brain.remove_sensors(kind)
    brain.add_sensors(info, trans=fname_trans)
    brain.remove_sensors()

    info["chs"][0]["coord_frame"] = 99
    with pytest.raises(RuntimeError, match='must be "meg", "head" or "mri"'):
        brain.add_sensors(info, trans=fname_trans)
    brain.close()

    # test sEEG projection onto inflated
    # make temp path to fake pial surface
    os.makedirs(tmp_path / subject / "surf", exist_ok=True)
    for hemi in ("lh", "rh"):
        # fake white surface for pial, and no .curv file
        copyfile(
            subjects_dir / subject / "surf" / f"{hemi}.white",
            tmp_path / subject / "surf" / f"{hemi}.pial",
        )
        copyfile(
            subjects_dir / subject / "surf" / f"{hemi}.inflated",
            tmp_path / subject / "surf" / f"{hemi}.inflated",
        )
    brain = Brain(
        hemi=hemi,
        surf=surf,
        size=size,
        title=title,
        cortex=cortex,
        units="m",
        subject=subject,
        subjects_dir=tmp_path,
    )
    proj_info = create_info([f"Ch{i}" for i in range(1, 7)], 1000, "seeg")
    pos = (
        np.array(
            [
                [25.85, 9.04, -5.38],
                [33.56, 9.04, -5.63],
                [40.44, 9.04, -5.06],
                [46.75, 9.04, -6.78],
                [-30.08, 9.04, 28.23],
                [-32.95, 9.04, 37.99],
                [-36.39, 9.04, 46.03],
            ]
        )
        / 1000
    )
    proj_info.set_montage(
        make_dig_montage(ch_pos=dict(zip(proj_info.ch_names, pos)), coord_frame="head")
    )
    brain.add_sensors(proj_info, trans=fname_trans)
    brain._subjects_dir = subjects_dir  # put back

    # add dipole
    dip = Dipole(
        times=[0],
        pos=[[-0.06439933, 0.00733009, 0.06280205]],
        amplitude=[3e-8],
        ori=[[0, 1, 0]],
        gof=50,
    )
    brain.add_dipole(dip, fname_trans, colors="blue", scales=5, alpha=0.5)
    brain.remove_dipole()

    with pytest.raises(ValueError, match="The number of colors"):
        brain.add_dipole(dip, fname_trans, colors=["red", "blue"])

    with pytest.raises(ValueError, match="The number of scales"):
        brain.add_dipole(dip, fname_trans, scales=[1, 2])

    fwd = read_forward_solution(fname_fwd)
    brain.add_forward(fwd, fname_trans, alpha=0.5, scale=10)
    brain.remove_forward()

    # fake incorrect coordinate frame
    fwd["coord_frame"] = 99
    with pytest.raises(RuntimeError, match='must be "head" or "mri"'):
        brain.add_forward(fwd, fname_trans)
    fwd["coord_frame"] = 2003
    with pytest.raises(RuntimeError, match='must be "head" or "mri"'):
        brain.add_forward(fwd, fname_trans)

    # add text
    brain.add_text(x=0, y=0, text="foo")
    with pytest.raises(ValueError, match="already exists"):
        brain.add_text(x=0, y=0, text="foo")
    brain.remove_text("foo")
    brain.add_text(x=0, y=0, text="foo")
    brain.remove_text()

    brain.close()

    # add annotation
    annots = [
        "aparc",
        subjects_dir / "fsaverage" / "label" / "lh.PALS_B12_Lobes.annot",
    ]
    borders = [True, 2]
    alphas = [1, 0.5]
    colors = [None, "r"]
    brain = Brain(
        subject="fsaverage",
        hemi="both",
        size=size,
        surf="inflated",
        subjects_dir=subjects_dir,
    )
    with pytest.raises(ValueError, match="does not exist"):
        brain.add_annotation("foo")
    brain.add_annotation(annots[1])
    brain.close()
    brain = Brain(
        subject="fsaverage",
        hemi=hemi,
        size=size,
        surf="inflated",
        subjects_dir=subjects_dir,
    )
    for a, b, p, color in zip(annots, borders, alphas, colors):
        brain.add_annotation(str(a), b, p, color=color)
    brain.close()


# TODO: Figure out why brain_gc is problematic here on PyQt5
@pytest.mark.allow_unclosed
@testing.requires_testing_data
@pytest.mark.parametrize(
    "sensor_colors, sensor_scales, expectation",
    [
        (
            {"seeg": ["k"] * 5},
            {"seeg": [2] * 6},
            pytest.raises(
                ValueError,
                match=r"Invalid value for the 'len\(sensor_colors\['seeg'\]\)' "
                r"parameter. Allowed values are \d+ and \d+, but got \d+ instead",
            ),
        ),
        (
            {"seeg": ["k"] * 6},
            {"seeg": [2] * 5},
            pytest.raises(
                ValueError,
                match=r"Invalid value for the 'len\(sensor_scales\['seeg'\]\)' "
                r"parameter. Allowed values are \d+ and \d+, but got \d+ instead",
            ),
        ),
        (
            "NotAColor",
            2,
            pytest.raises(
                ValueError,
                match=r".* is not a valid color value",
            ),
        ),
        (
            "k",
            "k",
            pytest.raises(
                AssertionError,
                match=r"scales for .* must contain only numerical values, got .* "
                r"instead.",
            ),
        ),
        (
            "k",
            2,
            nullcontext(),
        ),
        (
            ["k"] * 6,
            [2] * 6,
            nullcontext(),
        ),
        (
            {"seeg": ["k"] * 6},
            {"seeg": [2] * 6},
            nullcontext(),
        ),
    ],
)
def test_add_sensors_scales(
    renderer_interactive_pyvistaqt,
    sensor_colors,
    sensor_scales,
    expectation,
):
    """Test sensor_scales parameter."""
    kwargs = dict(subject=subject, subjects_dir=subjects_dir)
    hemi = "lh"
    surf = "white"
    cortex = "low_contrast"
    title = "test"
    size = (300, 300)

    brain = Brain(
        hemi=hemi,
        surf=surf,
        size=size,
        title=title,
        cortex=cortex,
        units="m",
        silhouette=dict(decimate=0.95),
        **kwargs,
    )

    proj_info = create_info([f"Ch{i}" for i in range(1, 7)], 1000, "seeg")
    pos = (
        np.array(
            [
                [25.85, 9.04, -5.38],
                [33.56, 9.04, -5.63],
                [40.44, 9.04, -5.06],
                [46.75, 9.04, -6.78],
                [-30.08, 9.04, 28.23],
                [-32.95, 9.04, 37.99],
            ]
        )
        / 1000
    )
    proj_info.set_montage(
        make_dig_montage(ch_pos=dict(zip(proj_info.ch_names, pos)), coord_frame="head")
    )
    with expectation:
        brain.add_sensors(
            proj_info,
            trans=fname_trans,
            sensor_colors=sensor_colors,
            sensor_scales=sensor_scales,
        )
    brain.close()


def _assert_view_allclose(
    brain,
    roll,
    distance,
    azimuth,
    elevation,
    focalpoint,
    align=True,
):
    __tracebackhide__ = True
    r_, d_, a_, e_, f_ = brain.get_view(align=align)
    assert_allclose(r_, roll, err_msg="Roll")
    assert_allclose(d_, distance, rtol=1e-5, err_msg="Distance")
    assert_allclose(a_, azimuth, rtol=1e-5, atol=1e-6, err_msg="Azimuth")
    assert_allclose(e_, elevation, rtol=1e-5, atol=1e-6, err_msg="Elevation")
    assert_allclose(f_, focalpoint, err_msg="Focal point")
    cam = brain._renderer.figure.plotter.camera
    assert_allclose(cam.GetFocalPoint(), focalpoint, err_msg="Camera focal point")
    assert_allclose(cam.GetDistance(), distance, rtol=1e-5, err_msg="Camera distance")
    assert_allclose(cam.GetRoll(), roll, atol=1e-5, err_msg="Camera roll")


@pytest.mark.parametrize("align", (True, False))
def test_view_round_trip(renderer_interactive_pyvistaqt, tmp_path, brain_gc, align):
    """Test get_view / set_view round-trip."""
    brain = _create_testing_brain(hemi="lh")
    img = brain.screenshot()
    roll, distance, azimuth, elevation, focalpoint = brain.get_view(align=align)
    brain.show_view(
        azimuth=azimuth,
        elevation=elevation,
        focalpoint=focalpoint,
        roll=roll,
        distance=distance,
        align=align,
    )
    img_1 = brain.screenshot()
    assert_allclose(img, img_1)
    _assert_view_allclose(brain, roll, distance, azimuth, elevation, focalpoint, align)

    # Now with custom values
    roll, distance, focalpoint = 1, 500, (1e-5, 1e-5, 1e-5)
    view_args = dict(roll=roll, distance=distance, focalpoint=focalpoint, align=align)
    brain.show_view(**view_args)
    _assert_view_allclose(brain, roll, distance, azimuth, elevation, focalpoint, align)

    # test get_view
    azimuth, elevation = 180.0, 90.0
    view_args.update(azimuth=azimuth, elevation=elevation)
    brain.show_view(**view_args)
    _assert_view_allclose(brain, roll, distance, azimuth, elevation, focalpoint, align)
    brain.close()


def test_image_screenshot(
    renderer_interactive_pyvistaqt,
    tmp_path,
    pixel_ratio,
    brain_gc,
):
    """Test screenshot and image saving."""
    size = (300, 300)
    brain = _create_testing_brain(hemi="rh", show_traces=False, size=size)
    azimuth, elevation = 180.0, 90.0
    fname = tmp_path / "test.png"
    assert not fname.is_file()
    brain.save_image(fname)
    assert fname.is_file()
    fp = np.array(brain._renderer.figure.plotter.renderer.ComputeVisiblePropBounds())
    fp = (fp[1::2] + fp[::2]) * 0.5
    for view_args in (
        dict(azimuth=azimuth, elevation=elevation, focalpoint="auto"),
        dict(view="lateral", hemi="rh"),
    ):
        brain.show_view(**view_args)
        _, _, a_, e_, f_ = brain.get_view()
        assert_allclose(a_, azimuth, atol=1e-6)
        assert_allclose(e_, elevation)
        assert_allclose(f_, fp, atol=1e-6)
    img = brain.screenshot(mode="rgba")
    want_size = np.array([size[0] * pixel_ratio, size[1] * pixel_ratio, 4])
    # on macOS sometimes matplotlib is HiDPI and VTK is not...
    div = 2 if np.allclose(img.shape[:2], want_size[:2] / 2.0, atol=15) else 1
    want_size[:2] /= div
    assert_allclose(img.shape, want_size, atol=15)
    brain.close()


@testing.requires_testing_data
@pytest.mark.skipif(
    os.getenv("CI_OS_NAME", "").startswith("macos"),
    reason="Unreliable/segfault on macOS CI",
)
@pytest.mark.parametrize("hemi", ("lh", "rh"))
def test_single_hemi(hemi, renderer_interactive_pyvistaqt, brain_gc):
    """Test single hemi support."""
    stc = read_source_estimate(fname_stc)
    idx, order = (0, 1) if hemi == "lh" else (1, -1)
    stc = SourceEstimate(
        getattr(stc, f"{hemi}_data"), [stc.vertices[idx], []][::order], 0, 1, "sample"
    )
    brain = stc.plot(
        subjects_dir=subjects_dir, hemi="both", size=300, cortex="0.5"
    )  # single cortex string arg
    brain.close()

    # test skipping when len(vertices) == 0
    stc.vertices[1 - idx] = np.array([])
    brain = stc.plot(subjects_dir=subjects_dir, hemi=hemi, size=300)
    brain.close()


@testing.requires_testing_data
@pytest.mark.slowtest
@pytest.mark.parametrize("interactive_state", (False, True))
def test_brain_save_movie(tmp_path, renderer, brain_gc, interactive_state):
    """Test saving a movie of a Brain instance."""
    imageio_ffmpeg = pytest.importorskip("imageio_ffmpeg")
    # TODO: Figure out why this fails -- some imageio_ffmpeg error
    if os.getenv("MNE_CI_KIND", "") == "conda" and platform.system() == "Linux":
        pytest.skip("Test broken for unknown reason on conda linux")

    brain = _create_testing_brain(
        hemi="lh", time_viewer=False, cortex=["r", "b"]
    )  # custom binarized
    filename = tmp_path / "brain_test.mov"

    try:
        # for coverage, we set interactivity
        if interactive_state:
            brain._renderer.plotter.enable()
        else:
            brain._renderer.plotter.disable()
        with pytest.raises(TypeError, match="unexpected keyword argument"):
            brain.save_movie(
                filename, time_dilation=1, tmin=1, tmax=1.1, bad_name="blah"
            )
        assert not filename.is_file()
        tmin = 1
        tmax = 5
        duration = np.floor(tmax - tmin)
        brain.save_movie(
            filename, time_dilation=1.0, tmin=tmin, tmax=tmax, interpolation="nearest"
        )
        assert filename.is_file()
        _, nsecs = imageio_ffmpeg.count_frames_and_secs(filename)
        assert_allclose(duration, nsecs, atol=0.2)

        os.remove(filename)
    finally:
        brain.close()


_TINY_SIZE = (350, 300)


def tiny(tmp_path):
    """Create a tiny fake brain."""
    # This is a minimal version of what we need for our viz-with-timeviewer
    # support currently
    subject = "test"
    (tmp_path / subject).mkdir()
    subject_dir = tmp_path / subject
    (subject_dir / "surf").mkdir()
    surf_dir = subject_dir / "surf"
    rng = np.random.RandomState(0)
    rr = rng.randn(4, 3)
    tris = np.array([[0, 1, 2], [2, 1, 3]])
    curv = rng.randn(len(rr))
    with open(surf_dir / "lh.curv", "wb") as fid:
        fid.write(np.array([255, 255, 255], dtype=np.uint8))
        fid.write(np.array([len(rr), 0, 1], dtype=">i4"))
        fid.write(curv.astype(">f4"))
    write_surface(surf_dir / "lh.white", rr, tris)
    write_surface(surf_dir / "rh.white", rr, tris)  # needed for vertex tc
    vertices = [np.arange(len(rr)), []]
    data = rng.randn(len(rr), 10)
    stc = SourceEstimate(data, vertices, 0, 1, subject)
    brain = stc.plot(subjects_dir=tmp_path, hemi="lh", surface="white", size=_TINY_SIZE)
    # in principle this should be sufficient:
    #
    # ratio = brain.mpl_canvas.canvas.window().devicePixelRatio()
    #
    # but in practice VTK can mess up sizes, so let's just calculate it.
    sz = brain.plotter.size()
    sz = (sz.width(), sz.height())
    sz_ren = brain.plotter.renderer.GetSize()
    ratio = np.round(np.median(np.array(sz_ren) / np.array(sz))).astype(int)
    return brain, ratio


@pytest.mark.filterwarnings("ignore:.*constrained_layout not applied.*:")
def test_brain_screenshot(renderer_interactive_pyvistaqt, tmp_path, brain_gc):
    """Test time viewer screenshot."""
    # This is broken on Conda + GHA for some reason
    from qtpy import API_NAME

    if (
        os.getenv("CONDA_PREFIX", "") != ""
        and os.getenv("GITHUB_ACTIONS", "") == "true"
        or API_NAME.lower() == "pyside6"
    ):
        pytest.skip("Test is unreliable on GitHub Actions conda runs and pyside6")
    tiny_brain, ratio = tiny(tmp_path)
    img_nv = tiny_brain.screenshot(time_viewer=False)
    want = (_TINY_SIZE[1] * ratio, _TINY_SIZE[0] * ratio, 3)
    assert img_nv.shape == want
    img_v = tiny_brain.screenshot(time_viewer=True)
    assert img_v.shape[1:] == want[1:]
    assert_allclose(img_v.shape[0], want[0] * 4 / 3, atol=3)  # some slop
    tiny_brain.close()


def _assert_brain_range(brain, rng):
    __tracebackhide__ = True
    assert brain._cmap_range == rng, "brain._cmap_range == rng"
    for hemi, layerer in brain._layered_meshes.items():
        for key, mesh in layerer._overlays.items():
            if key == "curv":
                continue
            assert (
                mesh._rng == rng
            ), f"_layered_meshes[{repr(hemi)}][{repr(key)}]._rng != {rng}"


@testing.requires_testing_data
@pytest.mark.slowtest
def test_brain_time_viewer(renderer_interactive_pyvistaqt, pixel_ratio, brain_gc):
    """Test time viewer primitives."""
    with pytest.raises(ValueError, match="between 0 and 1"):
        _create_testing_brain(hemi="lh", show_traces=-1.0)
    with pytest.raises(ValueError, match="got unknown keys"):
        _create_testing_brain(
            hemi="lh", surf="white", src="volume", volume_options={"foo": "bar"}
        )
    brain = _create_testing_brain(
        hemi="both",
        show_traces=False,
        brain_kwargs=dict(silhouette=dict(decimate=0.95)),
    )
    # test sub routines when show_traces=False
    brain._on_pick(None, None)
    brain._configure_vertex_time_course()
    brain._configure_label_time_course()
    brain.setup_time_viewer()  # for coverage
    brain.set_time(1)
    brain.set_time_point(0)
    brain.show_view("lat")
    brain.show_view("medial")
    brain.set_data_smoothing(1)
    _assert_brain_range(brain, [0.1, 0.3])
    from mne.utils import use_log_level

    with use_log_level("debug"):
        brain.update_lut(fmin=12.0)
    assert brain._data["fmin"] == 12.0
    brain.update_lut(fmax=4.0)
    _assert_brain_range(brain, [4.0, 4.0])
    brain.update_lut(fmid=6.0)
    _assert_brain_range(brain, [4.0, 6.0])
    brain.update_lut(fmid=4.0)
    brain._update_fscale(1.2**0.25)
    brain._update_fscale(1.2**-0.25)
    brain.update_lut(fmin=12.0, fmid=4.0)
    _assert_brain_range(brain, [4.0, 12.0])
    # one at a time no-op
    r_, d_, a_, e_, f_ = brain.get_view()
    _assert_view_allclose(brain, r_, d_, a_, e_, f_)
    brain.show_view(verbose="debug")  # should be a no-op
    _assert_view_allclose(brain, r_, d_, a_, e_, f_)
    brain._set_camera(verbose="debug")  # also no-op
    _assert_view_allclose(brain, r_, d_, a_, e_, f_)
    want_view = np.array([r_, d_, a_, e_], float)  # ignore focalpoint
    for k, v in (("roll", r_), ("distance", d_), ("azimuth", a_), ("elevation", e_)):
        brain.show_view(**{k: v})
        _assert_view_allclose(brain, r_, d_, a_, e_, f_)
    got_view = np.array(brain.get_view()[:4], float)
    assert_allclose(got_view, want_view, rtol=1e-5, atol=1e-6)
    brain._rotate_camera("azimuth", 15)
    want_view[2] += 15
    got_view = np.array(brain.get_view()[:4], float)
    # roll changes when you adjust these because of the affine
    assert_allclose(got_view[1:], want_view[1:], rtol=1e-5, atol=1e-6)
    brain._rotate_camera("elevation", 15)
    want_view[3] += 15
    got_view = np.array(brain.get_view()[:4], float)
    assert_allclose(got_view[1:], want_view[1:], rtol=1e-5, atol=1e-6)
    brain.toggle_interface()
    brain.toggle_interface(value=False)
    brain.set_playback_speed(0.1)
    brain.toggle_playback()
    brain.toggle_playback(value=False)
    brain.apply_auto_scaling()
    brain.restore_user_scaling()
    brain.reset()

    assert brain.help_canvas is not None
    assert not brain.help_canvas.canvas.isVisible()
    brain.help()
    assert brain.help_canvas.canvas.isVisible()

    # screenshot
    # Need to turn the interface back on otherwise the window is too wide
    # (it keeps the window size and expands the 3D area when the interface
    # is toggled off)
    brain.toggle_interface(value=True)
    brain.show_view(azimuth=180.0, elevation=90.0)
    img = brain.screenshot(mode="rgb")
    want_shape = np.array([300 * pixel_ratio, 300 * pixel_ratio, 3])
    assert_allclose(img.shape, want_shape, atol=30)
    brain.close()


@testing.requires_testing_data
@pytest.mark.parametrize(
    "hemi",
    [
        "lh",
        pytest.param("rh", marks=pytest.mark.slowtest),
        pytest.param("split", marks=pytest.mark.slowtest),
        pytest.param("both", marks=pytest.mark.slowtest),
    ],
)
@pytest.mark.parametrize(
    "src",
    [
        "surface",
        pytest.param("vector", marks=pytest.mark.slowtest),
        pytest.param("volume", marks=pytest.mark.slowtest),
        pytest.param("mixed", marks=pytest.mark.slowtest),
    ],
)
@pytest.mark.slowtest
def test_brain_traces(renderer_interactive_pyvistaqt, hemi, src, tmp_path, brain_gc):
    """Test brain traces."""
    hemi_str = list()
    if src in ("surface", "vector", "mixed"):
        hemi_str.extend([hemi] if hemi in ("lh", "rh") else ["lh", "rh"])
    if src in ("mixed", "volume"):
        hemi_str.extend(["vol"])

    # label traces
    brain = _create_testing_brain(
        hemi=hemi,
        surf="white",
        src=src,
        show_traces="label",
        volume_options=None,  # for speed, don't upsample
        n_time=5,
        initial_time=0,
    )
    if src == "surface":
        brain._data["src"] = None  # test src=None
    if src in ("surface", "vector", "mixed"):
        assert brain.show_traces
        assert brain.traces_mode == "label"
        brain.widgets["extract_mode"].set_value("max")

        # test picking a cell at random
        rng = np.random.RandomState(0)
        for idx, current_hemi in enumerate(hemi_str):
            if current_hemi == "vol":
                continue
            current_mesh = brain._layered_meshes[current_hemi]._polydata
            cell_id = rng.randint(0, current_mesh.n_cells)
            test_picker = TstVTKPicker(current_mesh, cell_id, current_hemi, brain)
            assert len(brain.picked_patches[current_hemi]) == 0
            brain._on_pick(test_picker, None)
            assert len(brain.picked_patches[current_hemi]) == 1
            for label_id in list(brain.picked_patches[current_hemi]):
                label = brain._annotation_labels[current_hemi][label_id]
                assert isinstance(label._line, Line2D)
            brain.widgets["extract_mode"].set_value("mean")
            brain.clear_glyphs()
            assert len(brain.picked_patches[current_hemi]) == 0
            brain._on_pick(test_picker, None)  # picked and added
            assert len(brain.picked_patches[current_hemi]) == 1
            brain._on_pick(test_picker, None)  # picked again so removed
            assert len(brain.picked_patches[current_hemi]) == 0
        # test switching from 'label' to 'vertex'
        brain.widgets["annotation"].set_value("None")
        brain.widgets["extract_mode"].set_value("max")
    else:  # volume
        assert "annotation" not in brain.widgets
        assert "extract_mode" not in brain.widgets
    brain.close()

    # test colormap
    if src != "vector":
        brain = _create_testing_brain(
            hemi=hemi,
            surf="white",
            src=src,
            show_traces=0.5,
            initial_time=0,
            volume_options=None,  # for speed, don't upsample
            n_time=1 if src == "mixed" else 5,
            diverging=True,
            add_data_kwargs=dict(colorbar_kwargs=dict(n_labels=3)),
        )
        # mne_analyze should be chosen
        ctab = brain._data["ctable"]
        assert_array_equal(ctab[0], [0, 255, 255, 255])  # opaque cyan
        assert_array_equal(ctab[-1], [255, 255, 0, 255])  # opaque yellow
        assert_allclose(ctab[len(ctab) // 2], [128, 128, 128, 0], atol=3)
        brain.close()

    # vertex traces
    brain = _create_testing_brain(
        hemi=hemi,
        surf="white",
        src=src,
        show_traces=0.5,
        initial_time=0,
        volume_options=None,  # for speed, don't upsample
        n_time=1 if src == "mixed" else 5,
        add_data_kwargs=dict(colorbar_kwargs=dict(n_labels=3)),
    )
    assert brain.show_traces
    assert brain.traces_mode == "vertex"
    assert hasattr(brain, "picked_points")
    assert hasattr(brain, "_spheres")
    assert brain._scalar_bar.GetNumberOfLabels() == 3

    # add foci should work for 'lh', 'rh' and 'vol'
    for current_hemi in hemi_str:
        brain.add_foci([[0, 0, 0]], hemi=current_hemi)
        assert_array_equal(brain._data[current_hemi]["foci"], [[0, 0, 0]])

    # test points picked by default
    picked_points = brain.get_picked_points()
    spheres = brain._spheres
    for current_hemi in hemi_str:
        assert len(picked_points[current_hemi]) == 1
    n_spheres = len(hemi_str)
    n_actors = n_spheres
    if hemi == "split" and src in ("mixed", "volume"):
        n_spheres += 1
    assert len(spheres) == n_spheres

    # test that there are actually enough actors
    assert len(brain._actors["data"]) == n_actors

    # test switching from 'vertex' to 'label'
    if src == "surface":
        brain.widgets["annotation"].set_value("aparc")
        brain.widgets["annotation"].set_value("None")
    # test removing points
    brain.clear_glyphs()
    assert len(spheres) == 0
    for key in ("lh", "rh", "vol"):
        assert len(picked_points[key]) == 0

    # test picking a cell at random
    rng = np.random.RandomState(0)
    for idx, current_hemi in enumerate(hemi_str):
        assert len(spheres) == 0
        if current_hemi == "vol":
            current_mesh = brain._data["vol"]["grid"]
            vertices = brain._data["vol"]["vertices"]
            values = current_mesh.cell_data["values"][vertices]
            cell_id = vertices[np.argmax(np.abs(values))]
        else:
            current_mesh = brain._layered_meshes[current_hemi]._polydata
            cell_id = rng.randint(0, current_mesh.n_cells)
        test_picker = TstVTKPicker(None, None, current_hemi, brain)
        assert brain._on_pick(test_picker, None) is None
        test_picker = TstVTKPicker(current_mesh, cell_id, current_hemi, brain)
        assert cell_id == test_picker.cell_id
        assert test_picker.point_id is None
        brain._on_pick(test_picker, None)
        brain._on_pick(test_picker, None)
        assert test_picker.point_id is not None
        assert len(picked_points[current_hemi]) == 1
        assert picked_points[current_hemi][0] == test_picker.point_id
        assert len(spheres) > 0
        sphere = spheres[-1]
        vertex_id = sphere._vertex_id
        assert vertex_id == test_picker.point_id
        line = sphere._line

        hemi_prefix = current_hemi[0].upper()
        if current_hemi == "vol":
            assert hemi_prefix + ":" in line.get_label()
            assert "MNI" in line.get_label()
            continue  # the MNI conversion is more complex
        hemi_int = 0 if current_hemi == "lh" else 1
        mni = vertex_to_mni(
            vertices=vertex_id,
            hemis=hemi_int,
            subject=brain._subject,
            subjects_dir=brain._subjects_dir,
        )
        label = f"{hemi_prefix}:{str(vertex_id).ljust(6)} MNI: " + ", ".join(
            f"{m:5.1f}" for m in mni
        )

        assert line.get_label() == label

        # remove the sphere by clicking in its vicinity
        old_len = len(spheres)
        test_picker._actors = sum((s._actors for s in spheres), [])
        brain._on_pick(test_picker, None)
        assert len(spheres) < old_len

    screenshot = brain.screenshot()
    screenshot_all = brain.screenshot(time_viewer=True)
    assert screenshot.shape[0] < screenshot_all.shape[0]
    # and the scraper for it (will close the instance)
    # only test one condition to save time
    if not (hemi == "rh" and src == "surface" and check_version("sphinx_gallery")):
        brain.close()
        return
    fnames = [str(tmp_path / f"temp_{ii}.png") for ii in range(2)]
    block_vars = dict(
        image_path_iterator=iter(fnames), example_globals=dict(brain=brain)
    )
    block = (
        "code",
        """
something
# brain.save_movie(time_dilation=1, framerate=1,
#                  interpolation='linear', time_viewer=True)
#
""",
        1,
    )
    gallery_conf = dict(
        src_dir=str(tmp_path),
        compress_images=[],
        image_srcset=[],
        matplotlib_animations=(False, None),
    )
    scraper = _BrainScraper()
    rst = scraper(block, block_vars, gallery_conf)
    assert brain.plotter is None  # closed
    gif_0 = fnames[0][:-3] + "gif"
    for fname in (gif_0, fnames[1]):
        fname = Path(fname)
        assert fname.stem in rst
        assert fname.is_file()
        img = image.imread(fname)
        assert_allclose(img.shape[1], screenshot.shape[1], atol=1)  # width
        assert img.shape[0] > screenshot.shape[0]  # larger height
        assert_allclose(img.shape[1], screenshot_all.shape[1], atol=1)
        assert_allclose(img.shape[0], screenshot_all.shape[0], atol=1)


# TODO: don't skip on Windows, see
# https://github.com/mne-tools/mne-python/pull/10935
# for some reason there is a dependency issue with ipympl even using pyvista
@pytest.mark.skipif(platform.system() == "Windows", reason="ipympl issue on Windows")
@testing.requires_testing_data
def test_brain_scraper(renderer_interactive_pyvistaqt, brain_gc, tmp_path):
    """Test a simple scraping example."""
    pytest.importorskip("sphinx_gallery")

    stc = read_source_estimate(fname_stc, subject="sample")
    size = (600, 400)
    brain = stc.plot(
        subjects_dir=subjects_dir,
        time_viewer=True,
        show_traces=True,
        hemi="split",
        size=size,
        views="lat",
    )
    fnames = [str(tmp_path / f"temp_{ii}.png") for ii in range(2)]
    block_vars = dict(
        image_path_iterator=iter(fnames), example_globals=dict(brain=brain)
    )
    block = ("code", "", 1)
    gallery_conf = dict(
        src_dir=str(tmp_path),
        compress_images=[],
        image_srcset=[],
        matplotlib_animations=(False, None),
    )
    scraper = _BrainScraper()
    rst = scraper(block, block_vars, gallery_conf)
    assert brain.plotter is None  # closed
    assert brain._cleaned
    del brain
    fname = Path(fnames[0])
    assert fname.stem in rst
    assert fname.is_file()
    img = image.imread(fname)
    w = img.shape[1]
    w0 = size[0]
    # On Linux+conda we get a width of 624, similar tweak in test_brain_init above
    assert np.isclose(w, w0, atol=30) or np.isclose(
        w, w0 * 2, atol=30
    ), f"w ∉ {{{w0}, {2 * w0}}}"  # HiDPI


@testing.requires_testing_data
@pytest.mark.slowtest
def test_brain_linkviewer(renderer_interactive_pyvistaqt, brain_gc):
    """Test _LinkViewer primitives."""
    brain1 = _create_testing_brain(hemi="lh", show_traces=False)
    brain2 = _create_testing_brain(hemi="lh", show_traces="separate")
    brain1._times = brain1._times * 2
    with pytest.warns(RuntimeWarning, match="linking time"):
        _LinkViewer(
            [brain1, brain2],
            time=True,
            camera=False,
            colorbar=False,
            picking=False,
        )
    brain1.close()

    brain_data = _create_testing_brain(hemi="split", show_traces="vertex")
    link_viewer = _LinkViewer(
        [brain2, brain_data],
        time=True,
        camera=True,
        colorbar=True,
        picking=True,
    )
    link_viewer.leader.set_time(1)
    link_viewer.leader.set_time_point(0)
    link_viewer.leader.update_lut(fmin=0, fmid=0.5, fmax=1)
    link_viewer.leader.set_playback_speed(0.1)
    link_viewer.leader.toggle_playback()
    ui_events.publish(link_viewer.leader, ui_events.TimeChange(time=0))
    brain2.close()
    brain_data.close()


def test_calculate_lut():
    """Test brain's colormap functions."""
    colormap = "coolwarm"
    alpha = 1.0
    fmin = 0.0
    fmid = 0.5
    fmax = 1.0
    center = None
    calculate_lut(colormap, alpha=alpha, fmin=fmin, fmid=fmid, fmax=fmax, center=center)
    center = 0.0
    cmap = _get_cmap(colormap)
    calculate_lut(cmap, alpha=alpha, fmin=fmin, fmid=fmid, fmax=fmax, center=center)

    zero_alpha = np.array([1.0, 1.0, 1.0, 0])
    half_alpha = np.array([1.0, 1.0, 1.0, 0.5])
    atol = 1.5 / 256.0

    # fmin < fmid < fmax
    lut = calculate_lut(colormap, alpha, 1, 2, 3)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0) * zero_alpha, atol=atol)
    assert_allclose(lut[127], cmap(0.5), atol=atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)
    # divergent
    lut = calculate_lut(colormap, alpha, 0, 1, 2, 0)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0), atol=atol)
    assert_allclose(lut[63], cmap(0.25), atol=atol)
    assert_allclose(lut[127], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[192], cmap(0.75), atol=atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)

    # fmin == fmid == fmax
    lut = calculate_lut(colormap, alpha, 1, 1, 1)
    zero_alpha = np.array([1.0, 1.0, 1.0, 0])
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0) * zero_alpha, atol=atol)
    assert_allclose(lut[1], cmap(0.5), atol=atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)
    # divergent
    lut = calculate_lut(colormap, alpha, 0, 0, 0, 0)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0), atol=atol)
    assert_allclose(lut[127], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)

    # fmin == fmid < fmax
    lut = calculate_lut(colormap, alpha, 1, 1, 2)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0.0) * zero_alpha, atol=atol)
    assert_allclose(lut[1], cmap(0.5), atol=atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)
    # divergent
    lut = calculate_lut(colormap, alpha, 1, 1, 2, 0)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0), atol=atol)
    assert_allclose(lut[62], cmap(0.245), atol=atol)
    assert_allclose(lut[64], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[127], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[191], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[193], cmap(0.755), atol=atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)
    lut = calculate_lut(colormap, alpha, 0, 0, 1, 0)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0), atol=atol)
    assert_allclose(lut[126], cmap(0.25), atol=atol)
    assert_allclose(lut[127], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[129], cmap(0.75), atol=atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)

    # fmin < fmid == fmax
    lut = calculate_lut(colormap, alpha, 1, 2, 2)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0) * zero_alpha, atol=atol)
    assert_allclose(lut[-2], cmap(0.5), atol=atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)
    # divergent
    lut = calculate_lut(colormap, alpha, 1, 2, 2, 0)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0), atol=atol)
    assert_allclose(lut[1], cmap(0.25), atol=2 * atol)
    assert_allclose(lut[32], cmap(0.375) * half_alpha, atol=atol)
    assert_allclose(lut[64], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[127], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[191], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[223], cmap(0.625) * half_alpha, atol=atol)
    assert_allclose(lut[-2], cmap(0.7475), atol=2 * atol)
    assert_allclose(lut[-1], cmap(1.0), atol=2 * atol)
    lut = calculate_lut(colormap, alpha, 0, 1, 1, 0)
    assert lut.shape == (256, 4)
    assert_allclose(lut[0], cmap(0), atol=atol)
    assert_allclose(lut[1], cmap(0.25), atol=2 * atol)
    assert_allclose(lut[64], cmap(0.375) * half_alpha, atol=atol)
    assert_allclose(lut[127], cmap(0.5) * zero_alpha, atol=atol)
    assert_allclose(lut[191], cmap(0.625) * half_alpha, atol=atol)
    assert_allclose(lut[-2], cmap(0.75), atol=2 * atol)
    assert_allclose(lut[-1], cmap(1.0), atol=atol)

    with pytest.raises(ValueError, match=r".*fmin \(1\) <= fmid \(0\) <= fma"):
        calculate_lut(colormap, alpha, 1, 0, 2)


def test_brain_ui_events(renderer_interactive_pyvistaqt, brain_gc):
    """Test responding to Brain related UI events."""
    brain = _create_testing_brain(hemi="lh", show_traces="vertex")

    ui_events.publish(brain, ui_events.TimeChange(time=1))
    assert brain._current_time == 1

    ui_events.publish(brain, ui_events.VertexSelect(hemi="lh", vertex_id=1))
    assert 1 in brain.picked_points["lh"]

    ui_events.publish(
        brain,
        ui_events.ColormapRange(
            kind="distributed_source_power", fmin=1, fmid=2, fmax=3, alpha=True
        ),
    )
    assert_array_equal(brain._data["ctable"][:3, 3], [0, 2, 4])

    # This event should be ignored.
    ui_events.publish(
        brain,
        ui_events.ColormapRange(
            kind="unknown_kind", fmin=10, fmid=11, fmax=12, alpha=True
        ),
    )
    # Should remain unchanged.
    assert_array_equal(brain._data["ctable"][:3, 3], [0, 2, 4])

    brain.close()


def _create_testing_brain(
    hemi, surf="inflated", src="surface", size=300, n_time=5, diverging=False, **kwargs
):
    assert src in ("surface", "vector", "mixed", "volume")
    meth = "plot"
    if src in ("surface", "mixed"):
        sample_src = read_source_spaces(src_fname)
        klass = MixedSourceEstimate if src == "mixed" else SourceEstimate
    if src == "vector":
        fwd = read_forward_solution(fname_fwd)
        fwd = pick_types_forward(fwd, meg=True, eeg=False)
        evoked = read_evokeds(fname_evoked, baseline=(None, 0))[0]
        noise_cov = read_cov(fname_cov)
        free = make_inverse_operator(evoked.info, fwd, noise_cov, loose=1.0)
        stc = apply_inverse(evoked, free, pick_ori="vector")
        return stc.plot(
            subject=subject,
            hemi=hemi,
            size=size,
            subjects_dir=subjects_dir,
            colormap="auto",
            **kwargs,
        )
    if src in ("volume", "mixed"):
        vol_src = setup_volume_source_space(
            subject,
            7.0,
            mri="aseg.mgz",
            volume_label="Left-Cerebellum-Cortex",
            subjects_dir=subjects_dir,
            add_interpolator=False,
        )
        assert len(vol_src) == 1
        assert vol_src[0]["nuse"] == 150
        if src == "mixed":
            sample_src = sample_src + vol_src
        else:
            sample_src = vol_src
            klass = VolSourceEstimate
            meth = "plot_3d"
    assert sample_src.kind == src

    # dense version
    rng = np.random.RandomState(0)
    vertices = [s["vertno"] for s in sample_src]
    n_verts = sum(len(v) for v in vertices)
    stc_data = np.zeros(n_verts * n_time)
    stc_size = stc_data.size
    stc_data[(rng.rand(stc_size // 20) * stc_size).astype(int)] = rng.rand(
        stc_data.size // 20
    )
    stc_data.shape = (n_verts, n_time)
    if diverging:
        stc_data -= 0.5
    stc = klass(stc_data, vertices, 1, 1)

    clim = dict(kind="value", lims=[0.1, 0.2, 0.3])
    if diverging:
        clim["pos_lims"] = clim.pop("lims")

    brain_data = getattr(stc, meth)(
        subject=subject,
        hemi=hemi,
        surface=surf,
        size=size,
        subjects_dir=subjects_dir,
        colormap="auto",
        clim=clim,
        src=sample_src,
        **kwargs,
    )
    return brain_data


# TODO: allow_unclosed for macOS here as the conda build shows some
# windows stay open afterward
@pytest.mark.allow_unclosed
def test_foci_mapping(tmp_path, renderer_interactive_pyvistaqt):
    """Test mapping foci to the surface."""
    tiny_brain, _ = tiny(tmp_path)
    foci_coords = tiny_brain.geo["lh"].coords[:2] + 0.01
    tiny_brain.add_foci(foci_coords, map_surface="white")
    assert_array_equal(tiny_brain._data["lh"]["foci"], tiny_brain.geo["lh"].coords[:2])
