# %%
"""
More plotting tools from nilearn
================================

In this example, we show how to use some plotting options available with
plotting functions of nilearn. These techniques are essential for
visualizing brain image analysis results.

Plotting functions of Nilearn, such as
:func:`~nilearn.plotting.plot_stat_map`, have a few useful parameters
which control what type of display object will be
returned, as well as how many cuts will be shown for example.

As we will see in the first part of this example, depending on the values of
the parameters ``display_mode`` and ``cut_coords``, plotting functions return
different display objects, all subclasses of
:class:`~nilearn.plotting.displays.OrthoSlicer`.

These objects implement various methods to interact with the figures. In the
second part of this example, we show how to use these methods to further
customize the figures obtained with plotting functions. More precisely, we
will show how to use :meth:`~nilearn.plotting.displays.OrthoSlicer.add_edges`,
:meth:`~nilearn.plotting.displays.OrthoSlicer.add_contours`, and
:meth:`~nilearn.plotting.displays.OrthoSlicer.add_markers`, all essential
in visualizing regions of interest images, or mask images overlaying on
subject specific anatomical / :term:`EPI` image.

The parameter ``display_mode`` is used to draw brain slices along given
specific directions, where directions can be one of 'ortho',
'tiled', 'mosaic', 'x', 'y', 'z', 'yx', 'xz', 'yz'. Whereas parameter
``cut_coords`` is used to specify a limited number of slices to visualize
along given specific slice direction.

The parameter ``cut_coords`` can also be used to draw the specific cuts in
the slices by giving its particular coordinates in :term:`MNI` space
accordingly with particular slice direction. This helps us point to the
activation specific location of the brain slices.

See :ref:`plotting` for more details.
"""

# %%
# Display objects returned by plotting functions
# -----------------------------------------------
#
# Plotting functions return different display objects depending on the values
# of the parameters ``display_mode`` and ``cut_coords``.
#
# We first retrieve data from nilearn provided (general-purpose) datasets.

from nilearn import datasets

# haxby dataset to have anatomical image, EPI images and masks
haxby_dataset = datasets.fetch_haxby()
haxby_anat_filename = haxby_dataset.anat[0]
haxby_mask_filename = haxby_dataset.mask_vt[0]
haxby_func_filename = haxby_dataset.func[0]

# example motor activation image distributed with nilearn
stat_img = datasets.load_sample_motor_activation_image()


# %%
# Now, we show from here how to visualize the retrieved datasets using plotting
# tools from nilearn.

from nilearn import plotting

# %%
# OrthoSlicer: Three views 'sagittal', 'coronal' and 'axial' with coordinates
# ```````````````````````````````````````````````````````````````````````````
#
# The first argument ``stat_img`` is a path to the filename of a contrast map.
# The optional argument ``display_mode`` is given as a string 'ortho' to
# visualize the map in three specific directions xyz. Because of this, the
# plotting function returns a :class:`~nilearn.plotting.displays.OrthoSlicer`
# object. The optional ``cut_coords`` argument is specified here as a list of
# integers representing coordinates of each slice in the order [x, y, z].
# By default the ``colorbar`` argument is set to ``True`` in
# :func:`~nilearn.plotting.plot_stat_map`.

plotting.plot_stat_map(
    stat_img,
    display_mode="ortho",
    cut_coords=[36, -27, 60],
    title="display_mode='ortho', cut_coords=[36, -27, 60]",
)

# %%
# ZSlicer: Single view 'axial' with number of cuts=5
# ``````````````````````````````````````````````````
#
# For axial visualization, we set ``display_mode='z'``. As a
# consequence :func:`~nilearn.plotting.plot_stat_map` returns a
# :class:`~nilearn.plotting.displays.ZSlicer` object.
# The parameter ``cut_coords`` is provided here as an integer (5) rather than
# a list, which implies that the number of cuts in the slices should be 5
# maximum. Note that the coordinates used to cut the slices are selected
# automatically.

plotting.plot_stat_map(
    stat_img,
    display_mode="z",
    cut_coords=5,
    title="display_mode='z', cut_coords=5",
)

# %%
# XSlicer: Single view 'sagittal' with only two slices
# ````````````````````````````````````````````````````
#
# For sagittal visualization, we set ``display_mode='x'`` which returns a
# :class:`~nilearn.plotting.displays.XSlicer` object.
# Additionally, we provide the coordinates of the slices as a list of
# integers.

plotting.plot_stat_map(
    stat_img,
    display_mode="x",
    cut_coords=[-36, 36],
    title="display_mode='x', cut_coords=[-36, 36]",
)

# %%
# YSlicer: Single view 'coronal' with single cut
# ``````````````````````````````````````````````
#
# For coronal view, we set ``display_mode='y'`` which returns a
# :class:`~nilearn.plotting.displays.YSlicer` object.
# ``cut_coords`` is provided as an integer (1), and the coordinates are,
# again, selected automatically.
import matplotlib.pyplot as plt

plotting.plot_stat_map(
    stat_img,
    display_mode="y",
    cut_coords=1,
    title="display_mode='y', cut_coords=1",
    figure=plt.figure(figsize=(5, 4)),
)

# %%
# XZSlicer: Two views 'sagittal' and 'axial' with given coordinates
# `````````````````````````````````````````````````````````````````
#
# In order to visualize both sagittal and axial views, we set
# ``display_mode='xz'``, where 'x' stands for sagittal and 'z' for axial view.
# Function :func:`~nilearn.plotting.plot_stat_map` thus returns a
# :class:`~nilearn.plotting.displays.XZSlicer` object.
# Finally, the argument ``cut_coords`` should match with the input number of
# views (two here). It is provided as a list of integers here to select the
# slices to be displayed.

plotting.plot_stat_map(
    stat_img,
    display_mode="xz",
    cut_coords=[36, 60],
    title="display_mode='xz', cut_coords=[36, 60]",
)

# %%
# YXSlicer: Two views 'coronal' and 'sagittal' with coordinates
# `````````````````````````````````````````````````````````````
#
# Similarly, we can set ``display_mode='yx'`` for combining a coronal with a
# sagittal view, which will return a
# :class:`~nilearn.plotting.displays.YXSlicer` object.
# The coordinates will be assigned in the order of direction as [x, y, z].

plotting.plot_stat_map(
    stat_img,
    display_mode="yx",
    cut_coords=[-27, 36],
    title="display_mode='yx', cut_coords=[-27, 36]",
)

# %%
# YZSlicer: Two views 'coronal' and 'axial' with coordinates
# ``````````````````````````````````````````````````````````
#
# We can set ``display_mode='yz'`` to combine a coronal with an axial
# view, which will return a :class:`~nilearn.plotting.displays.YZSlicer`
# object.

plotting.plot_stat_map(
    stat_img,
    display_mode="yz",
    cut_coords=[-27, 60],
    title="display_mode='yz', cut_coords=[-27, 60]",
)

# %%
# TiledSlicer: Three views in 2x2 fashion
# ```````````````````````````````````````
#
# If we want to combine three views in a 2x2 way, we can set
# ``display_mode='tiled'``, which will combine sagittal, coronal, and axial
# views. In this case, :func:`~nilearn.plotting.plot_stat_map` will return
# a :class:`~nilearn.plotting.displays.TiledSlicer` object.

plotting.plot_stat_map(
    stat_img,
    display_mode="tiled",
    cut_coords=[36, -27, 60],
    title="display_mode='tiled'",
)

# %%
# MosaicSlicer: Three views along multiple rows and columns
# `````````````````````````````````````````````````````````
#
# If we set ``display_mode='mosaic'``, we can easily combine sagittal,
# coronal, and axial views with different rows and columns. In this
# situation, :func:`~nilearn.plotting.plot_stat_map` returns a
# :class:`~nilearn.plotting.displays.MosaicSlicer` object.
#
# Below we show the default option ``cut_coords=None``.

plotting.plot_stat_map(
    stat_img,
    display_mode="mosaic",
    title="display_mode='mosaic' default cut_coords",
)

# %%
# We can also set the number of slices to be the same across views.
# In this case, we can specify it as an integer, i.e. ``cut_coords=3``.

plotting.plot_stat_map(
    stat_img,
    display_mode="mosaic",
    cut_coords=3,
    title="display_mode='mosaic' with cut_coords=3",
)

# %%
# It can be the case that we want to display a different number of cuts in
# each view. In this situation, we still set ``display_mode='mosaic'``, but
# we specify the number of slices as a tuple of length 3.

plotting.plot_stat_map(
    stat_img,
    display_mode="mosaic",
    cut_coords=(5, 4, 10),
    title="display_mode='mosaic' with cut_coords as tuple",
)

# %%
# Display object's features
# -------------------------
#
# In this second part, we demonstrate how to interact with the obtained
# figures. More precisely, we will show how to use specific methods of the
# display objects which can be helpful in projecting brain imaging results
# for further interpretation.

# Import image processing tool for basic processing of functional brain image
from nilearn import image

# Compute voxel-wise mean functional image across time dimension. Now we have
# functional image in 3D assigned in mean_haxby_img
mean_haxby_img = image.mean_img(haxby_func_filename, copy_header=True)

# %%
# Overlay anatomical image as edges: `add_edges`
# ``````````````````````````````````````````````
#
# Now let us see how to use the method
# :meth:`~nilearn.plotting.displays.OrthoSlicer.add_edges` for checking
# coregistration by overlaying anatomical image as edges (red) on top of
# mean functional image (background), both being of same subject.
#
# First, we call the :func:`~nilearn.plotting.plot_anat` plotting function,
# with a background image as first argument, in this case the mean
# :term:`fMRI` image.
#
# We then use the :meth:`~nilearn.plotting.displays.OrthoSlicer.add_edges`
# method. The first argument is the anatomical image and, by default,
# edges will be displayed in red ('r'). To choose a different color, use
# the ``color`` argument.

display = plotting.plot_anat(mean_haxby_img, title="add_edges")
display.add_edges(haxby_anat_filename, color="r")

# %%
# Plot the outline of a mask: `add_contours`
# ``````````````````````````````````````````
#
# Here, we show how to plot the outline of a mask (in red) on top of the
# mean :term:`EPI` image with the method
# :meth:`~nilearn.plotting.displays.OrthoSlicer.add_contours`.
# This method is useful for region specific interpretation of brain images
#
# As before, we call the :func:`~nilearn.plotting.plot_anat` function with a
# background image as first argument, in this case the mean :term:`fMRI`
# image, and argument ``cut_coords`` as a list for manual cuts with coordinates
# pointing at masked brain regions.
#
# We then use the :meth:`~nilearn.plotting.displays.OrthoSlicer.add_contours`
# method of the display object returned by
# :func:`~nilearn.plotting.plot_anat`. We provide the path to a mask image
# from the Haxby dataset as the first argument, and we provide ``levels`` as
# a list of values to select particular levels in the contour to display.
# We also specify ``colors='r'`` to display edges in red (See function
# :func:`~matplotlib.pyplot.contour` to use more options).

display = plotting.plot_anat(
    mean_haxby_img, title="add_contours", cut_coords=[-34, -39, -9]
)

display.add_contours(haxby_mask_filename, levels=[0.5], colors="r")

# %%
# Here, we plot the outline of the mask (in blue) with color fillings using
# the same method :meth:`~nilearn.plotting.displays.OrthoSlicer.add_contours`.
#
# By default, no color fillings will be shown using
# :meth:`~nilearn.plotting.displays.OrthoSlicer.add_contours`. To see
# contours with color fillings, use argument ``filled=True``. Here, contour
# colors are changed to blue 'b', and we specify ``alpha=0.7`` to set the
# transparency of the fillings.
# See function :func:`~matplotlib.pyplot.contourf` to use more options (given
# that ``filled`` should be ``True``).

display = plotting.plot_anat(
    mean_haxby_img,
    title="add_contours with filled=True",
    cut_coords=[-34, -39, -9],
)

display.add_contours(
    haxby_mask_filename, filled=True, alpha=0.7, levels=[0.5], colors="b"
)

# %%
# Plotting seeds: `add_markers`
# `````````````````````````````
#
# Plotting seed regions of interest as spheres using method
# :meth:`~nilearn.plotting.displays.OrthoSlicer.add_markers`
# with :term:`MNI` coordinates of interest.
#
# The coordinates of the seed regions should be specified as the first
# argument, and second argument ``marker_color`` is used to denote the
# color of the sphere (in this case yellow 'y'). The third argument
# ``marker_size`` is used to control the size of the sphere.

display = plotting.plot_anat(
    mean_haxby_img, title="add_markers", cut_coords=[-34, -39, -9]
)
coords = [(-34, -39, -9)]
display.add_markers(coords, marker_color="y", marker_size=100)

# %%
# Annotate plots: `annotate`
# ``````````````````````````
#
# It is possible to alter the default annotations of plots, using the
# method :meth:`~nilearn.plotting.displays.OrthoSlicer.annotate` of the
# display objects. For example, we can add a scale bar at the bottom
# right of each view:

display = plotting.plot_anat(
    mean_haxby_img, title="adding a scale bar", cut_coords=[-34, -39, -9]
)
display.annotate(scalebar=True)


# %%
# Further configuration can be achieved by setting ``scale_*`` keyword args.
# For instance, we can change the ``units`` to ``mm``, or use a different
# scale bar size.

display = plotting.plot_anat(
    mean_haxby_img, title="adding a scale bar", cut_coords=[-34, -39, -9]
)
display.annotate(scalebar=True, scale_size=25, scale_units="mm")

# %%
# Save plots to a file: `savefig`
# ```````````````````````````````
#
# Finally, we can save a plot to file in two different ways:
#
# First, we can save the :term:`contrast` maps plotted with the function
# :func:`~nilearn.plotting.plot_stat_map` using the built-in parameter
# ``output_file``. We provide the filename and the file extension as
# a string (supported extensions are .png, .pdf, .svg).
from pathlib import Path

output_dir = Path.cwd() / "results" / "plot_demo_more_plotting"
output_dir.mkdir(exist_ok=True, parents=True)
print(f"Output will be saved to: {output_dir}")

plotting.plot_stat_map(
    stat_img,
    title="Using plot_stat_map output_file",
    output_file=output_dir / "plot_stat_map.png",
)

# %%
# A second way to save plots is by using the method
# :meth:`~nilearn.plotting.displays.OrthoSlicer.savefig` of the display
# object returned.

display = plotting.plot_stat_map(stat_img, title="Using display savefig")

display.savefig(output_dir / "plot_stat_map_from_display.png")

# In non-interactive settings make sure you close your displays
display.close()

plotting.show()

# sphinx_gallery_dummy_images=17
