Source code for pygmt.figure
"""
Define the Figure class that handles all plotting.
"""
import base64
import os
from tempfile import TemporaryDirectory
try:
from IPython.display import Image
except ImportError:
Image = None
from pygmt.base_plotting import BasePlotting
from pygmt.clib import Session
from pygmt.exceptions import GMTError, GMTInvalidInput
from pygmt.helpers import (
build_arg_string,
fmt_docstring,
kwargs_to_strings,
launch_external_viewer,
unique_name,
use_alias,
)
# A registry of all figures that have had "show" called in this session.
# This is needed for the sphinx-gallery scraper in pygmt/sphinx_gallery.py
SHOWED_FIGURES = []
[docs]class Figure(BasePlotting):
"""
A GMT figure to handle all plotting.
Use the plotting methods of this class to add elements to the figure. You
can preview the figure using :meth:`pygmt.Figure.show` and save the figure
to a file using :meth:`pygmt.Figure.savefig`.
Unlike traditional GMT figures, no figure file is generated until you call
:meth:`pygmt.Figure.savefig` or :meth:`pygmt.Figure.psconvert`.
Examples
--------
>>> fig = Figure()
>>> fig.basemap(region=[0, 360, -90, 90], projection="W7i", frame=True)
>>> fig.savefig("my-figure.png")
>>> # Make sure the figure file is generated and clean it up
>>> import os
>>> os.path.exists("my-figure.png")
True
>>> os.remove("my-figure.png")
The plot region can be specified through ISO country codes (for example,
``'JP'`` for Japan):
>>> fig = Figure()
>>> fig.basemap(region="JP", projection="M3i", frame=True)
>>> # The fig.region attribute shows the WESN bounding box for the figure
>>> print(", ".join("{:.2f}".format(i) for i in fig.region))
122.94, 145.82, 20.53, 45.52
"""
def __init__(self):
self._name = unique_name()
self._preview_dir = TemporaryDirectory(prefix=self._name + "-preview-")
self._activate_figure()
def __del__(self):
# Clean up the temporary directory that stores the previews
if hasattr(self, "_preview_dir"):
self._preview_dir.cleanup()
def _activate_figure(self):
"""
Start and/or activate the current figure.
All plotting commands run afterward will append to this figure.
Unlike the command-line version (``gmt figure``), this method does not
trigger the generation of a figure file. An explicit call to
:meth:`pygmt.Figure.savefig` or :meth:`pygmt.Figure.psconvert` must be
made in order to get a file.
"""
# Passing format '-' tells pygmt.end to not produce any files.
fmt = "-"
with Session() as lib:
lib.call_module("figure", "{} {}".format(self._name, fmt))
def _preprocess(self, **kwargs):
"""
Call the ``figure`` module before each plotting command to ensure we're
plotting to this particular figure.
"""
self._activate_figure()
return kwargs
@property
def region(self):
"The geographic WESN bounding box for the current figure."
self._activate_figure()
with Session() as lib:
wesn = lib.extract_region()
return wesn
[docs] @fmt_docstring
@use_alias(
A="crop",
C="gs_option",
E="dpi",
F="prefix",
I="icc_gray",
T="fmt",
Q="anti_aliasing",
)
@kwargs_to_strings()
def psconvert(self, **kwargs):
"""
Convert [E]PS file(s) to other formats.
Converts one or more PostScript files to other formats (BMP, EPS, JPEG,
PDF, PNG, PPM, SVG, TIFF) using GhostScript.
If no input files are given, will convert the current active figure
(see :func:`pygmt.figure`). In this case, an output name must be given
using parameter *prefix*.
Full option list at :gmt-docs:`psconvert.html`
{aliases}
Parameters
----------
crop : str or bool
Adjust the BoundingBox and HiResBoundingBox to the minimum required
by the image content. Append ``u`` to first remove any GMT-produced
time-stamps. Default is True.
gs_option : str
Specify a single, custom option that will be passed on to
GhostScript as is.
dpi : int
Set raster resolution in dpi. Default = 720 for PDF, 300 for
others.
prefix : str
Force the output file name. By default output names are constructed
using the input names as base, which are appended with an
appropriate extension. Use this option to provide a different name,
but without extension. Extension is still determined automatically.
icc_gray : bool
Enforce gray-shades by using ICC profiles.
anti_aliasing : str
Set the anti-aliasing options for graphics or text. Append the size
of the subsample box (1, 2, or 4) [4]. Default is no anti-aliasing
(same as bits = 1).
fmt : str
Sets the output format, where *b* means BMP, *e* means EPS, *E*
means EPS with PageSize command, *f* means PDF, *F* means
multi-page PDF, *j* means JPEG, *g* means PNG, *G* means
transparent PNG (untouched regions are transparent), *m* means PPM,
*s* means SVG, and *t* means TIFF [default is JPEG]. To ``'bjgt'``
you can append ``'+m'`` in order to get a monochrome (grayscale)
image. The EPS format can be combined with any of the other
formats. For example, ``'ef'`` creates both an EPS and a PDF file.
Using ``'F'`` creates a multi-page PDF file from the list of input
PS or PDF files. It requires the *prefix* option.
"""
kwargs = self._preprocess(**kwargs)
# Default cropping the figure to True
if "A" not in kwargs:
kwargs["A"] = ""
with Session() as lib:
lib.call_module("psconvert", build_arg_string(kwargs))
[docs] def savefig(
self, fname, transparent=False, crop=True, anti_alias=True, show=False, **kwargs
):
"""
Save the figure to a file.
This method implements a matplotlib-like interface for
:meth:`~gmt.Figure.psconvert`.
Supported formats: PNG (``.png``), JPEG (``.jpg``), PDF (``.pdf``),
BMP (``.bmp``), TIFF (``.tif``), EPS (``.eps``), and KML (``.kml``).
The KML output generates a companion PNG file.
You can pass in any keyword arguments that
:meth:`~gmt.Figure.psconvert` accepts.
Parameters
----------
fname : str
The desired figure file name, including the extension. See the list
of supported formats and their extensions above.
transparent : bool
If True, will use a transparent background for the figure. Only
valid for PNG format.
crop : bool
If True, will crop the figure canvas (page) to the plot area.
anti_alias: bool
If True, will use anti aliasing when creating raster images (PNG,
JPG, TIf). More specifically, uses options ``Qt=2, Qg=2`` in
:meth:`~gmt.Figure.psconvert`. Ignored if creating vector graphics.
Overrides values of ``Qt`` and ``Qg`` passed in through ``kwargs``.
show: bool
If True, will open the figure in an external viewer.
dpi : int
Set raster resolution in dpi. Default is 720 for PDF, 300 for
others.
"""
# All supported formats
fmts = dict(png="g", pdf="f", jpg="j", bmp="b", eps="e", tif="t", kml="g")
prefix, ext = os.path.splitext(fname)
ext = ext[1:] # Remove the .
if ext not in fmts:
raise GMTInvalidInput("Unknown extension '.{}'".format(ext))
fmt = fmts[ext]
if transparent:
if fmt != "g":
raise GMTInvalidInput(
"Transparency unavailable for '{}', only for png.".format(ext)
)
fmt = fmt.upper()
if anti_alias:
kwargs["Qt"] = 2
kwargs["Qg"] = 2
if ext == "kml":
kwargs["W"] = "+k"
self.psconvert(prefix=prefix, fmt=fmt, crop=crop, **kwargs)
if show:
launch_external_viewer(fname)
[docs] def show(self, dpi=300, width=500, method="static"):
"""
Display a preview of the figure.
Inserts the preview in the Jupyter notebook output. You will need to
have IPython installed for this to work. You should have it if you are
using the notebook.
If ``method='external'``, makes PDF preview instead and opens it in the
default viewer for your operating system (falls back to the default web
browser). Note that the external viewer does not block the current
process, so this won't work in a script.
Parameters
----------
dpi : int
The image resolution (dots per inch).
width : int
Width of the figure shown in the notebook in pixels. Ignored if
``method='external'``.
method : str
How the figure will be displayed. Options are (1) ``'static'``: PNG
preview (default); (2) ``'external'``: PDF preview in an external
program.
Returns
-------
img : IPython.display.Image
Only if ``method != 'external'``.
"""
# Module level variable to know which figures had their show method
# called. Needed for the sphinx-gallery scraper.
SHOWED_FIGURES.append(self)
if method not in ["static", "external"]:
raise GMTInvalidInput("Invalid show method '{}'.".format(method))
if method == "external":
pdf = self._preview(fmt="pdf", dpi=dpi, anti_alias=False, as_bytes=False)
launch_external_viewer(pdf)
img = None
elif method == "static":
png = self._preview(
fmt="png", dpi=dpi, anti_alias=True, as_bytes=True, transparent=True
)
if Image is None:
raise GMTError(
" ".join(
[
"Cannot find IPython.",
"Make sure you have it installed",
"or use 'method=\"external\"' to open in an external viewer.",
]
)
)
img = Image(data=png, width=width)
return img
[docs] def shift_origin(self, xshift=None, yshift=None):
"""
Shift plot origin in x and/or y directions.
This method shifts plot origin relative to the current origin by
(*xshift*, *yshift*) and optionally append the length unit (**c**,
**i**, or **p**).
Prepend **a** to shift the origin back to the original position after
plotting, prepend **c** to center the plot on the center of the paper
(optionally add shift), prepend **f** to shift the origin relative to
the fixed lower left corner of the page, or prepend **r** [Default] to
move the origin relative to its current location.
Detailed usage at
:gmt-docs:`cookbook/options.html#plot-positioning-and-layout-the-x-y-options`
Parameters
----------
xshift : str
Shift plot origin in x direction.
yshift : str
Shift plot origin in y direction.
"""
self._preprocess()
args = ["-T"]
if xshift:
args.append("-X{}".format(xshift))
if yshift:
args.append("-Y{}".format(yshift))
with Session() as lib:
lib.call_module("plot", " ".join(args))
def _preview(self, fmt, dpi, as_bytes=False, **kwargs):
"""
Grab a preview of the figure.
Parameters
----------
fmt : str
The image format. Can be any extension that
:meth:`~gmt.Figure.savefig` recognizes.
dpi : int
The image resolution (dots per inch).
as_bytes : bool
If ``True``, will load the image as a bytes string and return that
instead of the file name.
Returns
-------
preview : str or bytes
If ``as_bytes=False``, this is the file name of the preview image
file. Else, it is the file content loaded as a bytes string.
"""
fname = os.path.join(self._preview_dir.name, "{}.{}".format(self._name, fmt))
self.savefig(fname, dpi=dpi, **kwargs)
if as_bytes:
with open(fname, "rb") as image:
preview = image.read()
return preview
return fname
def _repr_png_(self):
"""
Show a PNG preview if the object is returned in an interactive shell.
For the Jupyter notebook or IPython Qt console.
"""
png = self._preview(fmt="png", dpi=70, anti_alias=True, as_bytes=True)
return png
def _repr_html_(self):
"""
Show the PNG image embedded in HTML with a controlled width.
Looks better than the raw PNG.
"""
raw_png = self._preview(fmt="png", dpi=300, anti_alias=True, as_bytes=True)
base64_png = base64.encodebytes(raw_png)
html = '<img src="data:image/png;base64,{image}" width="{width}px">'
return html.format(image=base64_png.decode("utf-8"), width=500)