Version 3.0.3
"""
An agg http://antigrain.com/ backend
Features that are implemented
* capstyles and join styles
* dashes
* linewidth
* lines, rectangles, ellipses
* clipping to a rectangle
* output to RGBA and PNG, optionally JPEG and TIFF
* alpha blending
* DPI scaling properly - everything scales properly (dashes, linewidths, etc)
* draw polygon
* freetype2 w/ ft2font
TODO:
* integrate screen dpi w/ ppi and text
"""
try:
import threading
except ImportError:
import dummy_threading as threading
import numpy as np
from collections import OrderedDict
from math import radians, cos, sin
from matplotlib import cbook, rcParams, __version__
from matplotlib.backend_bases import (
_Backend, FigureCanvasBase, FigureManagerBase, RendererBase)
from matplotlib.font_manager import findfont, get_font
from matplotlib.ft2font import (LOAD_FORCE_AUTOHINT, LOAD_NO_HINTING,
LOAD_DEFAULT, LOAD_NO_AUTOHINT)
from matplotlib.mathtext import MathTextParser
from matplotlib.path import Path
from matplotlib.transforms import Bbox, BboxBase
from matplotlib import colors as mcolors
from matplotlib.backends._backend_agg import RendererAgg as _RendererAgg
from matplotlib import _png
from matplotlib.backend_bases import _has_pil
if _has_pil:
from PIL import Image
backend_version = 'v2.2'
[docs]def get_hinting_flag():
mapping = {
True: LOAD_FORCE_AUTOHINT,
False: LOAD_NO_HINTING,
'either': LOAD_DEFAULT,
'native': LOAD_NO_AUTOHINT,
'auto': LOAD_FORCE_AUTOHINT,
'none': LOAD_NO_HINTING
}
return mapping[rcParams['text.hinting']]
[docs]class RendererAgg(RendererBase):
"""
The renderer handles all the drawing primitives using a graphics
context instance that controls the colors/styles
"""
# we want to cache the fonts at the class level so that when
# multiple figures are created we can reuse them. This helps with
# a bug on windows where the creation of too many figures leads to
# too many open file handles. However, storing them at the class
# level is not thread safe. The solution here is to let the
# FigureCanvas acquire a lock on the fontd at the start of the
# draw, and release it when it is done. This allows multiple
# renderers to share the cached fonts, but only one figure can
# draw at time and so the font cache is used by only one
# renderer at a time.
lock = threading.RLock()
def __init__(self, width, height, dpi):
RendererBase.__init__(self)
self.dpi = dpi
self.width = width
self.height = height
self._renderer = _RendererAgg(int(width), int(height), dpi)
self._filter_renderers = []
self._update_methods()
self.mathtext_parser = MathTextParser('Agg')
self.bbox = Bbox.from_bounds(0, 0, self.width, self.height)
def __getstate__(self):
# We only want to preserve the init keywords of the Renderer.
# Anything else can be re-created.
return {'width': self.width, 'height': self.height, 'dpi': self.dpi}
def __setstate__(self, state):
self.__init__(state['width'], state['height'], state['dpi'])
def _update_methods(self):
self.draw_gouraud_triangle = self._renderer.draw_gouraud_triangle
self.draw_gouraud_triangles = self._renderer.draw_gouraud_triangles
self.draw_image = self._renderer.draw_image
self.draw_markers = self._renderer.draw_markers
self.draw_path_collection = self._renderer.draw_path_collection
self.draw_quad_mesh = self._renderer.draw_quad_mesh
self.copy_from_bbox = self._renderer.copy_from_bbox
self.get_content_extents = self._renderer.get_content_extents
[docs] def tostring_rgba_minimized(self):
extents = self.get_content_extents()
bbox = [[extents[0], self.height - (extents[1] + extents[3])],
[extents[0] + extents[2], self.height - extents[1]]]
region = self.copy_from_bbox(bbox)
return np.array(region), extents
[docs] def draw_path(self, gc, path, transform, rgbFace=None):
"""
Draw the path
"""
nmax = rcParams['agg.path.chunksize'] # here at least for testing
npts = path.vertices.shape[0]
if (nmax > 100 and npts > nmax and path.should_simplify and
rgbFace is None and gc.get_hatch() is None):
nch = np.ceil(npts / nmax)
chsize = int(np.ceil(npts / nch))
i0 = np.arange(0, npts, chsize)
i1 = np.zeros_like(i0)
i1[:-1] = i0[1:] - 1
i1[-1] = npts
for ii0, ii1 in zip(i0, i1):
v = path.vertices[ii0:ii1, :]
c = path.codes
if c is not None:
c = c[ii0:ii1]
c[0] = Path.MOVETO # move to end of last chunk
p = Path(v, c)
try:
self._renderer.draw_path(gc, p, transform, rgbFace)
except OverflowError:
raise OverflowError("Exceeded cell block limit (set "
"'agg.path.chunksize' rcparam)")
else:
try:
self._renderer.draw_path(gc, path, transform, rgbFace)
except OverflowError:
raise OverflowError("Exceeded cell block limit (set "
"'agg.path.chunksize' rcparam)")
[docs] def draw_mathtext(self, gc, x, y, s, prop, angle):
"""
Draw the math text using matplotlib.mathtext
"""
ox, oy, width, height, descent, font_image, used_characters = \
self.mathtext_parser.parse(s, self.dpi, prop)
xd = descent * sin(radians(angle))
yd = descent * cos(radians(angle))
x = np.round(x + ox + xd)
y = np.round(y - oy + yd)
self._renderer.draw_text_image(font_image, x, y + 1, angle, gc)
[docs] def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
"""
Render the text
"""
if ismath:
return self.draw_mathtext(gc, x, y, s, prop, angle)
flags = get_hinting_flag()
font = self._get_agg_font(prop)
if font is None:
return None
if len(s) == 1 and ord(s) > 127:
font.load_char(ord(s), flags=flags)
else:
# We pass '0' for angle here, since it will be rotated (in raster
# space) in the following call to draw_text_image).
font.set_text(s, 0, flags=flags)
font.draw_glyphs_to_bitmap(antialiased=rcParams['text.antialiased'])
d = font.get_descent() / 64.0
# The descent needs to be adjusted for the angle.
xo, yo = font.get_bitmap_offset()
xo /= 64.0
yo /= 64.0
xd = -d * sin(radians(angle))
yd = d * cos(radians(angle))
self._renderer.draw_text_image(
font, np.round(x - xd + xo), np.round(y + yd + yo) + 1, angle, gc)
[docs] def get_text_width_height_descent(self, s, prop, ismath):
"""
Get the width, height, and descent (offset from the bottom
to the baseline), in display coords, of the string *s* with
:class:`~matplotlib.font_manager.FontProperties` *prop*
"""
if ismath in ["TeX", "TeX!"]:
# todo: handle props
size = prop.get_size_in_points()
texmanager = self.get_texmanager()
fontsize = prop.get_size_in_points()
w, h, d = texmanager.get_text_width_height_descent(
s, fontsize, renderer=self)
return w, h, d
if ismath:
ox, oy, width, height, descent, fonts, used_characters = \
self.mathtext_parser.parse(s, self.dpi, prop)
return width, height, descent
flags = get_hinting_flag()
font = self._get_agg_font(prop)
font.set_text(s, 0.0, flags=flags)
w, h = font.get_width_height() # width and height of unrotated string
d = font.get_descent()
w /= 64.0 # convert from subpixels
h /= 64.0
d /= 64.0
return w, h, d
[docs] def draw_tex(self, gc, x, y, s, prop, angle, ismath='TeX!', mtext=None):
# todo, handle props, angle, origins
size = prop.get_size_in_points()
texmanager = self.get_texmanager()
Z = texmanager.get_grey(s, size, self.dpi)
Z = np.array(Z * 255.0, np.uint8)
w, h, d = self.get_text_width_height_descent(s, prop, ismath)
xd = d * sin(radians(angle))
yd = d * cos(radians(angle))
x = np.round(x + xd)
y = np.round(y + yd)
self._renderer.draw_text_image(Z, x, y, angle, gc)
[docs] def get_canvas_width_height(self):
'return the canvas width and height in display coords'
return self.width, self.height
def _get_agg_font(self, prop):
"""
Get the font for text instance t, caching for efficiency
"""
fname = findfont(prop)
font = get_font(fname)
font.clear()
size = prop.get_size_in_points()
font.set_size(size, self.dpi)
return font
[docs] def points_to_pixels(self, points):
"""
convert point measures to pixes using dpi and the pixels per
inch of the display
"""
return points * self.dpi / 72
[docs] def option_image_nocomposite(self):
# It is generally faster to composite each image directly to
# the Figure, and there's no file size benefit to compositing
# with the Agg backend
return True
[docs] def option_scale_image(self):
"""
agg backend doesn't support arbitrary scaling of image.
"""
return False
[docs] def restore_region(self, region, bbox=None, xy=None):
"""
Restore the saved region. If bbox (instance of BboxBase, or
its extents) is given, only the region specified by the bbox
will be restored. *xy* (a tuple of two floasts) optionally
specifies the new position (the LLC of the original region,
not the LLC of the bbox) where the region will be restored.
>>> region = renderer.copy_from_bbox()
>>> x1, y1, x2, y2 = region.get_extents()
>>> renderer.restore_region(region, bbox=(x1+dx, y1, x2, y2),
... xy=(x1-dx, y1))
"""
if bbox is not None or xy is not None:
if bbox is None:
x1, y1, x2, y2 = region.get_extents()
elif isinstance(bbox, BboxBase):
x1, y1, x2, y2 = bbox.extents
else:
x1, y1, x2, y2 = bbox
if xy is None:
ox, oy = x1, y1
else:
ox, oy = xy
# The incoming data is float, but the _renderer type-checking wants
# to see integers.
self._renderer.restore_region(region, int(x1), int(y1),
int(x2), int(y2), int(ox), int(oy))
else:
self._renderer.restore_region(region)
[docs] def start_filter(self):
"""
Start filtering. It simply create a new canvas (the old one is saved).
"""
self._filter_renderers.append(self._renderer)
self._renderer = _RendererAgg(int(self.width), int(self.height),
self.dpi)
self._update_methods()
[docs] def stop_filter(self, post_processing):
"""
Save the plot in the current canvas as a image and apply
the *post_processing* function.
def post_processing(image, dpi):
# ny, nx, depth = image.shape
# image (numpy array) has RGBA channels and has a depth of 4.
...
# create a new_image (numpy array of 4 channels, size can be
# different). The resulting image may have offsets from
# lower-left corner of the original image
return new_image, offset_x, offset_y
The saved renderer is restored and the returned image from
post_processing is plotted (using draw_image) on it.
"""
width, height = int(self.width), int(self.height)
buffer, (l, b, w, h) = self.tostring_rgba_minimized()
self._renderer = self._filter_renderers.pop()
self._update_methods()
if w > 0 and h > 0:
img = np.fromstring(buffer, np.uint8)
img, ox, oy = post_processing(img.reshape((h, w, 4)) / 255.,
self.dpi)
gc = self.new_gc()
if img.dtype.kind == 'f':
img = np.asarray(img * 255., np.uint8)
img = img[::-1]
self._renderer.draw_image(gc, l + ox, height - b - h + oy, img)
[docs]class FigureCanvasAgg(FigureCanvasBase):
"""
The canvas the figure renders into. Calls the draw and print fig
methods, creates the renderers, etc...
Attributes
----------
figure : `matplotlib.figure.Figure`
A high-level Figure instance
"""
[docs] def copy_from_bbox(self, bbox):
renderer = self.get_renderer()
return renderer.copy_from_bbox(bbox)
[docs] def restore_region(self, region, bbox=None, xy=None):
renderer = self.get_renderer()
return renderer.restore_region(region, bbox, xy)
[docs] def draw(self):
"""
Draw the figure using the renderer.
"""
self.renderer = self.get_renderer(cleared=True)
# acquire a lock on the shared font cache
RendererAgg.lock.acquire()
toolbar = self.toolbar
try:
self.figure.draw(self.renderer)
# A GUI class may be need to update a window using this draw, so
# don't forget to call the superclass.
super().draw()
finally:
RendererAgg.lock.release()
[docs] def get_renderer(self, cleared=False):
l, b, w, h = self.figure.bbox.bounds
key = w, h, self.figure.dpi
try: self._lastKey, self.renderer
except AttributeError: need_new_renderer = True
else: need_new_renderer = (self._lastKey != key)
if need_new_renderer:
self.renderer = RendererAgg(w, h, self.figure.dpi)
self._lastKey = key
elif cleared:
self.renderer.clear()
return self.renderer
[docs] def tostring_rgb(self):
'''Get the image as an RGB byte string.
`draw` must be called at least once before this function will work and
to update the renderer for any subsequent changes to the Figure.
Returns
-------
bytes
'''
return self.renderer.tostring_rgb()
[docs] def tostring_argb(self):
'''Get the image as an ARGB byte string
`draw` must be called at least once before this function will work and
to update the renderer for any subsequent changes to the Figure.
Returns
-------
bytes
'''
return self.renderer.tostring_argb()
[docs] def buffer_rgba(self):
'''Get the image as an RGBA byte string.
`draw` must be called at least once before this function will work and
to update the renderer for any subsequent changes to the Figure.
Returns
-------
bytes
'''
return self.renderer.buffer_rgba()
[docs] def print_raw(self, filename_or_obj, *args, **kwargs):
FigureCanvasAgg.draw(self)
renderer = self.get_renderer()
with cbook._setattr_cm(renderer, dpi=self.figure.dpi), \
cbook.open_file_cm(filename_or_obj, "wb") as fh:
fh.write(renderer._renderer.buffer_rgba())
print_rgba = print_raw
[docs] def print_png(self, filename_or_obj, *args, **kwargs):
"""
Write the figure to a PNG file.
Parameters
----------
filename_or_obj : str or PathLike or file-like object
The file to write to.
metadata : dict, optional
Metadata in the PNG file as key-value pairs of bytes or latin-1
encodable strings.
According to the PNG specification, keys must be shorter than 79
chars.
The `PNG specification`_ defines some common keywords that may be
used as appropriate:
- Title: Short (one line) title or caption for image.
- Author: Name of image's creator.
- Description: Description of image (possibly long).
- Copyright: Copyright notice.
- Creation Time: Time of original image creation
(usually RFC 1123 format).
- Software: Software used to create the image.
- Disclaimer: Legal disclaimer.
- Warning: Warning of nature of content.
- Source: Device used to create the image.
- Comment: Miscellaneous comment;
conversion from other image format.
Other keywords may be invented for other purposes.
If 'Software' is not given, an autogenerated value for matplotlib
will be used.
For more details see the `PNG specification`_.
.. _PNG specification: \
https://www.w3.org/TR/2003/REC-PNG-20031110/#11keywords
"""
FigureCanvasAgg.draw(self)
renderer = self.get_renderer()
version_str = (
'matplotlib version ' + __version__ + ', http://matplotlib.org/')
metadata = OrderedDict({'Software': version_str})
user_metadata = kwargs.pop("metadata", None)
if user_metadata is not None:
metadata.update(user_metadata)
with cbook._setattr_cm(renderer, dpi=self.figure.dpi), \
cbook.open_file_cm(filename_or_obj, "wb") as fh:
_png.write_png(renderer._renderer, fh,
self.figure.dpi, metadata=metadata)
[docs] def print_to_buffer(self):
FigureCanvasAgg.draw(self)
renderer = self.get_renderer()
with cbook._setattr_cm(renderer, dpi=self.figure.dpi):
return (renderer._renderer.buffer_rgba(),
(int(renderer.width), int(renderer.height)))
if _has_pil:
# add JPEG support
[docs] def print_jpg(self, filename_or_obj, *args, dryrun=False, **kwargs):
"""
Write the figure to a JPEG file.
Parameters
----------
filename_or_obj : str or PathLike or file-like object
The file to write to.
Other Parameters
----------------
quality : int
The image quality, on a scale from 1 (worst) to 100 (best).
The default is :rc:`savefig.jpeg_quality`. Values above
95 should be avoided; 100 completely disables the JPEG
quantization stage.
optimize : bool
If present, indicates that the encoder should
make an extra pass over the image in order to select
optimal encoder settings.
progressive : bool
If present, indicates that this image
should be stored as a progressive JPEG file.
"""
buf, size = self.print_to_buffer()
if dryrun:
return
# The image is "pasted" onto a white background image to safely
# handle any transparency
image = Image.frombuffer('RGBA', size, buf, 'raw', 'RGBA', 0, 1)
rgba = mcolors.to_rgba(rcParams['savefig.facecolor'])
color = tuple([int(x * 255) for x in rgba[:3]])
background = Image.new('RGB', size, color)
background.paste(image, image)
options = {k: kwargs[k]
for k in ['quality', 'optimize', 'progressive', 'dpi']
if k in kwargs}
options.setdefault('quality', rcParams['savefig.jpeg_quality'])
if 'dpi' in options:
# Set the same dpi in both x and y directions
options['dpi'] = (options['dpi'], options['dpi'])
return background.save(filename_or_obj, format='jpeg', **options)
print_jpeg = print_jpg
# add TIFF support
[docs] def print_tif(self, filename_or_obj, *args, dryrun=False, **kwargs):
buf, size = self.print_to_buffer()
if dryrun:
return
image = Image.frombuffer('RGBA', size, buf, 'raw', 'RGBA', 0, 1)
dpi = (self.figure.dpi, self.figure.dpi)
return image.save(filename_or_obj, format='tiff', dpi=dpi)
print_tiff = print_tif
@_Backend.export
class _BackendAgg(_Backend):
FigureCanvas = FigureCanvasAgg
FigureManager = FigureManagerBase