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