forked from 170010011/fr
540 lines
18 KiB
Python
540 lines
18 KiB
Python
"""
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A Cairo backend for matplotlib
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==============================
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:Author: Steve Chaplin and others
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This backend depends on cairocffi or pycairo.
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"""
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import gzip
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import math
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import numpy as np
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try:
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import cairo
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if cairo.version_info < (1, 11, 0):
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# Introduced create_for_data for Py3.
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raise ImportError
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except ImportError:
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try:
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import cairocffi as cairo
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except ImportError as err:
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raise ImportError(
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"cairo backend requires that pycairo>=1.11.0 or cairocffi"
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"is installed") from err
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from .. import cbook, font_manager
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from matplotlib.backend_bases import (
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_Backend, _check_savefig_extra_args, FigureCanvasBase, FigureManagerBase,
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GraphicsContextBase, RendererBase)
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from matplotlib.font_manager import ttfFontProperty
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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 Affine2D
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backend_version = cairo.version
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if cairo.__name__ == "cairocffi":
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# Convert a pycairo context to a cairocffi one.
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def _to_context(ctx):
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if not isinstance(ctx, cairo.Context):
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ctx = cairo.Context._from_pointer(
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cairo.ffi.cast(
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'cairo_t **',
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id(ctx) + object.__basicsize__)[0],
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incref=True)
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return ctx
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else:
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# Pass-through a pycairo context.
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def _to_context(ctx):
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return ctx
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def _append_path(ctx, path, transform, clip=None):
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for points, code in path.iter_segments(
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transform, remove_nans=True, clip=clip):
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if code == Path.MOVETO:
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ctx.move_to(*points)
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elif code == Path.CLOSEPOLY:
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ctx.close_path()
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elif code == Path.LINETO:
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ctx.line_to(*points)
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elif code == Path.CURVE3:
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cur = np.asarray(ctx.get_current_point())
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a = points[:2]
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b = points[-2:]
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ctx.curve_to(*(cur / 3 + a * 2 / 3), *(a * 2 / 3 + b / 3), *b)
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elif code == Path.CURVE4:
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ctx.curve_to(*points)
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def _cairo_font_args_from_font_prop(prop):
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"""
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Convert a `.FontProperties` or a `.FontEntry` to arguments that can be
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passed to `.Context.select_font_face`.
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"""
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def attr(field):
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try:
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return getattr(prop, f"get_{field}")()
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except AttributeError:
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return getattr(prop, field)
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name = attr("name")
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slant = getattr(cairo, f"FONT_SLANT_{attr('style').upper()}")
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weight = attr("weight")
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weight = (cairo.FONT_WEIGHT_NORMAL
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if font_manager.weight_dict.get(weight, weight) < 550
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else cairo.FONT_WEIGHT_BOLD)
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return name, slant, weight
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class RendererCairo(RendererBase):
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@cbook.deprecated("3.3")
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@property
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def fontweights(self):
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return {
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100: cairo.FONT_WEIGHT_NORMAL,
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200: cairo.FONT_WEIGHT_NORMAL,
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300: cairo.FONT_WEIGHT_NORMAL,
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400: cairo.FONT_WEIGHT_NORMAL,
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500: cairo.FONT_WEIGHT_NORMAL,
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600: cairo.FONT_WEIGHT_BOLD,
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700: cairo.FONT_WEIGHT_BOLD,
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800: cairo.FONT_WEIGHT_BOLD,
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900: cairo.FONT_WEIGHT_BOLD,
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'ultralight': cairo.FONT_WEIGHT_NORMAL,
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'light': cairo.FONT_WEIGHT_NORMAL,
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'normal': cairo.FONT_WEIGHT_NORMAL,
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'medium': cairo.FONT_WEIGHT_NORMAL,
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'regular': cairo.FONT_WEIGHT_NORMAL,
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'semibold': cairo.FONT_WEIGHT_BOLD,
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'bold': cairo.FONT_WEIGHT_BOLD,
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'heavy': cairo.FONT_WEIGHT_BOLD,
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'ultrabold': cairo.FONT_WEIGHT_BOLD,
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'black': cairo.FONT_WEIGHT_BOLD,
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}
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@cbook.deprecated("3.3")
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@property
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def fontangles(self):
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return {
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'italic': cairo.FONT_SLANT_ITALIC,
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'normal': cairo.FONT_SLANT_NORMAL,
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'oblique': cairo.FONT_SLANT_OBLIQUE,
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}
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def __init__(self, dpi):
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self.dpi = dpi
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self.gc = GraphicsContextCairo(renderer=self)
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self.text_ctx = cairo.Context(
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cairo.ImageSurface(cairo.FORMAT_ARGB32, 1, 1))
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self.mathtext_parser = MathTextParser('Cairo')
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RendererBase.__init__(self)
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def set_ctx_from_surface(self, surface):
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self.gc.ctx = cairo.Context(surface)
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# Although it may appear natural to automatically call
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# `self.set_width_height(surface.get_width(), surface.get_height())`
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# here (instead of having the caller do so separately), this would fail
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# for PDF/PS/SVG surfaces, which have no way to report their extents.
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def set_width_height(self, width, height):
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self.width = width
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self.height = height
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def _fill_and_stroke(self, ctx, fill_c, alpha, alpha_overrides):
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if fill_c is not None:
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ctx.save()
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if len(fill_c) == 3 or alpha_overrides:
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ctx.set_source_rgba(fill_c[0], fill_c[1], fill_c[2], alpha)
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else:
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ctx.set_source_rgba(fill_c[0], fill_c[1], fill_c[2], fill_c[3])
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ctx.fill_preserve()
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ctx.restore()
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ctx.stroke()
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def draw_path(self, gc, path, transform, rgbFace=None):
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# docstring inherited
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ctx = gc.ctx
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# Clip the path to the actual rendering extents if it isn't filled.
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clip = (ctx.clip_extents()
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if rgbFace is None and gc.get_hatch() is None
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else None)
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transform = (transform
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+ Affine2D().scale(1, -1).translate(0, self.height))
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ctx.new_path()
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_append_path(ctx, path, transform, clip)
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self._fill_and_stroke(
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ctx, rgbFace, gc.get_alpha(), gc.get_forced_alpha())
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def draw_markers(self, gc, marker_path, marker_trans, path, transform,
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rgbFace=None):
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# docstring inherited
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ctx = gc.ctx
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ctx.new_path()
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# Create the path for the marker; it needs to be flipped here already!
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_append_path(ctx, marker_path, marker_trans + Affine2D().scale(1, -1))
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marker_path = ctx.copy_path_flat()
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# Figure out whether the path has a fill
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x1, y1, x2, y2 = ctx.fill_extents()
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if x1 == 0 and y1 == 0 and x2 == 0 and y2 == 0:
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filled = False
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# No fill, just unset this (so we don't try to fill it later on)
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rgbFace = None
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else:
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filled = True
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transform = (transform
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+ Affine2D().scale(1, -1).translate(0, self.height))
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ctx.new_path()
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for i, (vertices, codes) in enumerate(
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path.iter_segments(transform, simplify=False)):
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if len(vertices):
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x, y = vertices[-2:]
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ctx.save()
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# Translate and apply path
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ctx.translate(x, y)
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ctx.append_path(marker_path)
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ctx.restore()
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# Slower code path if there is a fill; we need to draw
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# the fill and stroke for each marker at the same time.
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# Also flush out the drawing every once in a while to
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# prevent the paths from getting way too long.
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if filled or i % 1000 == 0:
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self._fill_and_stroke(
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ctx, rgbFace, gc.get_alpha(), gc.get_forced_alpha())
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# Fast path, if there is no fill, draw everything in one step
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if not filled:
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self._fill_and_stroke(
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ctx, rgbFace, gc.get_alpha(), gc.get_forced_alpha())
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def draw_image(self, gc, x, y, im):
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im = cbook._unmultiplied_rgba8888_to_premultiplied_argb32(im[::-1])
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surface = cairo.ImageSurface.create_for_data(
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im.ravel().data, cairo.FORMAT_ARGB32,
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im.shape[1], im.shape[0], im.shape[1] * 4)
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ctx = gc.ctx
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y = self.height - y - im.shape[0]
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ctx.save()
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ctx.set_source_surface(surface, float(x), float(y))
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ctx.paint()
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ctx.restore()
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def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
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# docstring inherited
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# Note: (x, y) are device/display coords, not user-coords, unlike other
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# draw_* methods
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if ismath:
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self._draw_mathtext(gc, x, y, s, prop, angle)
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else:
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ctx = gc.ctx
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ctx.new_path()
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ctx.move_to(x, y)
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ctx.select_font_face(*_cairo_font_args_from_font_prop(prop))
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ctx.save()
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ctx.set_font_size(prop.get_size_in_points() * self.dpi / 72)
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if angle:
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ctx.rotate(np.deg2rad(-angle))
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ctx.show_text(s)
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ctx.restore()
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def _draw_mathtext(self, gc, x, y, s, prop, angle):
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ctx = gc.ctx
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width, height, descent, glyphs, rects = self.mathtext_parser.parse(
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s, self.dpi, prop)
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ctx.save()
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ctx.translate(x, y)
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if angle:
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ctx.rotate(np.deg2rad(-angle))
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for font, fontsize, s, ox, oy in glyphs:
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ctx.new_path()
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ctx.move_to(ox, oy)
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ctx.select_font_face(
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*_cairo_font_args_from_font_prop(ttfFontProperty(font)))
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ctx.set_font_size(fontsize * self.dpi / 72)
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ctx.show_text(s)
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for ox, oy, w, h in rects:
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ctx.new_path()
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ctx.rectangle(ox, oy, w, h)
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ctx.set_source_rgb(0, 0, 0)
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ctx.fill_preserve()
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ctx.restore()
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def get_canvas_width_height(self):
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# docstring inherited
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return self.width, self.height
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def get_text_width_height_descent(self, s, prop, ismath):
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# docstring inherited
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if ismath:
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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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ctx = self.text_ctx
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# problem - scale remembers last setting and font can become
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# enormous causing program to crash
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# save/restore prevents the problem
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ctx.save()
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ctx.select_font_face(*_cairo_font_args_from_font_prop(prop))
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# Cairo (says it) uses 1/96 inch user space units, ref: cairo_gstate.c
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# but if /96.0 is used the font is too small
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ctx.set_font_size(prop.get_size_in_points() * self.dpi / 72)
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y_bearing, w, h = ctx.text_extents(s)[1:4]
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ctx.restore()
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return w, h, h + y_bearing
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def new_gc(self):
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# docstring inherited
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self.gc.ctx.save()
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self.gc._alpha = 1
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self.gc._forced_alpha = False # if True, _alpha overrides A from RGBA
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return self.gc
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def points_to_pixels(self, points):
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# docstring inherited
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return points / 72 * self.dpi
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class GraphicsContextCairo(GraphicsContextBase):
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_joind = {
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'bevel': cairo.LINE_JOIN_BEVEL,
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'miter': cairo.LINE_JOIN_MITER,
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'round': cairo.LINE_JOIN_ROUND,
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}
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_capd = {
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'butt': cairo.LINE_CAP_BUTT,
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'projecting': cairo.LINE_CAP_SQUARE,
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'round': cairo.LINE_CAP_ROUND,
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}
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def __init__(self, renderer):
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GraphicsContextBase.__init__(self)
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self.renderer = renderer
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def restore(self):
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self.ctx.restore()
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def set_alpha(self, alpha):
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GraphicsContextBase.set_alpha(self, alpha)
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_alpha = self.get_alpha()
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rgb = self._rgb
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if self.get_forced_alpha():
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self.ctx.set_source_rgba(rgb[0], rgb[1], rgb[2], _alpha)
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else:
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self.ctx.set_source_rgba(rgb[0], rgb[1], rgb[2], rgb[3])
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# def set_antialiased(self, b):
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# cairo has many antialiasing modes, we need to pick one for True and
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# one for False.
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def set_capstyle(self, cs):
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self.ctx.set_line_cap(cbook._check_getitem(self._capd, capstyle=cs))
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self._capstyle = cs
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def set_clip_rectangle(self, rectangle):
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if not rectangle:
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return
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x, y, w, h = np.round(rectangle.bounds)
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ctx = self.ctx
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ctx.new_path()
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ctx.rectangle(x, self.renderer.height - h - y, w, h)
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ctx.clip()
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def set_clip_path(self, path):
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if not path:
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return
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tpath, affine = path.get_transformed_path_and_affine()
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ctx = self.ctx
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ctx.new_path()
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affine = (affine
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+ Affine2D().scale(1, -1).translate(0, self.renderer.height))
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_append_path(ctx, tpath, affine)
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ctx.clip()
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def set_dashes(self, offset, dashes):
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self._dashes = offset, dashes
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if dashes is None:
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self.ctx.set_dash([], 0) # switch dashes off
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else:
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self.ctx.set_dash(
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list(self.renderer.points_to_pixels(np.asarray(dashes))),
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offset)
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def set_foreground(self, fg, isRGBA=None):
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GraphicsContextBase.set_foreground(self, fg, isRGBA)
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if len(self._rgb) == 3:
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self.ctx.set_source_rgb(*self._rgb)
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else:
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self.ctx.set_source_rgba(*self._rgb)
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def get_rgb(self):
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return self.ctx.get_source().get_rgba()[:3]
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def set_joinstyle(self, js):
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self.ctx.set_line_join(cbook._check_getitem(self._joind, joinstyle=js))
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self._joinstyle = js
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def set_linewidth(self, w):
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self._linewidth = float(w)
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self.ctx.set_line_width(self.renderer.points_to_pixels(w))
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class _CairoRegion:
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def __init__(self, slices, data):
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self._slices = slices
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self._data = data
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class FigureCanvasCairo(FigureCanvasBase):
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def copy_from_bbox(self, bbox):
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surface = self._renderer.gc.ctx.get_target()
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if not isinstance(surface, cairo.ImageSurface):
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raise RuntimeError(
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"copy_from_bbox only works when rendering to an ImageSurface")
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sw = surface.get_width()
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sh = surface.get_height()
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x0 = math.ceil(bbox.x0)
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x1 = math.floor(bbox.x1)
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y0 = math.ceil(sh - bbox.y1)
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y1 = math.floor(sh - bbox.y0)
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if not (0 <= x0 and x1 <= sw and bbox.x0 <= bbox.x1
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and 0 <= y0 and y1 <= sh and bbox.y0 <= bbox.y1):
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raise ValueError("Invalid bbox")
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sls = slice(y0, y0 + max(y1 - y0, 0)), slice(x0, x0 + max(x1 - x0, 0))
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data = (np.frombuffer(surface.get_data(), np.uint32)
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.reshape((sh, sw))[sls].copy())
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return _CairoRegion(sls, data)
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def restore_region(self, region):
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surface = self._renderer.gc.ctx.get_target()
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if not isinstance(surface, cairo.ImageSurface):
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raise RuntimeError(
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"restore_region only works when rendering to an ImageSurface")
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surface.flush()
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sw = surface.get_width()
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sh = surface.get_height()
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sly, slx = region._slices
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(np.frombuffer(surface.get_data(), np.uint32)
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.reshape((sh, sw))[sly, slx]) = region._data
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surface.mark_dirty_rectangle(
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slx.start, sly.start, slx.stop - slx.start, sly.stop - sly.start)
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@_check_savefig_extra_args
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def print_png(self, fobj):
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self._get_printed_image_surface().write_to_png(fobj)
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@_check_savefig_extra_args
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def print_rgba(self, fobj):
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width, height = self.get_width_height()
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buf = self._get_printed_image_surface().get_data()
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fobj.write(cbook._premultiplied_argb32_to_unmultiplied_rgba8888(
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np.asarray(buf).reshape((width, height, 4))))
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print_raw = print_rgba
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def _get_printed_image_surface(self):
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width, height = self.get_width_height()
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renderer = RendererCairo(self.figure.dpi)
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renderer.set_width_height(width, height)
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surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
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renderer.set_ctx_from_surface(surface)
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self.figure.draw(renderer)
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return surface
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def print_pdf(self, fobj, *args, **kwargs):
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return self._save(fobj, 'pdf', *args, **kwargs)
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def print_ps(self, fobj, *args, **kwargs):
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return self._save(fobj, 'ps', *args, **kwargs)
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def print_svg(self, fobj, *args, **kwargs):
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return self._save(fobj, 'svg', *args, **kwargs)
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def print_svgz(self, fobj, *args, **kwargs):
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return self._save(fobj, 'svgz', *args, **kwargs)
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@_check_savefig_extra_args
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def _save(self, fo, fmt, *, orientation='portrait'):
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# save PDF/PS/SVG
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dpi = 72
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self.figure.dpi = dpi
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w_in, h_in = self.figure.get_size_inches()
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width_in_points, height_in_points = w_in * dpi, h_in * dpi
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if orientation == 'landscape':
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width_in_points, height_in_points = (
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height_in_points, width_in_points)
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if fmt == 'ps':
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if not hasattr(cairo, 'PSSurface'):
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raise RuntimeError('cairo has not been compiled with PS '
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'support enabled')
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surface = cairo.PSSurface(fo, width_in_points, height_in_points)
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elif fmt == 'pdf':
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if not hasattr(cairo, 'PDFSurface'):
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raise RuntimeError('cairo has not been compiled with PDF '
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'support enabled')
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surface = cairo.PDFSurface(fo, width_in_points, height_in_points)
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elif fmt in ('svg', 'svgz'):
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if not hasattr(cairo, 'SVGSurface'):
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raise RuntimeError('cairo has not been compiled with SVG '
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'support enabled')
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if fmt == 'svgz':
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if isinstance(fo, str):
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fo = gzip.GzipFile(fo, 'wb')
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else:
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fo = gzip.GzipFile(None, 'wb', fileobj=fo)
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surface = cairo.SVGSurface(fo, width_in_points, height_in_points)
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else:
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raise ValueError("Unknown format: {!r}".format(fmt))
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# surface.set_dpi() can be used
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renderer = RendererCairo(self.figure.dpi)
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renderer.set_width_height(width_in_points, height_in_points)
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renderer.set_ctx_from_surface(surface)
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ctx = renderer.gc.ctx
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if orientation == 'landscape':
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ctx.rotate(np.pi / 2)
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ctx.translate(0, -height_in_points)
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# Perhaps add an '%%Orientation: Landscape' comment?
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self.figure.draw(renderer)
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ctx.show_page()
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surface.finish()
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if fmt == 'svgz':
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fo.close()
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@_Backend.export
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class _BackendCairo(_Backend):
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FigureCanvas = FigureCanvasCairo
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FigureManager = FigureManagerBase
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