锚定艺术家对象

这个使用没有辅助类的锚定对象的示例在Matplotlib axes_grid1 Toolkit中找到。此版本的图与Simple Anchored Artists中的版本类似，但它仅使用matplotlib命名空间实现，没有其他工具包的帮助。

锚定艺术家对象示例

  1. from matplotlib import pyplot as plt
  2. from matplotlib.patches import Rectangle, Ellipse
  3. from matplotlib.offsetbox import (
  4.     AnchoredOffsetbox, AuxTransformBox, DrawingArea, TextArea, VPacker)
  7. class AnchoredText(AnchoredOffsetbox):
  8.     def __init__(self, s, loc, pad=0.4, borderpad=0.5,
  9.                  prop=None, frameon=True):
  10.         self.txt = TextArea(s, minimumdescent=False)
  11.         super().__init__(loc, pad=pad, borderpad=borderpad,
  12.                          child=self.txt, prop=prop, frameon=frameon)
  15. def draw_text(ax):
  16.     """
  17.     Draw a text-box anchored to the upper-left corner of the figure.
  18.     """
  19.     at = AnchoredText("Figure 1a", loc='upper left', frameon=True)
  20.     at.patch.set_boxstyle("round,pad=0.,rounding_size=0.2")
  21.     ax.add_artist(at)
  24. class AnchoredDrawingArea(AnchoredOffsetbox):
  25.     def __init__(self, width, height, xdescent, ydescent,
  26.                  loc, pad=0.4, borderpad=0.5, prop=None, frameon=True):
  27.         self.da = DrawingArea(width, height, xdescent, ydescent)
  28.         super().__init__(loc, pad=pad, borderpad=borderpad,
  29.                          child=self.da, prop=None, frameon=frameon)
  32. def draw_circle(ax):
  33.     """
  34.     Draw a circle in axis coordinates
  35.     """
  36.     from matplotlib.patches import Circle
  37.     ada = AnchoredDrawingArea(20, 20, 0, 0,
  38.                               loc='upper right', pad=0., frameon=False)
  39.     p = Circle((10, 10), 10)
  40.     ada.da.add_artist(p)
  41.     ax.add_artist(ada)
  44. class AnchoredEllipse(AnchoredOffsetbox):
  45.     def __init__(self, transform, width, height, angle, loc,
  46.                  pad=0.1, borderpad=0.1, prop=None, frameon=True):
  47.         """
  48.         Draw an ellipse the size in data coordinate of the give axes.
  50.         pad, borderpad in fraction of the legend font size (or prop)
  51.         """
  52.         self._box = AuxTransformBox(transform)
  53.         self.ellipse = Ellipse((0, 0), width, height, angle)
  54.         self._box.add_artist(self.ellipse)
  55.         super().__init__(loc, pad=pad, borderpad=borderpad,
  56.                          child=self._box, prop=prop, frameon=frameon)
  59. def draw_ellipse(ax):
  60.     """
  61.     Draw an ellipse of width=0.1, height=0.15 in data coordinates
  62.     """
  63.     ae = AnchoredEllipse(ax.transData, width=0.1, height=0.15, angle=0.,
  64.                          loc='lower left', pad=0.5, borderpad=0.4,
  65.                          frameon=True)
  67.     ax.add_artist(ae)
  70. class AnchoredSizeBar(AnchoredOffsetbox):
  71.     def __init__(self, transform, size, label, loc,
  72.                  pad=0.1, borderpad=0.1, sep=2, prop=None, frameon=True):
  73.         """
  74.         Draw a horizontal bar with the size in data coordinate of the given
  75.         axes. A label will be drawn underneath (center-aligned).
  77.         pad, borderpad in fraction of the legend font size (or prop)
  78.         sep in points.
  79.         """
  80.         self.size_bar = AuxTransformBox(transform)
  81.         self.size_bar.add_artist(Rectangle((0, 0), size, 0, ec="black", lw=1.0))
  83.         self.txt_label = TextArea(label, minimumdescent=False)
  85.         self._box = VPacker(children=[self.size_bar, self.txt_label],
  86.                             align="center",
  87.                             pad=0, sep=sep)
  89.         super().__init__(loc, pad=pad, borderpad=borderpad,
  90.                          child=self._box, prop=prop, frameon=frameon)
  93. def draw_sizebar(ax):
  94.     """
  95.     Draw a horizontal bar with length of 0.1 in data coordinates,
  96.     with a fixed label underneath.
  97.     """
  98.     asb = AnchoredSizeBar(ax.transData,
  99.                           0.1,
  100.                           r"1$^{\prime}$",
  101.                           loc='lower center',
  102.                           pad=0.1, borderpad=0.5, sep=5,
  103.                           frameon=False)
  104.     ax.add_artist(asb)
  107. ax = plt.gca()
  108. ax.set_aspect(1.)
  110. draw_text(ax)
  111. draw_circle(ax)
  112. draw_ellipse(ax)
  113. draw_sizebar(ax)
  115. plt.show()

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