BboxImage 演示

BboxImage可用于根据边界框定位图像。此演示演示如何在text.Text的边界框内显示图像以及如何手动为图像创建边界框。

  1. import matplotlib.pyplot as plt
  2. import numpy as np
  3. from matplotlib.image import BboxImage
  4. from matplotlib.transforms import Bbox, TransformedBbox
  7. fig, (ax1, ax2) = plt.subplots(ncols=2)
  9. # ----------------------------
  10. # Create a BboxImage with Text
  11. # ----------------------------
  12. txt = ax1.text(0.5, 0.5, "test", size=30, ha="center", color="w")
  13. kwargs = dict()
  15. bbox_image = BboxImage(txt.get_window_extent,
  16.                        norm=None,
  17.                        origin=None,
  18.                        clip_on=False,
  19.                        **kwargs
  20.                        )
  21. a = np.arange(256).reshape(1, 256)/256.
  22. bbox_image.set_data(a)
  23. ax1.add_artist(bbox_image)
  25. # ------------------------------------
  26. # Create a BboxImage for each colormap
  27. # ------------------------------------
  28. a = np.linspace(0, 1, 256).reshape(1, -1)
  29. a = np.vstack((a, a))
  31. # List of all colormaps; skip reversed colormaps.
  32. maps = sorted(m for m in plt.cm.cmap_d if not m.endswith("_r"))
  34. ncol = 2
  35. nrow = len(maps)//ncol + 1
  37. xpad_fraction = 0.3
  38. dx = 1./(ncol + xpad_fraction*(ncol - 1))
  40. ypad_fraction = 0.3
  41. dy = 1./(nrow + ypad_fraction*(nrow - 1))
  43. for i, m in enumerate(maps):
  44.     ix, iy = divmod(i, nrow)
  46.     bbox0 = Bbox.from_bounds(ix*dx*(1 + xpad_fraction),
  47.                              1. - iy*dy*(1 + ypad_fraction) - dy,
  48.                              dx, dy)
  49.     bbox = TransformedBbox(bbox0, ax2.transAxes)
  51.     bbox_image = BboxImage(bbox,
  52.                            cmap=plt.get_cmap(m),
  53.                            norm=None,
  54.                            origin=None,
  55.                            **kwargs
  56.                            )
  58.     bbox_image.set_data(a)
  59.     ax2.add_artist(bbox_image)
  61. plt.show()

BboxImage 演示

参考

此示例中显示了以下函数，方法，类和模块的使用：

  1. import matplotlib
  2. matplotlib.image.BboxImage
  3. matplotlib.transforms.Bbox
  4. matplotlib.transforms.TransformedBbox
  5. matplotlib.text.Text

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