Coverage for /usr/lib/python3/dist-packages/matplotlib/_tight_bbox.py: 85%

1""" 

2Helper module for the *bbox_inches* parameter in `.Figure.savefig`. 

3""" 

4 

5from matplotlib.transforms import Bbox, TransformedBbox, Affine2D 

6 

7 

8def adjust_bbox(fig, bbox_inches, fixed_dpi=None): 

9 """ 

10 Temporarily adjust the figure so that only the specified area 

11 (bbox_inches) is saved. 

12 

13 It modifies fig.bbox, fig.bbox_inches, 

14 fig.transFigure._boxout, and fig.patch. While the figure size 

15 changes, the scale of the original figure is conserved. A 

16 function which restores the original values are returned. 

17 """ 

18 origBbox = fig.bbox 

19 origBboxInches = fig.bbox_inches 

20 orig_layout = fig.get_layout_engine() 

21 fig.set_layout_engine(None) 

22 _boxout = fig.transFigure._boxout 

23 

24 old_aspect = [] 

25 locator_list = [] 

26 sentinel = object() 

27 for ax in fig.axes: 

28 locator_list.append(ax.get_axes_locator()) 

29 current_pos = ax.get_position(original=False).frozen() 

30 ax.set_axes_locator(lambda a, r, _pos=current_pos: _pos) 

31 # override the method that enforces the aspect ratio on the Axes 

32 if 'apply_aspect' in ax.__dict__: 

33 old_aspect.append(ax.apply_aspect) 

34 else: 

35 old_aspect.append(sentinel) 

36 ax.apply_aspect = lambda pos=None: None 

37 

38 def restore_bbox(): 

39 for ax, loc, aspect in zip(fig.axes, locator_list, old_aspect): 

40 ax.set_axes_locator(loc) 

41 if aspect is sentinel: 

42 # delete our no-op function which un-hides the original method 

43 del ax.apply_aspect 

44 else: 

45 ax.apply_aspect = aspect 

46 

47 fig.bbox = origBbox 

48 fig.bbox_inches = origBboxInches 

49 fig.set_layout_engine(orig_layout) 

50 fig.transFigure._boxout = _boxout 

51 fig.transFigure.invalidate() 

52 fig.patch.set_bounds(0, 0, 1, 1) 

53 

54 if fixed_dpi is None: 

55 fixed_dpi = fig.dpi 

56 tr = Affine2D().scale(fixed_dpi) 

57 dpi_scale = fixed_dpi / fig.dpi 

58 

59 fig.bbox_inches = Bbox.from_bounds(0, 0, *bbox_inches.size) 

60 x0, y0 = tr.transform(bbox_inches.p0) 

61 w1, h1 = fig.bbox.size * dpi_scale 

62 fig.transFigure._boxout = Bbox.from_bounds(-x0, -y0, w1, h1) 

63 fig.transFigure.invalidate() 

64 

65 fig.bbox = TransformedBbox(fig.bbox_inches, tr) 

66 

67 fig.patch.set_bounds(x0 / w1, y0 / h1, 

68 fig.bbox.width / w1, fig.bbox.height / h1) 

69 

70 return restore_bbox 

71 

72 

73def process_figure_for_rasterizing(fig, bbox_inches_restore, fixed_dpi=None): 

74 """ 

75 A function that needs to be called when figure dpi changes during the 

76 drawing (e.g., rasterizing). It recovers the bbox and re-adjust it with 

77 the new dpi. 

78 """ 

79 

80 bbox_inches, restore_bbox = bbox_inches_restore 

81 restore_bbox() 

82 r = adjust_bbox(fig, bbox_inches, fixed_dpi) 

83 

84 return bbox_inches, r