88 lines
2.9 KiB
Python
88 lines
2.9 KiB
Python
"""
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Helper module for the *bbox_inches* parameter in `.Figure.savefig`.
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"""
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from matplotlib.transforms import Bbox, TransformedBbox, Affine2D
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def adjust_bbox(fig, bbox_inches, fixed_dpi=None):
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"""
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Temporarily adjust the figure so that only the specified area
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(bbox_inches) is saved.
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It modifies fig.bbox, fig.bbox_inches,
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fig.transFigure._boxout, and fig.patch. While the figure size
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changes, the scale of the original figure is conserved. A
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function which restores the original values are returned.
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"""
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origBbox = fig.bbox
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origBboxInches = fig.bbox_inches
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orig_tight_layout = fig.get_tight_layout()
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_boxout = fig.transFigure._boxout
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fig.set_tight_layout(False)
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old_aspect = []
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locator_list = []
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sentinel = object()
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for ax in fig.axes:
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locator_list.append(ax.get_axes_locator())
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current_pos = ax.get_position(original=False).frozen()
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ax.set_axes_locator(lambda a, r, _pos=current_pos: _pos)
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# override the method that enforces the aspect ratio on the Axes
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if 'apply_aspect' in ax.__dict__:
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old_aspect.append(ax.apply_aspect)
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else:
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old_aspect.append(sentinel)
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ax.apply_aspect = lambda pos=None: None
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def restore_bbox():
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for ax, loc, aspect in zip(fig.axes, locator_list, old_aspect):
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ax.set_axes_locator(loc)
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if aspect is sentinel:
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# delete our no-op function which un-hides the original method
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del ax.apply_aspect
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else:
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ax.apply_aspect = aspect
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fig.bbox = origBbox
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fig.bbox_inches = origBboxInches
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fig.set_tight_layout(orig_tight_layout)
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fig.transFigure._boxout = _boxout
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fig.transFigure.invalidate()
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fig.patch.set_bounds(0, 0, 1, 1)
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if fixed_dpi is None:
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fixed_dpi = fig.dpi
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tr = Affine2D().scale(fixed_dpi)
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dpi_scale = fixed_dpi / fig.dpi
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_bbox = TransformedBbox(bbox_inches, tr)
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fig.bbox_inches = Bbox.from_bounds(0, 0,
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bbox_inches.width, bbox_inches.height)
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x0, y0 = _bbox.x0, _bbox.y0
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w1, h1 = fig.bbox.width * dpi_scale, fig.bbox.height * dpi_scale
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fig.transFigure._boxout = Bbox.from_bounds(-x0, -y0, w1, h1)
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fig.transFigure.invalidate()
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fig.bbox = TransformedBbox(fig.bbox_inches, tr)
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fig.patch.set_bounds(x0 / w1, y0 / h1,
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fig.bbox.width / w1, fig.bbox.height / h1)
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return restore_bbox
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def process_figure_for_rasterizing(fig, bbox_inches_restore, fixed_dpi=None):
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"""
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A function that needs to be called when figure dpi changes during the
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drawing (e.g., rasterizing). It recovers the bbox and re-adjust it with
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the new dpi.
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"""
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bbox_inches, restore_bbox = bbox_inches_restore
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restore_bbox()
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r = adjust_bbox(fig, bbox_inches, fixed_dpi)
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return bbox_inches, r
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