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""" |
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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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_boxout = fig.transFigure._boxout |
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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 = ax.get_axes_locator() |
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if locator is not None: |
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ax.apply_aspect(locator(ax, None)) |
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locator_list.append(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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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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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.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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fig.bbox_inches = Bbox.from_bounds(0, 0, *bbox_inches.size) |
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x0, y0 = tr.transform(bbox_inches.p0) |
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w1, h1 = fig.bbox.size * 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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