49 lines
1.6 KiB
Python
49 lines
1.6 KiB
Python
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# piker: trading gear for hackers
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# Copyright (C) Tyler Goodlet (in stewardship for piker0)
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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"""
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Customization of ``pyqtgraph`` core routines to speed up our use mostly
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based on not requiring "scentific precision" for pixel perfect view
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transforms.
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"""
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import pyqtgraph as pg
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def invertQTransform(tr):
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"""Return a QTransform that is the inverse of *tr*.
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Raises an exception if tr is not invertible.
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Note that this function is preferred over QTransform.inverted() due to
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bugs in that method. (specifically, Qt has floating-point precision issues
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when determining whether a matrix is invertible)
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"""
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# see https://doc.qt.io/qt-5/qtransform.html#inverted
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# NOTE: if ``invertable == False``, ``qt_t`` is an identity
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qt_t, invertable = tr.inverted()
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return qt_t
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def _do_overrides() -> None:
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"""Dooo eeet.
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"""
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# we don't care about potential fp issues inside Qt
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pg.functions.invertQTransform = invertQTransform
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