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Add new curve doc string

incremental_update_paths
Tyler Goodlet 2022-06-02 13:36:55 -04:00
parent 4138cef512
commit c518553aa9
1 changed files with 27 additions and 9 deletions
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36
piker/ui/_curve.py
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@ -55,15 +55,28 @@ _line_styles: dict[str, int] = {
class FastAppendCurve(pg.GraphicsObject): class FastAppendCurve(pg.GraphicsObject):
''' '''
A faster, append friendly version of ``pyqtgraph.PlotCurveItem`` A faster, simpler, append friendly version of
built for real-time data updates. ``pyqtgraph.PlotCurveItem`` built for highly customizable real-time
updates.
The main difference is avoiding regeneration of the entire This type is a much stripped down version of a ``pyqtgraph`` style "graphics object" in
historical path where possible and instead only updating the "new" the sense that the internal lower level graphics which are drawn in the ``.paint()`` method
segment(s) via a ``numpy`` array diff calc. Further the "last" are actually rendered outside of this class entirely and instead are assigned as state
graphic segment is drawn independently such that near-term (high (instance vars) here and then drawn during a Qt graphics cycle.
frequency) discrete-time-sampled style updates don't trigger a full
path redraw. The main motivation for this more modular, composed design is that
lower level graphics data can be rendered in different threads and
then read and drawn in this main thread without having to worry
about dealing with Qt's concurrency primitives. See
``piker.ui._flows.Renderer`` for details and logic related to lower
level path generation and incremental update. The main differences in
the path generation code include:
- avoiding regeneration of the entire historical path where possible and instead
only updating the "new" segment(s) via a ``numpy`` array diff calc.
- here, the "last" graphics datum-segment is drawn independently
such that near-term (high frequency) discrete-time-sampled style
updates don't trigger a full path redraw.
''' '''
def __init__( def __init__(
@ -89,6 +102,9 @@ class FastAppendCurve(pg.GraphicsObject):
self._name = name self._name = name
self.path: Optional[QtGui.QPainterPath] = None self.path: Optional[QtGui.QPainterPath] = None
# additional path used for appends which tries to avoid
# triggering an update/redraw of the presumably larger
# historical ``.path`` above.
self.use_fpath = use_fpath self.use_fpath = use_fpath
self.fast_path: Optional[QtGui.QPainterPath] = None self.fast_path: Optional[QtGui.QPainterPath] = None
@ -119,11 +135,13 @@ class FastAppendCurve(pg.GraphicsObject):
# self._fill = True # self._fill = True
self._brush = pg.functions.mkBrush(hcolor(fill_color or color)) self._brush = pg.functions.mkBrush(hcolor(fill_color or color))
# NOTE: this setting seems to mostly prevent redraws on mouse
# interaction which is a huge boon for avg interaction latency.
# TODO: one question still remaining is if this makes trasform # TODO: one question still remaining is if this makes trasform
# interactions slower (such as zooming) and if so maybe if/when # interactions slower (such as zooming) and if so maybe if/when
# we implement a "history" mode for the view we disable this in # we implement a "history" mode for the view we disable this in
# that mode? # that mode?
# if step_mode:
# don't enable caching by default for the case where the # don't enable caching by default for the case where the
# only thing drawn is the "last" line segment which can # only thing drawn is the "last" line segment which can
# have a weird artifact where it won't be fully drawn to its # have a weird artifact where it won't be fully drawn to its