Add detailed comments, comment out fill mode

fast_step_curve
Tyler Goodlet 2021-12-07 16:09:47 -05:00
parent 4f899edcef
commit 18859e1b8c
1 changed files with 44 additions and 16 deletions

View File

@ -40,7 +40,8 @@ def step_path_arrays_from_1d(
include_endpoints: bool = False,
) -> (np.ndarray, np.ndarray):
'''Generate a "step mode" curve aligned with OHLC style bars
'''
Generate a "step mode" curve aligned with OHLC style bars
such that each segment spans each bar (aka "centered" style).
'''
@ -86,6 +87,18 @@ def step_path_arrays_from_1d(
# TODO: got a feeling that dropping this inheritance gets us even more speedups
class FastAppendCurve(pg.PlotCurveItem):
'''
A faster, append friendly version of ``pyqtgraph.PlotCurveItem``
built for real-time data updates.
The main difference is avoiding regeneration of the entire
historical path where possible and instead only updating the "new"
segment(s) via a ``numpy`` array diff calc. Further the "last"
graphic segment is drawn independently such that near-term (high
frequency) discrete-time-sampled style updates don't trigger a full
path redraw.
'''
def __init__(
self,
@ -115,7 +128,7 @@ class FastAppendCurve(pg.PlotCurveItem):
# flat-top style histogram-like discrete curve
self._step_mode: bool = step_mode
self._fill = False
# self._fill = True
self.setBrush(hcolor(fill_color or color))
# TODO: one question still remaining is if this makes trasform
@ -134,8 +147,8 @@ class FastAppendCurve(pg.PlotCurveItem):
profiler = pg.debug.Profiler(disabled=not pg_profile_enabled())
flip_cache = False
# print(f"xrange: {self._xrange}")
istart, istop = self._xrange
# print(f"xrange: {self._xrange}")
# compute the length diffs between the first/last index entry in
# the input data and the last indexes we have on record from the
@ -164,7 +177,8 @@ class FastAppendCurve(pg.PlotCurveItem):
# if self._step_mode:
# self.path.closeSubpath()
# TODO: get this working - right now it's giving heck on vwap...
# TODO: get this piecewise prepend working - right now it's
# giving heck on vwap...
# if prepend_length:
# breakpoint()
@ -186,6 +200,10 @@ class FastAppendCurve(pg.PlotCurveItem):
x[-append_length - 2:-1],
y[-append_length - 2:-1],
)
# [1:] since we don't need the vertical line normally at
# the beginning of the step curve taking the first (x,
# y) poing down to the x-axis **because** this is an
# appended path graphic.
new_x = new_x[1:]
new_y = new_y[1:]
@ -207,15 +225,20 @@ class FastAppendCurve(pg.PlotCurveItem):
# other merging ideas:
# https://stackoverflow.com/questions/8936225/how-to-merge-qpainterpaths
if self._step_mode:
if self._fill:
# XXX: super slow set "union" op
self.path = self.path.united(append_path).simplified()
# path.addPath(append_path)
# path.closeSubpath()
else:
# path.addPath(append_path)
self.path.connectPath(append_path)
# TODO: try out new work from `pyqtgraph` main which
# should repair horrid perf:
# https://github.com/pyqtgraph/pyqtgraph/pull/2032
# ok, nope still horrible XD
# if self._fill:
# # XXX: super slow set "union" op
# self.path = self.path.united(append_path).simplified()
# # path.addPath(append_path)
# # path.closeSubpath()
else:
# print(f"append_path br: {append_path.boundingRect()}")
# self.path.moveTo(new_x[0], new_y[0])
@ -238,6 +261,8 @@ class FastAppendCurve(pg.PlotCurveItem):
x0, x_last = self._xrange = x[0], x[-1]
y_last = y[-1]
# draw the "current" step graphic segment so it lines up with
# the "middle" of the current (OHLC) sample.
if self._step_mode:
self._last_line = QLineF(
x_last - 0.5, 0,
@ -259,6 +284,7 @@ class FastAppendCurve(pg.PlotCurveItem):
self.update()
if flip_cache:
# XXX: seems to be needed to avoid artifacts (see above).
self.setCacheMode(QtWidgets.QGraphicsItem.DeviceCoordinateCache)
def boundingRect(self):
@ -310,7 +336,6 @@ class FastAppendCurve(pg.PlotCurveItem):
p.fillRect(self._last_step_rect, brush)
# p.drawPath(self.path)
# profiler('.drawPath()')
# else:
@ -322,6 +347,9 @@ class FastAppendCurve(pg.PlotCurveItem):
p.drawPath(self.path)
profiler('.drawPath()')
if self._fill:
print('FILLED')
p.fillPath(self.path, brush)
# TODO: try out new work from `pyqtgraph` main which
# should repair horrid perf:
# https://github.com/pyqtgraph/pyqtgraph/pull/2032
# if self._fill:
# brush = self.opts['brush']
# p.fillPath(self.path, brush)