piker/piker/ui/_ohlc.py

282 lines
8.4 KiB
Python

# piker: trading gear for hackers
# Copyright (C) 2018-present Tyler Goodlet (in stewardship of piker0)
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
"""
Super fast OHLC sampling graphics types.
"""
from __future__ import annotations
import numpy as np
from PyQt5 import (
QtGui,
QtWidgets,
)
from PyQt5.QtCore import (
QLineF,
QRectF,
)
from PyQt5.QtWidgets import QGraphicsItem
from PyQt5.QtGui import QPainterPath
from ._curve import FlowGraphic
from .._profile import pg_profile_enabled, ms_slower_then
from ..log import get_logger
from .._profile import Profiler
log = get_logger(__name__)
def bar_from_ohlc_row(
row: np.ndarray,
# 0.5 is no overlap between arms, 1.0 is full overlap
bar_w: float,
bar_gap: float = 0.16
) -> tuple[QLineF]:
'''
Generate the minimal ``QLineF`` lines to construct a single
OHLC "bar" for use in the "last datum" of a series.
'''
open, high, low, close, index = row
# TODO: maybe consider using `QGraphicsLineItem` ??
# gives us a ``.boundingRect()`` on the objects which may make
# computing the composite bounding rect of the last bars + the
# history path faster since it's done in C++:
# https://doc.qt.io/qt-5/qgraphicslineitem.html
mid: float = (bar_w / 2) + index
# high -> low vertical (body) line
if low != high:
hl = QLineF(mid, low, mid, high)
else:
# XXX: if we don't do it renders a weird rectangle?
# see below for filtering this later...
hl = None
# NOTE: place the x-coord start as "middle" of the drawing range such
# that the open arm line-graphic is at the left-most-side of
# the index's range according to the view mapping coordinates.
# open line
o = QLineF(index + bar_gap, open, mid, open)
# close line
c = QLineF(
mid, close,
index + bar_w - bar_gap, close,
)
return [hl, o, c]
class BarItems(FlowGraphic):
'''
"Price range" bars graphics rendered from a OHLC sampled sequence.
'''
# XXX: causes this weird jitter bug when click-drag panning
# where the path curve will awkwardly flicker back and forth?
cache_mode: int = QGraphicsItem.NoCache
def __init__(
self,
*args,
**kwargs,
) -> None:
super().__init__(*args, **kwargs)
self._last_bar_lines: tuple[QLineF, ...] | None = None
def x_last(self) -> None | float:
'''
Return the last most x value of the close line segment
or if not drawn yet, ``None``.
'''
if self._last_bar_lines:
close_arm_line = self._last_bar_lines[-1]
return close_arm_line.x2() if close_arm_line else None
else:
return None
# Qt docs: https://doc.qt.io/qt-5/qgraphicsitem.html#boundingRect
def boundingRect(self):
# profiler = Profiler(
# msg=f'BarItems.boundingRect(): `{self._name}`',
# disabled=not pg_profile_enabled(),
# ms_threshold=ms_slower_then,
# )
# TODO: Can we do rect caching to make this faster
# like `pg.PlotCurveItem` does? In theory it's just
# computing max/min stuff again like we do in the udpate loop
# anyway. Not really sure it's necessary since profiling already
# shows this method is faf.
# boundingRect _must_ indicate the entire area that will be
# drawn on or else we will get artifacts and possibly crashing.
# (in this case, QPicture does all the work of computing the
# bounding rect for us).
# apparently this a lot faster says the docs?
# https://doc.qt.io/qt-5/qpainterpath.html#controlPointRect
hb = self.path.controlPointRect()
hb_tl, hb_br = (
hb.topLeft(),
hb.bottomRight(),
)
mn_y = hb_tl.y()
mx_y = hb_br.y()
most_left = hb_tl.x()
most_right = hb_br.x()
# profiler('calc path vertices')
# need to include last bar height or BR will be off
# OHLC line segments: [hl, o, c]
last_lines: tuple[QLineF] | None = self._last_bar_lines
if last_lines:
(
hl,
o,
c,
) = last_lines
most_right = c.x2() + 1
ymx = ymn = c.y2()
if hl:
y1, y2 = hl.y1(), hl.y2()
ymn = min(y1, y2)
ymx = max(y1, y2)
mx_y = max(ymx, mx_y)
mn_y = min(ymn, mn_y)
# profiler('calc last bar vertices')
return QRectF(
most_left,
mn_y,
most_right - most_left + 1,
mx_y - mn_y,
)
def paint(
self,
p: QtGui.QPainter,
opt: QtWidgets.QStyleOptionGraphicsItem,
w: QtWidgets.QWidget
) -> None:
profiler = Profiler(
disabled=not pg_profile_enabled(),
ms_threshold=ms_slower_then,
)
# p.setCompositionMode(0)
# TODO: one thing we could try here is pictures being drawn of
# a fixed count of bars such that based on the viewbox indices we
# only draw the "rounded up" number of "pictures worth" of bars
# as is necesarry for what's in "view". Not sure if this will
# lead to any perf gains other then when zoomed in to less bars
# in view.
p.setPen(self.last_step_pen)
if self._last_bar_lines:
p.drawLines(*tuple(filter(bool, self._last_bar_lines)))
profiler('draw last bar')
p.setPen(self._pen)
p.drawPath(self.path)
profiler(f'draw history path: {self.path.capacity()}')
def draw_last_datum(
self,
path: QPainterPath,
src_data: np.ndarray,
reset: bool,
array_key: str,
index_field: str,
) -> None:
# relevant fields
fields: list[str] = [
'open',
'high',
'low',
'close',
index_field,
]
ohlc = src_data[fields]
# last_row = ohlc[-1:]
# individual values
last_row = o, h, l, last, i = ohlc[-1]
# times = src_data['time']
# if times[-1] - times[-2]:
# breakpoint()
index = src_data[index_field]
step_size = index[-1] - index[-2]
# generate new lines objects for updatable "current bar"
bg: float = 0.16 * step_size
self._last_bar_lines = bar_from_ohlc_row(
last_row,
bar_w=step_size,
bar_gap=bg,
)
# assert i == graphics.start_index - 1
# assert i == last_index
body, larm, rarm = self._last_bar_lines
# XXX: is there a faster way to modify this?
rarm.setLine(rarm.x1(), last, rarm.x2(), last)
# writer is responsible for changing open on "first" volume of bar
larm.setLine(larm.x1(), o, larm.x2(), o)
if l != h: # noqa
if body is None:
body = self._last_bar_lines[0] = QLineF(
i + bg, l,
i + step_size - bg, h,
)
else:
# update body
body.setLine(
body.x1(), l,
body.x2(), h,
)
# XXX: pretty sure this is causing an issue where the
# bar has a large upward move right before the next
# sample and the body is getting set to None since the
# next bar is flat but the shm array index update wasn't
# read by the time this code runs. Iow we're doing this
# removal of the body for a bar index that is now out of
# date / from some previous sample. It's weird though
# because i've seen it do this to bars i - 3 back?
return ohlc[index_field], ohlc['close']