piker/piker/ui/_ohlc.py

270 lines
8.5 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
from typing import (
Optional,
TYPE_CHECKING,
)
import numpy as np
import pyqtgraph as pg
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import QLineF, QPointF
from .._profile import pg_profile_enabled, ms_slower_then
from ._style import hcolor
from ..log import get_logger
from ._curve import FastAppendCurve
from ._compression import ohlc_flatten
from ._pathops import gen_ohlc_qpath
if TYPE_CHECKING:
from ._chart import LinkedSplits
log = get_logger(__name__)
def bar_from_ohlc_row(
row: np.ndarray,
w: float = 0.43
) -> 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[
['open', 'high', 'low', 'close', 'index']]
# 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
# high -> low vertical (body) line
if low != high:
hl = QLineF(index, low, index, 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 - w, open, index, open)
# close line
c = QLineF(index, close, index + w, close)
return [hl, o, c]
class BarItems(pg.GraphicsObject):
'''
"Price range" bars graphics rendered from a OHLC sampled sequence.
'''
sigPlotChanged = QtCore.pyqtSignal(object)
# 0.5 is no overlap between arms, 1.0 is full overlap
w: float = 0.43
def __init__(
self,
linked: LinkedSplits,
plotitem: 'pg.PlotItem', # noqa
pen_color: str = 'bracket',
last_bar_color: str = 'bracket',
name: Optional[str] = None,
) -> None:
super().__init__()
self.linked = linked
# XXX: for the mega-lulz increasing width here increases draw
# latency... so probably don't do it until we figure that out.
self._color = pen_color
self.bars_pen = pg.mkPen(hcolor(pen_color), width=1)
self.last_bar_pen = pg.mkPen(hcolor(last_bar_color), width=2)
self._name = name
self._ds_line_xy: Optional[
tuple[np.ndarray, np.ndarray]
] = None
# NOTE: this prevents redraws on mouse interaction which is
# a huge boon for avg interaction latency.
# TODO: one question still remaining is if this makes trasform
# interactions slower (such as zooming) and if so maybe if/when
# we implement a "history" mode for the view we disable this in
# that mode?
self.setCacheMode(QtWidgets.QGraphicsItem.DeviceCoordinateCache)
self._pi = plotitem
self.path = QtGui.QPainterPath()
self.fast_path = QtGui.QPainterPath()
self._xrange: tuple[int, int]
self._vrange = None
self._last_bar_lines: Optional[tuple[QLineF, ...]] = None
# track the current length of drawable lines within the larger array
self.start_index: int = 0
self.stop_index: int = 0
# downsampler-line state
self._in_ds: bool = False
self._ds_line: Optional[FastAppendCurve] = None
self._dsi: tuple[int, int] = 0, 0
self._xs_in_px: float = 0
def x_uppx(self) -> int:
if self._ds_line:
return self._ds_line.x_uppx()
else:
return 0
def draw_last(
self,
last: np.ndarray,
) -> None:
# generate new lines objects for updatable "current bar"
self._last_bar_lines = bar_from_ohlc_row(last, self.w)
# last bar update
i, o, h, l, last, v = last[
['index', 'open', 'high', 'low', 'close', 'volume']
]
# assert i == self.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, l, i, h)
else:
# update body
body.setLine(i, l, i, 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?
def boundingRect(self):
# Qt docs: https://doc.qt.io/qt-5/qgraphicsitem.html#boundingRect
# 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(),
)
# need to include last bar height or BR will be off
mx_y = hb_br.y()
mn_y = hb_tl.y()
last_lines = self._last_bar_lines
if last_lines:
body_line = self._last_bar_lines[0]
if body_line:
mx_y = max(mx_y, max(body_line.y1(), body_line.y2()))
mn_y = min(mn_y, min(body_line.y1(), body_line.y2()))
return QtCore.QRectF(
# top left
QPointF(
hb_tl.x(),
mn_y,
),
# bottom right
QPointF(
hb_br.x() + 1,
mx_y,
)
)
def paint(
self,
p: QtGui.QPainter,
opt: QtWidgets.QStyleOptionGraphicsItem,
w: QtWidgets.QWidget
) -> None:
if self._in_ds:
return
profiler = pg.debug.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_bar_pen)
if self._last_bar_lines:
p.drawLines(*tuple(filter(bool, self._last_bar_lines)))
profiler('draw last bar')
p.setPen(self.bars_pen)
p.drawPath(self.path)
profiler(f'draw history path: {self.path.capacity()}')