Factor color and cache mode settings into `FlowGraphics`

Curve-path colouring and cache mode settings are used (and can thus be
factored out of) all child types; this moves them into the parent type's
`.__init__()` and adjusts all sub-types match:

- the bulk was moved out of the `Curve.__init__()` including all
  previous commentary around cache settings.
- adjust `BarItems` to use a `NoCache` mode and instead use the
  `last_step_pen: pg.Pen` and `._pen` inside it's `.pain()` instead of
  defining functionally duplicate vars.
- adjust all (transitive) calls to `BarItems` to use the new kwargs
  names.

piker/ui/_chart.py

@@ -1152,8 +1152,6 @@ class ChartPlotWidget(pg.PlotWidget):
 
         if is_ohlc:
             graphics = BarItems(
-                linked=self.linked,
-                plotitem=pi,
                 color=color,
                 name=name,
                 **graphics_kwargs,

piker/ui/_curve.py

@@ -60,11 +60,82 @@ class FlowGraphic(pg.GraphicsObject):
 
     '''
     # sub-type customization methods
-    declare_paintables: Optional[Callable] = None
+    declare_paintables: Callable | None = None
-    sub_paint: Optional[Callable] = None
+    sub_paint: Callable | None = None
 
-    # TODO: can we remove this?
+    # XXX-NOTE-XXX: graphics caching B)
-    # sub_br: Optional[Callable] = None
+    # see explanation for different caching modes:
+    # https://stackoverflow.com/a/39410081
+    cache_mode: int = QGraphicsItem.DeviceCoordinateCache
+    # XXX: WARNING item caching seems to only be useful
+    # if we don't re-generate the entire QPainterPath every time
+    # don't ever use this - it's a colossal nightmare of artefacts
+    # and is disastrous for performance.
+    # QGraphicsItem.ItemCoordinateCache
+    # TODO: still questions todo with coord-cacheing that we should
+    # probably talk to a core dev about:
+    # - 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?
+
+    def __init__(
+        self,
+        *args,
+        name: str | None = None,
+
+        # line styling
+        color: str = 'bracket',
+        last_step_color: str = 'original',
+        fill_color: Optional[str] = None,
+        style: str = 'solid',
+
+        **kwargs
+
+    ) -> None:
+
+        self._name = name
+
+        # primary graphics item used for history
+        self.path: QPainterPath = QPainterPath()
+
+        # additional path that can be optionally used for appends which
+        # tries to avoid triggering an update/redraw of the presumably
+        # larger historical ``.path`` above. the flag to enable
+        # this behaviour is found in `Renderer.render()`.
+        self.fast_path: QPainterPath | None = None
+
+        # TODO: evaluating the path capacity stuff and see
+        # if it really makes much diff pre-allocating it.
+        # self._last_cap: int = 0
+        # cap = path.capacity()
+        # if cap != self._last_cap:
+        #     print(f'NEW CAPACITY: {self._last_cap} -> {cap}')
+        #     self._last_cap = cap
+
+        # all history of curve is drawn in single px thickness
+        self._color: str = color
+        pen = pg.mkPen(hcolor(color), width=1)
+        pen.setStyle(_line_styles[style])
+
+        if 'dash' in style:
+            pen.setDashPattern([8, 3])
+
+        self._pen = pen
+        self._brush = pg.functions.mkBrush(
+            hcolor(fill_color or color)
+        )
+
+        # last segment is drawn in 2px thickness for emphasis
+        self.last_step_pen = pg.mkPen(
+            hcolor(last_step_color),
+            width=2,
+        )
+        self._last_line: QLineF = QLineF()
+
+        super().__init__(*args, **kwargs)
+
+        # apply cache mode
+        self.setCacheMode(self.cache_mode)
 
     def x_uppx(self) -> int:
 
@@ -112,82 +183,32 @@ class Curve(FlowGraphic):
       updates don't trigger a full path redraw.
 
     '''
-    cache_mode: int = QGraphicsItem.DeviceCoordinateCache
+    # TODO: can we remove this?
+    # sub_br: Optional[Callable] = None
 
     def __init__(
         self,
         *args,
 
-        step_mode: bool = False,
+        # color: str = 'default_lightest',
-        color: str = 'default_lightest',
+        # fill_color: Optional[str] = None,
-        fill_color: Optional[str] = None,
+        # style: str = 'solid',
-        style: str = 'solid',
-        name: Optional[str] = None,
 
         **kwargs
 
     ) -> None:
 
-        self._name = name
-
         # brutaaalll, see comments within..
         self.yData = None
         self.xData = None
 
-        # self._last_cap: int = 0
-        self.path: Optional[QPainterPath] = None
-
-        # additional path that can be optionally used for appends which
-        # tries to avoid triggering an update/redraw of the presumably
-        # larger historical ``.path`` above. the flag to enable
-        # this behaviour is found in `Renderer.render()`.
-        self.fast_path: QPainterPath | None = None
-
         # TODO: we can probably just dispense with the parent since
         # we're basically only using the pen setting now...
         super().__init__(*args, **kwargs)
 
-        # all history of curve is drawn in single px thickness
-        pen = pg.mkPen(hcolor(color))
-        pen.setStyle(_line_styles[style])
-
-        if 'dash' in style:
-            pen.setDashPattern([8, 3])
-
-        self._pen = pen
-
-        # last segment is drawn in 2px thickness for emphasis
-        # self.last_step_pen = pg.mkPen(hcolor(color), width=2)
-        self.last_step_pen = pg.mkPen(pen, width=2)
-
         self._last_line: QLineF = QLineF()
 
-        # flat-top style histogram-like discrete curve
-        # self._step_mode: bool = step_mode
-
         # self._fill = True
-        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
-        # 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?
-        # don't enable caching by default for the case where the
-        # only thing drawn is the "last" line segment which can
-        # have a weird artifact where it won't be fully drawn to its
-        # endpoint (something we saw on trade rate curves)
-        self.setCacheMode(self.cache_mode)
-
-        # XXX-NOTE-XXX: graphics caching.
-        # see explanation for different caching modes:
-        # https://stackoverflow.com/a/39410081 seems to only be useful
-        # if we don't re-generate the entire QPainterPath every time
-        # don't ever use this - it's a colossal nightmare of artefacts
-        # and is disastrous for performance.
-        # self.setCacheMode(QtWidgets.QGraphicsItem.ItemCoordinateCache)
 
         # allow sub-type customization
         declare = self.declare_paintables
@@ -318,14 +339,10 @@ class Curve(FlowGraphic):
 
         p.setPen(self.last_step_pen)
         p.drawLine(self._last_line)
-        profiler('.drawLine()')
+        profiler('last datum `.drawLine()`')
-        p.setPen(self._pen)
 
+        p.setPen(self._pen)
         path = self.path
-        # cap = path.capacity()
-        # if cap != self._last_cap:
-        #     print(f'NEW CAPACITY: {self._last_cap} -> {cap}')
-        #     self._last_cap = cap
 
         if path:
             p.drawPath(path)

piker/ui/_display.py

@@ -447,7 +447,8 @@ async def graphics_update_loop(
                 # and quote_rate >= _quote_throttle_rate * 2
                 and quote_rate >= display_rate
             ):
-                log.warning(f'High quote rate {symbol.key}: {quote_rate}')
+                pass
+                # log.warning(f'High quote rate {symbol.key}: {quote_rate}')
 
             last_quote_s = time.time()
 
@@ -493,9 +494,9 @@ def graphics_update_cycle(
 
     profiler = Profiler(
         msg=f'Graphics loop cycle for: `{ds.fqsn}`',
-        delayed=True,
         disabled=not pg_profile_enabled(),
         ms_threshold=ms_slower_then,
+        delayed=True,
         # ms_threshold=4,
     )
 
@@ -1319,7 +1320,7 @@ async def display_symbol_data(
                     is_ohlc=True,
 
                     color=bg_chart_color,
-                    last_bar_color=bg_last_bar_color,
+                    last_step_color=bg_last_bar_color,
                 )
 
                 # ensure the last datum graphic is generated
@@ -1356,7 +1357,7 @@ async def display_symbol_data(
                     is_ohlc=True,
 
                     color=bg_chart_color,
-                    last_bar_color=bg_last_bar_color,
+                    last_step_color=bg_last_bar_color,
                 )
                 rt_pi.vb.maxmin = partial(
                     rt_chart.maxmin,

piker/ui/_ohlc.py

@@ -18,13 +18,8 @@ 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 (
     QtGui,
     QtWidgets,
@@ -33,18 +28,14 @@ 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 ._style import hcolor
 from ..log import get_logger
 from .._profile import Profiler
 
-if TYPE_CHECKING:
-    from ._chart import LinkedSplits
-
 
 log = get_logger(__name__)
 
@@ -100,30 +91,18 @@ class BarItems(FlowGraphic):
     "Price range" bars graphics rendered from a OHLC sampled sequence.
 
     '''
-    def __init__(
-        self,
-        linked: LinkedSplits,
-        plotitem: 'pg.PlotItem',  # noqa
-        color: str = 'bracket',
-        last_bar_color: str = 'original',
-
-        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 = color
-        self.bars_pen = pg.mkPen(hcolor(color), width=1)
-        self.last_bar_pen = pg.mkPen(hcolor(last_bar_color), width=2)
-        self._name = name
-
     # XXX: causes this weird jitter bug when click-drag panning
     # where the path curve will awkwardly flicker back and forth?
-        self.setCacheMode(QtWidgets.QGraphicsItem.DeviceCoordinateCache)
+    cache_mode: int = QGraphicsItem.NoCache
 
-        self.path = QPainterPath()
+    def __init__(
+        self,
+        *args,
+        **kwargs,
+
+    ) -> None:
+
+        super().__init__(*args, **kwargs)
         self._last_bar_lines: tuple[QLineF, ...] | None = None
 
     def x_last(self) -> None | float:
@@ -218,12 +197,12 @@ class BarItems(FlowGraphic):
         # 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)
+        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.bars_pen)
+        p.setPen(self._pen)
         p.drawPath(self.path)
         profiler(f'draw history path: {self.path.capacity()}')
 
@@ -299,5 +278,4 @@ class BarItems(FlowGraphic):
             # date / from some previous sample. It's weird though
             # because i've seen it do this to bars i - 3 back?
 
-        # return ohlc['time'], ohlc['close']
         return ohlc[index_field], ohlc['close']