From 6a644d2f455ed2ad103180126e3b5446072bbc25 Mon Sep 17 00:00:00 2001 From: Tyler Goodlet Date: Wed, 9 Mar 2022 11:01:01 -0500 Subject: [PATCH] Add a downsampled line-curve support to `BarItems` In effort to start getting some graphics speedups as detailed in #109, this adds a `FastAppendCurve`to every `BarItems` as a `._ds_line` which is only displayed (instead of the normal mult-line bars curve) when the "width" of a bar is indistinguishable on screen from a line -> so once the view coordinates map to > 2 pixels on the display device. `BarItems.maybe_paint_line()` takes care of this scaling detection logic and is called by the associated view's `.sigXRangeChanged` signal handler. --- piker/ui/_interaction.py | 16 ++++++ piker/ui/_ohlc.py | 112 +++++++++++++++++++++++++++++++++++---- 2 files changed, 119 insertions(+), 9 deletions(-) diff --git a/piker/ui/_interaction.py b/piker/ui/_interaction.py index dca41855..5b0145ff 100644 --- a/piker/ui/_interaction.py +++ b/piker/ui/_interaction.py @@ -36,6 +36,7 @@ from ..log import get_logger from ._style import _min_points_to_show from ._editors import SelectRect from . import _event +from ._ohlc import BarItems log = get_logger(__name__) @@ -429,6 +430,12 @@ class ChartView(ViewBox): def maxmin(self, callback: Callable) -> None: self._maxmin = callback + + def maybe_downsample_graphics(self): + for graphic in self._chart._graphics.values(): + if isinstance(graphic, BarItems): + graphic.maybe_paint_line() + def wheelEvent( self, ev, @@ -775,6 +782,15 @@ class ChartView(ViewBox): ''' vb.sigXRangeChanged.connect(vb._set_yrange) + + # TODO: a smarter way to avoid calling this needlessly? + # 2 things i can think of: + # - register downsample-able graphics specially and only + # iterate those. + # - only register this when certain downsampleable graphics are + # "added to scene". + vb.sigXRangeChanged.connect(vb.maybe_downsample_graphics) + # mouse wheel doesn't emit XRangeChanged vb.sigRangeChangedManually.connect(vb._set_yrange) vb.sigResized.connect(vb._set_yrange) # splitter(s) resizing diff --git a/piker/ui/_ohlc.py b/piker/ui/_ohlc.py index 4331f036..8ed14080 100644 --- a/piker/ui/_ohlc.py +++ b/piker/ui/_ohlc.py @@ -29,6 +29,10 @@ from PyQt5.QtCore import QLineF, QPointF from .._profile import pg_profile_enabled from ._style import hcolor +from ..log import get_logger + + +log = get_logger(__name__) def _mk_lines_array( @@ -170,8 +174,10 @@ def gen_qpath( class BarItems(pg.GraphicsObject): - """Price range bars graphics rendered from a OHLC sequence. - """ + ''' + "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 @@ -183,11 +189,15 @@ class BarItems(pg.GraphicsObject): plotitem: 'pg.PlotItem', # noqa pen_color: str = 'bracket', last_bar_color: str = 'bracket', - ) -> None: - super().__init__() + name: Optional[str] = None, + + ) -> None: + + super().__init__() # 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) @@ -219,15 +229,20 @@ class BarItems(pg.GraphicsObject): self.start_index: int = 0 self.stop_index: int = 0 + self._in_ds: bool = False + def draw_from_data( self, data: np.ndarray, start: int = 0, + ) -> QtGui.QPainterPath: - """Draw OHLC datum graphics from a ``np.ndarray``. + ''' + Draw OHLC datum graphics from a ``np.ndarray``. This routine is usually only called to draw the initial history. - """ + + ''' hist, last = data[:-1], data[-1] self.path = gen_qpath(hist, start, self.w) @@ -249,14 +264,28 @@ class BarItems(pg.GraphicsObject): # https://doc.qt.io/qt-5/qgraphicsitem.html#update self.update() + from ._curve import FastAppendCurve + self._ds_line = FastAppendCurve( + y=data['close'], + x=data['index'], + name='ohlc_ds_line', + color=self._color, + # use_polyline=True, # pretty sure this is slower? + ) + self.update_from_array(data) + self._pi.addItem(self._ds_line) + self._ds_line.hide() + return self.path def update_from_array( self, array: np.ndarray, just_history=False, + ) -> None: - """Update the last datum's bar graphic from input data array. + ''' + Update the last datum's bar graphic from input data array. This routine should be interface compatible with ``pg.PlotCurveItem.setData()``. Normally this method in @@ -266,7 +295,16 @@ class BarItems(pg.GraphicsObject): does) so this "should" be simpler and faster. This routine should be made (transitively) as fast as possible. - """ + + ''' + # XXX: always do this? + if self._in_ds: + self._ds_line.update_from_array( + x=array['index'], + y=array['close'], + ) + return + # index = self.start_index istart, istop = self._xrange @@ -400,14 +438,59 @@ class BarItems(pg.GraphicsObject): ) + def maybe_paint_line( + self, + x_gt: float = 2., + + ) -> bool: + ''' + Call this when you want to stop drawing individual + bars and instead use a ``FastAppendCurve`` intepolation + line (normally when the width of a bar (aka 1.0 in the x) + is less then a pixel width on the device). + + ''' + # this is the ``float`` value of the "number of x units" (in + # view coords) that a pixel spans. + xs_in_px = self.pixelVectors()[0].x() + if ( + not self._in_ds + and xs_in_px >= x_gt + ): + # TODO: a `.ui()` log level? + log.info(f'downsampling to line graphic') + self._in_ds = True + self.hide() + self._pi.addItem(self._ds_line) + self._ds_line.show() + return True + + elif ( + self._in_ds + and xs_in_px < x_gt + ): + log.info(f'showing bars graphic') + self._in_ds = False + self.show() + self._ds_line.hide() + self._pi.removeItem(self._ds_line) + return False + def paint( self, p: QtGui.QPainter, opt: QtWidgets.QStyleOptionGraphicsItem, w: QtWidgets.QWidget + ) -> None: - profiler = pg.debug.Profiler(disabled=not pg_profile_enabled()) + if self._in_ds: + return + + profiler = pg.debug.Profiler( + disabled=not pg_profile_enabled(), + delayed=False, + ) # p.setCompositionMode(0) @@ -424,3 +507,14 @@ class BarItems(pg.GraphicsObject): p.setPen(self.bars_pen) p.drawPath(self.path) profiler('draw history path') + profiler.finish() + + # NOTE: for testing paint frequency as throttled by display loop. + # now = time.time() + # global _last_draw + # print(f'DRAW RATE {1/(now - _last_draw)}') + # _last_draw = now + + +# import time +# _last_draw: float = time.time()