From 8195fae289ebf172596fdafbe8d49e08c741feaa Mon Sep 17 00:00:00 2001
From: Tyler Goodlet <jgbt@protonmail.com>
Date: Fri, 15 Apr 2022 18:47:45 -0400
Subject: [PATCH] Add a `trigger_all` arg to update cycle func; allows hard
 history updates

---
 piker/ui/_chart.py   |  6 ++++--
 piker/ui/_display.py | 35 +++++++++++++++++++++++++++++------
 piker/ui/_fsp.py     |  9 +++++++--
 3 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/piker/ui/_chart.py b/piker/ui/_chart.py
index 79abf215..3fcaae07 100644
--- a/piker/ui/_chart.py
+++ b/piker/ui/_chart.py
@@ -356,9 +356,11 @@ class LinkedSplits(QWidget):
 
         self._symbol: Symbol = None
 
-    def graphics_cycle(self) -> None:
+    def graphics_cycle(self, **kwargs) -> None:
         from . import _display
-        return _display.graphics_update_cycle(self.display_state)
+        ds = self.display_state
+        if ds:
+            return _display.graphics_update_cycle(ds, **kwargs)
 
     @property
     def symbol(self) -> Symbol:
diff --git a/piker/ui/_display.py b/piker/ui/_display.py
index ae6d0c77..1cb13f52 100644
--- a/piker/ui/_display.py
+++ b/piker/ui/_display.py
@@ -290,6 +290,7 @@ async def graphics_update_loop(
 def graphics_update_cycle(
     ds: DisplayState,
     wap_in_history: bool = False,
+    trigger_all: bool = False,  # flag used by prepend history updates
 
 ) -> None:
 
@@ -307,10 +308,6 @@ def graphics_update_cycle(
     tick_margin = vars['tick_margin']
 
     for sym, quote in ds.quotes.items():
-        brange, mx_in_view, mn_in_view, mx_vlm_in_view = ds.maxmin()
-        l, lbar, rbar, r = brange
-        mx = mx_in_view + tick_margin
-        mn = mn_in_view - tick_margin
 
         # NOTE: vlm may be written by the ``brokerd`` backend
         # event though a tick sample is not emitted.
@@ -333,13 +330,39 @@ def graphics_update_cycle(
             )
         vars['i_last'] = i_step
 
+        (
+            brange,
+            mx_in_view,
+            mn_in_view,
+            mx_vlm_in_view,
+        ) = ds.maxmin()
+
+        l, lbar, rbar, r = brange
+        mx = mx_in_view + tick_margin
+        mn = mn_in_view - tick_margin
+        liv = r > i_step  # the last datum is in view
+
+        # don't real-time "shift" the curve to the
+        # left under the following conditions:
+        if (
+            (
+                i_diff > 0  # no new sample step
+                and liv
+            )
+            or trigger_all
+        ):
+            # TODO: we should track and compute whether the last
+            # pixel in a curve should show new data based on uppx
+            # and then iff update curves and shift?
+            chart.increment_view(steps=i_diff)
+
         if vlm_chart:
             vlm_chart.update_curve_from_array('volume', array)
             ds.vlm_sticky.update_from_data(*array[-1][['index', 'volume']])
 
             if (
-                mx_vlm_in_view != vars['last_mx_vlm']
-                or mx_vlm_in_view > vars['last_mx_vlm']
+                mx_vlm_in_view > vars['last_mx_vlm']
+                or trigger_all
             ):
                 # print(f'mx vlm: {last_mx_vlm} -> {mx_vlm_in_view}')
                 vlm_chart.view._set_yrange(
diff --git a/piker/ui/_fsp.py b/piker/ui/_fsp.py
index 678b5d8e..a1193327 100644
--- a/piker/ui/_fsp.py
+++ b/piker/ui/_fsp.py
@@ -50,7 +50,6 @@ from ._forms import (
     mk_form,
     open_form_input_handling,
 )
-from . import _display
 from ..fsp._api import maybe_mk_fsp_shm, Fsp
 from ..fsp import cascade
 from ..fsp._volume import (
@@ -442,7 +441,13 @@ class FspAdmin:
             async with stream.subscribe() as stream:
                 async for msg in stream:
                     if msg == 'update':
-                        self.linked.graphics_cycle()
+                        # if the chart isn't hidden try to update
+                        # the data on screen.
+                        if not self.linked.isHidden():
+                            log.info(f'Re-syncing graphics for fsp: {ns_path}')
+                            self.linked.graphics_cycle(trigger_all=True)
+                    else:
+                        log.info(f'recved unexpected fsp engine msg: {msg}')
 
             await complete.wait()