Merge 1fae90c into b845a11

apstools/utils.py

@@ -30,11 +30,14 @@
    ~replay
    ~run_in_thread
    ~safe_ophyd_name
+   ~select_live_plot
+   ~select_mpl_figure
    ~show_ophyd_symbols
    ~split_quoted_line
    ~summarize_runs
    ~text_encode
    ~to_unicode_or_bust
+   ~trim_plot
    ~trim_string_for_EPICS
    ~unix
 
@@ -1276,7 +1279,16 @@ def plot_prune_fifo(bec, n, y, x):
         *object* :
         instance of ophyd.Signal (or subclass),
         independent (x) axis
+
+    DEPRECATED: Will be removed by end of 2020-12.
+    Use :meth:`trim_plot` instead.
+    Note the order of parameters is different in :meth:`trim_plot`.
     """
+    warnings.warn(
+        "DEPRECATED: plot_prune_fifo() will be removed"
+        " in a future release.  Use trim_plot() instead."
+        "  Note the order of parameters is different in trim_plot()."
+        )
 
     if n < 0:
         raise ValueError(
@@ -1310,6 +1322,119 @@ def plot_prune_fifo(bec, n, y, x):
         return lp
 
 
+def select_mpl_figure(x, y):
+    """
+    get the MatPlotLib Figure window for y vs x
+
+    PARAMETERS
+
+    x
+        *object*:
+        X axis object (an ``ophyd.Signal``)
+    y
+        ophyd object:
+        X axis object (an ``ophyd.Signal``)
+
+    RETURNS
+
+    object or ``None``:
+        Instance of ``matplotlib.pyplot.Figure()``
+    """
+    import matplotlib.pyplot as plt
+    figure_name = f"{y.name} vs {x.name}"
+    if figure_name in plt.get_figlabels():
+        return plt.figure(figure_name)
+
+
+def select_live_plot(bec, signal):
+    """
+    get the *first* live plot that matches ``signal``
+
+    PARAMETERS
+
+    bec
+        *object*:
+        instance of ``bluesky.callbacks.best_effort.BestEffortCallback``
+    signal
+        *object*:
+        The Y axis object (an ``ophyd.Signal``)
+
+    RETURNS
+
+    *object*:
+        Instance of ``bluesky.callbacks.best_effort.LivePlotPlusPeaks()``
+        or ``None``
+    """
+    for live_plot_dict in bec._live_plots.values():
+        live_plot = live_plot_dict.get(signal.name)
+        if live_plot is not None:
+            return live_plot
+
+
+def trim_plot(bec, n, x, y):
+    """
+    find the plot with axes x and y and replot with at most the last *n* lines
+
+    Note: this is not a bluesky plan.  Call it as normal Python function.
+
+    EXAMPLE::
+
+        trim_plot(bec, 1, m1, noisy)
+
+    PARAMETERS
+
+    bec
+        *object* :
+        instance of BestEffortCallback
+
+    n
+        *int* :
+        number of plots to keep
+
+    x
+        *object* :
+        instance of ophyd.Signal (or subclass),
+        independent (x) axis
+
+    y
+        *object* :
+        instance of ophyd.Signal (or subclass),
+        dependent (y) axis
+
+    (new in release 1.3.5, replaces :meth:`plot_prune_fifo`)
+    """
+    # liveplot = select_live_plot(bec, y)
+    # if liveplot is None:
+    #     logger.debug("no live plot found with signal '%s'", y.name)
+    #     return
+
+    fig = select_mpl_figure(x, y)
+    if fig is None:
+        logger.debug("no figure found with '%s vs %s'", y.name, x.name)
+        return
+    if len(fig.axes) == 0:
+        logger.debug("no plots on figure: '%s vs %s'", y.name, x.name)
+        return
+
+    ax = fig.axes[0]
+    while len(ax.lines) > n:
+        try:
+            ax.lines[0].remove()
+        except ValueError as exc:
+            if not str(exc).endswith("x not in list"):
+                logger.warning(
+                    "%s vs %s: mpl remove() error: %s",
+                    y.name, x.name, str(exc))
+    ax.legend()
+    # liveplot.update_plot()
+    # Rescale and redraw.  
+    #  (from bluesky.callbacks.mpl_plotting.update_plot)
+    ax.relim(visible_only=True)
+    ax.autoscale_view(tight=True)
+    ax.figure.canvas.draw_idle()
+    logger.debug("trim complete")
+
+
 def print_snapshot_list(db, printing=True, **search_criteria):
     """
     print (stdout) a list of all snapshots in the databroker