👌 Add minor ticks to linlog plots

changelog.md

@@ -5,6 +5,7 @@
 ## 0.8.0 (Unreleased)
 
 - 🩹 Fix crashes of plot_doas and plot_coherent_artifact for non dispersive IRF (#173)
+- 👌 Add minor ticks to linlog plots (#183)
 - 🚧📦 Remove upper python version limit (#174)
 
 (changes-0_7_0)=

pyglotaran_extras/plotting/plot_concentrations.py

@@ -4,6 +4,7 @@
 from typing import TYPE_CHECKING
 
 from pyglotaran_extras.plotting.style import PlotStyle
+from pyglotaran_extras.plotting.utils import MinorSymLogLocator
 from pyglotaran_extras.plotting.utils import add_cycler_if_not_none
 from pyglotaran_extras.plotting.utils import get_shifted_traces
 
@@ -69,3 +70,4 @@ def plot_concentrations(
 
     if linlog:
         ax.set_xscale("symlog", linthresh=linthresh, linscale=linscale)
+        ax.xaxis.set_minor_locator(MinorSymLogLocator(linthresh))

pyglotaran_extras/plotting/plot_data.py

@@ -12,6 +12,7 @@
 from pyglotaran_extras.plotting.plot_svd import plot_lsv_data
 from pyglotaran_extras.plotting.plot_svd import plot_rsv_data
 from pyglotaran_extras.plotting.plot_svd import plot_sv_data
+from pyglotaran_extras.plotting.utils import MinorSymLogLocator
 from pyglotaran_extras.plotting.utils import not_single_element_dims
 from pyglotaran_extras.plotting.utils import shift_time_axis_by_irf_location
 
@@ -109,6 +110,7 @@ def plot_data_overview(
 
     if linlog:
         data_ax.set_xscale("symlog", linthresh=linthresh)
+        data_ax.xaxis.set_minor_locator(MinorSymLogLocator(linthresh))
     return fig, (data_ax, lsv_ax, sv_ax, rsv_ax)
 
 
@@ -150,4 +152,5 @@ def _plot_single_trace(
 
     if linlog:
         ax.set_xscale("symlog", linthresh=linthresh)
+        ax.xaxis.set_minor_locator(MinorSymLogLocator(linthresh))
     return fig, ax

pyglotaran_extras/plotting/plot_residual.py

@@ -7,6 +7,7 @@
 
 from pyglotaran_extras.plotting.plot_irf_dispersion_center import _plot_irf_dispersion_center
 from pyglotaran_extras.plotting.style import PlotStyle
+from pyglotaran_extras.plotting.utils import MinorSymLogLocator
 from pyglotaran_extras.plotting.utils import add_cycler_if_not_none
 from pyglotaran_extras.plotting.utils import shift_time_axis_by_irf_location
 
@@ -83,4 +84,5 @@ def plot_residual(
         ax.legend()
     if linlog:
         ax.set_xscale("symlog", linthresh=linthresh)
+        ax.xaxis.set_minor_locator(MinorSymLogLocator(linthresh))
     ax.set_title(title)

pyglotaran_extras/plotting/plot_svd.py

@@ -6,6 +6,7 @@
 from glotaran.io.prepare_dataset import add_svd_to_dataset
 
 from pyglotaran_extras.plotting.style import PlotStyle
+from pyglotaran_extras.plotting.utils import MinorSymLogLocator
 from pyglotaran_extras.plotting.utils import add_cycler_if_not_none
 from pyglotaran_extras.plotting.utils import shift_time_axis_by_irf_location
 
@@ -140,6 +141,7 @@ def plot_lsv_data(
     ax.set_title("data. LSV")
     if linlog:
         ax.set_xscale("symlog", linthresh=linthresh)
+        ax.xaxis.set_minor_locator(MinorSymLogLocator(linthresh))
 
 
 def plot_rsv_data(
@@ -240,6 +242,7 @@ def plot_lsv_residual(
     ax.set_title("res. LSV")
     if linlog:
         ax.set_xscale("symlog", linthresh=linthresh)
+        ax.xaxis.set_minor_locator(MinorSymLogLocator(linthresh))
 
 
 def plot_rsv_residual(

pyglotaran_extras/plotting/plot_traces.py

@@ -8,6 +8,7 @@
 
 from pyglotaran_extras.io.utils import result_dataset_mapping
 from pyglotaran_extras.plotting.style import PlotStyle
+from pyglotaran_extras.plotting.utils import MinorSymLogLocator
 from pyglotaran_extras.plotting.utils import PlotDuplicationWarning
 from pyglotaran_extras.plotting.utils import add_cycler_if_not_none
 from pyglotaran_extras.plotting.utils import add_unique_figure_legend
@@ -97,6 +98,7 @@ def plot_data_and_fits(
             [next(axis._get_lines.prop_cycler) for _ in range(2)]
     if linlog:
         axis.set_xscale("symlog", linthresh=linthresh)
+        axis.xaxis.set_minor_locator(MinorSymLogLocator(linthresh))
     if show_zero_line is True:
         axis.axhline(0, color="k", linewidth=1)
     axis.set_ylabel(y_label)

pyglotaran_extras/plotting/utils.py

@@ -7,6 +7,7 @@
 
 import numpy as np
 import xarray as xr
+from matplotlib.ticker import Locator
 
 from pyglotaran_extras.inspect.utils import pretty_format_numerical_iterable
 from pyglotaran_extras.io.utils import result_dataset_mapping
@@ -482,3 +483,98 @@ def not_single_element_dims(data_array: xr.DataArray) -> list[Hashable]:
         Names of dimensions in ``data`` which don't have a size equal to one.
     """
     return [dim for dim, values in data_array.coords.items() if values.size != 1]
+
+
+class MinorSymLogLocator(Locator):
+    """Dynamically find minor tick positions based on major ticks for a symlog scaling.
+
+    Ref.: https://stackoverflow.com/a/45696768
+    """
+
+    def __init__(self, linthresh: float, nints: int = 10) -> None:
+        """Ticks will be placed between the major ticks.
+
+        The placement is linear for x between -linthresh and linthresh,
+        otherwise its logarithmically. nints gives the number of
+        intervals that will be bounded by the minor ticks.
+
+        Parameters
+        ----------
+        linthresh : float
+            A single float which defines the range (-x, x), within which the plot is linear.
+        nints : int
+            Number of minor tick between major ticks. Defaults to 10
+        """
+        self.linthresh = linthresh
+        self.nintervals = nints
+
+    def __call__(self) -> list[float]:
+        """Return the locations of the ticks.
+
+        Returns
+        -------
+        list[float]
+            Minor ticks position.
+        """
+        # Return the locations of the ticks
+        majorlocs = self.axis.get_majorticklocs()
+
+        if len(majorlocs) == 1:
+            return self.raise_if_exceeds(np.array([]))
+
+        # add temporary major tick locs at either end of the current range
+        # to fill in minor tick gaps
+        dmlower = majorlocs[1] - majorlocs[0]  # major tick difference at lower end
+        dmupper = majorlocs[-1] - majorlocs[-2]  # major tick difference at upper end
+
+        # add temporary major tick location at the lower end
+        if majorlocs[0] != 0.0 and (
+            (majorlocs[0] != self.linthresh and dmlower > self.linthresh)
+            or (dmlower == self.linthresh and majorlocs[0] < 0)
+        ):
+            majorlocs = np.insert(majorlocs, 0, majorlocs[0] * 10.0)
+        else:
+            majorlocs = np.insert(majorlocs, 0, majorlocs[0] - self.linthresh)
+
+        # add temporary major tick location at the upper end
+        if majorlocs[-1] != 0.0 and (
+            (np.abs(majorlocs[-1]) != self.linthresh and dmupper > self.linthresh)
+            or (dmupper == self.linthresh and majorlocs[-1] > 0)
+        ):
+            majorlocs = np.append(majorlocs, majorlocs[-1] * 10.0)
+        else:
+            majorlocs = np.append(majorlocs, majorlocs[-1] + self.linthresh)
+
+        # iterate through minor locs
+        minorlocs: list[float] = []
+
+        # handle the lowest part
+        for i in range(1, len(majorlocs)):
+            majorstep = majorlocs[i] - majorlocs[i - 1]
+            if abs(majorlocs[i - 1] + majorstep / 2) < self.linthresh:
+                ndivs = self.nintervals
+            else:
+                ndivs = self.nintervals - 1
+
+            minorstep = majorstep / ndivs
+            locs = np.arange(majorlocs[i - 1], majorlocs[i], minorstep)[1:]
+            minorlocs.extend(locs)
+
+        return self.raise_if_exceeds(np.array(minorlocs))
+
+    def tick_values(self, vmin: float, vmax: float) -> None:
+        """Return the values of the located ticks given **vmin** and **vmax** (not implemented).
+
+        Parameters
+        ----------
+        vmin : float
+            Minimum value.
+        vmax : float
+            Maximum value.
+
+        Raises
+        ------
+        NotImplementedError
+            Not used
+        """
+        raise NotImplementedError(f"Cannot get tick locations for a {type(self)} type.")