feat: add option to turn off optimization

CHANGELOG.md

@@ -19,6 +19,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 * Add support of `regions.Regions` [#163]
+* Add option to turn off optimization in `fill`. The optimization degrades MOCs that are
+way more precise than the given WCS [#166]
 * Creation of a MOC from a zone (defined by min/max ra and dec)`MOC.from_zone`
 * Creation of a single MOC from a lot of small cones is faster with the new option in
 `MOC.from_cones`: the keyword 'union_strategy' can now take the value 'small_cones'.

python/mocpy/moc/moc.py

@@ -384,20 +384,26 @@ def contains_lonlat(self, lon, lat, keep_inside=True):
 
     # TODO: implement: def contains_including_surrounding(self, lon, lat, distance)
 
-    def fill(self, ax, wcs, **kw_mpl_pathpatch):
+    def fill(self, ax, wcs, optimize=True, **kw_mpl_pathpatch):
         """
         Draw the MOC on a matplotlib axis.
 
-        This performs the projection of the cells from the world coordinate system to the pixel image coordinate system.
-        You are able to specify various styling kwargs for `matplotlib.patches.PathPatch`
-        (see the `list of valid keywords <https://matplotlib.org/api/_as_gen/matplotlib.patches.PathPatch.html#matplotlib.patches.PathPatch>`__).
+        This performs the projection of the cells from the world coordinate system to the
+        pixel image coordinate system. You can provide style keyword arguments as in
+        `matplotlib.patches.PathPatch`
+        (see the `list of valid keywords
+        <https://matplotlib.org/api/_as_gen/matplotlib.patches.PathPatch.html#matplotlib.patches.PathPatch>`__).
 
         Parameters
         ----------
         ax : `matplotlib.axes.Axes`
             Matplotlib axis.
         wcs : `astropy.wcs.WCS`
             WCS defining the World system <-> Image system projection.
+        optimize : bool, optional
+            If this is set to True, the MOC will be degraded so that no HEALPix will be
+            smaller than one pixel as defined by the WCS. It can be useful to deactivate this
+            optimization for svg outputs or if you take an insert of a WCS. Default is True.
         kw_mpl_pathpatch
             Plotting arguments for `matplotlib.patches.PathPatch`.
 
@@ -418,7 +424,7 @@ def fill(self, ax, wcs, **kw_mpl_pathpatch):
         >>> ax = fig.add_subplot(projection=wcs)
         >>> moc.fill(ax, wcs, color='blue')
         """
-        fill.fill(self, ax, wcs, **kw_mpl_pathpatch)
+        fill.fill(self, ax, wcs, optimize=optimize, **kw_mpl_pathpatch)
 
     def border(self, ax, wcs, **kw_mpl_pathpatch):
         """

python/mocpy/moc/plot/fill.py

@@ -112,7 +112,7 @@ def add_patches_to_mpl_axe(patches, ax, wcs, **kw_mpl_pathpatch):
     _set_wcs(ax, wcs)
 
 
-def fill(moc, ax, wcs, **kw_mpl_pathpatch):
+def fill(moc, ax, wcs, *, optimize=True, **kw_mpl_pathpatch):
     """Fill the figure's ax with the patches.
 
     Parameters
@@ -122,11 +122,15 @@ def fill(moc, ax, wcs, **kw_mpl_pathpatch):
     ax : matplotlib.pyplot.axes
     wcs : astropy.wcs.WCS
         projection from astropy
+    optimize : bool, optional
+        If this is set to True, the MOC will be degraded so that no HEALPix will be
+        smaller than one pixel as defined by the WCS. It can be useful to deactivate this
+        optimization for svg outputs or if you take an insert of a WCS. Default to True.
     """
     # Simplify the MOC for plotting purposes:
     # 1. Degrade the MOC if the FOV is enough big so that we cannot see the smallest HEALPix cells.
     # 2. For small FOVs, plot the MOC & POLYGONAL_MOC_FROM_FOV.
-    moc_to_plot = build_plotting_moc(moc=moc, wcs=wcs)
+    moc_to_plot = build_plotting_moc(moc=moc, wcs=wcs, optimize=optimize)
 
     # If the FOV contains no cells, then moc_to_plot (i.e. the intersection between the moc
     # and the MOC created from the FOV polygon) will be empty.

python/mocpy/moc/plot/utils.py

@@ -22,20 +22,21 @@ def _set_wcs(ax, wcs):
     ax.set_ylim([y_min, y_max])
 
 
-def build_plotting_moc(moc, wcs):
+def build_plotting_moc(moc, wcs, optimize=True):
     """Plot a moc."""
-    # Get the WCS cdelt giving the deg.px^(-1) resolution.
-    cdelt = wcs.wcs.cdelt
-    # Convert in rad.px^(-1)
-    cdelt = np.abs((2 * np.pi / 360) * cdelt[0])
-    # Get the minimum depth such as the resolution of a cell is contained in 1px.
-    depth_res = int(np.floor(np.log2(np.sqrt(np.pi / 3) / cdelt)))
-    depth_res = max(depth_res, 0)
-    # Degrade the moc to that depth for plotting purposes. It is not necessary to plot pixels
-    # that we will not see because they are contained in 1px.
-    moc_plot = moc
-    if moc.max_order > depth_res:
-        moc_plot = moc.degrade_to_order(depth_res)
+    moc_plot = moc  # creates a copy to keep the original moc untouched
+    if optimize:
+        # Get the WCS cdelt giving the deg.px^(-1) resolution.
+        cdelt = wcs.wcs.cdelt
+        # Convert in rad.px^(-1)
+        cdelt = np.abs((2 * np.pi / 360) * cdelt[0])
+        # Get the minimum depth such as the resolution of a cell is contained in 1px.
+        depth_res = int(np.floor(np.log2(np.sqrt(np.pi / 3) / cdelt)))
+        depth_res = max(depth_res, 0)
+        # Degrade the moc to that depth for plotting purposes. It is not necessary to plot pixels
+        # that we will not see because they are contained in 1px.
+        if moc.max_order > depth_res:
+            moc_plot = moc.degrade_to_order(depth_res)
 
     # Get the MOC delimiting the FOV polygon
     width_px = int(wcs.wcs.crpix[0] * 2.0)  # Supposing the wcs is centered in the axis
@@ -56,7 +57,7 @@ def build_plotting_moc(moc, wcs):
     Y_px = np.append(Y_px, Y[-1, :-1])
     Y_px = np.append(Y_px, Y[1:, 0][::-1])
 
-    # Disable the output of warnings when encoutering NaNs.
+    # Disable the output of warnings when encountering NaNs.
     warnings.filterwarnings("ignore")
     # Inverse projection from pixel coordinate space to the world coordinate space
     viewport = pixel_to_skycoord(X_px, Y_px, wcs)