Remove convert_exec arguments, update documentation

.gitignore

@@ -64,6 +64,7 @@ scripts/*.tar.*
 scripts/G4EMLOW*/
 
 # Images
+*.png
 *.ppm
 *.voxel
 *.vti
@@ -103,4 +104,4 @@ CMakeSettings.json
 .vscode/
 
 # Python pickle files
-*.pkl
+*.pkl

docs/source/io_formats/plots.rst

@@ -10,9 +10,9 @@ of the plots.xml is simply ``<plots>`` and any number output plots can be
 defined with ``<plot>`` sub-elements.  Two plot types are currently implemented
 in openMC:
 
-* ``slice``  2D pixel plot along one of the major axes. Produces a PPM image
+* ``slice``  2D pixel plot along one of the major axes. Produces a PNG image
   file.
-* ``voxel``  3D voxel data dump. Produces a binary file containing voxel xyz
+* ``voxel``  3D voxel data dump. Produces an HDF5 file containing voxel xyz
   position and cell or material id.
 
 
@@ -68,20 +68,14 @@ sub-elements:
   :type:
     Keyword for type of plot to be produced. Currently only "slice" and "voxel"
     plots are implemented. The "slice" plot type creates 2D pixel maps saved in
-    the PPM file format. PPM files can be displayed in most viewers (e.g. the
-    default Gnome viewer, IrfanView, etc.).  The "voxel" plot type produces a
-    binary datafile containing voxel grid positioning and the cell or material
-    (specified by the ``color`` tag) at the center of each voxel. These
-    datafiles can be processed into VTK files using the :ref:`scripts_voxel`
-    script provided with OpenMC, and subsequently viewed with a 3D viewer such
-    as VISIT or Paraview. See the :ref:`io_voxel` for information about the
-    datafile structure.
+    the PNG file format. The "voxel" plot type produces a binary datafile
+    containing voxel grid positioning and the cell or material (specified by the
+    ``color`` tag) at the center of each voxel. Voxel plot files can be
+    processed into VTK files using the :ref:`scripts_voxel` script provided with
+    OpenMC and subsequently viewed with a 3D viewer such as VISIT or Paraview.
+    See the :ref:`io_voxel` for information about the datafile structure.
 
-    .. note:: Since the PPM format is saved without any kind of compression,
-              the resulting file sizes can be quite large.  Saving the image in
-              the PNG format can often times reduce the file size by orders of
-              magnitude without any loss of image quality. Likewise,
-              high-resolution voxel files produced by OpenMC can be quite large,
+    .. note:: High-resolution voxel files produced by OpenMC can be quite large,
               but the equivalent VTK files will be significantly smaller.
 
     *Default*: "slice"
@@ -94,11 +88,6 @@ attribute or sub-element:
     directions for "slice" and "voxel" plots, respectively. Should be two or
     three integers separated by spaces.
 
-    .. warning:: The ``pixels`` input determines the output file size.  For the
-                 PPM format, 10 million pixels will result in a file just under
-                 30 MB in size. A 10 million voxel binary file will be around
-                 40 MB.
-
     .. warning:: If the aspect ratio defined in ``pixels`` does not match the
                  aspect ratio defined in ``width`` the plot may appear stretched
                  or squeezed.

openmc/executor.py

@@ -137,9 +137,14 @@ def plot_geometry(output=True, openmc_exec='openmc', cwd='.'):
     _run([openmc_exec, '-p'], output, cwd)
 
 
-def plot_inline(plots, openmc_exec='openmc', cwd='.', convert_exec='convert'):
+def plot_inline(plots, openmc_exec='openmc', cwd='.'):
     """Display plots inline in a Jupyter notebook.
 
+    .. versionchanged:: 0.13.0
+        The *convert_exec* argument was removed since OpenMC now produces
+        .png images directly.
+
+
     Parameters
     ----------
     plots : Iterable of openmc.Plot
@@ -148,9 +153,6 @@ def plot_inline(plots, openmc_exec='openmc', cwd='.', convert_exec='convert'):
         Path to OpenMC executable
     cwd : str, optional
         Path to working directory to run in
-    convert_exec : str, optional
-        Command that can convert PPM files into PNG files. Only used if your
-        OpenMC installation was not compiled against libpng.
 
     Raises
     ------
@@ -170,7 +172,7 @@ def plot_inline(plots, openmc_exec='openmc', cwd='.', convert_exec='convert'):
     plot_geometry(False, openmc_exec, cwd)
 
     if plots is not None:
-        images = [_get_plot_image(p, convert_exec) for p in plots]
+        images = [_get_plot_image(p) for p in plots]
         display(*images)
 
 

openmc/plots.py

@@ -166,28 +166,15 @@ _SVG_COLORS = {
 }
 
 
-def _get_plot_image(plot, convert_exec):
+def _get_plot_image(plot):
     from IPython.display import Image
 
-    # Check for .png first
+    # Make sure .png file was created
     stem = plot.filename if plot.filename is not None else f'plot_{plot.id}'
     png_file = f'{stem}.png'
-    if Path(png_file).exists():
-        return Image(png_file)
+    if not Path(png_file).exists():
+        raise FileNotFoundError(f"Could not find .png image for plot {plot.id}")
 
-    # If .png doesn't exist, try finding .ppm
-    ppm_file = f'{stem}.ppm'
-    if not Path(ppm_file).exists():
-        raise FileNotFoundError(f"Could not find image for plot {plot.id}")
-
-    # Check that 'convert' command exists
-    if shutil.which(convert_exec) is None:
-        raise RuntimeError(
-            f"ImageMagick is needed to convert {ppm_file} to .png format. Please "
-            "install ImageMagick and try again.")
-
-    # Convert .ppm to .png and return image
-    subprocess.check_call([convert_exec, ppm_file, png_file])
     return Image(png_file)
 
 
@@ -697,13 +684,14 @@ class Plot(IDManagerMixin):
 
         return element
 
-    def to_ipython_image(self, openmc_exec='openmc', cwd='.',
-                         convert_exec='convert'):
+    def to_ipython_image(self, openmc_exec='openmc', cwd='.'):
         """Render plot as an image
 
-        This method runs OpenMC in plotting mode to produce a .png file. If your
-        installation of OpenMC was not compiled against libpng, try converting
-        the fallback .ppm file to .png using ImageMagick's convert command.
+        This method runs OpenMC in plotting mode to produce a .png file.
+
+        .. versionchanged:: 0.13.0
+            The *convert_exec* argument was removed since OpenMC now produces
+            .png images directly.
 
         Parameters
         ----------
@@ -711,9 +699,6 @@ class Plot(IDManagerMixin):
             Path to OpenMC executable
         cwd : str, optional
             Path to working directory to run in
-        convert_exec : str, optional
-            Command that can convert PPM files into PNG files. Only used if your
-            OpenMC installation was not compiled against libpng.
 
         Returns
         -------
@@ -728,7 +713,7 @@ class Plot(IDManagerMixin):
         openmc.plot_geometry(False, openmc_exec, cwd)
 
         # Return produced image
-        return _get_plot_image(self, convert_exec)
+        return _get_plot_image(self)
 
 
 class Plots(cv.CheckedList):

tests/unit_tests/test_model.py

@@ -329,8 +329,7 @@ def test_plots(run_in_tmpdir, pin_model_attributes, mpi_intracomm):
     test_model = openmc.Model(geom, mats, settings, tals, plots)
 
     # This test cannot check the correctness of the plot, but it can
-    # check that a plot was made and that the expected ppm and png files are
-    # there
+    # check that a plot was made and that the expected png files are there
 
     # We will run the test twice, the first time without C API, the second with
     for i in range(2):