add a script that renames files for ffmpeg

this script will interpret our generated filenames and rename
them in a way that ffmpeg can natively process to generate videos.

rename_for_ffmpeg.py

@@ -0,0 +1,61 @@
+#! /usr/bin/env python3
+
+import argparse
+from pathlib import Path
+import shutil
+
+def meta_from_fname(fname):
+    metadata = {}
+    items = fname.split('_')
+    for i in items:
+        metadata[i[0]] = float(i[1:])
+    return metadata
+
+def fname_from_meta(meta):
+    fname = ''
+    for k,v in meta.items():
+        if isinstance(v, (float, int)):
+            if fname != '':
+                fname += '_'
+            fname += str(k)
+            if k == 'x' or k == 'y' or k == 'z':
+                fname += f"{v:.2f}"
+            elif k == 'a':
+                fname += f"{int(v)}"
+            else:
+                fname += f"{int(v)}"
+        else:
+            # ignore other objects that were made, like the 'r_um' Rect
+            pass
+    return fname
+
+def main():
+    parser = argparse.ArgumentParser(description="Rename files for ffmpeg")
+    parser.add_argument(
+        "--idir", required=False, help="input directory", default="."
+    )
+    parser.add_argument(
+        "--oname", required=False, help="base name of outputs", default='-ffmpeg.png'
+    )
+    parser.add_argument(
+        "--odir", required=False, help="directory for outputs", default="anim"
+    )
+    args = parser.parse_args()
+
+    base_path = Path(args.idir)
+    files = [file for file in base_path.glob('*.png') if file.is_file()]
+
+    # Load based on filenames, and finalize the overall area
+    flist = {}
+    for file in files:
+        if '_r' + str(2) in file.stem: # filter image revs by the initial default rev
+            meta = meta_from_fname(file.stem)
+            flist[meta['a']] = meta
+
+    flist = sorted(flist.items())
+
+    for i, (_u, file) in enumerate(flist):
+        shutil.copy('./' + fname_from_meta(file) + '.png', args.odir + '/' + str(i).zfill(4) + args.oname)
+
+if __name__ == "__main__":
+    main()