annotating images uses multiprocessing

ideas.md

@@ -1,3 +0,0 @@
-Further Ideas:
-
-- automatic use of cached values

mtor/imageproc.py

@@ -23,7 +23,6 @@ def scale_and_colorize(tif_array, parameters):
     adjusted_array = (tif_array.data - parameters.offset) // parameters.scale
 
     # paint roi
-
     top = parameters.roi_top
     bottom = parameters.roi_bottom
     right = parameters.roi_right

mtor/postproc.py

@@ -1,3 +1,5 @@
+import functools
+import multiprocessing
 import pathlib
 
 from PIL import Image, ImageDraw, ImageFont
@@ -12,28 +14,44 @@ def stem_file_list(selected_files):
 
 def annotate_color_coded_images(file_stems, parameters):
     colors = {LABEL_DISCARDED: (198, 78, 82), LABEL_SELECTED: (74, 114, 174)}
-    top = parameters.roi_top
-    bottom = parameters.roi_bottom
-    left = parameters.roi_left
-    right = parameters.roi_right
+    roi_rectangle = [
+        (parameters.roi_left, parameters.roi_top),
+        (parameters.roi_right, parameters.roi_bottom),
+    ]
+    font_y_pos = parameters.image_height - 25 - 18
+    color_coded_images = [
+        p
+        for p in parameters.colored_dir.iterdir()
+        if not p.name.startswith(".")
+    ]
+    func = functools.partial(
+        annotate_one_color_coded_image,
+        file_stems=file_stems,
+        roi_rectangle=roi_rectangle,
+        colors=colors,
+        font_y_pos=font_y_pos,
+    )
+    cpu_count = multiprocessing.cpu_count()
+    total = len(color_coded_images)
+    with multiprocessing.Pool(cpu_count) as mpp:
+        list(tqdm(mpp.imap(func, color_coded_images), total=total))
+
+
+def annotate_one_color_coded_image(
+    path, file_stems, roi_rectangle, colors, font_y_pos
+):
+    # fonts can't be pickled, we need to open it every time.
     try:
         font = ImageFont.truetype("Courier New.ttf", 18)
     except OSError:
         font = None
-    font_y_pos = parameters.image_height - 25 - 18
-    for path in tqdm(list(parameters.colored_dir.iterdir())):
-        if not path.stem.startswith("."):
-            label = (
-                LABEL_SELECTED if path.stem in file_stems else LABEL_DISCARDED
-            )
+    label = LABEL_SELECTED if path.stem in file_stems else LABEL_DISCARDED
     new_path = path.with_name(f"{path.stem}_{label}{path.suffix}")
     img = Image.open(path)
     # draw a colored roi
     draw = ImageDraw.Draw(img)
     color = colors[label]
-            draw.rectangle(
-                [(left, top), (right, bottom)], outline=color, width=2
-            )
+    draw.rectangle(roi_rectangle, outline=color, width=2)
     # add sequence number
     sequence_nr = RE_DIGITS.search(path.name).group()
     draw.text((25, font_y_pos), sequence_nr, font=font)