Watch also monitors loaded images

docs/getting_started.md

@@ -22,4 +22,6 @@
     deck.render("slides.pdf")
     ```
 
-* Run `python slides.py`. It creates file `slides.pdf`.
+* Run `python slides.py`. It creates file `slides.pdf`.
+
+If you do not want to build your script manually, you can use [Automatic slide rebuilding](guide/watch.md)

docs/guide/watch.md

@@ -0,0 +1,13 @@
+# Slides rebuilding
+
+Nelsie can automatically rebuild slides when the source Python file is changed or when images used in slides are
+changed.
+It is started by the following command (lets assume that our slides are defined in `slides.py`).
+
+```commandline
+$ python3 -m nelsie watch slides.py
+```
+
+Nelsie builds the slides and starts to watch `slides.py` and used images and rebuilds the slides when relevant files are
+changed.
+Note that if the first build fails, the watch is not started.

mkdocs.yml

@@ -31,6 +31,7 @@ nav:
       - guide/box.md
       - guide/colors.md
       - guide/list.md
+      - guide/watch.md
 
 theme:
   name: material

python/nelsie/__main__.py

@@ -2,6 +2,7 @@
 import importlib
 import traceback
 from . import nelsie as nelsie_rs
+from . import watch
 
 
 def parse_args():
@@ -13,20 +14,25 @@ def parse_args():
 
 
 def load_py_file(filename):
+    watch._WATCH_SET = set()
     importlib.machinery.SourceFileLoader("slides", filename).load_module()
+    s = watch._WATCH_SET
+    watch._WATCH_SET = None
+    s.add(filename)
+    return list(s)
 
 
 def main():
     args = parse_args()
     source_filename = args.source_filename
     print("Initial build", source_filename)
-    load_py_file(source_filename)
+    files = load_py_file(source_filename)
     print("Watching", source_filename)
     while True:
-        nelsie_rs.watch(source_filename)
+        nelsie_rs.watch(files)
         print("Building ...", source_filename)
         try:
-            load_py_file(source_filename)
+            files = load_py_file(source_filename)
             print("... finished")
         except Exception:
             traceback.print_exc()

python/nelsie/box.py

@@ -16,6 +16,7 @@
 from .layoutexpr import LayoutExpr
 from .shapes import Path
 from .textstyle import TextStyle, _data_to_text_style
+from .watch import watch_path
 
 
 @dataclass
@@ -95,11 +96,14 @@ def image(self, path: str, enable_steps=True, shift_steps=0, **box_args):
         Create a box with an image. Supported formats: SVG, PNG, JPEG, GIF, ORA
         """
         assert shift_steps >= 0
+
         slide = self.get_box().slide
         if slide.image_directory is not None:
             path = os.path.join(slide.image_directory, path)
+        path = os.path.abspath(path)
+        watch_path(path)
         image = ImageContent(
-            path=os.path.abspath(path),
+            path=path,
             enable_steps=enable_steps,
             shift_steps=shift_steps,
         )

python/nelsie/watch.py

@@ -0,0 +1,6 @@
+_WATCH_SET: None | set = None
+
+
+def watch_path(path):
+    if _WATCH_SET is not None:
+        _WATCH_SET.add(path)

src/pyinterface/watch.rs

@@ -5,16 +5,17 @@ use std::thread::sleep;
 use std::time::Duration;
 
 #[pyfunction]
-pub fn watch(py: Python<'_>, path: &str) -> PyResult<()> {
+pub fn watch(py: Python<'_>, paths: Vec<String>) -> PyResult<()> {
     let (tx, rx) = std::sync::mpsc::channel();
 
     let mut watcher = RecommendedWatcher::new(tx, Config::default())
         .map_err(|e| PyException::new_err(e.to_string()))?;
 
-    watcher
-        .watch(path.as_ref(), RecursiveMode::NonRecursive)
-        .map_err(|e| PyException::new_err(e.to_string()))?;
-
+    for path in paths {
+        watcher
+            .watch(path.as_ref(), RecursiveMode::NonRecursive)
+            .map_err(|e| PyException::new_err(e.to_string()))?;
+    }
     loop {
         py.check_signals()?;
         if let Ok(Ok(event)) = rx.recv_timeout(Duration::from_secs(1)) {

tests/test_reload.py → tests/test_watch.py

@@ -3,16 +3,23 @@
 import sys
 import time
 import hashlib
+import shutil
+import os
+from conftest import ASSETS_DIR
 
 
-def test_reload(tmp_path):
+def test_watch(tmp_path):
+    def copy_image(name):
+        shutil.copy(str(os.path.join(ASSETS_DIR, name)), str(tmp_path.joinpath("test.jpeg")))
+
     def write(content):
         tmp_path.joinpath("slides.py").write_text(
             f"""
 from nelsie import SlideDeck
 
 deck = SlideDeck()
 
+@deck.slide()
 def test(slide):
     {content}
 
@@ -24,17 +31,28 @@ def make_hash():
             return hashlib.md5(f.read())
 
     with change_workdir(tmp_path):
+        copy_image("testimg.jpeg")
         write("slide.box(width=100, height=100, bg_color='green')")
         p = subprocess.Popen([sys.executable, "-m", "nelsie", "watch", "slides.py"])
         time.sleep(1.0)
 
         hash1 = make_hash()
         assert p.poll() is None
 
-        write("slide.box(width=100, height=100, bg_color='blue')")
+        copy_image("testimg.png")
         time.sleep(1.0)
         hash2 = make_hash()
-        assert hash1 != hash2
+        assert hash1.hexdigest() == hash2.hexdigest()
+
+        write("slide.image('test.jpeg', width=100, height=100)")
+        time.sleep(1.0)
+        hash3 = make_hash()
+        assert hash1.hexdigest() != hash3.hexdigest()
+
+        copy_image("testimg.jpeg")
+        time.sleep(1.0)
+        hash4 = make_hash()
+        assert hash3.hexdigest() != hash4.hexdigest()
 
         assert p.poll() is None
         p.kill()