Merge pull request #2 from wortelus/caching

Caching

.gitignore

@@ -2,3 +2,4 @@
 __pycache__/
 venv
 /ms33558.ttf
+img-cache.pkl

README.md

@@ -77,6 +77,11 @@ Instructions for **Windows**
 running `python .\main.py` under the *xplane-streamdeck* directory, 
 while having the Stream Deck plugged in already
 
+The program supports image caching, which saves several seconds of image preloading during launch
+- To enable it, set `cache-path` field in `config.yaml`
+- NOTE: If you are tweaking your image set or configuration, it is recommended disable this feature 
+to always see the up-to-date configuration state and avoid runtime errors
+
 ### Additional Info
 
 ![lower overhead](misc/lwrovhd.jpg)
@@ -97,7 +102,6 @@ while having the Stream Deck plugged in already
 **Refer to the `B737-800X/README.md` for a guide on how to create/edit buttons.**
 
 ### What is planned / WIP?
-- Caching of preloaded graphics
 - More types of labels
 - Multi deck support
 

config.yaml

@@ -4,6 +4,9 @@ xp-port: 49000
 server-ip: 127.0.0.1
 server-port: 49008
 default-font: ms33558.ttf
+# comment out following line to disable image caching
+# the images will have to load for several seconds every time, but it is suitable for tweaking
+cache-path: ./img-cache.pkl
 stream-decks:
   - serial: CL41I1A00651
     keys: 32

main.py

@@ -1,6 +1,8 @@
 import math
+import pickle
 import threading
 import time
+from os.path import exists
 
 import numpy as np
 import yaml
@@ -203,12 +205,48 @@ def main():
               "Have you installed it correctly?")
         print(e)
 
+    cache_path = None
+    caching_enabled = False
+    load_cached_img = False
+    if "cache-path" in global_cfg:
+        cache_path = global_cfg["cache-path"]
+        # check cache_path if is not False or None -> implicating it is enabled in config
+        # and check if it exists
+        # then we will load the cache file, thus skipping the loader load_images_datarefs_all
+        if cache_path:
+            caching_enabled = True
+            if exists(global_cfg["cache-path"]):
+                load_cached_img = True
+
     global presets_all
-    presets_all = preprocessing.load_all_presets(keys_dir, key_count)
+    presets_all = preprocessing.load_all_presets(keys_dir, key_count, preload_labels=load_cached_img)
     global datarefs_all
     datarefs_all = preprocessing.load_datarefs(presets_all)
     global images_all
-    images_all = preprocessing.load_images_datarefs_all(current_deck, presets_all)
+
+    if not caching_enabled:
+        print("note: caching is disabled, loading will be noticeably slower")
+        print("you can enable it by setting the field 'cache-path' in config.yaml")
+        images_all = preprocessing.load_images_datarefs_all(current_deck, presets_all)
+    elif load_cached_img:
+        # images are stored as cache, open and load
+        print("cache file {} is present, skipping pre-generation.".format(cache_path))
+        print("note: if you changed configuration or icon set, you should delete the {} cache file".format(cache_path))
+        print("loading cache...")
+        with open(cache_path, 'rb') as f:
+            # load and convert it to runtime format
+            images_save_format = pickle.load(f)
+            images_all = preprocessing.convert_to_runtime_format(images_save_format)
+    else:
+        # caching is enabled, but cache file not found
+        print("cache file {} not found, starting the pre-generation.".format(cache_path))
+        images_all = preprocessing.load_images_datarefs_all(current_deck, presets_all)
+        # save images to cache-path
+        print("saving the pregen to {}".format(cache_path))
+        with open(cache_path, 'wb') as f:
+            # convert to save format and save it
+            images_save_format = preprocessing.convert_to_save_format(images_all)
+            pickle.dump(images_save_format, f)
 
     global directory_stack
     directory_stack = []
@@ -228,6 +266,8 @@ def main():
     deck_show(current_deck, current_datarefs)
     deck_show_static(current_deck)
 
+    print("xplane-streamdeck ready...")
+
     try:
         while True:
             time.sleep(0.05)

preprocessing.py

@@ -155,7 +155,7 @@ def count_presets(target_dir):
     return len(glob.glob1(target_dir, "*.yaml"))
 
 
-def load_preset(target_dir, yaml_keyset, deck_key_count):
+def load_preset(target_dir, yaml_keyset, deck_key_count, preload_labels=False):
     with open(os.path.join(target_dir, yaml_keyset)) as stream:
         try:
             preset_cfg = safe_load(stream)
@@ -196,6 +196,19 @@ def load_preset(target_dir, yaml_keyset, deck_key_count):
             key.get("gauge"),
             key.get("display"),
         )
+
+        # restoring images from cache file (preload_labels flag)
+        # this applies to buttons with 'label' parameter set
+        # If set to True, we must 'correct' image file_names here, because the
+        # image post-loader load_images_datarefs_all is not called during current session
+        if preload_labels:
+            btn = preset[index]
+            for i, state_name in enumerate(btn.file_names):
+                # change state name for storing, allowing same icons with different labels
+                if btn.label:
+                    state_name = btn.label + state_name
+                    preset[index].file_names[i] = state_name
+
         if cmd_type == "dir":
             other_keysets = np.append(other_keysets, name)
 
@@ -206,16 +219,18 @@ def add_yaml_suffix(filename):
     return filename + ".yaml"
 
 
-def load_all_presets(target_dir, deck_key_count):
+def load_all_presets(target_dir, deck_key_count, preload_labels=False):
     presets_all = {}
     # read root
-    preset, keysets = load_preset(target_dir, ACTION_CFG, deck_key_count)
+    preset, keysets = load_preset(target_dir, ACTION_CFG, deck_key_count,
+                                  preload_labels=preload_labels)
     presets_all[ACTION_CFG_NAME] = preset
     # execute while there are keysets to be read and loaded into presets
     while keysets.size > 0:
         for _, key_set in enumerate(keysets):
             if key_set not in presets_all and key_set != "return":
-                preset, other_keysets = load_preset(target_dir, add_yaml_suffix(key_set), deck_key_count)
+                preset, other_keysets = load_preset(target_dir, add_yaml_suffix(key_set), deck_key_count,
+                                                    preload_labels=preload_labels)
                 presets_all[key_set] = preset
                 keysets = np.unique(np.concatenate((keysets, other_keysets), 0))
 
@@ -311,7 +326,9 @@ def load_images_datarefs(deck, presets_dir):
             if state_name not in set_images:
                 state_image = render_key_image(deck, state_name, button.label)
 
-                # change state name for storing, allowing same icons with different labels
+                # change file_names in preset according to images_all, allowing same icons with different labels
+                # notice how this is executed in the post-processing stage
+                # i.e. after the presets have long been generated
                 if button.label:
                     state_name = button.label + state_name
                     button.file_names[i] = state_name
@@ -328,3 +345,25 @@ def load_images_datarefs_all(deck, presets_all):
         set_images_all.update(images_single_dir)
 
     return set_images_all
+
+#
+# pickle helpers
+#
+
+# pickle is unable to handler 'memoryview' objects, we must convert them to bytearray and vice versa
+
+
+def convert_to_save_format(images_all):
+    images_bytearray = {}
+    for key, img in images_all.items():
+        images_bytearray[key] = img.tobytes()
+
+    return images_bytearray
+
+
+def convert_to_runtime_format(images_save_format):
+    images_all = {}
+    for key, img in images_save_format.items():
+        images_all[key] = memoryview(img)
+
+    return images_all