Update val_batch*.jpg for Chinese fonts (#6526)

* Update plots for Chinese fonts

* make is_chinese() non-str safe

* Add global FONT

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update general.py

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

utils/general.py

@@ -37,6 +37,7 @@ FILE = Path(__file__).resolve()
 ROOT = FILE.parents[1]  # YOLOv5 root directory
 NUM_THREADS = min(8, max(1, os.cpu_count() - 1))  # number of YOLOv5 multiprocessing threads
 VERBOSE = str(os.getenv('YOLOv5_VERBOSE', True)).lower() == 'true'  # global verbose mode
+FONT = 'Arial.ttf'  # https://ultralytics.com/assets/Arial.ttf
 
 torch.set_printoptions(linewidth=320, precision=5, profile='long')
 np.set_printoptions(linewidth=320, formatter={'float_kind': '{:11.5g}'.format})  # format short g, %precision=5
@@ -55,6 +56,21 @@ def is_kaggle():
         return False
 
 
+def is_writeable(dir, test=False):
+    # Return True if directory has write permissions, test opening a file with write permissions if test=True
+    if test:  # method 1
+        file = Path(dir) / 'tmp.txt'
+        try:
+            with open(file, 'w'):  # open file with write permissions
+                pass
+            file.unlink()  # remove file
+            return True
+        except OSError:
+            return False
+    else:  # method 2
+        return os.access(dir, os.R_OK)  # possible issues on Windows
+
+
 def set_logging(name=None, verbose=VERBOSE):
     # Sets level and returns logger
     if is_kaggle():
@@ -68,6 +84,22 @@ def set_logging(name=None, verbose=VERBOSE):
 LOGGER = set_logging('yolov5')  # define globally (used in train.py, val.py, detect.py, etc.)
 
 
+def user_config_dir(dir='Ultralytics', env_var='YOLOV5_CONFIG_DIR'):
+    # Return path of user configuration directory. Prefer environment variable if exists. Make dir if required.
+    env = os.getenv(env_var)
+    if env:
+        path = Path(env)  # use environment variable
+    else:
+        cfg = {'Windows': 'AppData/Roaming', 'Linux': '.config', 'Darwin': 'Library/Application Support'}  # 3 OS dirs
+        path = Path.home() / cfg.get(platform.system(), '')  # OS-specific config dir
+        path = (path if is_writeable(path) else Path('/tmp')) / dir  # GCP and AWS lambda fix, only /tmp is writeable
+    path.mkdir(exist_ok=True)  # make if required
+    return path
+
+
+CONFIG_DIR = user_config_dir()  # Ultralytics settings dir
+
+
 class Profile(contextlib.ContextDecorator):
     # Usage: @Profile() decorator or 'with Profile():' context manager
     def __enter__(self):
@@ -152,34 +184,6 @@ def get_latest_run(search_dir='.'):
     return max(last_list, key=os.path.getctime) if last_list else ''
 
 
-def user_config_dir(dir='Ultralytics', env_var='YOLOV5_CONFIG_DIR'):
-    # Return path of user configuration directory. Prefer environment variable if exists. Make dir if required.
-    env = os.getenv(env_var)
-    if env:
-        path = Path(env)  # use environment variable
-    else:
-        cfg = {'Windows': 'AppData/Roaming', 'Linux': '.config', 'Darwin': 'Library/Application Support'}  # 3 OS dirs
-        path = Path.home() / cfg.get(platform.system(), '')  # OS-specific config dir
-        path = (path if is_writeable(path) else Path('/tmp')) / dir  # GCP and AWS lambda fix, only /tmp is writeable
-    path.mkdir(exist_ok=True)  # make if required
-    return path
-
-
-def is_writeable(dir, test=False):
-    # Return True if directory has write permissions, test opening a file with write permissions if test=True
-    if test:  # method 1
-        file = Path(dir) / 'tmp.txt'
-        try:
-            with open(file, 'w'):  # open file with write permissions
-                pass
-            file.unlink()  # remove file
-            return True
-        except OSError:
-            return False
-    else:  # method 2
-        return os.access(dir, os.R_OK)  # possible issues on Windows
-
-
 def is_docker():
     # Is environment a Docker container?
     return Path('/workspace').exists()  # or Path('/.dockerenv').exists()
@@ -207,7 +211,7 @@ def is_ascii(s=''):
 
 def is_chinese(s='人工智能'):
     # Is string composed of any Chinese characters?
-    return re.search('[\u4e00-\u9fff]', s)
+    return True if re.search('[\u4e00-\u9fff]', str(s)) else False
 
 
 def emojis(str=''):
@@ -378,6 +382,15 @@ def check_file(file, suffix=''):
         return files[0]  # return file
 
 
+def check_font(font=FONT):
+    # Download font to CONFIG_DIR if necessary
+    font = Path(font)
+    if not font.exists() and not (CONFIG_DIR / font.name).exists():
+        url = "https://ultralytics.com/assets/" + font.name
+        LOGGER.info(f'Downloading {url} to {CONFIG_DIR / font.name}...')
+        torch.hub.download_url_to_file(url, str(font), progress=False)
+
+
 def check_dataset(data, autodownload=True):
     # Download and/or unzip dataset if not found locally
     # Usage: https://github.com/ultralytics/yolov5/releases/download/v1.0/coco128_with_yaml.zip