Merge pull request pklaus#7 from DL6ER/enhance

Add template and import-export features

Author: DL6ER

.devcontainer/devcontainer.json

@@ -26,9 +26,11 @@
         }
     },
     "runArgs": [
-//        "-v",
-//        "/dev/bus/lp0:/dev/bus/lp0",
-//        "/dev/bus/lp1:/dev/bus/lp1",
-//        "/dev/bus/lp2:/dev/bus/lp2"
+        "-e",
+        "TZ=Europe/Berlin"
+        //        "-v",
+        //        "/dev/usb/lp0:/dev/usb/lp0",
+        //        "/dev/usb/lp1:/dev/usb/lp1",
+        //        "/dev/usb/lp2:/dev/usb/lp2"
     ]
-}
+}

README.md

@@ -34,6 +34,10 @@ Additional printer support comes from [matmair/brother_ql-inventree](https://git
 
 ![Native dark mode](./screenshots/image6.png)
 
+### Template support
+
+![Template support](./screenshots/image7.png)
+
 ## New Features
 
 - Automatic printer and label detection
@@ -57,6 +61,8 @@ Additional printer support comes from [matmair/brother_ql-inventree](https://git
     - **QL-1110NWB**
     - **QL-1115NWB**
 -   Support individual fonts/sizes and spacing for each line of text on the labels
+-   Dynamic content replacement, e.g., using `{{datetime}}` and `{{counter}}` templates
+-   Import and export of labels in an easily editable format (JSON)
 -   Allow text inversion for emphasized text even without color
 -   Auto-fit images best onto the labels to avoid cropping
 -   Allow text together with images

app/labeldesigner/label.py

@@ -1,9 +1,13 @@
 from enum import Enum, auto
+import os
+import uuid
 from qrcode import QRCode, constants
 from PIL import Image, ImageDraw, ImageFont
 import logging
 import barcode
 from barcode.writer import ImageWriter
+import datetime
+import re
 
 logger = logging.getLogger(__name__)
 
@@ -82,7 +86,8 @@ def __init__(
             border_thickness=1,
             border_roundness=0,
             border_distance=(0, 0),
-            border_color=(0, 0, 0)):
+            border_color=(0, 0, 0),
+            timestamp=0):
         self._width = width
         self._height = height
         self.label_content = label_content
@@ -91,7 +96,8 @@ def __init__(
         self.barcode_type = barcode_type
         self._label_margin = label_margin
         self._fore_color = fore_color
-        self.text = text
+        self.text = None
+        self.input_text = text
         self._qr_size = qr_size
         self.qr_correction = qr_correction
         self._image = image
@@ -100,6 +106,8 @@ def __init__(
         self._border_roundness = border_roundness
         self._border_distance = border_distance
         self._border_color = border_color
+        self._counter = 1
+        self._timestamp = timestamp
 
     @property
     def label_content(self):
@@ -108,10 +116,11 @@ def label_content(self):
     @label_content.setter
     def label_content(self, value):
         self._label_content = value
-    
-    @property
-    def want_text(self):
-        return self._label_content not in (LabelContent.QRCODE_ONLY,) and len(self.text) > 0
+
+    def want_text(self, img):
+        # We always want to draw text (even when empty) when no image is
+        # provided to avoid an error 500 because we created no image at all
+        return img is None or self._label_content not in (LabelContent.QRCODE_ONLY,) and len(self.text) > 0 and len(self.text[0]['text']) > 0
 
     @property
     def need_image_text_distance(self):
@@ -156,7 +165,51 @@ def label_type(self):
     def label_type(self, value):
         self._label_type = value
 
+    def process_templates(self):
+        # Loop over text lines and replace
+        # {{datetime:x}} by current datetime in specified format x
+        # {{counter}} by an incrementing counter
+        self.text = self.input_text.copy()
+        for line in self.text:
+            # Replace {{counter}} with current counter value
+            line['text'] = line['text'].replace("{{counter}}", str(self._counter))
+
+            # Replace {{datetime:x}} with current datetime formatted as x
+            def datetime_replacer(match):
+                fmt = match.group(1)
+                if self._timestamp > 0:
+                    now = datetime.datetime.fromtimestamp(self._timestamp)
+                else:
+                    now = datetime.datetime.now()
+                return now.strftime(fmt)
+            # Performance issue mitigation
+            if len(line['text']) < 100:
+                line['text'] = re.sub(r"\{\{datetime:([^}]+)\}\}", datetime_replacer, line['text'])
+
+            # Replace {{uuid}} with a new UUID
+            if "{{uuid}}" in line['text']:
+                line['text'] = line['text'].replace("{{uuid}}", str(uuid.uuid4()))
+
+            # Replace {{short-uuid}} with a shortened UUID
+            if "{{short-uuid}}" in line['text']:
+                line['text'] = line['text'].replace("{{short-uuid}}", str(uuid.uuid4())[:8])
+
+            # Replace {{env:var}} with the value of the environment variable var
+            def env_replacer(match):
+                var_name = match.group(1)
+                return os.getenv(var_name, "")
+            # Performance issue mitigation
+            if len(line['text']) < 100:
+                line['text'] = re.sub(r"\{\{env:([^}]+)\}\}", env_replacer, line['text'])
+
+        # Increment counter
+        self._counter += 1
+
     def generate(self, rotate = False):
+        # Process possible templates in the text
+        self.process_templates()
+
+        # Generate codes or load images if requested
         if self._label_content in (LabelContent.QRCODE_ONLY, LabelContent.TEXT_QRCODE):
             if self.barcode_type == "QR":
                 img = self._generate_qr()
@@ -221,7 +274,7 @@ def generate(self, rotate = False):
         else:
             img_width, img_height = (0, 0)
 
-        if self.want_text:
+        if self.want_text(img):
             bboxes = self._draw_text(None, [])
             textsize = self._compute_bbox(bboxes)
         else:
@@ -276,7 +329,7 @@ def generate(self, rotate = False):
         if img is not None:
             imgResult.paste(img, image_offset)
 
-        if self.want_text:
+        if self.want_text(img):
             self._draw_text(imgResult, bboxes, text_offset)
 
         # Check if the image needs rotation (only applied when generating
@@ -338,7 +391,12 @@ def _draw_text(self, img = None, bboxes = [], text_offset = (0, 0)):
             img = Image.new('L', (20, 20), 'white')
         draw = ImageDraw.Draw(img)
         y = 0
-        logger.warning("Drawing text with offset %s", text_offset)
+
+        # Fix for completely empty text
+        if len(self.text) == 0 or len(self.text[0]['text']) == 0:
+            self.text[0]['text'] = " "
+
+        # Iterate over lines of text
         for i, line in enumerate(self.text):
             color = self._fore_color
 
@@ -366,7 +424,7 @@ def _draw_text(self, img = None, bboxes = [], text_offset = (0, 0)):
                 logger.error(f"Unsupported alignment: {align}")
                 return
 
-            if do_draw and 'font_inverted' in line and line['font_inverted'] == "true":
+            if do_draw and 'font_inverted' in line and line['font_inverted']:
                 # Draw a filled rectangle
                 center_x = 0
                 if anchor == "lt":

app/labeldesigner/printer.py

@@ -92,20 +92,21 @@ def process_queue(self) -> bool:
             logger.info('Label printed successfully and printer is ready for next job')
             return True
 
+        logger.warning("Failed to print label")
         return False
 
 def get_ptr_status(device_specifier):
     status = {
         "errors": [],
         "path": device_specifier,
-        "media_category": "DK",
+        "media_category": None,
         "media_length": 0,
-        "media_type": "Continuous length tape",
-        "media_width": 62,
+        "media_type": None,
+        "media_width": None,
         "model": "Unknown",
-        "model_code": 56,
+        "model_code": None,
         "phase_type": "Unknown",
-        "series_code": 52,
+        "series_code": None,
         "setting": None,
         "status_code": 0,
         "status_type": "Unknown",

app/labeldesigner/routes.py

@@ -102,7 +102,7 @@ def get_printer_status():
 
 
 @bp.route('/api/print', methods=['POST', 'GET'])
-def print_text():
+def print_label():
     """
     API to print a label
 
@@ -188,6 +188,7 @@ def create_label_from_request(request):
         'image_bw_threshold': int(d.get('image_bw_threshold', 70)),
         'image_fit': int(d.get('image_fit', 1)) > 0,
         'print_color': d.get('print_color', 'black'),
+        'timestamp': int(d.get('timestamp', 0))
     }
 
     def get_label_dimensions(label_size):
@@ -299,5 +300,6 @@ def get_uploaded_image(image):
         border_thickness=context['border_thickness'],
         border_roundness=context['border_roundness'],
         border_distance=(context['border_distanceX'], context['border_distanceY']),
-        border_color=border_color
+        border_color=border_color,
+        timestamp=context['timestamp']
     )