Document template support

Signed-off-by: DL6ER <[email protected]>

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

@@ -1,4 +1,6 @@
 from enum import Enum, auto
+import os
+import uuid
 from qrcode import QRCode, constants
 from PIL import Image, ImageDraw, ImageFont
 import logging
@@ -94,7 +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
@@ -162,7 +165,47 @@ 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)
+            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, "")
+            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()
@@ -348,22 +391,6 @@ def _draw_text(self, img = None, bboxes = [], text_offset = (0, 0)):
         # Fix for completely empty text
         if len(self.text) == 0 or len(self.text[0]['text']) == 0:
             self.text[0]['text'] = " "
-            
-        # Loop over text lines and replace
-        # {{datetime:x}} by current datetime in specified format x
-        # {{counter}} by an incrementing counter
-        for line in self.text:
-            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)
-            line['text'] = re.sub(r"\{\{datetime:([^}]+)\}\}", datetime_replacer, line['text'])
-        self._counter += 1
 
         # Iterate over lines of text
         for i, line in enumerate(self.text):

app/labeldesigner/templates/labeldesigner.html

@@ -324,6 +324,33 @@
         <fieldset class="form-group" id="groupLabelText">
             <label for="labelText" style="margin-top: 10px; margin-bottom: 0">Label Text:</label>
             <textarea rows="7" id="labelText" class="form-control" onChange="preview()" onInput="preview()" data-default=""></textarea>
+            <!-- Template info box -->
+            <div class="card mt-2" style="font-size: 0.95em;">
+                <div class="card-header p-2" style="cursor: pointer; user-select: none;" data-toggle="collapse"
+                    data-target="#templateInfoBox" aria-expanded="false" aria-controls="templateInfoBox">
+                    <span class="fas fa-info-circle" aria-hidden="true"></span>
+                    <span style="margin-left: 0.5em;">About label templates <span
+                            class="fas fa-chevron-down float-right"></span></span>
+                </div>
+                <div id="templateInfoBox" class="collapse">
+                    <div class="card-body pt-2 pb-2">
+                        <strong>Templates</strong> allow you to insert dynamic content into your label text. Supported
+                        templates:<br>
+                        <ul style="margin-bottom: 0.5em;">
+                            <li><code>{{'{{datetime:%H:%M:%S %d.%m.%Y'}}}}</code> — Inserts the current date and time when printing.
+                                You can customize the format using <a href="https://strftime.org/" target="_blank"
+                                    rel="noopener">strftime</a> options.</li>
+                            <li><code>{{'{{counter'}}}}</code> — Inserts an up-counting number, increasing for every printed label.
+                            </li>
+                            <li><code>{{'{{uuid'}}}}</code> — Inserts a random UUID (Universally Unique Identifier).</li>
+                            <li><code>{{'{{short-uuid'}}}}</code> — Inserts a shortened version of a UUID.</li>
+                            <li><code>{{'{{env:var}}'}}</code> — Inserts the value of the environment variable <code>var</code>.
+                            </li>
+                        </ul>
+                        <span class="text-muted">Templates are replaced at print time.</span>
+                    </div>
+                </div>
+            </div>
         </fieldset>
     </div>
     <div class="col-md-4">

docker-compose.yml

@@ -6,8 +6,12 @@ services:
     restart: always
     ports:
       - "8013:8013"
+    environment:
+      - TZ=Europe/Berlin
 #    devices:
 #      - "/dev/usb/lp0:/dev/usb/lp0"
+    volumes:
+      - /etc/timezone:/etc/timezone:ro
     command: >
       --model QL-800
       --default-label-size 62

screenshots/image7.png

@@ -24,8 +24,8 @@ def verify_image(response_data, expected_image_path):
     if not UPDATE_IMAGES and os.path.isfile(expected_image_path):
         with open(expected_image_path, 'rb') as f:
             expected_data = f.read()
-        assert response_data == expected_data
-        return
+        if response_data != expected_data:
+            raise AssertionError("Generated image does not match expected image")
 
     # Write image into file
     with open(expected_image_path, 'wb') as f:
@@ -333,38 +333,26 @@ def test_image_black_fit(client):
     image_test(client, image_mode="black", fit=True)
 
 
-def test_generate_datetime(client):
+def test_generate_template(client):
     data = EXAMPLE_FORMDATA.copy()
     # Mock current datetime.now
-    data['timestamp'] = int(datetime(2023, 1, 1, 12, 0, 0).timestamp())
+    data['timestamp'] = int(datetime(2023, 3, 18, 12, 15, 30).timestamp())
 
     data['text'] = json.dumps([
         {
             'font_family': 'DejaVu Sans',
             'font_style': 'Regular',
-            'text': '{{datetime:%d.%m.%Y %H:%M:%S}}',
+            'text': '{{datetime:%d.%m.%Y %H:%M:%S}} COUNTER: {{counter}}',
             'font_size': '30',
             'align': 'left'
-        }
-    ])
-
-    response = client.post('/labeldesigner/api/preview', data=data)
-    assert response.status_code == 200
-    assert response.content_type in ['image/png', 'text/plain']
-
-    # Check image
-    verify_image(response.data, 'tests/datetime.png')
-
-
-def test_generate_counter(client):
-    data = EXAMPLE_FORMDATA.copy()
-    data['text'] = json.dumps([
+        },
         {
             'font_family': 'DejaVu Sans',
             'font_style': 'Regular',
-            'text': '{{counter}}',
-            'font_size': '60',
-            'align': 'left'
+            'text': '>> {{datetime:Label created at %H:%M on %m/%d/%y}} <<',
+            'font_size': '20',
+            'align': 'right',
+            'font_inverted': True
         }
     ])
 
@@ -373,7 +361,7 @@ def test_generate_counter(client):
     assert response.content_type in ['image/png', 'text/plain']
 
     # Check image
-    verify_image(response.data, 'tests/counter.png')
+    verify_image(response.data, 'tests/template.png')
 
 
 # We cannot test the print functionality without a physical printer