Label sheet printer (#5883)

* Add skeleton for new label sheet plugin

* Add custom printing options serializer

* Render individual label outputs to HTML

* Extract page size and column size

* Check label dimensions before printing

* Split labels into multiple pages / sheets

* Render out multiple labels onto a single sheet

* Cleanup base label template

- Allow @page style to *not* be generated
- Pass through as optional context variable
- Check that it still works for single label printing (default behaviour unchanged)
- Prevents multiple @page styles from being generated on label sheet output

* Fix stylesheets for part labels

* Cleanup stock location labels

* Cleanup more label templates

* Check if label can actually fit on page

* Generate output to PDF and return correct response

* Update panel.md

* Fix unit tests

* More unit test fixes

InvenTree/label/api.py

@@ -221,6 +221,10 @@ class LabelPrintMixin(LabelFilterMixin):
         # Label template
         label = self.get_object()
 
+        # Check the label dimensions
+        if label.width <= 0 or label.height <= 0:
+            raise ValidationError('Label has invalid dimensions')
+
         # if the plugin returns a serializer, validate the data
         if serializer := plugin.get_printing_options_serializer(request, data=request.data):
             serializer.is_valid(raise_exception=True)

InvenTree/label/models.py

@@ -191,10 +191,38 @@ class LabelTemplate(MetadataMixin, models.Model):
 
         return template_string.render(context)
 
-    def context(self, request):
-        """Provides context data to the template."""
+    def generate_page_style(self, **kwargs):
+        """Generate @page style for the label template.
+
+        This is inserted at the top of the style block for a given label
+        """
+
+        width = kwargs.get('width', self.width)
+        height = kwargs.get('height', self.height)
+        margin = kwargs.get('margin', 0)
+
+        return f"""
+        @page {{
+            size: {width}mm {height}mm;
+            margin: {margin}mm;
+        }}
+        """
+
+    def context(self, request, **kwargs):
+        """Provides context data to the template.
+
+        Arguments:
+            request: The HTTP request object
+            kwargs: Additional keyword arguments
+        """
+
         context = self.get_context_data(request)
 
+        # By default, each label is supplied with '@page' data
+        # However, it can be excluded, e.g. when rendering a label sheet
+        if kwargs.get('insert_page_style', True):
+            context['page_style'] = self.generate_page_style()
+
         # Add "basic" context data which gets passed to every label
         context['base_url'] = get_base_url(request=request)
         context['date'] = datetime.datetime.now().date()
@@ -213,18 +241,31 @@ class LabelTemplate(MetadataMixin, models.Model):
 
         return context
 
-    def render_as_string(self, request, **kwargs):
-        """Render the label to a HTML string.
+    def render_as_string(self, request, target_object=None, **kwargs):
+        """Render the label to a HTML string"""
 
-        Useful for debug mode (viewing generated code)
-        """
-        return render_to_string(self.template_name, self.context(request), request)
+        if target_object:
+            self.object_to_print = target_object
 
-    def render(self, request, **kwargs):
+        context = self.context(request, **kwargs)
+
+        return render_to_string(
+            self.template_name,
+            context,
+            request
+        )
+
+    def render(self, request, target_object=None, **kwargs):
         """Render the label template to a PDF file.
 
         Uses django-weasyprint plugin to render HTML template
         """
+
+        if target_object:
+            self.object_to_print = target_object
+
+        context = self.context(request, **kwargs)
+
         wp = WeasyprintLabelMixin(
             request,
             self.template_name,
@@ -235,7 +276,7 @@ class LabelTemplate(MetadataMixin, models.Model):
         )
 
         return wp.render_to_response(
-            self.context(request),
+            context,
             **kwargs
         )
 

InvenTree/label/templates/label/buildline/buildline_label_base.html

@@ -16,9 +16,9 @@ Refer to the documentation for a full list of available template variables.
 }
 
 .qr {
+  position: absolute;
   height: 28mm;
   width: 28mm;
-  position: relative;
   top: 0mm;
   right: 0mm;
   float: right;

InvenTree/label/templates/label/label_base.html

@@ -4,15 +4,18 @@
 
 <head>
     <style>
-        @page {
-            {% localize off %}
-            size: {{ width }}mm {{ height }}mm;
-            {% endlocalize %}
-            {% block margin %}
-            margin: 0mm;
-            {% endblock margin %}
-        }
 
+        {% block page_style %}
+        {% if page_style %}
+        /* @page styling */
+        {% localize off %}
+        {{ page_style }}
+        {% endlocalize %}
+        {% endif %}
+        {% endblock page_style %}
+
+        {% block body_style %}
+        /* body styling */
         body {
             font-family: Arial, Helvetica, sans-serif;
             margin: 0mm;
@@ -21,20 +24,27 @@
             page-break-before: always;
             page-break-after: always;
         }
+        {% endblock body_style %}
 
         img {
             display: inline-block;
             image-rendering: pixelated;
         }
 
+        /* Global content wrapper div which takes up entire page area */
         .content {
-            width: 100%;
+            {% localize off %}
+            width: {{ width }}mm;
+            height: {{ height }}mm;
+            {% endlocalize %}
             break-after: always;
             position: relative;
+            left: 0mm;
+            top: 0mm;
         }
 
         {% block style %}
-        /* User-defined styles can go here */
+        /* User-defined styles can go here, and override any styles defined above */
         {% endblock style %}
 
     </style>

InvenTree/label/templates/label/part/part_label.html

@@ -5,7 +5,7 @@
 {% block style %}
 
 .qr {
-    position: fixed;
+    position: absolute;
     left: 0mm;
     top: 0mm;
     {% localize off %}
@@ -16,7 +16,7 @@
 
 .part {
     font-family: Arial, Helvetica, sans-serif;
-    display: inline;
+    display: flex;
     position: absolute;
     {% localize off %}
     left: {{ height }}mm;

InvenTree/label/templates/label/part/part_label_code128.html

@@ -5,7 +5,7 @@
 {% block style %}
 
 .qr {
-    position: fixed;
+    position: absolute;
     left: 0mm;
     top: 0mm;
     {% localize off %}
@@ -16,7 +16,7 @@
 
 .part {
     font-family: Arial, Helvetica, sans-serif;
-    display: inline;
+    display: flex;
     position: absolute;
     {% localize off %}
     left: {{ height }}mm;

InvenTree/label/templates/label/stockitem/qr.html

@@ -5,7 +5,7 @@
 {% block style %}
 
 .qr {
-    position: fixed;
+    position: absolute;
     left: 0mm;
     top: 0mm;
     {% localize off %}

InvenTree/label/templates/label/stocklocation/qr.html

@@ -5,7 +5,7 @@
 {% block style %}
 
 .qr {
-    position: fixed;
+    position: absolute;
     left: 0mm;
     top: 0mm;
     {% localize off %}
@@ -17,6 +17,5 @@
 {% endblock style %}
 
 {% block content %}
-
 <img class='qr' alt="{% trans 'QR Code' %}" src='{% qrcode qr_data %}'>
 {% endblock content %}

InvenTree/label/templates/label/stocklocation/qr_and_text.html

@@ -5,7 +5,7 @@
 {% block style %}
 
 .qr {
-    position: fixed;
+    position: absolute;
     left: 0mm;
     top: 0mm;
     {% localize off %}
@@ -16,7 +16,7 @@
 
 .loc {
     font-family: Arial, Helvetica, sans-serif;
-    display: inline;
+    display: flex;
     position: absolute;
     {% localize off %}
     left: {{ height }}mm;