Merge pull request #1564 from doccano/enhancement/assignRandomColor

Assign label colors automatically

backend/api/migrations/0018_alter_label_background_color.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.2.8 on 2021-11-17 05:56
+
+import api.models
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('api', '0017_example_uuid'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='label',
+            name='background_color',
+            field=models.CharField(default=api.models.generate_random_hex_color, max_length=7),
+        ),
+    ]

backend/api/models.py

@@ -1,3 +1,4 @@
+import random
 import string
 import uuid
 from typing import Literal
@@ -94,6 +95,10 @@ class ImageClassificationProject(Project):
         return task == 'image'
 
 
+def generate_random_hex_color():
+    return f'#{random.randint(0, 0xFFFFFF):06x}'
+
+
 class Label(models.Model):
     text = models.CharField(max_length=100, db_index=True)
     prefix_key = models.CharField(
@@ -119,7 +124,7 @@ class Label(models.Model):
         on_delete=models.CASCADE,
         related_name='labels'
     )
-    background_color = models.CharField(max_length=7, default='#209cee')
+    background_color = models.CharField(max_length=7, default=generate_random_hex_color)
     text_color = models.CharField(max_length=7, default='#ffffff')
     created_at = models.DateTimeField(auto_now_add=True, db_index=True)
     updated_at = models.DateTimeField(auto_now=True)

backend/api/tests/test_models.py

@@ -3,7 +3,8 @@ from django.db.utils import IntegrityError
 from django.test import TestCase, override_settings
 from model_mommy import mommy
 
-from ..models import Category, Label, Span, TextLabel
+from ..models import (Category, Label, Span, TextLabel,
+                      generate_random_hex_color)
 
 
 @override_settings(STATICFILES_STORAGE='django.contrib.staticfiles.storage.StaticFilesStorage')
@@ -141,3 +142,11 @@ class TestSeq2seqAnnotation(TestCase):
             TextLabel(example=a.example,
                       user=a.user,
                       text=a.text).save()
+
+
+class TestGeneratedColor(TestCase):
+
+    def test_length(self):
+        for i in range(100):
+            color = generate_random_hex_color()
+            self.assertEqual(len(color), 7)