backgorund image change and change function display color

1 files changed, 13 insertions, 2 deletions

diff --git a/blog/views.py b/blog/views.py
index 26d75e69..e1113016 100644
--- a/blog/views.py
+++ b/blog/views.py
@@ -12,6 +12,8 @@ import json
 from .models import Post, Comment
 from .context_processors import recent_posts
 from announcements.models import Announcement
+from PIL import Image
+from io import BytesIO
 
 # Create your views here.
 
@@ -178,6 +180,15 @@ def tex(request):
 
     import requests
 
-    image = requests.get('https://latex.codecogs.com/png.image?%5Cinline%20%5Clarge%20%5Cdpi%7B300%7D%5Cbg%7Bblack%7D' + expression).content
+    image = requests.get('https://latex.codecogs.com/png.image?%5Cinline%20%5Clarge%20%5Cdpi%7B300%7D%5Cbg%7Btransparent%7D' + expression).content
 
-    return HttpResponse(image, content_type='image/png')
+    # Image is a transparent GIF with black text. Invert the colors.
+    image = Image.open(BytesIO(image))
+    image = image.convert('RGB')
+    image = Image.eval(image, lambda x: 255 - x)
+    image = image.convert('RGBA')
+
+    # Convert back to gif and return
+    output = BytesIO()
+    image.save(output, format='GIF')
+    return HttpResponse(output.getvalue(), content_type='image/gif')