From 759b6ec373e4e704a431ba8f37aa0598b004de9b Mon Sep 17 00:00:00 2001
From: Jens Kraemer <jk@jkraemer.net>
Date: Tue, 11 Dec 2018 16:06:52 +0800
Subject: [PATCH] makes sure the generated thumbnail is always of at least the
 requested size

---
 app/models/attachment.rb     |  2 +-
 test/unit/attachment_test.rb | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/app/models/attachment.rb b/app/models/attachment.rb
index cc9b5f930..bc88beaf2 100644
--- a/app/models/attachment.rb
+++ b/app/models/attachment.rb
@@ -209,7 +209,7 @@ class Attachment < ActiveRecord::Base
       size = options[:size].to_i
       if size > 0
         # Limit the number of thumbnails per image
-        size = (size / 50) * 50
+        size = (size / 50.0).ceil * 50
         # Maximum thumbnail size
         size = 800 if size > 800
       else
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
index 2bee67ed2..52f81e31b 100644
--- a/test/unit/attachment_test.rb
+++ b/test/unit/attachment_test.rb
@@ -440,6 +440,24 @@ class AttachmentTest < ActiveSupport::TestCase
       attachment = Attachment.find(16)
       assert_nil attachment.thumbnail
     end
+
+    def test_thumbnail_should_be_at_least_of_requested_size
+      set_fixtures_attachments_directory
+      attachment = Attachment.find(16)
+      Attachment.clear_thumbnails
+      [
+        [0, 100],
+        [49, 50],
+        [50, 50],
+        [51, 100],
+        [100, 100],
+        [101, 150],
+      ].each do |size, generated_size|
+        thumbnail = attachment.thumbnail(size: size)
+        assert_equal "16_8e0294de2441577c529f170b6fb8f638_#{generated_size}.thumb",
+          File.basename(thumbnail)
+      end
+    end
   else
     puts '(ImageMagick convert not available)'
   end
-- 
2.11.0