FEATURE: Add dark mode option for category backgrounds (#24003)

Adds a new upload field for a dark mode category background that will be used as an alternative when Discourse is using a dark mode theme.

app/assets/javascripts/discourse/app/components/edit-category-images.hbs

@@ -32,3 +32,14 @@
     @id="category-background-uploader"
   />
 </section>
+
+<section class="field category-background-image">
+  <label>{{i18n "category.background_image_dark"}}</label>
+  <UppyImageUploader
+    @imageUrl={{this.backgroundDarkImageUrl}}
+    @onUploadDone={{action "backgroundDarkUploadDone"}}
+    @onUploadDeleted={{action "backgroundDarkUploadDeleted"}}
+    @type="category_background_dark"
+    @id="category-dark-background-uploader"
+  />
+</section>

app/assets/javascripts/discourse/app/components/edit-category-images.js

@@ -8,6 +8,11 @@ export default buildCategoryPanel("images").extend({
     return uploadedBackgroundUrl || "";
   },
 
+  @discourseComputed("category.uploaded_background_dark.url")
+  backgroundDarkImageUrl(uploadedBackgroundDarkUrl) {
+    return uploadedBackgroundDarkUrl || "";
+  },
+
   @discourseComputed("category.uploaded_logo.url")
   logoImageUrl(uploadedLogoUrl) {
     return uploadedLogoUrl || "";
@@ -42,6 +47,14 @@ export default buildCategoryPanel("images").extend({
     backgroundUploadDeleted() {
       this._deleteUpload("category.uploaded_background");
     },
+
+    backgroundDarkUploadDone(upload) {
+      this._setFromUpload("category.uploaded_background_dark", upload);
+    },
+
+    backgroundDarkUploadDeleted() {
+      this._deleteUpload("category.uploaded_background_dark");
+    },
   },
 
   _deleteUpload(path) {

app/assets/javascripts/discourse/app/models/category.js

@@ -232,6 +232,7 @@ const Category = RestModel.extend({
         uploaded_logo_id: this.get("uploaded_logo.id"),
         uploaded_logo_dark_id: this.get("uploaded_logo_dark.id"),
         uploaded_background_id: this.get("uploaded_background.id"),
+        uploaded_background_dark_id: this.get("uploaded_background_dark.id"),
         allow_badges: this.allow_badges,
         category_setting_attributes: this.category_setting,
         custom_fields: this.custom_fields,

app/controllers/categories_controller.rb

@@ -459,6 +459,7 @@ class CategoriesController < ApplicationController
             :uploaded_logo_id,
             :uploaded_logo_dark_id,
             :uploaded_background_id,
+            :uploaded_background_dark_id,
             :slug,
             :allow_badges,
             :topic_template,

app/models/category.rb

@@ -29,6 +29,7 @@ class Category < ActiveRecord::Base
   belongs_to :uploaded_logo, class_name: "Upload"
   belongs_to :uploaded_logo_dark, class_name: "Upload"
   belongs_to :uploaded_background, class_name: "Upload"
+  belongs_to :uploaded_background_dark, class_name: "Upload"
 
   has_many :topics
   has_many :category_users
@@ -115,8 +116,13 @@ class Category < ActiveRecord::Base
 
   after_save do
     if saved_change_to_uploaded_logo_id? || saved_change_to_uploaded_logo_dark_id? ||
-         saved_change_to_uploaded_background_id?
-      upload_ids = [self.uploaded_logo_id, self.uploaded_logo_dark_id, self.uploaded_background_id]
+         saved_change_to_uploaded_background_id? || saved_change_to_uploaded_background_dark_id?
+      upload_ids = [
+        self.uploaded_logo_id,
+        self.uploaded_logo_dark_id,
+        self.uploaded_background_id,
+        self.uploaded_background_dark_id,
+      ]
       UploadReference.ensure_exist!(upload_ids: upload_ids, target: self)
     end
   end
@@ -1185,6 +1191,7 @@ end
 #  allow_unlimited_owner_edits_on_first_post :boolean          default(FALSE), not null
 #  default_slow_mode_seconds                 :integer
 #  uploaded_logo_dark_id                     :integer
+#  uploaded_background_dark_id               :integer
 #
 # Indexes
 #

app/models/category_list.rb

@@ -16,6 +16,7 @@ class CategoryList
   def self.included_associations
     [
       :uploaded_background,
+      :uploaded_background_dark,
       :uploaded_logo,
       :uploaded_logo_dark,
       :topic_only_relative_url,

app/models/site.rb

@@ -81,6 +81,7 @@ class Site
                   :uploaded_logo,
                   :uploaded_logo_dark,
                   :uploaded_background,
+                  :uploaded_background_dark,
                   :tags,
                   :tag_groups,
                   :form_templates,

app/serializers/basic_category_serializer.rb

@@ -35,6 +35,7 @@ class BasicCategorySerializer < ApplicationSerializer
   has_one :uploaded_logo, embed: :object, serializer: CategoryUploadSerializer
   has_one :uploaded_logo_dark, embed: :object, serializer: CategoryUploadSerializer
   has_one :uploaded_background, embed: :object, serializer: CategoryUploadSerializer
+  has_one :uploaded_background_dark, embed: :object, serializer: CategoryUploadSerializer
 
   def include_parent_category_id?
     parent_category_id

config/locales/client.en.yml

@@ -3734,6 +3734,7 @@ en:
       logo: "Category Logo Image"
       logo_dark: "Dark Mode Category Logo Image"
       background_image: "Category Background Image"
+      background_image_dark: "Dark Category Background Image"
       badge_colors: "Badge colors"
       background_color: "Background color"
       foreground_color: "Foreground color"

db/migrate/20231018225833_add_dark_mode_background_to_categories.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddDarkModeBackgroundToCategories < ActiveRecord::Migration[7.0]
+  def change
+    add_column :categories, :uploaded_background_dark_id, :integer, index: true
+  end
+end

lib/stylesheet/compiler.rb

@@ -34,7 +34,7 @@ module Stylesheet
         when Stylesheet::Manager::COLOR_SCHEME_STYLESHEET
           file += importer.import_color_definitions
           file += importer.import_wcag_overrides
-          file += importer.category_backgrounds
+          file += importer.category_backgrounds(options[:color_scheme_id])
           file += importer.font
         end
       end

lib/stylesheet/importer.rb

@@ -95,11 +95,16 @@ module Stylesheet
       contents
     end
 
-    def category_backgrounds
+    def category_backgrounds(color_scheme_id)
+      is_dark_color_scheme =
+        color_scheme_id.present? && ColorScheme.find_by_id(color_scheme_id)&.is_dark?
+
       contents = +""
       Category
         .where("uploaded_background_id IS NOT NULL")
-        .each { |c| contents << category_css(c) if c.uploaded_background&.url.present? }
+        .each do |c|
+          contents << category_css(c, is_dark_color_scheme) if c.uploaded_background&.url.present?
+        end
 
       contents
     end
@@ -215,9 +220,20 @@ module Stylesheet
       @theme == :nil ? nil : @theme
     end
 
-    def category_css(category)
+    def category_css(category, is_dark_color_scheme)
       full_slug = category.full_slug.split("-")[0..-2].join("-")
-      "body.category-#{full_slug} { background-image: url(#{upload_cdn_path(category.uploaded_background.url)}) }\n"
+
+      # in case we're using a dark color scheme, we define the background using the dark image
+      # if one is available. Otherwise, we use the light image by default.
+      if is_dark_color_scheme && category.uploaded_background_dark&.url.present?
+        return category_background_css(full_slug, category.uploaded_background_dark.url)
+      end
+
+      category_background_css(full_slug, category.uploaded_background.url)
+    end
+
+    def category_background_css(full_slug, background_url)
+      "body.category-#{full_slug} { background-image: url(#{upload_cdn_path(background_url)}) }"
     end
 
     def font_css(font)

lib/tasks/site.rake

@@ -220,6 +220,7 @@ task "site:export_structure", [:zip_path] => :environment do |task, args|
       uploaded_logo_id: data.set_upload(c.uploaded_logo_id),
       uploaded_logo_dark_id: data.set_upload(c.uploaded_logo_dark_id),
       uploaded_background_id: data.set_upload(c.uploaded_background_id),
+      uploaded_background_dark_id: data.set_upload(c.uploaded_background_dark_id),
       topic_featured_link_allowed: c.topic_featured_link_allowed,
       all_topics_wiki: c.all_topics_wiki,
       show_subcategory_list: c.show_subcategory_list,

lib/tasks/uploads.rake

@@ -965,6 +965,7 @@ def analyze_missing_s3
       %i[categories uploaded_logo_id],
       %i[categories uploaded_logo_dark_id],
       %i[categories uploaded_background_id],
+      %i[categories uploaded_background_dark_id],
       %i[custom_emojis upload_id],
       %i[theme_fields upload_id],
       %i[user_exports upload_id],

spec/jobs/clean_up_uploads_spec.rb

@@ -229,6 +229,16 @@ RSpec.describe Jobs::CleanUpUploads do
     expect(Upload.exists?(id: category_background_upload.id)).to eq(true)
   end
 
+  it "does not delete category dark background uploads" do
+    category_background_dark_upload = fabricate_upload
+    Fabricate(:category, uploaded_background_dark: category_background_dark_upload)
+
+    Jobs::CleanUpUploads.new.execute(nil)
+
+    expect(Upload.exists?(id: expired_upload.id)).to eq(false)
+    expect(Upload.exists?(id: category_background_dark_upload.id)).to eq(true)
+  end
+
   it "does not delete post uploads" do
     upload = fabricate_upload
     Fabricate(:post, uploads: [upload])

spec/lib/stylesheet/importer_spec.rb

@@ -3,33 +3,114 @@
 require "stylesheet/importer"
 
 RSpec.describe Stylesheet::Importer do
-  def compile_css(name)
-    Stylesheet::Compiler.compile_asset(name)[0]
+  def compile_css(name, options = {})
+    Stylesheet::Compiler.compile_asset(name, options)[0]
   end
 
   describe "#category_backgrounds" do
-    it "applies CDN to background category images" do
-      expect(compile_css("color_definitions")).to_not include("body.category-")
-
+    it "uses the correct background image based in the color scheme" do
       background = Fabricate(:upload)
+      background_dark = Fabricate(:upload)
+
       parent_category = Fabricate(:category)
       category =
         Fabricate(
           :category,
           parent_category_id: parent_category.id,
           uploaded_background: background,
+          uploaded_background_dark: background_dark,
         )
 
-      expect(compile_css("color_definitions")).to include(
+      # light color schemes
+      ["Neutral", "Shades of Blue", "WCAG", "Summer", "Solarized Light"].each do |scheme_name|
+        scheme = ColorScheme.create_from_base(name: "Light Test", base_scheme_id: scheme_name)
+
+        compiled_css = compile_css("color_definitions", { color_scheme_id: scheme.id })
+
+        expect(compiled_css).to include(
+          "body.category-#{parent_category.slug}-#{category.slug}{background-image:url(#{background.url})}",
+        )
+        expect(compiled_css).not_to include(background_dark.url)
+      end
+
+      # dark color schemes
+      [
+        "Dark",
+        "Grey Amber",
+        "Latte",
+        "Dark Rose",
+        "WCAG Dark",
+        "Dracula",
+        "Solarized Dark",
+      ].each do |scheme_name|
+        scheme = ColorScheme.create_from_base(name: "Light Test", base_scheme_id: scheme_name)
+
+        compiled_css = compile_css("color_definitions", { color_scheme_id: scheme.id })
+
+        expect(compiled_css).not_to include(background.url)
+        expect(compiled_css).to include(
+          "body.category-#{parent_category.slug}-#{category.slug}{background-image:url(#{background_dark.url})}",
+        )
+      end
+    end
+
+    it "applies CDN to background category images" do
+      expect(compile_css("color_definitions")).to_not include("body.category-")
+
+      background = Fabricate(:upload)
+      background_dark = Fabricate(:upload)
+
+      parent_category = Fabricate(:category)
+      category =
+        Fabricate(
+          :category,
+          parent_category_id: parent_category.id,
+          uploaded_background: background,
+          uploaded_background_dark: background_dark,
+        )
+
+      compiled_css = compile_css("color_definitions")
+      expect(compiled_css).to include(
         "body.category-#{parent_category.slug}-#{category.slug}{background-image:url(#{background.url})}",
       )
 
       GlobalSetting.stubs(:cdn_url).returns("//awesome.cdn")
-      expect(compile_css("color_definitions")).to include(
+      compiled_css = compile_css("color_definitions")
+      expect(compiled_css).to include(
         "body.category-#{parent_category.slug}-#{category.slug}{background-image:url(//awesome.cdn#{background.url})}",
       )
     end
 
+    it "applies CDN to dark background category images" do
+      scheme = ColorScheme.create_from_base(name: "Dark Test", base_scheme_id: "Dark")
+      expect(compile_css("color_definitions", { color_scheme_id: scheme.id })).to_not include(
+        "body.category-",
+      )
+
+      background = Fabricate(:upload)
+      background_dark = Fabricate(:upload)
+
+      parent_category = Fabricate(:category)
+      category =
+        Fabricate(
+          :category,
+          parent_category_id: parent_category.id,
+          uploaded_background: background,
+          uploaded_background_dark: background_dark,
+        )
+
+      compiled_css = compile_css("color_definitions", { color_scheme_id: scheme.id })
+      expect(compiled_css).to include(
+        "body.category-#{parent_category.slug}-#{category.slug}{background-image:url(#{background_dark.url})}",
+      )
+
+      GlobalSetting.stubs(:cdn_url).returns("//awesome.cdn")
+      compiled_css = compile_css("color_definitions", { color_scheme_id: scheme.id })
+      expect(compiled_css).to include(
+        "body.category-#{parent_category.slug}-#{category.slug}{background-image:url(//awesome.cdn#{background_dark.url})}",
+      )
+    end
+
     it "applies S3 CDN to background category images" do
       setup_s3
       SiteSetting.s3_use_iam_profile = true
@@ -40,7 +121,32 @@ RSpec.describe Stylesheet::Importer do
       background = Fabricate(:upload_s3)
       category = Fabricate(:category, uploaded_background: background)
 
-      expect(compile_css("color_definitions")).to include(
+      compiled_css = compile_css("color_definitions")
+      expect(compiled_css).to include(
+        "body.category-#{category.slug}{background-image:url(https://s3.cdn/original",
+      )
+    end
+
+    it "applies S3 CDN to dark background category images" do
+      scheme = ColorScheme.create_from_base(name: "Dark Test", base_scheme_id: "WCAG Dark")
+
+      setup_s3
+      SiteSetting.s3_use_iam_profile = true
+      SiteSetting.s3_upload_bucket = "test"
+      SiteSetting.s3_region = "ap-southeast-2"
+      SiteSetting.s3_cdn_url = "https://s3.cdn"
+
+      background = Fabricate(:upload_s3)
+      background_dark = Fabricate(:upload_s3)
+      category =
+        Fabricate(
+          :category,
+          uploaded_background: background,
+          uploaded_background_dark: background_dark,
+        )
+
+      compiled_css = compile_css("color_definitions", { color_scheme_id: scheme.id })
+      expect(compiled_css).to include(
         "body.category-#{category.slug}{background-image:url(https://s3.cdn/original",
       )
     end

spec/models/upload_reference_spec.rb

@@ -22,6 +22,7 @@ RSpec.describe UploadReference do
     fab!(:upload1) { Fabricate(:upload) }
     fab!(:upload2) { Fabricate(:upload) }
     fab!(:upload3) { Fabricate(:upload) }
+    fab!(:upload4) { Fabricate(:upload) }
 
     it "creates upload references" do
       category = nil
@@ -32,13 +33,14 @@ RSpec.describe UploadReference do
             uploaded_logo_id: upload1.id,
             uploaded_logo_dark_id: upload2.id,
             uploaded_background_id: upload3.id,
+            uploaded_background_dark_id: upload4.id,
           )
-      }.to change { UploadReference.count }.by(3)
+      }.to change { UploadReference.count }.by(4)
 
       upload_reference = UploadReference.last
       expect(upload_reference.target).to eq(category)
 
-      expect { category.destroy! }.to change { UploadReference.count }.by(-3)
+      expect { category.destroy! }.to change { UploadReference.count }.by(-4)
     end
   end
 

spec/requests/api/schemas/json/category_create_response.json

@@ -260,6 +260,12 @@
             "string",
             "null"
           ]
+        },
+        "uploaded_background_dark": {
+          "type": [
+            "string",
+            "null"
+          ]
         }
       },
       "required": [
@@ -310,7 +316,8 @@
         "search_priority",
         "uploaded_logo",
         "uploaded_logo_dark",
-        "uploaded_background"
+        "uploaded_background",
+        "uploaded_background_dark"
       ]
     }
   },

spec/requests/api/schemas/json/category_list_response.json

@@ -167,6 +167,12 @@
                     "string",
                     "null"
                   ]
+                },
+                "uploaded_background_dark": {
+                  "type": [
+                    "string",
+                    "null"
+                  ]
                 }
               },
               "required": [
@@ -206,7 +212,8 @@
                 "subcategory_ids",
                 "uploaded_logo",
                 "uploaded_logo_dark",
-                "uploaded_background"
+                "uploaded_background",
+                "uploaded_background_dark"
               ]
             }
         }

spec/requests/api/schemas/json/category_update_response.json

@@ -263,6 +263,12 @@
             "string",
             "null"
           ]
+        },
+        "uploaded_background_dark": {
+          "type": [
+            "string",
+            "null"
+          ]
         }
       },
       "required": [
@@ -314,7 +320,8 @@
         "search_priority",
         "uploaded_logo",
         "uploaded_logo_dark",
-        "uploaded_background"
+        "uploaded_background",
+        "uploaded_background_dark"
       ]
     }
   },

spec/requests/api/schemas/json/site_response.json

@@ -701,6 +701,12 @@
                 "null"
               ]
             },
+            "uploaded_background_dark": {
+              "type": [
+                "string",
+                "null"
+              ]
+            },
             "can_edit": {
               "type": "boolean"
             },
@@ -752,6 +758,7 @@
             "uploaded_logo",
             "uploaded_logo_dark",
             "uploaded_background",
+            "uploaded_background_dark",
             "can_edit"
           ]
         }