[gnome-documents: 1/2] epub: Implement Night Mode

[Christopher Davis <christopherdavis src gnome org>]

commit 8ef78fc30b0abc8997690eebeac6a9521e7d118a
Author: Ryan Gonzalez <rymg19 gmail com>
Date:   Wed Jan 16 21:23:18 2019 -0600

    epub: Implement Night Mode
    
    Night Mode in Books now inverts the colors like Documents does, whereas before it simply set the window's 
theme to dark.
    
    Closes #30.

 src/epubview.js | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
---
diff --git a/src/epubview.js b/src/epubview.js
index 88b9580c..6f347265 100644
--- a/src/epubview.js
+++ b/src/epubview.js
@@ -28,6 +28,7 @@ const WebKit2 = imports.gi.WebKit2;
 
 const _ = imports.gettext.gettext;
 
+const Application = imports.application;
 const Documents = imports.documents;
 const Preview = imports.preview;
 const Utils = imports.utils;
@@ -69,6 +70,13 @@ var EPUBView = new Lang.Class({
     createView: function() {
         let view = new Gepub.Widget();
 
+        this.invertedStyle = new WebKit2.UserStyleSheet(
+            'body { background: black; filter: invert(100%); }',
+            WebKit2.UserContentInjectedFrames.ALL_FRAMES,
+            WebKit2.UserStyleLevel.USER,
+            null, null,
+        );
+
         let fc = view.get_find_controller();
         fc.connect('found-text', Lang.bind(this, function(view, matchCount, data) {
             let hasResults = matchCount > 0;
@@ -160,6 +168,15 @@ var EPUBView = new Lang.Class({
         return true;
     },
 
+    set nightMode(v) {
+        if (this.view && Application.application.isBooks) {
+            if (v)
+                this.view.get_user_content_manager().add_style_sheet(this.invertedStyle);
+            else
+                this.view.get_user_content_manager().remove_all_style_sheets();
+        }
+    },
+
     search: function(str) {
         this.parent(str);