Merge branch 'Ban3-visibility-api'

CHANGELOG.asciidoc

@@ -43,6 +43,8 @@ Added
 - New `:debug-log-level` command to change the console loglevel on-the-fly.
 - New `general -> yank-ignored-url-parameters` option to configure which URL
   parameters (like `utm_source` etc.) to strip off when yanking an URL.
+- Support for the
+  https://developer.mozilla.org/en-US/docs/Web/API/Page_Visibility_API[HTML5 page visibility API]
 
 Changed
 ~~~~~~~

README.asciidoc

@@ -197,6 +197,7 @@ Contributors, sorted by the number of commits in descending order:
 * Michał Góral
 * Michael Ilsaas
 * Martin Zimmermann
+* Jussi Timperi
 * Fritz Reichwald
 * Brian Jackson
 * sbinix

qutebrowser/browser/webkit/webview.py

@@ -72,6 +72,14 @@ class WebView(QWebView):
 
         page = webpage.BrowserPage(self.win_id, self._tab_id, tab.data,
                                    parent=self)
+
+        try:
+            page.setVisibilityState(
+                QWebPage.VisibilityStateVisible if self.isVisible()
+                else QWebPage.VisibilityStateHidden)
+        except AttributeError:
+            pass
+
         self.setPage(page)
 
         mode_manager = objreg.get('mode-manager', scope='window',
@@ -240,3 +248,35 @@ class WebView(QWebView):
         self.shutting_down.connect(menu.close)
         modeman.instance(self.win_id).entered.connect(menu.close)
         menu.exec_(e.globalPos())
+
+    def showEvent(self, e):
+        """Extend showEvent to set the page visibility state to visible.
+
+        Args:
+            e: The QShowEvent.
+
+        Return:
+            The superclass event return value.
+        """
+        try:
+            self.page().setVisibilityState(QWebPage.VisibilityStateVisible)
+        except AttributeError:
+            pass
+
+        super().showEvent(e)
+
+    def hideEvent(self, e):
+        """Extend hideEvent to set the page visibility state to hidden.
+
+        Args:
+            e: The QHideEvent.
+
+        Return:
+            The superclass event return value.
+        """
+        try:
+            self.page().setVisibilityState(QWebPage.VisibilityStateHidden)
+        except AttributeError:
+            pass
+
+        super().hideEvent(e)