EvPresentationView: Render correctly on hi-dpi displays

Create rendering jobs with a scale that incorporate the scale factor of
the widget, and then use cairo_surface_set_device_scale() to make the
resulting surfaces render at the correct size. Handle changes to the scale
factor both for the cached surfaces, and also for the monitor dimensions,
which are reported in scaled coordinates.

https://bugzilla.gnome.org/show_bug.cgi?id=723431

origin commit:
https://git.gnome.org/browse/evince/commit/?id=37c13b

libview/ev-view-presentation.c

@@ -283,11 +283,28 @@ ev_view_presentation_transition_animation_frame (EvViewPresentation *pview,
 	gtk_widget_queue_draw (GTK_WIDGET (pview));
 }
 
+static cairo_surface_t *
+get_surface_from_job (EvViewPresentation *pview,
+		      EvJob              *job)
+{
+	cairo_surface_t *surface;
+
+	if (!job)
+		return NULL;
+
+	surface = EV_JOB_RENDER(job)->surface;
+	if (!surface)
+		return NULL;
+
+	return surface;
+}
+
 static void
 ev_view_presentation_animation_start (EvViewPresentation *pview,
 				      gint                new_page)
 {
 	EvTransitionEffect *effect = NULL;
+	EvJob              *job;
 	cairo_surface_t    *surface;
 	gint                jump;
 
@@ -311,11 +328,12 @@ ev_view_presentation_animation_start (EvViewPresentation *pview,
 
 	jump = new_page - pview->current_page;
 	if (jump == -1)
-		surface = pview->prev_job ? EV_JOB_RENDER (pview->prev_job)->surface : NULL;
+		job = pview->prev_job;
 	else if (jump == 1)
-		surface = pview->next_job ? EV_JOB_RENDER (pview->next_job)->surface : NULL;
+		job = pview->next_job;
 	else
-		surface = NULL;
+		job = NULL;
+	surface = get_surface_from_job (pview, job);
 	if (surface)
 		ev_transition_animation_set_dest_surface (pview->animation, surface);
 
@@ -342,7 +360,7 @@ job_finished_cb (EvJob              *job,
 
 	if (pview->animation) {
 		ev_transition_animation_set_dest_surface (pview->animation,
-							  job_render->surface);
+							  get_surface_from_job (pview, job));
 	} else {
 		ev_view_presentation_transition_start (pview);
 		gtk_widget_queue_draw (GTK_WIDGET (pview));
@@ -1064,7 +1082,7 @@ ev_view_presentation_draw (GtkWidget *widget,
 		return TRUE;
 	}
 
-	surface = pview->curr_job ? EV_JOB_RENDER (pview->curr_job)->surface : NULL;
+	surface = get_surface_from_job (pview, pview->curr_job);
 	if (surface) {
 		ev_view_presentation_update_current_surface (pview, surface);
 	} else if (pview->current_surface) {
@@ -1212,19 +1230,25 @@ ev_view_presentation_motion_notify_event (GtkWidget      *widget,
 	return FALSE;
 }
 
-static gboolean
-init_presentation (GtkWidget *widget)
+static void
+ev_view_presentation_update_monitor_geometry (EvViewPresentation *pview)
 {
-	EvViewPresentation *pview = EV_VIEW_PRESENTATION (widget);
-	GdkDisplay         *display = gtk_widget_get_display (widget);
+	GdkScreen          *screen = gtk_widget_get_screen (GTK_WIDGET (pview));
 	GdkRectangle        monitor;
-	GdkMonitor         *monitor_num;
-
-	monitor_num = gdk_display_get_monitor_at_window (display, gtk_widget_get_window (widget));
-	gdk_monitor_get_geometry (monitor_num, &monitor);
+	gint                monitor_num;
 
+	monitor_num = gdk_screen_get_monitor_at_window (screen, gtk_widget_get_window (GTK_WIDGET (pview)));
+	gdk_screen_get_monitor_geometry (screen, monitor_num, &monitor);
 	pview->monitor_width = monitor.width;
 	pview->monitor_height = monitor.height;
+}
+
+static gboolean
+init_presentation (GtkWidget *widget)
+{
+	EvViewPresentation *pview = EV_VIEW_PRESENTATION (widget);
+
+	ev_view_presentation_update_monitor_geometry (pview);
 
 	ev_view_presentation_update_current_page (pview, pview->current_page);
 	ev_view_presentation_hide_cursor_timeout_start (pview);
@@ -1378,6 +1402,14 @@ ev_view_presentation_get_property (GObject    *object,
         }
 }
 
+	static void
+ev_view_presentation_notify_scale_factor (EvViewPresentation *pview)
+{
+	ev_view_presentation_update_monitor_geometry (pview);
+	ev_view_presentation_reset_jobs (pview);
+	ev_view_presentation_update_current_page (pview, pview->current_page);
+}
+
 static GObject *
 ev_view_presentation_constructor (GType                  type,
 				  guint                  n_construct_properties,
@@ -1397,6 +1429,9 @@ ev_view_presentation_constructor (GType                  type,
 		ev_page_cache_set_flags (pview->page_cache, EV_PAGE_DATA_INCLUDE_LINKS);
 	}
 
+	g_signal_connect (object, "notify::scale-factor",
+			  G_CALLBACK (ev_view_presentation_notify_scale_factor), NULL);
+
 	return object;
 }