[evince] libview: Make caret cursor blink

[Carlos Garcia Campos <carlosgc src gnome org>]

commit e6f7250f8bf12a3f5fffaa50a9e306c7dde8075d
Author: Carlos Garcia Campos <carlosgc gnome org>
Date:   Thu Jun 13 19:08:44 2013 +0200

    libview: Make caret cursor blink
    
    Based on GtkEntry and GtkTextView implementation, the caret cursor
    blinks when the view is active and caret navigation is enabled. It stops
    blinking after a while if there's no user interaction. It uses
    GtkSettings:gtk-cursor-blink-time and
    GtkSettings:gtk-cursor-blink-timeout.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=702076

 libview/ev-view-private.h |    3 +
 libview/ev-view.c         |  284 +++++++++++++++++++++++++++++++++++---------
 2 files changed, 229 insertions(+), 58 deletions(-)
---
diff --git a/libview/ev-view-private.h b/libview/ev-view-private.h
index fda40a9..135e9cf 100644
--- a/libview/ev-view-private.h
+++ b/libview/ev-view-private.h
@@ -211,6 +211,9 @@ struct _EvView {
        /* Caret navigation */
        gboolean caret_enabled;
        gint     cursor_offset;
+       gboolean cursor_visible;
+       guint    cursor_blink_timeout_id;
+       guint    cursor_blink_time;
 };
 
 struct _EvViewClass {
diff --git a/libview/ev-view.c b/libview/ev-view.c
index 826ba4d..5760cc3 100644
--- a/libview/ev-view.c
+++ b/libview/ev-view.c
@@ -3113,6 +3113,209 @@ ev_view_synctex_backward_search (EvView *view,
 }
 
 /* Caret navigation */
+#define CURSOR_ON_MULTIPLIER 2
+#define CURSOR_OFF_MULTIPLIER 1
+#define CURSOR_PEND_MULTIPLIER 3
+#define CURSOR_DIVIDER 3
+
+static gboolean
+cursor_should_blink (EvView *view)
+{
+       if (view->caret_enabled &&
+           view->rotation == 0 &&
+           gtk_widget_has_focus (GTK_WIDGET (view))) {
+               GtkSettings *settings;
+               gboolean blink;
+
+               settings = gtk_widget_get_settings (GTK_WIDGET (view));
+               g_object_get (settings, "gtk-cursor-blink", &blink, NULL);
+
+               return blink;
+       }
+
+       return FALSE;
+}
+
+static gint
+get_cursor_blink_time (EvView *view)
+{
+       GtkSettings *settings = gtk_widget_get_settings (GTK_WIDGET (view));
+       gint time;
+
+       g_object_get (settings, "gtk-cursor-blink-time", &time, NULL);
+
+       return time;
+}
+
+static gint
+get_cursor_blink_timeout_id (EvView *view)
+{
+       GtkSettings *settings = gtk_widget_get_settings (GTK_WIDGET (view));
+       gint timeout;
+
+       g_object_get (settings, "gtk-cursor-blink-timeout", &timeout, NULL);
+
+       return timeout;
+}
+
+static gboolean
+get_caret_cursor_rect_from_offset (EvView       *view,
+                                  gint          offset,
+                                  gint          page,
+                                  GdkRectangle *rect)
+{
+       EvRectangle *areas = NULL;
+       EvRectangle *doc_rect;
+       guint        n_areas = 0;
+
+       if (!view->caret_enabled)
+               return FALSE;
+
+       /* Disable caret navigation on rotated pages */
+       if (view->rotation != 0)
+               return FALSE;
+
+       if (!view->page_cache)
+               return FALSE;
+
+       ev_page_cache_get_text_layout (view->page_cache, page, &areas, &n_areas);
+       if (!areas)
+               return FALSE;
+
+       if (offset > n_areas)
+               return FALSE;
+
+       doc_rect = areas + offset;
+       if (offset == n_areas ||
+           ((doc_rect->x1 == doc_rect->x2 || doc_rect->y1 == doc_rect->y2) && offset > 0)) {
+               EvRectangle *prev;
+               EvRectangle  last_rect;
+
+               /* Special characters like \n have an empty bounding box
+                * and the end of a page doesn't have any bounding box,
+                * use the size of the previous area.
+                */
+               prev = areas + offset - 1;
+               last_rect.x1 = prev->x2;
+               last_rect.y1 = prev->y1;
+               last_rect.x2 = prev->x2 + (prev->x2 - prev->x1);
+               last_rect.y2 = prev->y2;
+
+               _ev_view_transform_doc_rect_to_view_rect (view, page, &last_rect, rect);
+
+               return TRUE;
+       }
+
+       _ev_view_transform_doc_rect_to_view_rect (view, page, doc_rect, rect);
+
+       return TRUE;
+}
+
+static void
+show_cursor (EvView *view)
+{
+       GtkWidget   *widget;
+       GdkRectangle view_rect;
+
+       if (view->cursor_visible)
+               return;
+
+       widget = GTK_WIDGET (view);
+       view->cursor_visible = TRUE;
+       if (gtk_widget_has_focus (widget)
+           && get_caret_cursor_rect_from_offset (view, view->cursor_offset, view->current_page, &view_rect)) 
{
+               view_rect.x = view_rect.x - view->scroll_x;
+               view_rect.y = view_rect.y - view->scroll_y;
+               gtk_widget_queue_draw_area (widget, view_rect.x, view_rect.y, view_rect.width, 
view_rect.height);
+       }
+}
+
+static void
+hide_cursor (EvView *view)
+{
+       GtkWidget   *widget;
+       GdkRectangle view_rect;
+
+       if (!view->cursor_visible)
+               return;
+
+       widget = GTK_WIDGET (view);
+       view->cursor_visible = FALSE;
+       if (gtk_widget_has_focus (widget)
+           && get_caret_cursor_rect_from_offset (view, view->cursor_offset, view->current_page, &view_rect)) 
{
+               view_rect.x = view_rect.x - view->scroll_x;
+               view_rect.y = view_rect.y - view->scroll_y;
+               gtk_widget_queue_draw_area (widget, view_rect.x, view_rect.y, view_rect.width, 
view_rect.height);
+       }
+}
+
+static gboolean
+blink_cb (EvView *view)
+{
+       gint blink_timeout;
+       guint blink_time;
+
+       blink_timeout = get_cursor_blink_timeout_id (view);
+       if (view->cursor_blink_time > 1000 * blink_timeout && blink_timeout < G_MAXINT / 1000) {
+               /* We've blinked enough without the user doing anything, stop blinking */
+               show_cursor (view);
+               view->cursor_blink_timeout_id = 0;
+
+               return FALSE;
+       }
+
+       blink_time = get_cursor_blink_time (view);
+       if (view->cursor_visible) {
+               hide_cursor (view);
+               blink_time *= CURSOR_OFF_MULTIPLIER;
+       } else {
+               show_cursor (view);
+               view->cursor_blink_time += blink_time;
+               blink_time *= CURSOR_ON_MULTIPLIER;
+       }
+
+       view->cursor_blink_timeout_id = gdk_threads_add_timeout (blink_time / CURSOR_DIVIDER, 
(GSourceFunc)blink_cb, view);
+
+       return FALSE;
+}
+
+static void
+ev_view_check_cursor_blink (EvView *view)
+{
+       if (cursor_should_blink (view)) {
+               if (view->cursor_blink_timeout_id == 0) {
+                       show_cursor (view);
+                       view->cursor_blink_timeout_id = gdk_threads_add_timeout (get_cursor_blink_time (view) 
* CURSOR_ON_MULTIPLIER / CURSOR_DIVIDER,
+                                                                                (GSourceFunc)blink_cb, view);
+               }
+
+               return;
+       }
+
+       if (view->cursor_blink_timeout_id > 0) {
+               g_source_remove (view->cursor_blink_timeout_id);
+               view->cursor_blink_timeout_id = 0;
+       }
+
+       view->cursor_visible = TRUE;
+       view->cursor_blink_time = 0;
+}
+
+static void
+ev_view_pend_cursor_blink (EvView *view)
+{
+       if (!cursor_should_blink (view))
+               return;
+
+       if (view->cursor_blink_timeout_id > 0)
+               g_source_remove (view->cursor_blink_timeout_id);
+
+       show_cursor (view);
+       view->cursor_blink_timeout_id = gdk_threads_add_timeout (get_cursor_blink_time (view) * 
CURSOR_PEND_MULTIPLIER / CURSOR_DIVIDER,
+                                                                (GSourceFunc)blink_cb, view);
+}
+
+
 void
 ev_view_set_caret_navigation_enabled (EvView   *view,
                                      gboolean enabled)
@@ -3121,6 +3324,7 @@ ev_view_set_caret_navigation_enabled (EvView   *view,
 
        if (view->caret_enabled != enabled) {
                view->caret_enabled = enabled;
+               ev_view_check_cursor_blink (view);
                gtk_widget_queue_draw (GTK_WIDGET (view));
        }
 }
@@ -3549,59 +3753,6 @@ ev_view_realize (GtkWidget *widget)
                                          window);
 }
 
-static gboolean
-get_caret_cursor_rect_from_offset (EvView       *view,
-                                  gint          offset,
-                                  gint          page,
-                                  GdkRectangle *rect)
-{
-       EvRectangle *areas = NULL;
-       EvRectangle *doc_rect;
-       guint        n_areas = 0;
-
-       if (!view->caret_enabled)
-               return FALSE;
-
-       /* Disable caret navigation on rotated pages */
-       if (view->rotation != 0)
-               return FALSE;
-
-       if (!view->page_cache)
-               return FALSE;
-
-       ev_page_cache_get_text_layout (view->page_cache, page, &areas, &n_areas);
-       if (!areas)
-               return FALSE;
-
-       if (offset > n_areas)
-               return FALSE;
-
-       doc_rect = areas + offset;
-       if (offset == n_areas ||
-           ((doc_rect->x1 == doc_rect->x2 || doc_rect->y1 == doc_rect->y2) && offset > 0)) {
-               EvRectangle *prev;
-               EvRectangle  last_rect;
-
-               /* Special characters like \n have an empty bounding box
-                * and the end of a page doesn't have any bounding box,
-                * use the size of the previous area.
-                */
-               prev = areas + offset - 1;
-               last_rect.x1 = prev->x2;
-               last_rect.y1 = prev->y1;
-               last_rect.x2 = prev->x2 + (prev->x2 - prev->x1);
-               last_rect.y2 = prev->y2;
-
-               _ev_view_transform_doc_rect_to_view_rect (view, page, &last_rect, rect);
-
-               return TRUE;
-       }
-
-       _ev_view_transform_doc_rect_to_view_rect (view, page, doc_rect, rect);
-
-       return TRUE;
-}
-
 static void
 get_cursor_color (GtkStyleContext *context,
                  GdkRGBA         *color)
@@ -3701,7 +3852,7 @@ ev_view_draw (GtkWidget *widget,
 
                draw_one_page (view, i, cr, &page_area, &border, &clip_rect, &page_ready);
 
-               if (page_ready && view->caret_enabled && view->current_page == i)
+               if (page_ready && view->caret_enabled && view->current_page == i && view->cursor_visible)
                        draw_caret_cursor (view, cr);
                if (page_ready && view->find_pages && view->highlight_find_results)
                        highlight_find_results (view, cr, i);
@@ -4689,6 +4840,8 @@ caret_key_press_event (EvView      *view,
        if (view->rotation != 0)
                return FALSE;
 
+       view->cursor_blink_time = 0;
+
        switch (event->keyval) {
        case GDK_KEY_Left:
                if (event->state & GDK_CONTROL_MASK)
@@ -4718,6 +4871,8 @@ caret_key_press_event (EvView      *view,
                return FALSE;
        }
 
+       ev_view_pend_cursor_blink (view);
+
        return TRUE;
 }
 
@@ -4753,8 +4908,12 @@ static gint
 ev_view_focus_in (GtkWidget     *widget,
                  GdkEventFocus *event)
 {
-       if (EV_VIEW (widget)->pixbuf_cache)
-               ev_pixbuf_cache_style_changed (EV_VIEW (widget)->pixbuf_cache);
+       EvView *view = EV_VIEW (widget);
+
+       if (view->pixbuf_cache)
+               ev_pixbuf_cache_style_changed (view->pixbuf_cache);
+
+       ev_view_check_cursor_blink (view);
        gtk_widget_queue_draw (widget);
 
        return FALSE;
@@ -4764,8 +4923,12 @@ static gint
 ev_view_focus_out (GtkWidget     *widget,
                   GdkEventFocus *event)
 {
-       if (EV_VIEW (widget)->pixbuf_cache)
-               ev_pixbuf_cache_style_changed (EV_VIEW (widget)->pixbuf_cache);
+       EvView *view = EV_VIEW (widget);
+
+       if (view->pixbuf_cache)
+               ev_pixbuf_cache_style_changed (view->pixbuf_cache);
+
+       ev_view_check_cursor_blink (view);
        gtk_widget_queue_draw (widget);
 
        return FALSE;
@@ -5105,6 +5268,11 @@ ev_view_dispose (GObject *object)
                view->drag_info.release_timeout_id = 0;
        }
 
+       if (view->cursor_blink_timeout_id) {
+               g_source_remove (view->cursor_blink_timeout_id);
+               view->cursor_blink_timeout_id = 0;
+       }
+
         gtk_scrollable_set_hadjustment (GTK_SCROLLABLE (view), NULL);
         gtk_scrollable_set_vadjustment (GTK_SCROLLABLE (view), NULL);