[evince] libview: Expose an accessible name for form field push buttons

[Joanmarie Diggs <joanied src gnome org>]

commit 11225b2360cc019c7dea39a50fe74a6e043c6315
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Wed Jul 30 11:54:06 2014 +0200

    libview: Expose an accessible name for form field push buttons
    
    https://bugzilla.gnome.org/show_bug.cgi?id=733919

 libview/ev-form-field-accessible.c |  117 ++++++++++++++++++++++++++++++++++++
 1 files changed, 117 insertions(+), 0 deletions(-)
---
diff --git a/libview/ev-form-field-accessible.c b/libview/ev-form-field-accessible.c
index 715ef01..0b38e52 100644
--- a/libview/ev-form-field-accessible.c
+++ b/libview/ev-form-field-accessible.c
@@ -28,6 +28,10 @@ struct _EvFormFieldAccessiblePrivate {
        EvPageAccessible *page;
        EvFormField      *form_field;
        EvRectangle       area;
+
+       gchar            *name;
+       gint              start_index;
+       gint              end_index;
 };
 
 static void ev_form_field_accessible_component_iface_init (AtkComponentIface *iface);
@@ -78,6 +82,115 @@ ev_form_field_accessible_component_iface_init (AtkComponentIface *iface)
        iface->grab_focus = ev_form_field_accessible_grab_focus;
 }
 
+static gboolean
+get_indices_in_parent (AtkObject *atk_object,
+                      gint *start,
+                      gint *end)
+{
+       EvFormFieldAccessiblePrivate *priv;
+       EvView *view;
+       EvRectangle *areas = NULL;
+       guint n_areas = 0;
+       gint last_zero_sized_index = -1;
+       gint i;
+
+       priv = EV_FORM_FIELD_ACCESSIBLE (atk_object)->priv;
+       if (priv->start_index != -1 && priv->end_index != -1) {
+               *start = priv->start_index;
+               *end = priv->end_index;
+               return TRUE;
+       }
+
+       view = ev_page_accessible_get_view (priv->page);
+       if (!view->page_cache)
+               return FALSE;
+
+       ev_page_cache_get_text_layout (view->page_cache,
+                                      ev_page_accessible_get_page (priv->page),
+                                      &areas, &n_areas);
+       if (!areas)
+               return FALSE;
+
+       for (i = 0; i < n_areas; i++) {
+               EvRectangle *rect = areas + i;
+               gdouble      c_x, c_y;
+
+               c_x = rect->x1 + (rect->x2 - rect->x1) / 2.;
+               c_y = rect->y1 + (rect->y2 - rect->y1) / 2.;
+
+               if (c_x >= priv->area.x1 && c_x <= priv->area.x2 &&
+                   c_y >= priv->area.y1 && c_y <= priv->area.y2) {
+                       priv->start_index = i;
+                       break;
+               }
+       }
+
+       if (priv->start_index == -1)
+               return FALSE;
+
+       for (i = priv->start_index + 1; i < n_areas; i++) {
+               EvRectangle *rect = areas + i;
+               gdouble      c_x, c_y;
+
+               /* A zero-sized text rect suggests a line break. If it is within the text of the
+                * field, we want to preserve it; if it is the character immediately after, we
+                * do not. We won't know which it is until we find the first text rect that is
+                * outside of the area occupied by the field.
+                */
+               if (rect->y1 == rect->y2) {
+                       last_zero_sized_index = i;
+                       continue;
+               }
+
+               c_x = rect->x1 + (rect->x2 - rect->x1) / 2.;
+               c_y = rect->y1 + (rect->y2 - rect->y1) / 2.;
+
+               if (c_x < priv->area.x1 || c_x > priv->area.x2 ||
+                   c_y < priv->area.y1 || c_y > priv->area.y2) {
+                       priv->end_index = last_zero_sized_index + 1 == i ? i - 1 : i;
+                       break;
+               }
+       }
+
+       if (priv->end_index == -1)
+               return FALSE;
+
+       *start = priv->start_index;
+       *end = priv->end_index;
+       return TRUE;
+}
+
+static gchar *
+get_text_under_element (AtkObject *atk_object)
+{
+       gint start = -1;
+       gint end = -1;
+
+       if (get_indices_in_parent (atk_object, &start, &end) && start != end)
+               return atk_text_get_text (ATK_TEXT (atk_object_get_parent (atk_object)), start, end);
+
+       return NULL;
+}
+
+static const gchar *
+ev_form_field_accessible_get_name (AtkObject *atk_object)
+{
+       EvFormFieldAccessiblePrivate *priv;
+
+       priv = EV_FORM_FIELD_ACCESSIBLE (atk_object)->priv;
+       if (priv->name)
+               return priv->name;
+
+       if (EV_IS_FORM_FIELD_BUTTON (priv->form_field)) {
+               EvFormFieldButton *button = EV_FORM_FIELD_BUTTON (priv->form_field);
+
+               if (button->type == EV_FORM_FIELD_BUTTON_PUSH)
+                       priv->name = get_text_under_element (atk_object);
+       }
+
+       return priv->name;
+}
+
 static AtkObject *
 ev_form_field_accessible_get_parent (AtkObject *atk_object)
 {
@@ -201,6 +314,7 @@ ev_form_field_accessible_finalize (GObject *object)
        EvFormFieldAccessiblePrivate *priv = EV_FORM_FIELD_ACCESSIBLE (object)->priv;
 
        g_object_unref (priv->form_field);
+       g_free (priv->name);
 
        G_OBJECT_CLASS (ev_form_field_accessible_parent_class)->finalize (object);
 }
@@ -212,6 +326,7 @@ ev_form_field_accessible_class_init (EvFormFieldAccessibleClass *klass)
        AtkObjectClass *atk_class = ATK_OBJECT_CLASS (klass);
 
        object_class->finalize = ev_form_field_accessible_finalize;
+       atk_class->get_name = ev_form_field_accessible_get_name;
        atk_class->get_parent = ev_form_field_accessible_get_parent;
        atk_class->get_role = ev_form_field_accessible_get_role;
        atk_class->ref_state_set = ev_form_field_accessible_ref_state_set;
@@ -223,6 +338,8 @@ static void
 ev_form_field_accessible_init (EvFormFieldAccessible *accessible)
 {
        accessible->priv = G_TYPE_INSTANCE_GET_PRIVATE (accessible, EV_TYPE_FORM_FIELD_ACCESSIBLE, 
EvFormFieldAccessiblePrivate);
+       accessible->priv->start_index = -1;
+       accessible->priv->end_index = -1;
 }
 
 EvFormFieldAccessible*