[shotwell] Extract function to scroll to item

[Jens Georg <jensgeorg src gnome org>]

commit 83d11b3a95e177170f1b2cf5fbcf7a4d5f4639c0
Author: Jens Georg <mail jensge org>
Date:   Sat Feb 23 19:39:14 2019 +0100

    Extract function to scroll to item
    
    Code was copied into three places. Time to make it a function

 src/MapWidget.vala | 21 ++------------------
 src/Page.vala      | 57 +++++++++++++++++++++---------------------------------
 2 files changed, 24 insertions(+), 54 deletions(-)
---
diff --git a/src/MapWidget.vala b/src/MapWidget.vala
index 3b41a5f5..3959649f 100644
--- a/src/MapWidget.vala
+++ b/src/MapWidget.vala
@@ -509,25 +509,8 @@ private class MapWidget : Gtk.Bin {
 
             CheckerboardItem item = m.view as CheckerboardItem;
 
-            if (!did_adjust_view) {
-                // if first item is in any way out of view, scroll to it
-                Gtk.Adjustment vadj = page.get_vadjustment();
-
-                if (!(get_adjustment_relation(vadj, item.allocation.y) == AdjustmentRelation.IN_RANGE
-                      && (get_adjustment_relation(vadj, item.allocation.y + item.allocation.height) == 
AdjustmentRelation.IN_RANGE))) {
-
-                    // scroll to see the new item
-                    int top = 0;
-                    if (item.allocation.y < vadj.get_value()) {
-                        top = item.allocation.y;
-                        top -= CheckerboardLayout.ROW_GUTTER_PADDING / 2;
-                    } else {
-                        top = item.allocation.y + item.allocation.height - (int) vadj.get_page_size();
-                        top += CheckerboardLayout.ROW_GUTTER_PADDING / 2;
-                    }
-
-                    vadj.set_value(top);
-                }
+            if (!did_adjust_view && page is CheckerboardPage) {
+                (page as CheckerboardPage).scroll_to_item(item);
                 did_adjust_view = true;
             }
             item.brighten();
diff --git a/src/Page.vala b/src/Page.vala
index 666dbdf1..59cbfb8b 100644
--- a/src/Page.vala
+++ b/src/Page.vala
@@ -1384,6 +1384,26 @@ public abstract class CheckerboardPage : Page {
         
         base.switching_from();
     }
+
+    public void scroll_to_item(CheckerboardItem item) {
+        Gtk.Adjustment vadj = get_vadjustment();
+        if (!(get_adjustment_relation(vadj, item.allocation.y) == AdjustmentRelation.IN_RANGE
+              && (get_adjustment_relation(vadj, item.allocation.y + item.allocation.height) == 
AdjustmentRelation.IN_RANGE))) {
+
+            // scroll to see the new item
+            int top = 0;
+            if (item.allocation.y < vadj.get_value()) {
+                top = item.allocation.y;
+                top -= CheckerboardLayout.ROW_GUTTER_PADDING / 2;
+            } else {
+                top = item.allocation.y + item.allocation.height - (int) vadj.get_page_size();
+                top += CheckerboardLayout.ROW_GUTTER_PADDING / 2;
+            }
+
+            vadj.set_value(top);
+
+        }
+    }
     
     public override void switched_to() {
         layout.set_in_view(true);
@@ -1394,23 +1414,7 @@ public abstract class CheckerboardPage : Page {
             CheckerboardItem? item = (CheckerboardItem?) get_view().get_selected_at(0);
 
             // if item is in any way out of view, scroll to it
-            Gtk.Adjustment vadj = get_vadjustment();
-            if (!(get_adjustment_relation(vadj, item.allocation.y) == AdjustmentRelation.IN_RANGE
-                && (get_adjustment_relation(vadj, item.allocation.y + item.allocation.height) == 
AdjustmentRelation.IN_RANGE))) {
-
-                    // scroll to see the new item
-                    int top = 0;
-                    if (item.allocation.y < vadj.get_value()) {
-                        top = item.allocation.y;
-                        top -= CheckerboardLayout.ROW_GUTTER_PADDING / 2;
-                    } else {
-                        top = item.allocation.y + item.allocation.height - (int) vadj.get_page_size();
-                        top += CheckerboardLayout.ROW_GUTTER_PADDING / 2;
-                    }
-
-                    vadj.set_value(top);
-
-                }
+            scroll_to_item(item);
         }
 
         base.switched_to();
@@ -1891,24 +1895,7 @@ public abstract class CheckerboardPage : Page {
             get_view().select_marked(marker);
         }
         layout.set_cursor(item);
-        
-        // if item is in any way out of view, scroll to it
-        Gtk.Adjustment vadj = get_vadjustment();
-        if (get_adjustment_relation(vadj, item.allocation.y) == AdjustmentRelation.IN_RANGE
-            && (get_adjustment_relation(vadj, item.allocation.y + item.allocation.height) == 
AdjustmentRelation.IN_RANGE))
-            return;
-
-        // scroll to see the new item
-        int top = 0;
-        if (item.allocation.y < vadj.get_value()) {
-            top = item.allocation.y;
-            top -= CheckerboardLayout.ROW_GUTTER_PADDING / 2;
-        } else {
-            top = item.allocation.y + item.allocation.height - (int) vadj.get_page_size();
-            top += CheckerboardLayout.ROW_GUTTER_PADDING / 2;
-        }
-        
-        vadj.set_value(top);
+        scroll_to_item(item);
     }
     
     public void move_cursor(CompassPoint point) {