Factor out a convenience function to retrieve a (business) owner starting from a transaction

src/engine/gncOwner.c

@@ -637,6 +637,31 @@ gboolean gncOwnerGetOwnerFromLot (GNCLot *lot, GncOwner *owner)
     return (owner->owner.undefined != NULL);
 }
 
+gboolean gncOwnerGetOwnerFromTxn (Transaction *txn, GncOwner *owner)
+{
+    Split *apar_split = NULL;
+
+    if (!txn || !owner) return FALSE;
+
+    if (xaccTransGetTxnType (txn) == TXN_TYPE_NONE)
+        return FALSE;
+
+    apar_split = xaccTransGetFirstAPARAcctSplit (txn);
+    if (apar_split)
+    {
+        GNCLot *lot = xaccSplitGetLot (apar_split);
+        GncInvoice *invoice = gncInvoiceGetInvoiceFromLot (lot);
+        if (invoice)
+            gncOwnerCopy (gncInvoiceGetOwner (invoice), owner);
+        else if (!gncOwnerGetOwnerFromLot (lot, owner))
+                return FALSE;
+
+        return TRUE; // Got owner from either invoice or lot
+    }
+
+    return FALSE;
+}
+
 gboolean gncOwnerIsValid (const GncOwner *owner)
 {
     if (!owner) return FALSE;

src/engine/gncOwner.h

@@ -195,6 +195,15 @@ gint gncOwnerLotsSortFunc (GNCLot *lotA, GNCLot *lotB);
  */
 gboolean gncOwnerGetOwnerFromLot (GNCLot *lot, GncOwner *owner);
 
+/** Convenience function to get the owner from a transaction.
+ * Transactions don't really have an owner. What this function will
+ * do it figure out whether the transaction is part of a business
+ * transaction (either a posted invoice/bill/voucher/credit note or
+ * a payment transaction) and use the business object behind it
+ * to extract owner information.
+ */
+gboolean gncOwnerGetOwnerFromTxn (Transaction *txn, GncOwner *owner);
+
 gboolean gncOwnerGetOwnerFromTypeGuid (QofBook *book, GncOwner *owner, QofIdType type, GncGUID *guid);
 
 /** Get the kvp-frame from the underlying owner object */

src/gnome/dialog-print-check.c

@@ -1706,28 +1706,20 @@ gnc_ui_print_check_dialog_create(GtkWidget *parent,
      * it would create build problems */
     if (g_list_length(pcd->splits) == 1)
     {
+        GncOwner txn_owner;
+
         trans = xaccSplitGetParent((Split *)(pcd->splits->data));
-        if (xaccTransGetTxnType (trans) == TXN_TYPE_PAYMENT)
+        if (gncOwnerGetOwnerFromTxn (trans, &txn_owner))
         {
-            Split *apar_split = xaccTransGetFirstAPARAcctSplit (trans);
-            if (apar_split)
-            {
-                GNCLot *lot = xaccSplitGetLot (apar_split);
-                GncOwner owner;
-                if (!gncOwnerGetOwnerFromLot (lot, &owner))
-                {
-                    GncInvoice *invoice = gncInvoiceGetInvoiceFromLot (lot);
-                    if (invoice)
-                        gncOwnerCopy (gncOwnerGetEndOwner (gncInvoiceGetOwner (invoice)), &owner);
-                }
-
-                /* Got a business owner, get the address */
-                gtk_entry_set_text(GTK_ENTRY(pcd->check_address_name), gncOwnerGetName(&owner));
-                gtk_entry_set_text(GTK_ENTRY(pcd->check_address_1), gncAddressGetAddr1 (gncOwnerGetAddr(&owner)));
-                gtk_entry_set_text(GTK_ENTRY(pcd->check_address_2), gncAddressGetAddr2 (gncOwnerGetAddr(&owner)));
-                gtk_entry_set_text(GTK_ENTRY(pcd->check_address_3), gncAddressGetAddr3 (gncOwnerGetAddr(&owner)));
-                gtk_entry_set_text(GTK_ENTRY(pcd->check_address_4), gncAddressGetAddr4 (gncOwnerGetAddr(&owner)));
-            }
+            GncOwner owner;
+            gncOwnerCopy (gncOwnerGetEndOwner (&txn_owner), &owner);
+
+            /* Got a business owner, get the address */
+            gtk_entry_set_text(GTK_ENTRY(pcd->check_address_name), gncOwnerGetName(&owner));
+            gtk_entry_set_text(GTK_ENTRY(pcd->check_address_1), gncAddressGetAddr1 (gncOwnerGetAddr(&owner)));
+            gtk_entry_set_text(GTK_ENTRY(pcd->check_address_2), gncAddressGetAddr2 (gncOwnerGetAddr(&owner)));
+            gtk_entry_set_text(GTK_ENTRY(pcd->check_address_3), gncAddressGetAddr3 (gncOwnerGetAddr(&owner)));
+            gtk_entry_set_text(GTK_ENTRY(pcd->check_address_4), gncAddressGetAddr4 (gncOwnerGetAddr(&owner)));
         }
     }